FR3117310A1 - antimicrobial liquid composition and its use as a preservative activator for cosmetic products - Google Patents

Abstract

The present application relates to an antimicrobial composition essentially comprising ingredients of natural origin, exhibiting bactericidal activity, in particular on Gram-negative bacteria, and fungicide, which makes it suitable for use as a preservative activator in products cosmetics. Due to the selection of the components of this antimicrobial composition, it has very broad compatibility with most formulations of cosmetic products, and can in particular be integrated into these formulations without destabilizing them or having to modify them, while maintaining the transparency of said cosmetic products.

Description

antimicrobial liquid composition and its use as a preservative activator for cosmetic products

The invention relates to the field of the preservation of cosmetic products, and more specifically to the field of cosmetic product preservative activators.

Essential oils are widely known for their antibacterial and antifungal activities. Many patents have attempted to combine them with other ingredients.

Lonza patent WO 2014/014416 teaches antimicrobial compositions composed of a preservative active and a potentiator of said active. The preservative active can be chosen from a multitude of compounds, ranging from cinnamaldehyde to sorbic acid or benzoic acid, and essential oils of wintergreen or lemongrass. The potentiator can be chosen from erythorbic acid or gluconic acid, or their salts. Regarding gluconic acid, its cyclic form, known as gluconolactone, is preferred. Lemongrass oil is cited in this application, and the antibacterial activity data presented show that this essential oil does not have sufficient activity to act as a preservative or preservative activator. Many additives are mentioned in this application, including solubilizers, without any indication being given as to their nature or their usefulness for the composition or for the cosmetic formulation.

CleanWell patent US6346281 proposes combining lemongrass essential oil with metal ions, such as copper sulphate, and with a "biosurfactant" and a solvent. The "biosurfactant" can be either "BOD" or Tween-80 which is a polyethoxylated sorbitan. The solvent can be chosen from organic solvents such as ethanol. According to another Cleanwell patent WO 2010/059399, the combination of thyme oil with copper ions Cu2+ and an alkylpolyglucoside makes it possible to obtain a composition capable of foaming, useful for the treatment and prevention of bacterial infections resistant to antibiotics, in particular strains of Staphylococcus a ureus resistant to methicillin.

Reckitt Benckiser patent US5403587 combines an essential oil of thyme or lemongrass with an ethoxylated fatty acid, a "nonoxynol-10" carboxylic acid, or a sodium salt of coconut fatty acid, and with a surfactant and an organic solvent. The surfactant and the organic solvent are essential to provide a composition in liquid form capable of being dispersed or solubilized. The surfactant can be chosen from anionic or amphoteric surfactants. These combinations exhibit anti-bacterial activity on S.Aureus and on P.Aeruginosa.

The Procter & Gamble patent WO2008/126057 discloses antimicrobial compositions for the care of the mouth. They include a mixture of essential oils containing acyclic compounds and cyclic compounds. The addition of gluconic acid is recommended for its chelating power of the calcium ions located on the walls of the bacteria, which contributes to improving the bactericidal power of the composition. As additives, the composition can include all surfactants, but anionic surfactants, cationic surfactants, or zwitterionic surfactants are preferred. Nonionic surfactants are also cited, and the patent emphasizes nonionic surfactants prepared by condensation of alkylene oxide, i.e. polyethoxylated nonionic surfactants.

Indusco US9687002 proposes putting lemongrass essential oil in a microemulsion in water with citric acid, lactic acid or acetic acid added as a pH buffer. The microemulsion is obtained thanks to at least two surfactants having an HLB between 9 and 18, and these surfactants can be nonionic surfactants. The microemulsion makes it possible to obtain a stable composition, i.e. remaining macroscopically homogeneous, and transparent.

L'Oreal FR3061010 discloses essential oil nanoemulsions obtained by emulsification of these essential oils in a mixture of water and water-soluble organic solvent by surfactants chosen from anionic, nonionic, amphoteric, zwitterionic or cationic surfactants. These nanoemulsions are prepared for their topical use for the treatment of bacterial or fungal infections. Lemongrass essential oil is presented although no antimicrobial activity is attributed to it. Among the nonionic surfactants, alkyl polyglucosides are preferred, and particularly caprylyl/capryl glucoside, such as Oramix™ CG110 from Seppic. In the unique example of this patent, Oramix™ CG110 is formulated with ten essential oils, ethanol and water. The quantity of Oramix™ CG110 used there is 0.05% by weight relative to the total weight of the formulation. In general, L'Oréal FR3061010 recommends using a quantity of nonionic surfactant of less than 1% by weight relative to the total weight of the nanoemulsion. It is the combination of a nonionic surfactant and ethanol that makes it possible to obtain a nanoemulsion. This state of nanoemulsion has advantages in terms of texture, softness to the touch, and transparency.

According to the Nestec patent WO2012/072488 located in the field of food, the emulsification of essential oils makes it possible to increase their effectiveness or to reduce the quantity of essential oil necessary. This patent uses acacia gum as an emulsifier to form emulsions of essential oil in water.

Technical problem

In recent years, cosmetics has been facing an increasingly difficult situation in an area that is just as essential as the effectiveness of cosmetic products in themselves: namely, the preservation of cosmetic products, in the microbiological sense of the term. Cosmetic products are aqueous media conducive to the development of bacteria, fungi and yeasts. To ensure consumer safety, molecules or compounds with antibacterial and antifungal activities must be added to cosmetic products. The regulations strictly regulate the nature of these molecules or compounds, as well as the doses at which they can be added to cosmetic products, as for example in France in cosmetic regulation No. 1223/2009 in appendix 5 entitled "list of preservatives allowed in cosmetic products”, which has sixty authorized preservatives.

In fact, the number of authorized preservatives that are actually used by producers of cosmetic products is much lower, and close to fifteen preservatives. The unanimous conservatives can even be counted on the fingers of one hand. Producers limit themselves to these preservatives either in anticipation of regulatory changes, or out of a need to meet consumer expectations of having the cleanest or most natural cosmetic products possible.

To succeed in satisfying this consumer expectation, producers of cosmetic products go even further by trying to reduce the quantity of preservative to its minimum, or even to a value lower than its known minimum required dose, and by combining it with d other molecules or compounds called "preservative activator" in order to obtain a preservative effect. These "preservative activators" are not preservatives listed as such, but have activities, in particular antimicrobial, which complement or increase the antimicrobial activity of preservatives.

Essential oils are part of these natural molecules or of natural origin with antimicrobial activities complementary to preservatives. However, their use as a preservative activator is not simple, and requires solutions to several technical problems.

Essential oils are natural extracts insoluble in water, known since antiquity for their antiseptic activities, but also for their potential allergenicity, which requires finding, for their use in cosmetics, a balanced dose between the need for increase this dose, to increase the antiseptic activity, and the need to reduce this dose, so as not to cause an allergy. In addition, it is generally sought that the antiseptic activity has the widest possible spectrum, in order to be able to inhibit the growth or kill all microorganisms, namely bacteria, fungi, yeasts, and viruses. The search for a balanced dose and a broad spectrum of activity often leads to the use of a cocktail of essential oils at very low doses, or to the combination of a few essential oils with other antimicrobial active ingredients or with compounds that potentiate or acting in synergy with essential oils. This goes in the direction of making the antimicrobial composition more complex, and increasing the risks of harmful interactions.

A first technical problem to be solved is therefore to find a preservative activator with the simplest possible composition, such as a combination of a minimum of essential oils and a minimum of other ingredients, ideally a single essential oil and a only additional ingredient. This combination should be capable of activating a preservative, i.e. developing a full spectrum of antimicrobial activity in combination with the preservative, i.e. exhibiting antibacterial activity against gram-negative bacteria and gram-positive bacteria and antifungal activity against fungi and yeasts. This combination could also present a broad spectrum of antimicrobial activity on its own under “ideal” conditions, in particular in vitro on agar.

Modern cosmetics pose an additional problem for the use of essential oils, namely the need to make them active in cosmetic formulations comprising an aqueous phase, and a multitude of ingredients likely to interact negatively with the essential oil. To exert its antimicrobial activity in the aqueous phase, the essential oil should be finely dispersed or dissolved in this aqueous phase. This dispersion or this solubilization are generally carried out, at the very least, by adding a solubilizing surfactant, and more advantageously, by additionally adding a water-soluble organic solvent, to the formulation of the cosmetic product. All categories of solubilizing surfactants have been considered by the prior art.

Concerning the solubilizing surfactants of the category of ionic surfactants, combinations of essential oils and such surfactants have shown their antimicrobial efficacy, but unfortunately have the major drawback of prohibiting the incorporation of a surfactant of opposite ionic charge in the cosmetic formulation. The interaction of surfactants with opposite charges, at best, cancels their respective properties, at worst, causes phase shifts or the formation of solid particles in the cosmetic formulation.

Another technical problem is therefore to find an antimicrobial composition comprising a solubilizing surfactant compatible with the vast majority of the constituents of cosmetic products, as also in particular with ionic surfactants. Thus, such an antimicrobial composition can be used and be suitable for all dosage forms of cosmetic products, namely, aqueous phase, oil-in-water emulsion, and water-in-oil emulsion. More specifically, the solubilizing surfactant should be compatible with anionic surfactants, cationic surfactants, thickening polymers, conditioning agents, dyes, pigments and iron oxides.

More generally, the cosmetic product stabilized microbiologically by the preservative activator must also have good physico-chemical stability during its storage, over a period of at least six or twelve months. The cosmetic product must thus retain its physical state. In the case of an emulsion, the latter must remain macroscopically homogeneous and not exhibit any phase shift. In the case of a transparent aqueous solution, or a transparent micellar solution, the latter must retain their transparency after the antimicrobial composition has been added.

Finally, as regards the compatibility requirements, the antimicrobial composition must be able to be added to the cosmetic product while maintaining the sensory profile of said cosmetic product intact. The sensory profile can be divided into three categories of descriptors: visual, olfactory, and touched. Regarding the visual and the olfactory, a pure white and odorless cosmetic product is generally sought after by consumers, although consumers may also accept colored or scented cosmetic products. Regarding the touch, consumers are very often intransigent: they demand that the product be as pleasant as possible during its application. Maintaining the touch descriptor is therefore the most essential.

Regarding water-soluble organic solvents, their effectiveness in solubilizing essential oils unfortunately extends, in most cases, to all the oils and fats present in the formulation, as well as to other ingredients such as amphiphilic surfactants or hydrophobic. If this proves possible, the formulation must then be adjusted, generally made more complex by the addition of additional ingredients. If this is not possible, then the state of the cosmetic formulation may be modified or even degraded. For example, the foam no longer has the expected quality or effectiveness; the detergent power is reduced; the texture of the formulation is too liquid or too thick; the emulsion exhibits a phase shift. Another technical problem is therefore to eliminate the need to use an organic solvent to solubilize the essential oil. This problem can also be formulated as that of finding a solubilizing agent that manages to solubilize the essential oil without the need to add an organic solvent.

To fulfill its function as a preservative activator, an antimicrobial composition must make it possible to improve or maintain the microbiological preservation or the microbiological stability of a cosmetic product, by being used together with a minimum or reduced quantity of usual preservative. A list of the usual preservatives in question can, for example, be found in cosmetic regulation No. 1223/2009 in appendix 5 entitled “list of preservatives allowed in cosmetic products”. Advantageously, the antimicrobial composition should also be free of preservatives suspected of causing allergies. This activation effect of the preservative must also be long-lasting, ideally to be concomitant with the microbiological stabilization of the preservative itself.

An additional requirement on the nature of the preservative activator is to be composed only of natural products or products of natural origin, which can result in a preservative activator having a content of natural origin, denoted CNO, according to the ISO 16128-2 standard, the closest to the ideal value which is 100%.

Another requirement for the preservative activator is to be composed only of easily biodegradable products, without any detrimental effect on the environment, and in particular to be free of ethoxylated or silicone compounds.

A final requirement relates to the state in which the antimicrobial composition is present. It must be as neutral as possible, that is to say as transparent, as odorless and as colorless as possible.

To sum up, the technical problem that arises for the preservative activator is to be of great naturalness and simplicity, while having a broad activation spectrum, good ease of use, and broad compatibility with ingredients of cosmetic compositions, and no negative effects on the environment.

The known solutions do not make it possible to satisfy all these technical problems at the same time. The antimicrobial composition that is the subject of the present application makes it possible to solve all of these technical problems.

Other characteristics, details and advantages of the invention will appear on reading the detailed description below, and on analyzing the appended drawings, in which:

Fig. 1

shows the results of antimicrobial activity testing of the antimicrobial liquid composition on Escherichia coli ATCC® 8739.

Fig. 2

shows the results of antimicrobial activity testing of the antimicrobial liquid composition against Candida albicans ATCC® 10231.

Fig. 3

shows the results of antimicrobial activity testing of the antimicrobial liquid composition against Aspergillus brasiliensis ATCC® 16404.

Fig. 4

shows the results of antimicrobial activity testing of the antimicrobial liquid composition against Staphylococcus aureus ATCC® 6538.

Fig. 5

shows the results of antimicrobial activity testing of the antimicrobial liquid composition against Pseudomonas aeruginosa ATCC® 9027.

For clarity, in this application:

- the expression “to be composed of” will have the same meaning as the expression “to understand”, namely to define an open composition.

- the constituents other than water, of the antimicrobial composition that is the subject of the present application are sometimes marketed in the form of aqueous solutions, composed of water and one of the said constituents. In order to get rid of this water content, which can vary according to the constituents and their suppliers, the mass percentages of said constituents other than water in the antimicrobial composition, expressed in% by dry weight, are the mass percentages of the dry masses into said constituents, in other words the mass percentages of said dry constituents, water being excluded.

– The liquid antimicrobial composition that is the subject of the present application is an aqueous composition. The quantities of antimicrobial liquid composition used are expressed in gross mass percentages, denoted as % gross weight, accounting for the antimicrobial liquid composition in its entirety, in other words taking into account all of its constituents, including water.

A first object of the present application is an antimicrobial composition.

A second object of the present application is the use of this antimicrobial composition as a cosmetic product preservative activator.

A third object of the present application is a cosmetic product comprising, as preservative activator, a composition according to the first object of the present application, and comprising a preservative.

Activity a antimicrobial

Within the meaning of the invention, an antimicrobial composition is a composition which has antimicrobial activity, that is to say capable of slowing down the growth of at least certain bacteria, fungi or yeasts, better at inhibiting the growth and at lowering the presence in numbers of at least some of them by preventing them from developing and multiplying, and even better to make their presence undetectable and to make them disappear completely by killing them. Therefore, the definition encompasses a growth inhibition under the known terms of bacteriostatic and fungistatic, and also a lethal activity, called bactericidal or fungicidal.

Preservative activator cosmetic product

A preservative enhancer is a compound that has insufficient antimicrobial activity by itself in the cosmetic product, but is capable of increasing the antimicrobial activity of a preservative in the cosmetic product. The preservative activator cannot microbiologically stabilize an aqueous medium by itself, and therefore cannot be qualified as a preservative within the meaning of the regulations. The combination of a preservative with a preservative activator has sufficient antimicrobial activity to microbiologically stabilize a cosmetic product. It is generally desired that this stabilization occur at a dose of preservative lower than the dose required when the preservative is used alone.

The antimicrobial liquid composition that is the subject of the present application can be qualified as a liquid composition with a preservative-activating effect because it satisfies the preceding definition of preservative-activating agent. Preferably, the antimicrobial liquid composition is therefore a liquid composition with a preservative-activating effect.

Composition liquid antimicrobial

According to one embodiment, the liquid antimicrobial composition that is the subject of the present application comprises, preferably consists of:
- from one to four essential oils,
- from one to four nonionic surfactants,
- from one to four carboxylic acids in free form,
- some water.

According to another embodiment, the antimicrobial liquid composition comprises, or consists of:
- from one to three essential oils,
- from one to three nonionic surfactants,
- from one to three carboxylic acids in free form,
- some water.

According to another embodiment, the antimicrobial liquid composition comprises, or consists of:
- one to two essential oils,
- one to two nonionic surfactants,
- one to two carboxylic acids in free form,
- some water.

According to another embodiment, the antimicrobial liquid composition comprises, or consists of:
- an essential oil,
- a nonionic surfactant,
- a carboxylic acid in free form,
- some water.

According to another embodiment, the antimicrobial liquid composition comprises, or consists of:
- from one to four, preferably from one to three, more preferably from one to two essential oils, and most preferably a single essential oil,
- from one to four, preferably from one to three, more preferably from one to two nonionic surfactants, and most preferably a single nonionic surfactant,
- from one to four, preferentially from one to three, more preferentially from one to two carboxylic acids in the free form, and very preferentially a single free carboxylic acid,
- from one to four, preferably from one to three, more preferably from one to two carboxylic acid salts, and most preferably a single carboxylic acid salt,
- some water.

In all the previous embodiments, the total amount of essential oils present in the liquid antimicrobial composition can also range from 0.1% to 10% by dry weight, preferably from 0.5% to 7% by dry weight, more preferably from 1% to 5% by dry weight, and most preferably from 1.5% to 3% by dry weight, relative to the total weight of the antimicrobial liquid composition.

In all the preceding embodiments, the total amount of nonionic surfactants present in the antimicrobial liquid composition can also range from 1% to 40% by dry weight, preferably from 5% to 30% by dry weight, more preferably from 7 .5% to 20% by dry weight, relative to the total weight of the antimicrobial liquid composition.

In all the preceding embodiments, the total quantity of free carboxylic acids present in the liquid antimicrobial composition can also range from 10% to 70% by dry weight, preferentially from 20% to 60% by dry weight, more preferentially from 25% to 50% by dry weight, and most preferably from 27.5% to 40% by dry weight, relative to the total weight of the antimicrobial liquid composition.

In all the previous embodiments, the amount of water present in the liquid antimicrobial composition can also range from 20% to 75% by weight, preferably from 30% to 65% by weight, more preferably from 35% to 55% by weight, based on the total weight of the liquid antimicrobial composition.

In all the preceding embodiments, the total quantity of carboxylic acid salts present in the antimicrobial liquid composition can further range from 1% to 50% by dry weight, preferentially from 5% to 30% by dry weight, more preferentially from 10% to 20% by dry weight, and most preferably from 15% to 17.5% by dry weight, relative to the total weight of the antimicrobial liquid composition.

In all the preceding embodiments, the ratio of the total dry mass of nonionic surfactants to the total dry mass of essential oils may also be greater than or equal to 2, preferably greater than or equal to 3, more preferably greater than or equal to 4, and most preferably greater than or equal to 5.

Antimicrobial liquid composition: m odes of achievement favorite

According to one embodiment, the liquid antimicrobial composition that is the subject of the present application comprises, preferably consists of:
- an essential oil chosen from the essential oils of clove, lemongrass, Bourbon geranium, geranium grass, gingergrass, noble laurel, lemongrass, West Indian lemongrass, Indian lemongrass, East Indian, Lemon Bed, Lemon Balm, Palmarose, Chilli, Crown Pepper, Oregano, Tea Tree, Thyme, Lemongrass,
- a nonionic surfactant chosen from alkyl(poly)glycosides, preferably from alkyl(poly)glucosides,
- a free carboxylic acid chosen from gluconic acid, succinic acid,
- some water.

According to one embodiment, the antimicrobial liquid composition comprises, preferably consists of:
- an essential oil chosen from essential oils of citronella, and essential oils of lemongrass from western India, lemongrass from eastern India, and preferably from essential oils of species of the genus Cymbopogon ,
- a nonionic surfactant chosen from alkyl(poly)glycosides, preferably from alkyl(poly)glucosides,
- a free carboxylic acid chosen from gluconic acid, succinic acid,
- some water.

According to one embodiment, the antimicrobial liquid composition comprises, preferably consists of:
- essential oil of one of the species of the genus Cymbopogon,
- caprylyl/capryl glucoside,
- gluconic acid,
- some water.

According to one embodiment, the antimicrobial liquid composition comprises:
- essential oil of one of the species of the Cymbopogon genus present at a mass percentage ranging from 0.1% to 10% by dry weight, preferably from 0.5% to 7% by dry weight, more preferably from 1% to 5% by dry weight, and most preferably from 1.5% to 3% by dry weight,
- caprylyl/capryl glucoside present at a mass percentage ranging from 1% to 40% by dry weight, preferably from 5% to 30% by dry weight, more preferably from 7.5% to 20% by dry weight,
- free gluconic acid present at a mass percentage ranging from 10% to 70% by dry weight, preferably from 20% to 60% by dry weight, more preferably from 25% to 50% by dry weight, and most preferably from 27.5% to 40% by dry weight,
- water present at a mass percentage ranging from 20% to 75% by weight, preferably from 30% to 65% by weight, more preferably from 35% to 55% by weight,
the mass percentages being expressed relative to the total weight of the antimicrobial liquid composition.

According to one embodiment, the antimicrobial liquid composition consists of:
- essential oil of one of the species of the Cymbopogon genus present at a mass percentage ranging from 0.1% to 10% by dry weight, preferably from 0.5% to 7% by dry weight, more preferably from 1% to 5% by dry weight, and most preferably from 1.5% to 3% by dry weight,
- caprylyl/capryl glucoside present at a mass percentage ranging from 1% to 40% by dry weight, preferably from 5% to 30% by dry weight, and more preferably from 7.5% to 20% by dry weight,
- free gluconic acid present at a mass percentage ranging from 10% to 70% by dry weight, preferably from 20% to 60% by dry weight, more preferably from 25% to 50% by dry weight, and most preferably from 27.5% to 40% by dry weight,
- water present at a mass percentage ranging from 20% to 75% by weight, or from 30% to 65% by weight, or from 35% to 55% by weight,
the mass percentages being expressed relative to the total weight of the antimicrobial liquid composition,
the sum of the mass percentages of all the constituents being equal to 100%.

According to one embodiment, the liquid antimicrobial composition that is the subject of the present application comprises, preferably consists of:
- an essential oil chosen from the essential oils of clove, lemongrass, Bourbon geranium, geranium grass, gingergrass, noble laurel, lemongrass, West Indian lemongrass, Indian lemongrass, East Indian, Lemon Bed, Lemon Balm, Palmarose, Chilli, Crown Pepper, Oregano, Tea Tree, Thyme, Lemongrass,
- a nonionic surfactant chosen from alkyl(poly)glycosides, preferably from alkyl(poly)glucosides,
- a free carboxylic acid chosen from gluconic acid, succinic acid,
- and/or a salt of said carboxylic acid, chosen from calcium, sodium, potassium, calcium, magnesium, zinc salts,
- some water.

According to one embodiment, the object antimicrobial liquid composition comprises, preferably consists of:
- an essential oil chosen from essential oils of citronella, and essential oils of lemongrass from western India, lemongrass from eastern India, and preferably from essential oils of species of the genus Cymbopogon ,
- a nonionic surfactant chosen from alkyl(poly)glycosides, preferably from alkyl(poly)glucosides,
- a free carboxylic acid chosen from gluconic acid, succinic acid,
- and/or a salt of said carboxylic acid, chosen from calcium, sodium, potassium, calcium, magnesium, zinc salts,

According to one embodiment, the object antimicrobial liquid composition comprises, preferably consists of:
- essential oil of one of the species of the genus Cymbopogon,
- caprylyl/capryl glucoside,
- gluconic acid,
- sodium gluconate,
- some water.

According to one embodiment, the antimicrobial liquid composition comprises:
- essential oil of one of the species of the Cymbopogon genus present at a mass percentage ranging from 0.1% to 10% by dry weight, preferably from 0.5% to 7% by dry weight, more preferably from 1% to 5% by dry weight, and most preferably from 1.5% to 3% by dry weight,
- caprylyl/capryl glucoside present at a mass percentage ranging from 1% to 40% by dry weight, preferably from 5% to 30% by dry weight, more preferably from 7.5% to 20% by dry weight,
- free gluconic acid present at a mass percentage ranging from 10% to 70% by dry weight, preferably from 20% to 60% by dry weight, more preferably from 25% to 50% by dry weight, and most preferably from 27.5% to 40% by dry weight,
- sodium gluconate present at a mass percentage ranging from 1% to 50% by dry weight, preferably from 5% to 30% by dry weight, more preferably from 10% to 20% by dry weight, and most preferably from 15% at 17.5% by dry weight,
- water present at a mass percentage ranging from 20% to 75% by weight, preferably from 30% to 65% by weight, more preferably from 35% to 55% by weight,
the mass percentages being expressed relative to the total weight of the antimicrobial liquid composition.

According to one embodiment, the antimicrobial liquid composition consists of:
- essential oil of one of the species of the Cymbopogon genus present at a mass percentage ranging from 0.1% to 10% by dry weight, preferably from 0.5% to 7% by dry weight, more preferably from 1% to 5% by dry weight, and most preferably from 1.5% to 3% by dry weight,
- caprylyl/capryl glucoside present at a mass percentage ranging from 1% to 40% by dry weight, preferably from 5% to 30% by dry weight, and more preferably from 7.5% to 20% by dry weight,
- free gluconic acid present at a mass percentage ranging from 10% to 70% by dry weight, preferably from 20% to 60% by dry weight, more preferably from 25% to 50% by dry weight, and most preferably from 27.5% to 40% by dry weight,
- sodium gluconate present at a mass percentage ranging from 1% to 50% by dry weight, preferably from 5% to 30% by dry weight, more preferably from 10% to 20% by dry weight, and most preferably from 15% at 17.5% by dry weight,
- water present at a mass percentage ranging from 20% to 75% by weight, or from 30% to 65% by weight, or from 35% to 55% by weight,
the mass percentages being expressed relative to the total weight of the antimicrobial liquid composition,
the sum of the mass percentages of all the constituents being equal to 100%.

Antimicrobial composition: modes of achievement active molecules

According to one embodiment of the antimicrobial composition subject of the present application is an antimicrobial composition comprising, or consisting of:
- at least one active molecule chosen from phenols, monoterpenols, sesquiterpenols, terpene oxides, aromatic aldehydes or terpene aldehydes, phenylpropenes, monoterpene hydrocarbons, sesquiterpene hydrocarbons, or mixtures thereof,
- a nonionic surfactant,
- a free carboxylic acid,
- some water.

According to one embodiment of the antimicrobial composition subject of the present application is an antimicrobial composition comprising, or consisting of:
- at least one active molecule chosen from neral, geranial, geraniol, or mixtures thereof,
- a nonionic surfactant,
- a free carboxylic acid,
- some water.

According to one embodiment of the antimicrobial composition subject of the present application is an antimicrobial composition comprising, or consisting of:
- at least one active molecule chosen from neral, geranial, geraniol, or mixtures thereof,
- a nonionic surfactant,
- a free carboxylic acid,
- a salt of said carboxylic acid,
- some water.

According to one embodiment of the antimicrobial composition subject of the present application is an antimicrobial composition comprising, or consisting of:
- at least one active molecule chosen from neral, geranial, geraniol, or mixtures thereof,
- a nonionic surfactant chosen from alkyl(poly)glycosides, preferably from alkyl(poly)glucosides,
- a carboxylic acid chosen from gluconic acid, succinic acid,
- and/or a salt of said carboxylic acid, chosen from sodium, potassium, calcium, magnesium and zinc salts,
- some water.

According to one embodiment is an antimicrobial composition comprising, or consisting of:
- from 10% to 50% by dry weight in general, preferably from 20% to 40% by dry weight,
- from 20% to 60% by dry weight in geranial, preferably from 30% to 50% by dry weight,
- from 1% to 25% by dry weight in geraniol, preferably from 2.5% to 15% by dry weight, more preferably from 4% to 10% by dry weight,
- from 1% to 40% by dry weight of nonionic surfactant, preferably from 5% to 30% by dry weight, more preferably from 7.5% to 20% by dry weight,
- from 10% to 70% by dry weight of carboxylic acid, preferably from 20% to 60% by dry weight, more preferably from 25% to 50% by dry weight, and most preferably from 27.5% to 40% by dry weight,
- from 1% to 50% by dry weight of carboxylic acid salt, preferably from 5% to 30% by dry weight, more preferably from 10% to 20% by dry weight, and most preferably from 15% to 17.5 % dry weight,
- from 20% to 75% by weight of water, or from 30% to 65% by weight, or from 35% to 55% by weight.

According to one embodiment is an antimicrobial composition comprising, or consisting of:
- from 10% to 50% by dry weight in general, preferably from 20% to 40% by dry weight,
- from 20% to 60% by dry weight in geranial, preferably from 30% to 50% by dry weight,
- from 1% to 25% by dry weight in geraniol, preferably from 2.5% to 15% by dry weight, more preferably from 4% to 10% by dry weight,
- from 1% to 40% by dry weight of capryl/caprylyl glucoside, preferably from 5% to 30% by dry weight, more preferably from 7.5% to 20% by dry weight,
- from 10% to 70% by dry weight of gluconic acid, preferably from 20% to 60% by dry weight, more preferably from 25% to 50% by dry weight, and most preferably from 27.5% to 40% by dry weight,
- from 1% to 50% by dry weight of sodium gluconate, preferably from 5% to 30% by dry weight, more preferably from 10% to 20% by dry weight, and most preferably from 15% to 17.5% by dry weight,
- from 20% to 75% by weight of water, preferably from 30% to 65% by weight, more preferably from 35% to 55% by dry weight.

Composition structure antimicrobial

The antimicrobial composition subject of the present application is in the form of a liquid, which is a dispersion of an oily phase in an aqueous phase. This dispersion can be either an oil-in-water emulsion, or an oil-in-water microemulsion, or an oil-in-water nanoemulsion, or a micellar solution, depending on the nature and the amounts of the constituents of the composition and its process. of production. According to one embodiment, the antimicrobial composition is an oil-in-water emulsion, and has oil phase droplet sizes ranging from 0.3 micrometers to 10 micrometers. According to another embodiment, the antimicrobial composition is an oil-in-water microemulsion or an oil-in-water micellar composition, and has droplet sizes ranging from 0.001 micrometers to 0.3 micrometers. The small sizes of the droplets, or microdroplets or micelles, of the antimicrobial liquid composition render it opalescent or transparent. In addition, they also help improve the stability of the oil in water, and improve its antimicrobial activity and its effectiveness as a preservative activator.

According to one embodiment, the oily dispersed phase comprises the essential oil; the aqueous phase comprises the carboxylic acid and/or the carboxylic acid salt; and the surfactant is located at the interface between the two phases. The oily phase may include a "non-essential" oil, such as triglycerides, in order to adjust the concentration of essential oil in the oily phase, and also to reduce the potential allergenicity of the essential oil. The oily phase can also include oils such as methyl esters of vegetable oils, or triglycerides of short fatty acids. The oily phase and the aqueous phase can also comprise additives without antimicrobial activity such as rheology agents, soluble dyes, pigments, perfumes, humectants, bulking agents.

According to another embodiment, the oily dispersed phase consists of the essential oil; the aqueous phase consists of water, free carboxylic acid and/or carboxylic acid salt; and the nonionic surfactant is distributed between the two phases. In this embodiment, the aqueous phase contains water as the sole and unique solvent, and is therefore free of any other solvent, in particular of any organic solvent.

Essential oil :

An essential oil is a natural oil extracted by dry process or by the use of organic solvents or water vapor from vegetable matter, generally leaves, flowers, fruits, berries, stems, roots or bark of cultivated or wild plants. According to the definition given in international standard ISO 9235 and adopted by the European Pharmacopoeia Commission, an essential oil is a product generally of complex composition, obtained from a botanically defined plant raw material, either by steam distillation of water, either by dry distillation, or by extraction using liquid, gaseous or supercritical solvents, or by a suitable mechanical process without heating (cold expression). The essential oil is most often separated from the aqueous phase by a physical process that does not lead to a significant change in the composition. These essential oils can also be prepared by synthesis, and in this case be identical to natural essential oils, or else have a higher content of specific molecules than natural essential oils. It can also be a mixture of a natural essential oil, and specific synthetic molecules.

The essential oil used according to the invention can be obtained from any plant material derived from the whole plant or from any part of said plant such as for example the leaves, the stems, the flowers, the petals, the seeds, the fruits , buds, roots, twigs of plants and/or whole plants.

The essential oil in accordance with the invention can be prepared according to the techniques mentioned above and will preferably be obtained according to the classic technique of steam distillation or cold expression.

The essential oil useful for the antimicrobial composition that is the subject of the present application can be chosen from the essential oils of ajwain (also called Indian thyme), star anise (also called star anise), basil, Chinese cinnamon or from Ceylon, cardamom, lemongrass from Ceylon or Sri Lanka, lemongrass from India, lemongrass from Java, clove, coriander, cypress from Provence, lemon eucalyptus, eucalyptus globulus, eucalyptus radiata, black spruce, tarragon, fennel, wintergreen, red cedar, geranium grass, rose geranium, bourbon geranium, gingergrass, cloves, fragrant inula, noble laurel, reydovan lavandin, fine lavender, cineole spike lavender, true lavender, lavandin, super lavandin, lemongrass, west indian lemongrass, east indian lemongrass India, lemon-litsea, garden marjoram, shell marjoram, team-tree linear leaves, field mint, peppermint, lemon balm, red myrtle, neroli, niaouli, oregano, flowering oregano, Greek oregano, compact oregano, green oregano , oregano from Spain, palmarose or palmarosa (also called "geranium of the Indies" and scientific name Cymbopogon martinii ), bigarade petitgrain, pepper, Scots pine, ravintsara (also called ravintsare or camphor tree Madagascar), cineole rosemary, camphor rosemary, officinal rosemary, saro, garden savory, mountain savory, lemongrass, wild thyme, wild thyme, borneol thyme, carvacrol thyme, linalool thyme, thujanol thyme, thymol thyme, tea tree (also called tea tree or melaleuca), exotic verbena, Indian verbena, or a mixture of these oils.

According to one embodiment, the essential oil useful for the antimicrobial composition which is the subject of the present application is chosen from the essential oils of clove, lemongrass, Bourbon geranium, geranium grass, gingergrass, noble laurel, lemongrass, west indian lemongrass, east indian lemongrass, lemongrass, lemon balm, palmarose, chili pepper, crown pepper, oregano, tea tree , thyme, lemongrass. Preferably, the essential oil is chosen from essential oils of citronella, essential oils of lemongrass, essential oils of palmarose, essential oils of gingergrass, essential oils of geranium grass. Most preferably, the essential oil is chosen from essential oils of citronella, and essential oils of lemongrass from western India, lemongrass from eastern India.

According to one embodiment, the essential oil is chosen from essential oils of species of the genus Cymbopogon . Preferably, among the essential oils of species of the Cymbopogon genus, the oils obtained from the following species are useful for the antimicrobial liquid composition which is the subject of the present application:
- Cymbopogon citratus ( DC .) Stap f . , also called West Indian lemongrass,
- Cymbopogon flexuosus Stapf., also called East Indian lemongrass (in French: lemongrass de l'est de l'Inde),
- Cymbopogon nardus , also called Ceylon lemongrass or Sri Lankan lemongrass,
- Cymbopogon nardus (L. ) Watson , Cymbopogon nardus (L.) Rendel
- Cymbopogon schoenanthus (L.) , also called Camel grass, geranium grass,
- Cymbopogon winterianus Jowitt, also called Java lemongrass,
- Cymbopogon m artinii var. sofia , also called gingergrass,
- and Cymbopogon martinii var. motia ., Cymbogopon maartinii roxb . , also called palmarosa.

Preferably, the Cymbopogon essential oil is chosen from the essential oils of the Cymbopogon flexuosus Stapf species. and Cymbopogon citratus (DC.) Stapf . . Most preferably, the essential oil is an essential oil of citronella of the species Cymbopogon citratus (DC.) Stapf .

Cymbopogon is a genus of monocotyledonous plants in the family Poaceae, subfamily Panicoideae, which includes about fifty species native to tropical and subtropical regions of Africa, Asia and Australia. They are herbaceous plants, generally perennial, rarely annual, cespitose or rhizomatous, whose stems (culms) can reach 15 to 300 cm in length.

Wintergreen essential oils are those of the Gaulth e ria procumbens species. Thyme essential oils are those of the species Thymus mastichina , or Thymus vulgaris , or Thymus zygis , or Thymus thymi . Tea tree essential oils are those of the Melaleuca alternifolia species. The essential oils of the crown pepper are those of the species Pimenta racemosa , or Pimenta acris . Oregano essential oils are those of the species Origanum heracleoticum , or Origanum majorana , or Origanum vulgare , or Origanum compactum . Lemon balm essential oils are those of the species Melissa officinalis .

Lemongrass is a tall grass, native to India and Southeast Asia that can reach 1.50 meters in height. It consists of narrow, lanceolate leaves whose stalks resemble branches. Its fragrance, reminiscent of the smell of lemon, is the origin of the name of the plant. This plant from tropical zones, native to India and Skri Lanka, also grows in Africa, South America, Central America and Madagascar. Its essential oil is obtained by distillation of chopped leaves that are harvested several times a year. This distillation is carried out without adding water or water vapor in a closed enclosure designed so that the liquid is recovered in its lower part.

Cymbopogon species essential oil is selected from Cymbopogon species oils rich in citral, neral, geraniol and geraniol. Preferably, the essential oil of species of the genus Cymbopogon is chosen from essential oils of species of the genus Cymbopogon having approximately 30% by weight in neral, approximately 40% by weight in geranial, and 5% by weight in geraniol. These mass percentages are usually determined by chromatography. Lemongrass essential oils from Cymbopogon flexuosus and Cymbopogon citratus usually meet these weight percentages.

By way of example of lemongrass essential oils useful for the liquid antimicrobial composition which is the subject of the present application, mention may be made of those marketed under the names "Cymbopogon flexuosus Oil®" by Elixens, and "HE Lemongrass citratus" of Sri -Lanka by H. Reynaud & Son.

The essential oil can also be chosen advantageously from other oils rich in citral, neral, geranial and geraniol. It may be, for example, essential oil of lemony litsea which contains approximately 40% by weight of geranial and approximately 30% by weight of neral or essential oil of lemon balm of the species Melissa officinalis , relative to the total weight of essential oil. It can also be an essential oil rich in geraniol and geranial such as in particular the essential oil of palmarosa ( Cymbopogon martini ) which usually contains between 80% to 85% by weight of geraniol relative to the total weight of essential oil.

Another essential oil poor in at least one phenol, monoterpenol, terpene oxide, aromatic aldehyde, terpene aldehyde, phenylpropene, monoterpene hydrocarbon, and sesquiterpene hydrocarbon, can be added to the composition that is the subject of the present application, for example to flavor it, change its smell or act on its antimicrobial activity. It can be chosen from essential oil of cedar, essential oil of sweet orange, essential oil of lemon, essential oil of green or red mandarin, or essential oil of wintergreen.

The total amount of essential oils present in the antimicrobial liquid composition can range from 0.1% to 10% by dry weight, preferably from 0.5% to 7% by dry weight, more preferably from 1% to 5% by weight dry, and most preferably from 1.5% to 3% by dry weight, relative to the total weight of the antimicrobial liquid composition.

The ratio of the total dry mass of nonionic surfactants to the total dry mass of essential oils may also be greater than or equal to 2, preferably greater than or equal to 3, more preferably greater than or equal to 4, and most preferably greater than or equal to equal to 5. The essential oil(s) are advantageously present in the antimicrobial composition in a quantity which is lacking with respect to the quantity of nonionic surfactant(s). The selection of this default situation makes it possible to best solubilize the essential oil or oils in the water of the antimicrobial liquid composition, and also contributes to maintaining this solubilization in the water of the cosmetic product when the said liquid antimicrobial composition is diluted in the said cosmetic product, and in particular in the water of said cosmetic product.

M active molecules essential oils:

According to one embodiment, the essential oil(s) useful for the antimicrobial liquid composition which is the subject of the present application comprises or comprises at least one active molecule chosen from:

a) phenols, preferably chosen from thymol, borneol, carvacrol and eugenol,

b) monoterpene alcohols (called monoterpenols) or sesquiterpene alcohols (called sesquiterpenols), preferably chosen from geraniol, linalool, thujanol (also sometimes denoted “thuyanol”), trans-thujanol-4, myrcenol, terpinene-4 -ol, menthol, piperitol, citronellol, borneol, nerol, carotol, viridiflorol, farnesol, cedrol, bisabolol, patchoulol, santalol, eudesmol, globulol, nerolidol and sclareol,

c) terpene oxides, preferably chosen from eucalyptol (also called 1.8 cineole), bisabolol oxide and beta-caryophyllene oxide,

d) aromatic aldehydes or terpene aldehydes, preferably chosen from cinnamaldehyde, benzaldehyde, methoxy-cinnamaldehyde, neral, geranial, citronellal and cuminal,

e) phenylpropenes, preferably chosen from estragole (also called methylchavicol) and anethole,

f) monoterpene hydrocarbons (called monoterpenes) or sesquiterpenes (called sesquiterpenes), preferably chosen from β-caryophyllene, alpha-pinene, beta-pinene, limonene, delta-3-carene, camphene, γ- terpinene, humulene, chamazulene, zingiberene and azulene.

g) esters chosen from eugenyl acetate, linalyl acetate, methyl salicylate.

The essential oil may in particular be an oil rich in phenols, in particular in carvacrol (present for example in the essential oil of savory), in thymol (present for example in the essential oil of thyme with thymol) and in eugenol (present for example in clove essential oil). These phenols are responsible for the fungicidal and bactericidal activities of the essential oils that contain them. Mention may more particularly be made, as oils rich in phenols, of the essential oils of thyme (Thymus mastichina, Thymus vulgaris, Thymus zygis, Thymus thymi), pepper (Pimenta racemosa, Pimenta acris), ajowan (Trachyspermum ammi), clove (Eugenia caryophyllus), mountain savory (Satureja montana), oregano (Origanum heracleoticum (Greek oregano), Origanum majorana, Origanum vulgare, Origanum compactum (Compact oregano), Spanish oregano (Corydothymus capitatus), Ceylon cinnamon (Cinnamomum verum).

According to another embodiment, the essential oils useful for the antimicrobial composition are the essential oils which are chosen from all those described in the “essential oil” part of the present application, and which comprise at least one active molecule chosen from phenols , monoterpenols, sesquiterpenols, terpene oxides, aromatic aldehydes, terpene aldehydes, phenylpropenes, monoterpene hydrocarbons, sesquiterpene hydrocarbons. Preferably, the sum of the mass percentages of all the active molecules is greater than or equal to 40% by dry weight, or greater than or equal to 50% by dry weight, relative to the total weight of essential oil.

According to another embodiment, the essential oil will comprise at least one active molecule chosen from phenols, monoterpenols, sesquiterpenols, terpene oxides, aromatic aldehydes, terpene aldehydes, and more preferably from phenols, monoterpenols , terpene aldehydes. Preferably, the sum of the mass percentages of all the active molecules is greater than or equal to 40% by dry weight, or greater than or equal to 50% by dry weight, relative to the total dry weight of essential oil.

According to one embodiment, the essential oil will comprise at least one active molecule chosen from monoterpenols, which are alcohols with 10 carbon atoms, preferably geraniol, linalool, thujanol, myrcenol, terpineol, menthol and piperitol. Essential oils that include these active molecules are palmarosa Cymbopogon martinii , spike lavender Lavandula spica , peppermint Mentha piperita , marjoram Origanum majorana , and tea tree essential oils. species Melaleuca alternifolia.

According to one embodiment, the essential oil will comprise at least one active molecule chosen from terpene aldehydes, which have no aromatic ring, preferably neral, geranial, citronellal and cuminal, which are known to be advantageously less aggressive than benzene-ring aldehydes. The essential oils that include these active molecules are the essential oils of Leptospermum scoparium (Manuka), Litsea citrata (Lemon litsea), Cymbopogon citratus (Indian verbena), Cymbopogon flexuasus (Lemongrass), Cymbopogon nardus (Ceylon or Sri lemon grass). Lanka), Cymbopogon winterianus (Java lemongrass), Cinnamomum zeylanicum (Ceylon cinnamon, bark and twigs) and Cinnamomum cassia (Chinese cinnamon). Preferably, the essential oil of a species of the genus Cymbopogon comprises a mass percentage of terpene aldehydes greater than or equal to 50% by dry weight, or greater than or equal to 60% by dry weight, relative to the weight of said essential oil.

According to one embodiment, the essential oil will comprise at least one active molecule chosen from the active molecules which make up the essential oil of lemongrass of the species Cymbopogon flexuosus and Cymbopogon citratus : the trans isomer of citral, known under the name geranial or citral A, IUPAC name (E)-3,7-Dimethylocta-2,6-dienal; the cis isomer of citral, known as neral, or citral B, IUPAC name (Z)-3,7-Dimethylocta-2,6-dienal; geraniol, IUPAC name (2E)-3,7-dimethylocta-2,6-dien-1-ol.

Thus, according to this embodiment, the essential oil will comprise at least one active molecule chosen from citral and geranial, and preferably the essential oil consists of citral and geranial. According to a variant of this embodiment, the essential oil comprises, or consists of, geranial, neral and geraniol. According to another variant of this embodiment, the essential oil comprises, or consists of, 40% by dry weight in geraniol, 30% by dry weight in neral and 5% by dry weight of geraniol, relative to the weight of said essential oil.

Still according to this embodiment, the antimicrobial composition which is the subject of the present application comprises, or consists of:
- an essential oil consisting of citral and geraniol, preferably a lemongrass oil consisting of citral and geraniol,
- an alkylglucoside bearing fatty chains with 6 to 12 carbon atoms, preferably caprylyl/capryl glucoside,
- a carboxylic acid, preferably gluconic acid or succinic acid, most preferably gluconic acid,
- a carboxylic acid salt, preferably sodium gluconate or sodium succinate, most preferably sodium gluconate,
- water.

Again according to this embodiment, the antimicrobial composition comprises, or consists of:
- an essential oil, preferably lemongrass comprising at least 50% by weight of citral and geraniol relative to the weight of said essential oil, at a mass percentage of 0.1% to 10% by dry weight, preferably 0, 5% to 7% by dry weight, more preferably from 1% to 5% by dry weight, and most preferably from 1.5% to 3% by dry weight,
- from 1% to 40% by dry weight of an alkylglucoside bearing fatty chains containing 6 to 12 carbon atoms, preferably caprylyl/capryl glucoside, preferably from 5% to 30% by dry weight, more preferably 7, 5% to 20% by dry weight,
- from 10% to 70% by dry weight of gluconic acid, succinic acid, sodium gluconate or sodium succinate, preferably from 20% to 60% by dry weight, more preferably from 25% to 50% by dry weight, and most preferably from 27.5% to 40% by dry weight,
- and water,
the mass percentages being expressed relative to the total weight of said antimicrobial composition.

The embodiments with terpene aldehydes, and without benzene aldehydes, have the advantage of being known to be generally less irritating and less allergenic for the skin than the embodiments with benzene aldehydes.

Surfactant non ionic :

According to one embodiment, the nonionic surfactant is chosen from:

- alcohols, alpha-diols and (C1-C20)alkylphenols, these compounds being polyethoxylated and/or polypropoxylated and/or polyglycerolated, the number of ethylene oxide and/or propylene oxide groups possibly ranging from 1 to 100, and the number of glycerol groups possibly ranging from 2 to 30; or alternatively these compounds comprising at least one fatty chain comprising from 8 to 40 carbon atoms, in particular from 16 to 30 carbon atoms; in particular alcohols comprising at least one C8 to C40 alkyl chain, saturated or not, linear or branched, oxyethylenated comprising from 1 to 100 moles of ethylene oxide, preferably from 2 to 50, more particularly from 2 to 40 moles of ethylene oxide and comprising one or two fatty chains;

- condensates of ethylene oxide and propylene oxide with fatty alcohols;

- polyethoxylated fatty amides preferably having from 2 to 30 ethylene oxide units, polyglycerolated fatty amides comprising on average from 1 to 5 glycerol groups and in particular from 1.5 to 4;

- ethoxylated sorbitan fatty acid esters preferably having from 2 to 40 ethylene oxide units;

- sucrose fatty acid esters;

- polyoxyalkylenated fatty acid esters, preferably polyoxyethylenated, having from 2 to 150 moles of ethylene oxide, including oxyethylenated vegetable oils;

- N-(C6-C24 alkyl)glucamine derivatives,

- amine oxides such as (C10-C14 alkyl)amine oxides or N-(C10-C14 acyl)-aminopropylmorpholine oxides;

- and mixtures thereof.

According to another embodiment, the nonionic surfactant is chosen from alkyl(poly)glycosides, which are represented by the following general formula:

R ₁ 0-(R ₂ O) _t -(G) _v

in which:

- R ₁ represents: a linear or branched alkyl or alkenyl radical containing 6 to 24 carbon atoms, or 6 to 18 carbon atoms, or 6 to 12 carbon atoms; or an alkylphenyl radical whose linear or branched alkyl radical contains 6 to 24 carbon atoms, or 6 to 18 carbon atoms, or 6 to 12 carbon atoms,

- R ₂ represents an alkylene radical containing 2 to 4 carbon atoms,

- G represents a sugar unit comprising 5 to 6 carbon atoms,

- t denotes a value ranging from 0 to 10, preferably from 0 to 4,

- v denotes a value ranging from 1 to 15, preferably from 1 to 4.

Preferably, the alkyl(poly)glycoside surfactants are compounds of the formula described above in which:

- R ₁ denotes a saturated or unsaturated, linear or branched alkyl radical comprising from 6 to 18 carbon atoms, or from 6 to 12 carbon atoms,

- R ₂ represents an alkylene radical containing 2 to 4 carbon atoms,

- t denotes a value ranging from 0 to 3, preferably equal to 0,

- G denotes glucose, fructose or galactose, preferably glucose;

- the degree of polymerization, that is to say the value of v, which can range from 1 to 15, preferably from 1 to 4; the average degree of polymerization being more particularly between 1 and 2.

The glucosidic bonds between the sugar units are generally of the 1-6 or 1-4 type, preferably of the 1-4 type. Preferably, the alkyl(poly)glycoside surfactant is an alkyl(poly)glucoside surfactant, that is to say an alkyl(poly)glycoside surfactant where G is glucose. C6/C16-(poly)glucosides 1,4 alkyl, C6/C12-(poly)glucosides 1,4, and in particular decylglucosides, dodecylglucosides, hetpoglucosides, caprylyl glucosides, capryl glucosides and caprylyl/capryl glucosides.

Among the commercial products, mention may be made of the products sold by the company Cognis under the names PLANTAREN® (600 CS/U, 1200 and 2000) or PLANTACARE® (818, 1200 and 2000); the products sold by the company SEPPIC under the names ORAMIX CG 110 and ORAMIX® NS 100; the products sold by the company BASF under the name LUTENSOL GD 70 or else the products sold by the company CHEM Y under the name AG10 LK.

The nonionic surfactant can also be chosen from alkyl(poly)glycosides, preferably alkyl(poly)glucosides, with an HLB greater than or equal to 10, or greater than or equal to 12, or greater than or equal to 14.

The alkyl(poly)glycosides, preferably the alkyl(poly)glucosides, can also be combined with fatty alcohols.

The total amount of nonionic surfactants in the antimicrobial liquid composition is greater than or equal to 1% by weight, preferably greater than or equal to 5% by weight, more preferably greater than or equal to 7.5% by weight, and most preferably greater than or equal to equal to 10% by weight, relative to the total weight of said antimicrobial liquid composition.

Advantageously, the total amount of nonionic surfactants present in the antimicrobial liquid composition can range from 1% to 50% by weight, preferably from 5% to 40% by weight, more preferably from 7.5% to 30% by weight, and most preferably from 10% to 20% by weight, relative to the total weight of the antimicrobial liquid composition.

The ratio of the total dry mass of nonionic surfactants to the total dry mass of essential oils may also be greater than or equal to 2, preferably greater than or equal to 3, more preferably greater than or equal to 4, and most preferably greater than or equal to equal to 5. The nonionic surfactant(s) are advantageously present in the antimicrobial composition in an amount which is in excess relative to the amount of the essential oil(s). The selection of this situation of excess makes it possible to best solubilize the essential oil or oils in the water of the antimicrobial liquid composition, and also contributes to maintaining this solubilization in the water of the cosmetic product when the said antimicrobial liquid composition is diluted in said cosmetic product, and in particular in the water of said cosmetic product.

Carboxylic acid free :

The free carboxylic acid useful for the antimicrobial composition which is the subject of the present application is chosen from monocarboxylic acids and polycarboxylic acids, linear or branched, preferentially from monocarboxylic acids, dicarboxylic acids, and tricarboxylic acids, most preferentially from acids monocarboxylic and dicarboxylic acids.

By "free", we mean that the carboxylic acid function is either in its protonated form COOH, or in its ionized form COO- associated with a counter ion H+ or H3O+, and this in proportions dependent on the pH value of the solution. aqueous acid and the strength of the acid characterized by its pKa.

According to one embodiment, the carboxylic acid is chosen from monocarboxylic acids whose carbon chain consists of 2 to 12 carbon atoms, or 3 to 8 carbon atoms. These include gluconic acid (pKa=3.86), lactic acid, glycolic acid, glucuronic acid, maltobionic acid, lactobionic acid, malic acid, tartaric acid, mandelic acid, fatty acids (or aliphatic chain carboxylic acids) having a carbon chain of 4 to 12 atoms, preferably natural fatty acids such as in particular propionic, butyric, caproic, caprylic, capric and lauric acids. According to a variant of this embodiment, the carboxylic acid is chosen from gluconic acid, glucuronic acid, maltobionic acid, preferably the carboxylic acid is gluconic acid. According to a variant of this embodiment, the monocarboxylic acid is the cyclic form of gluconic acid, called gluconolactone.

According to another embodiment, the carboxylic acid is chosen from polycarboxylic acids, and preferably from dicarboxylic acids and tricarboxylic acids, and most preferably from aspartic acid, adipic acid, malonic acid, pimelic acid, succinic acid, glucaric acid, and glutaric acid, and even more preferably is succinic acid.

The carboxylic acid(s) or polycarboxylic acid(s) useful for the antimicrobial liquid composition which is the subject of the present application are further characterized by a pKa value ranging from 3 to 6, preferably from 4 to 6.

The total amount of free carboxylic acid(s) present in the liquid antimicrobial composition can range from 10% to 70% by dry weight, preferably from 20% to 60% by dry weight, more preferably from 25% to 50% by dry weight, and most preferably from 27.5% to 40% by dry weight, relative to the total weight of the antimicrobial liquid composition.

Carboxylic acid salt:

The carboxylic acid salt useful for the antimicrobial composition which is the subject of the present application is chosen from salts of monocarboxylic acids or salts of linear or branched polycarboxylic acids. In an acid salt, the carboxylic acid function is either in the protonated form COOH, or in the ionized form COO- associated with a metallic counter ion M+, and this in proportions dependent on the pH value of the aqueous acid solution , the acidity constant pKa of the corresponding free acid, and the dissociation constant of the salt pKd.

The carboxylic acid salt(s) is or are chosen from the salts of sodium, magnesium, zinc, calcium, potassium, iron, lithium, carboxylic acid chosen from the carboxylic acids of the "acid" part. free carboxylic acid” of the present application.

According to one embodiment, the carboxylic acid salt is a salt of the free carboxylic acid useful for the composition that is the subject of the present application. According to a variant of this embodiment, said carboxylic acid is distributed in at most 35% by dry weight in salt of said carboxylic acid and in at least 65% by dry weight in said free carboxylic acid. One such variant is gluconic acid broken down to 35% by dry weight as sodium gluconate and 65% by dry weight as free gluconic acid. Advantageously, such a mixture of acid and its salt has a pH that is better tolerated by the skin and is less irritating than the acid alone can be.

According to one embodiment, the carboxylic acid salt or salts is or are chosen from sodium, magnesium, zinc, calcium, potassium, iron or lithium salts of gluconic acid or succinic acid, and preferably the carboxylic acid salt(s) are chosen from sodium gluconate and sodium succinate, and most preferably the carboxylic acid salt is sodium gluconate.

The total amount of carboxylic acid salts present in the antimicrobial liquid composition can range from 1% to 50% by dry weight, preferably from 5% to 30% by dry weight, more preferably from 10% to 20% by dry weight, and most preferably from 15% to 17.5% by dry weight, relative to the total weight of the antimicrobial liquid composition.

pH of the antimicrobial liquid composition:

The pH of the antimicrobial liquid composition that is the subject of the present application can range from 2 to 9, preferentially from 3 to 8, more preferentially from 4 to 7, and even more preferentially from 4.5 to 6.5, and even more preferentially from 4.5 to 6.

Water :

The water present in the antimicrobial liquid composition can be decarbonated water, or demineralized water.

The amount of water present in the antimicrobial liquid composition can range from 20% to 75% by weight, preferably from 30% to 65% by weight, more preferably from 35% to 55% by weight, relative to the total weight of the antimicrobial liquid composition.

Preservation of cosmetic product

A cosmetic product must remain microbiologically stable for the entire duration of its storage, i.e. until its expiry date for optimal use, and also for the entire duration of its use by the consumer, i.e. that is to say until its expiry date after opening. This microbiological stability makes it possible to guarantee the absence of microorganisms, in particular pathogenic microorganisms, in the said product, and to guarantee that the user uses a healthy product from a microbiological point of view. This is called “conservation”. “Preservation” therefore means the absence of pathogenic microorganisms and microbiological stability, i.e. the absence of growth of populations of pathogenic microorganisms.

The international standard ISO 11930 entitled "ISO11930 Cosmetics - Microbiology - Evaluation of the antimicrobial protection of a cosmetic product" specifies a procedure for the interpretation of the data resulting from the test of the effectiveness of the antimicrobial protection and/or the assessment of the microbiological risk during the overall evaluation of the antimicrobial protection of a cosmetic product. This standard makes it possible in particular to classify the level of microbiological protection of a cosmetic product against the main pathogens: bacteria, namely Escherichia Coli, Staphylococcus Aureus, Pseudomonas Aeruginosa, and fungi, namely Candida Albicans and Aspergillus Brasiliensis . The classification is made by monitoring the reduction in the number of colony-forming units (noted cfu/mL) seven, fourteen and twenty-eight days after the cosmetic product has been inoculated with a microorganism. The reduction in the number of colony forming units is expressed in logarithm base 10, for example one log reduction corresponds to a reduction of 10^1, i.e. 10, cfu/mL, or two log reduction corresponds to a reduction of 10 ^2, i.e. 100, cfu/mL.

Use as a preservative activator

A second object of the present application is the use of the antimicrobial composition as an activator for the preservative of cosmetic products or as an agent for aiding the preservation of cosmetic products. The antimicrobial activity, in particular antibacterial and antifungal, has been demonstrated in in-vitro tests which show the synergies between the constituents of the antimicrobial composition. However, the composition of a cosmetic product is very different from that of an in-vitro test culture medium. In a cosmetic product, interactions between the constituents of the antimicrobial composition and the ingredients of the cosmetic product may occur, resulting in the alteration or suppression of the antimicrobial activity. It may then be necessary to increase the dose of antimicrobial composition to regain the antimicrobial activity in situ.

According to one embodiment, the antimicrobial composition that is the subject of the present application can be used as a cosmetic product preservative activator.

Implemented at mass percentages of less than 5% by gross weight, or even 2.5% by gross weight, relative to the total weight of the cosmetic product, the antimicrobial composition proves by itself insufficiently effective in preserving a cosmetic product . It is sufficiently effective against certain microorganisms, in particular against fungi and yeasts, for example against Aspergillus Brasiliensis and Candida Albicans. However, associated with a usual preservative, the antimicrobial composition combines its antimicrobial activity with the activity of said preservative, or can even potentiate the activity of said preservative. It is then possible to use a reduced dose of preservative, in combination with an appropriate dose of antimicrobial composition, to successfully stabilize the microbiology of the cosmetic product, or even reduce the load of microorganisms, that is to say reduce the number of colony-forming units according to the ISO 11930 standard. The antimicrobial composition thus effectively makes it possible to reduce the quantity of preservative necessary to preserve the cosmetic product, and this over periods equivalent to the usual preservatives used at the recommended doses, which are generally equal at the maximum concentrations allowed in ready-to-use cosmetic products. These maximum concentrations vary depending on whether the product is to be rinsed out, without rinsing, to be applied to the skin, the hair, for oral use, and according to the chemical nature of the preservative. In appendix 5 of cosmetics regulation No. 1223/2009, they can thus range from 2.5% by gross weight to 1% by gross weight, or even 0.1% by gross weight, in relation to the weight of the cosmetic product.

According to a variant of the "preservative activator" embodiment, the preservative can be chosen from propionic acid, calcium propionate, formaldehyde, paraformaldehyde, o-phenylphenol or its salts, zinc pyrithione, sulphites , bisulfites or metabisulfites of sodium, ammonium, potassium, chlorobutanol, methylparaben, ethylparaben, propylparaben, butylparaben, formic acid, sodium formate, benzoic acid and its salts, sorbic acid and its salts. Regarding the usual preservatives in question and their dosages according to specific applications, refer to the list of cosmetic regulation No. 1223/2009 in appendix 5 entitled "list of preservatives allowed in cosmetic products".

According to another variant of the "preservative activator" embodiment, the preservative which will be activated by the joint presence of the antimicrobial liquid composition then acting as a preservative activator, will be chosen from: benzoic acid, sodium benzoate, salicylic acid and its salts, sorbic acid, calcium sorbate, sodium sorbate, potassium sorbate, dehydroacetic acid, sodium dehydroacetate, undecylenic acid, calcium undecylenate, potassium undecylenate, sodium undecylenate, phenoxyethanol, 1,2-Dimethylol-5,6 -dimethylhydantoin, benzyl alcohol, chlorhexidine, chlorhexidine diacetate, chlorhexidine digluconate, chlorhexidine dihydrochloride, behentrimonium chloride, cetrimonium chloride, cetrimonium bromide, laurtrimonium chloride, laurtrimonium bromide, steartrimonium chloride, steartrimonium bromide, hexamidine, hexamidine diisethionate, chlorphenesin, benzalkonium chloride, bean bromide nzalkonium, benzalkonium saccharinate, ethyl lauroyl arginate.

Preferably, the preservative activated by the antimicrobial liquid composition is chosen from formic acid and its salts, dehydroacetic acid and its salts, benzoic acid and its salts, sorbic acid and its salts, phenoxyethanol, benzyl alcohol and its salts. More preferably, the preservative activated by the antimicrobial liquid composition is chosen from benzoic acid, sorbic acid, phenoxyethanol, benzyl alcohol, sodium benzoate, potassium sorbate. Most preferably, the preservative activated by the liquid antimicrobial composition is chosen from salts of benzoic acid, and salts of sorbic acid.

According to one embodiment, the preservative activated by the liquid antimicrobial composition is chosen from sodium benzoate and potassium sorbate.

According to one embodiment, the preservative activated by the antimicrobial liquid composition is chosen from sorbic acid and its calcium, sodium, potassium, magnesium or zinc salts, or a mixture thereof. Even more preferably, the preservative is chosen from sorbic acid, calcium sorbate, sodium sorbate, potassium sorbate. Most preferably, the preservative is potassium sorbate.

The use of an antimicrobial liquid composition to activate a cosmetic product preservative in a cosmetic product can be made with:
- an amount of antimicrobial liquid composition which can range from at least 0.1% by gross weight, preferably at least 0.5% by gross weight, more preferably at least 0.75% by gross weight, preferably at least 1 % by gross weight, and even more preferably at least 1.5% by gross weight,
- and an amount of preservative which can be up to 2.5% by gross weight, preferably up to 1.5% by gross weight, more preferably up to 1% by gross weight, preferably up to 0 7% by gross weight, and even more preferably up to 0.6% by gross weight,
relative to the total weight of the cosmetic product.

The use of an antimicrobial liquid composition to activate a cosmetic product preservative in a cosmetic product can be made with:
- an amount of antimicrobial liquid composition which can range from 0.1% to 5% by gross weight, preferably from 0.5% to 3% by gross weight, more preferably from 0.75% to 2% by gross weight, and most preferably from 1% to 1.5% by gross weight, of said at least one antimicrobial liquid composition,
- and an amount of usual preservative, which can be from 0.1% to 2.5% by gross weight, preferably from 0.2% to 1.5% by gross weight, more preferably from 0.3% to 1 % by gross weight, and most preferably from 0.4% to 0.7% by gross weight,
relative to the total weight of the cosmetic product.

Depending on the nature of the preservative used, the antimicrobial composition makes it possible to reduce by at least 35%, or even by at least 50%, or even better still by at least 60%, the amount of usual preservative used in cosmetic formulations. Thus it is generally possible to use them only at very low levels not exceeding 0.5% by gross weight, or even 0.4% by gross weight, relative to the total weight of the cosmetic product. The microbiological stability may be equal or even better than with the usual preservative used alone and at the recommended dose.

From a sensory point of view, the microbiological preservation of the cosmetic product due to the combination of the preservative activator which is the subject of the present application and a usual preservative, contributes to, or guarantees, a stability of the texture, a stability viscosity, absence of lumps, absence of granules, absence of emulsion separation, odor stability, color stability, and pH stability. In the case of a cosmetic product in the form of an emulsion, the microbiological preservation in particular allows the emulsion to remain in a physical state identical to or close to its initial physical state, that is to say in particular a structure of macroscopically homogeneous and microscopically discrete emulsion, and that this state has characteristics identical or close to those initial (that is to say those measurable at the end of its preparation). The microbiological preservation of a cosmetic product contributes to, or also guarantees that, the organoleptic qualities, and in particular the sensory profile, remain identical or close to those initially obtained following the preparation of the emulsion.

Used as a preservative activator, the antimicrobial composition can be added to the cosmetic product at the end of preparation, in other words after it has been prepared, when the preparation of said cosmetic product comprises high temperature heating steps 60- 80°C for periods exceeding a few minutes. When the preparation of the cosmetic product is carried out entirely at room temperature, the antimicrobial composition can be added from the first stages of preparation, but it is preferable to add it at the end of the preparation of the cosmetic product.

According to one embodiment, the antimicrobial composition is a preservative activator for the following preservatives: benzoic acid, sodium benzoate, salicylic acid and its salts, sorbic acid, calcium sorbate, sodium sorbate, potassium sorbate, dehydroacetic acid, sodium dehydroacetate, undecylenic acid, calcium undecylenate, potassium undecylenate, sodium undecylenate, phenoxyethanol, 1,2-Dimethylol-5,6-dimethylhydantoin, benzyl alcohol, chlorhexidine, chlorhexidine diacetate, chlorhexidine digluconate, chlorhexidine dihydrochloride, ethyl lauroyl arginate.

Product cosmetic:

A fourth object of the present application is a cosmetic product containing, as preservative activator, an antimicrobial liquid composition according to the first object of the present application, and at least one usual cosmetic product preservative.

The cosmetic product that is the subject of the present application comprises at least one antimicrobial liquid composition according to the present application, and at least one preservative chosen from: benzoic acid, sodium benzoate, salicylic acid and its salts, sorbic acid, calcium sorbate, sorbate of sodium, potassium sorbate, dehydroacetic acid, sodium dehydroacetate, undecylenic acid, calcium undecylenate, potassium undecylenate, sodium undecylenate, phenoxyethanol, 1,2-Dimethylol-5,6-dimethylhydantoin, benzyl alcohol, chlorhexidine, chlorhexidine diacetate , chlorhexidine digluconate, chlorhexidine dihydrochloride, behentrimonium chloride, cetrimonium chloride, cetrimonium bromide, laurtrimonium chloride, laurtrimonium bromide, steartrimonium chloride, steartrimonium bromide, hexamidine, hexamidine diisethionate, chlorphenesin, benzalkonium chloride, benzalkonium bromide, benzalkonium saccharinate, ethyl lauroyl arginate.

Preferably, the cosmetic product comprises at least one antimicrobial liquid composition according to the present application, and at least one preservative chosen from benzoic acid and its salts, sorbic acid and its salts, phenoxyethanol, benzyl alcohol and its salts.

More preferably, the cosmetic product comprises at least one antimicrobial liquid composition according to the present application, and at least one preservative chosen from benzoic acid, sorbic acid, phenoxyethanol, benzyl alcohol, sodium benzoate, sorbate potassium, and more preferably the preservative is potassium sorbate.

According to one embodiment, the cosmetic product comprises:
- up to 2.5% by gross weight, preferably up to 1.5% by gross weight, more preferably up to 1% by gross weight, preferably up to 0.7% by gross weight, and even more preferably up to 0.6% by gross weight, of said at least one preservative,
- and at least 0.1% by gross weight, preferably at least 0.5% by gross weight, more preferably at least 0.75% by gross weight, preferably at least 1% by gross weight, and even more more preferably at least 1.5% by gross weight, of said at least one antimicrobial liquid composition,
relative to the total weight of the cosmetic product.

Preferably, the cosmetic product comprises:
- up to 0.5% by gross weight, preferably up to 0.4% by gross weight of said at least one preservative,
- and at least 2.0% by gross weight, preferably at least 3% by gross weight, of said at least one antimicrobial liquid composition,
relative to the total weight of the cosmetic product.

Most preferably, the cosmetic product comprises:
- from 0.1% to 2.5% by gross weight, preferably from 0.2% to 1.5% by gross weight, more preferably from 0.3% to 1% by gross weight, and most preferably from 0 4% to 0.7% by gross weight, of said at least one preservative,
- and from 0.1% to 5% by gross weight, preferably from 0.5% to 3% by gross weight, more preferably from 0.75% to 2% by weight, gross and most preferably from 1% to 1 5% by gross weight of said at least one antimicrobial liquid composition,
relative to the total weight of the cosmetic product.

According to one embodiment, the cosmetic product comprises a single and unique antimicrobial liquid composition according to the present application, and a single and unique preservative.

The cosmetic product can be in any known form or physical state, namely an oil-in-water emulsion, a water-in-oil emulsion, a suspension, a foam, a true solution, a micellar solution, a hydroalcoholic, a paste, a gel, a powder, a tablet, a wipe. Preferably, the product is in a form chosen from an oil-in-water emulsion, a water-in-oil emulsion, a suspension, a foam, a true solution, a micellar solution, a hydroalcoholic solution, a paste, a freeze. Most preferably, the product is in a form chosen from an oil-in-water emulsion, a water-in-oil emulsion, a suspension, a foam, a true solution, a micellar solution, a paste, a gel.

The cosmetic product, due to the neutrality of the composition according to the invention and its high compatibility with the vast majority of oils and fatty substances, alcohols, surfactants, emulsifiers, solubilizers, conditioners, film-forming agents, thickeners, gelling agents, neutralization, or even also active agents, can be formulated without particular difficulty and in a very broad way with the ingredients usually retained.

Technical effects:

The selection of the constituents of the antimicrobial liquid composition that is the subject of the present application makes it possible both to obtain excellent antimicrobial activity, very good compatibility with the vast majority of cosmetic product formulation ingredients, great ease of use and high transparency, while also respecting the environment and the health of humans, animal and plant species.

First, the antibacterial activity of the liquid antimicrobial composition is due to the unexpected synergies between its constituents. These synergies make it possible in particular in the first place to have an antibacterial activity on both gram-negative type bacteria and on gram-positive type bacteria.

With regard to bacteria of the gram-positive type, the Applicant has been able to note a synergy between the three constituents which allows bactericidal activity on these bacteria, such as on Staphylococcus Aureus , for example.

Regarding gram-negative bacteria, two synergies also arise. A first synergy occurs between the carboxylic acid and the nonionic surfactant, such as for example between gluconic acid/gluconate salt and caprylyl/capryl glucoside. This first synergy allows bactericidal activity on gram-negative type bacteria similar to Pseudomonas a eruginosa . A second synergy occurs between the essential oil and the nonionic surfactant, such as between the essential oil of lemongrass of the Cymbopogon flexuosus species and the caprylyl/capryl glucoside. This second synergy allows bactericidal activity on gram -negative type bacteria similar to Escherichia coli . Thanks to these two synergies, the liquid antimicrobial composition which is the subject of the present application can thus have a bactericidal activity on almost all bacteria of the gram-negative type.

Secondly, the antimicrobial liquid composition that is the subject of the application also has, as the Applicant has been able to observe, a very good antifungal activity, by potentiation of the antifungal activity known by the essential oil, and in particular the essential oil of lemongrass lemongrass.

The combination of the antibacterial and antifungal activities of the liquid antimicrobial composition which is the subject of the present application makes it suitable for use as an activator for a microbiological preservative of aqueous media, such as cosmetic products. In cosmetic products such as micellar solutions, lotions, aqueous gels, and creams, the antimicrobial composition inhibits the growth of the bacteria, yeast, and fungal population. This stabilization concerns both "endogenous" micro-organisms in the cosmetic product (i.e. those initially present in the cosmetic product at the end of its manufacture) or "exogenous" micro-organisms (i.e. those inoculated following contamination of the cosmetic product by the user).

The antimicrobial liquid composition thus makes it possible to make a reduced quantity of preservative suitable for preserving a cosmetic product, or even in certain cases permitted by the regulations, could make it possible to stabilize the microbiology of a cosmetic product without recourse to a usual listed preservative. In particular, it makes it possible to reduce the quantity of parabens, phenoxyethanol, formaldehyde, benzoic acid or sorbic acid used in cosmetic products, or even to avoid using them in certain cases permitted by the regulations.

In addition, in a completely unexpected way compared to the general knowledge of those skilled in the art, the antimicrobial liquid composition which is the subject of the present application is capable of activating the preservatives generally recognized as not very active at neutral pH, that is to say at pH ranging from 5 to 7, or even from 6 to 7, such as benzoic acid salts or sorbic acid salts. The antimicrobial liquid composition makes it possible in particular to activate sodium benzoate and potassium sorbate, and preferably potassium sorbate, in cosmetic products whose pH is 6. The combination of an antimicrobial liquid composition which is the subject of the application and potassium sorbate thus makes it possible to achieve a category "A" level of conservation according to the ISO 11930 standard.

The selection of a nonionic surfactant makes the liquid antimicrobial composition compatible with ionic surfactants and zwitterionic surfactants. It is therefore possible to add the antimicrobial composition to a cosmetic product comprising another type of surfactant while maintaining good physical stability of the state of the cosmetic product, and retaining the effects of ionic or zwitterionic surfactants, that is to say say without masking or neutralizing the effects of these surfactants. For example, the antimicrobial composition can be added to a shampoo or a shower gel, which generally comprise anionic surfactants, often in high amounts, while retaining the detergent power of the anionic surfactants, and retaining the liquid or gel monophasic state. The liquid antimicrobial composition can also be added to a coloring solution or hair conditioner, generally comprising cationic surfactants or cationic polymers, while retaining the coloring ability and conditioning ability of the hair.

In addition, the selection of a ratio of the dry mass of nonionic surfactant to the dry mass of essential oil greater than or equal to 2 makes it possible to obtain a stable antimicrobial liquid composition, without phase shift or precipitation over time, while being transparent or opalescent, in the concentrated state or even after high dilution in water. According to the embodiment where the nonionic surfactant is caprylyl/capryl glucoside, a value of the ratio of the mass of caprylyl/capryl glucoside to the mass of essential oil greater than or equal to 2, preferably greater than or equal to 3, more preferably greater than or equal to 4, most preferably greater than or equal to 5, makes it possible to obtain a liquid antimicrobial composition that is completely transparent and stable over time in the concentrated state and in the state diluted in water. Cosmetic product formulators generally prefer to employ transparent ingredients to formulate their products.

The transparency of the antimicrobial liquid composition and the compatibility with ionic surfactants allow the addition of this antimicrobial composition to cosmetic products which are themselves transparent, such as micellar waters or gels, while maintaining transparency.

The antimicrobial liquid composition is in the form of a macroscopically homogeneous liquid, which allows easy use during the production of cosmetic products. Handling a liquid requires less individual or collective protective equipment than handling a pulverulent powder. The transfer between container and the precise dosage are also much simpler and more reliable than for a pulverulent powder.

The choice of the constituents of the antimicrobial liquid composition which is the subject of the present application also has the advantage of giving it an index of content of natural origin, denoted CNO, of 100% if the nonionic surfactant is not ethoxylated and is retained among sucrose fatty esters or alkyl(poly)glucosides obtained solely from plant resources.

The antimicrobial composition that is the subject of the present application constitutes a preservative activator which offers good stability and compatibility with cosmetic products, allowing transparency without crystallization or precipitation problems.

Other possible applications:

The antimicrobial composition according to the invention can also find non-cosmetic uses and can in particular be suitable for microbiologically stabilizing pharmaceutical, food or industrial compositions such as, for example, liquid detergent compositions, liquid washing compositions, starchy adhesives.

Another object of the present application is the use of an antimicrobial composition according to the present application for killing microorganisms, or pathogenic microorganisms, or inhibiting the growth of microorganisms or pathogenic microorganisms, on or in a non-living or artificial substrate . Such an application concerns, for example, the disinfection of surfaces (floors, walls, doors, door handles), disinfection/conservation of industrial liquid products such as aqueous solutions of starches, proteins, or fibers.

Examples

Example 1: preparing a composition liquid antimicrobial

The following protocol describes the preparation of an antimicrobial composition consisting of essential oil, gluconic acid, sodium gluconate and a solubilizing surfactant. When the solubilizing surfactant is in the form of a powder, it is dissolved in a minimum amount of water. In an open beaker, the required amount of essential oil is slowly added to the required amount of solubilizing surfactant solution, with gentle stirring (eg 500-1000 rpm using a Rayneri motor fitted with a propeller) and at room temperature (22 °C), until a homogeneous solution is obtained. This aqueous solution of essential oil and solubilizer is added to an aqueous solution of gluconic acid composed of the required quantity of free gluconic acid and sodium gluconate, with gentle stirring (for example 500-1000 rpm with a Rayneri motor equipped of a propeller) and at room temperature (22°C), until a homogeneous solution is obtained.

Example 2 : selection of a solubilizing surfactant to meet transparency criteria

This example presents the selection of a solubilizing surfactant and the ratio of the gross mass of surfactant to the gross mass of essential oil, to obtain an aqueous solution of essential oil of lemongrass Cymbopogon flexuosus which is transparent both in the state concentrated than when diluted in water. A solubilizing surfactant will be acceptable if both transparency criteria are met. Only the main surfactants tested which gave results are presented here. The ratio of the gross mass of surfactant to the gross mass of essential oil is denoted “raw TA/HE ratio” below.

For each solubilizing surfactant to be tested (Table 1), a liquid composition is prepared with the following masses of constituents:
- 1.2 grams of gluconic acid (in dry form),
- 3 demineralized water,
- 2.4 grams of lemongrass essential oil "Cymbopogon flexuosus Oil®" from the supplier Elixens,
- 14.4 or 19.2 or 24 gross grams, i.e. grams of product in its commercially available form, of a solubilizing surfactant from Table 1 (all being nonionic surfactants) to achieve a crude TA/HE ratio, respectively, of 6, 8 or 10.

The protocol for preparing a liquid composition is as follows:
- a first premix is prepared by dissolving the gluconic acid in the mass of water with gentle stirring at 20-22°C,
- a second premix is prepared by adding to the mass of essential oil, the required mass of solubilizing surfactant, and stirring to allow the essential oil to be well dispersed and to obtain a homogeneous liquid,
- the second pre-mixture is then added to the first pre-mixture, and the mixture is maintained under gentle non-shearing agitation for about 20 minutes, to allow time for the pre-mixture of surfactant and essential oil to disperse, and thus the liquid composition to stabilize.

Immediately after the preparation, the state of the liquid composition prepared is observed with the naked eye in order to evaluate its transparency and its homogeneity, in particular over the entire height of the sample, and in order to search for the possible presence of several phases or solid particles (which would have formed by instantaneous precipitation, or by slower crystallization). This state is referred to as “concentrated liquid composition”. On half of the volume of liquid composition, these observations are continued during storage at a temperature of 20-22° C. for 1 month.

On the other half, a water dilution behavior test is carried out. 1.5 grams of the liquid composition are diluted in a mass of water of 98.5 grams. The state of the water to which the liquid composition has been added is observed with the naked eye, in order to assess its transparency and its homogeneity, in particular over the entire height of the sample, and to search for the possible presence of several phases. or solid particles. This is the state "after dilution in water". These observations are continued during storage at a temperature of 20-22° C. for 1 month.

For the "concentrated composition" state and for the "after dilution in water" state, transparency and homogeneity are qualified and evaluated as follows:
- “failure”: presence of solid particles, in particular at the bottom of the sample; or presence of at least 2 phases, generally including a supernatant; presence of a paste, in particular at the bottom of the sample; slight to strong turbidity, visible to the naked eye; heterogeneous transparency, with a visibly different upper and lower part; creamy appearance, notably ivory.
- “success”: almost imperceptible opalescence; homogeneous and almost perfect transparency to the naked eye; no turbidity visible to the naked eye.

The transparency and homogeneity results of the "concentrated liquid composition" are presented in Table 2, and the transparency and homogeneity results "after dilution in water" are presented in Table 3.

Ref. NOT trade name ( Producer ) INCI AT Resassol® Apostrophy (Res Pharma Industriale) Caprylyl/Capryl Glucoside (and) Water (and) Polyglyceryl-3 Cocoate (and) Polyglyceryl-10 Laurate (and) Citric Acid B Lamesoft® OD (BASF) Coco-Caprylate (and) Lauryl Glucoside (and) Glycerin (and) Polyglyceryl-2 Dipolyhydroxystearate (and) Polyglyceryl-3 Diisostearate VS Symbio®Solv Clear Plus MB (Evonik Operations GmbH) Caprylyl/Capryl Glucoside (and) Aqua (and) Sodium Cocoyl Glutamate (and) Glyceryl Caprylate (and) Citric Acid (and) Polyglyceryl-6 Oleate (and) Sodium Surfactin D1 Tegosoft® PC 41 (Evonik Operations GmbH) Polyglyceryl-4 Caprate D2 Emulpharma® ECO 10 (Res Pharma Industriale) Polyglyceryl-10 Laurate (and) water D3 Polyaldo® 10-1-CC (Lonza) Polyglyceryl-10 Caprylate/Caprate D4 NatraGem® E145 (Croda) Polyglyceryl-4 Laurate/Succinate D5 Decaglyn 10-MAC (Nikkol) Polyglyceryl-10 Decamacadamiate E Sepiclear™ G7 (Seppic) Heptyl Glucoside F Oramix™ CG 110 (Seppic) Caprylyl/Capryl Glucoside G Poly Suga® Mulse D9 (Colonial Chemical Inc.) Sorbitan Oleate Decylglucoside Crosspolymer

Solubilizing surfactant
Ref. Criterion of transparency and homogeneity
concentrated liquid composition
For a value of the raw TA/HE ratio of: 6 8 10 AT failure failure success B failure failure failure VS failure failure failure D1 to D5 failure failure failure E failure failure success F failure success success G failure failure failure

Solubilizing surfactant
Ref. Criterion of transparency and homogeneity
after dilution in water
For a value of the raw TA/HE ratio of: 6 8 10 AT failure failure failure B failure failure success VS failure failure success D1 to D5 failure failure failure E failure failure failure F failure success success G success success success

Surfactants B, C and G fail to provide a concentrated liquid composition that is transparent, but allow transparency when diluted in water. They may therefore be suitable for the liquid antimicrobial composition which is the subject of the present application.

Among all the tests carried out, only the solubilizing surfactant F, that is to say caprylyl/capryl glucoside, makes it possible to satisfy both the criterion of transparency and homogeneity of the concentrated liquid composition, and the same criterion after dilution in water, and this for values of the crude TA/HE ratio ranging from 8 to 10. In the case of the nonionic solubilizing surfactant caprylyl/capryl glucoside, the values of the crude TA/HE ratio ranging from 8 to 10 equivalent at values of a ratio of the dry mass of surfactant to the dry mass of essential oil ranging from 4 to 5 (because this surfactant comprises 50% water and 50% dry caprylyl/capryl glucoside).

Example 3 : preparations of antimicrobial compositions

The ingredients used are shown in Table 4. The compositions of the antimicrobial compositions that are the subject of the present application are shown in Table 5.

Commercial Product (Supplier) Composition of the commercial product (% weight) Gluconic acid solution 60/35 (Arugula) 40% water +
60% dry matter consisting of 65% gluconic acid and 35% sodium gluconate Oramix CG110 (SEPPIC) 50% caprylyl/capryl glucoside + 50% water Cymbopogon flexuosus oil® (Elixens) 100% Cymbopogon flexuosus lemongrass essential oil

Commercial Product (Supplier) Antimicrobial Composition 40 (%wt) Antimicrobial composition 43 (%wt) Gluconic acid solution 60/35 (Arugula) 57.13 78.00 Oramix CG110 (SEPPIC) 39.00 20.00 Cymbopogon flexuosus lemongrass essential oil 3.93 2.00

The antimicrobial compositions 40 and 43 are prepared according to the following protocol:

In an open beaker, the required amount of essential oil is slowly added to the required amount of solubilizing surfactant solution, with gentle stirring, for example 500-1000 rpm using a Rayneri motor equipped with a propeller, and at an ambient temperature of 22 °C, until a homogeneous solution is obtained. This aqueous solution of essential oil and solubilizer is added to an aqueous solution of gluconic acid and sodium gluconate.

Example 4 :m highlights microbiological stabilizing properties

The antibacterial and antifungal activities of the compositions prepared in Example 1 are demonstrated through in vitro growth tests on standard culture media for the following microorganisms: Escherichia coli ATCC® 8739, Pseudomonas Aeruginosa ATCC® 9027, Staphylococcus Aureus ATCC® 6538, Candida Albicans ATCC® 10231, and Aspergillus Brasiliensis ATCC® 16404. These tests include comparisons with the constituents of the compositions taken in isolation, and taken in combination of two constituents, in order to identify the synergies of antimicrobial activity on these microorganisms.

For each microorganism, as many test tubes are prepared as there are products to be tested, i.e. the antimicrobial composition, the constituents alone, or the combinations of two constituents, as well as a control, with the medium of culture adapted to the micro-organism: “potato dextrose broth” for Aspergillus Brasiliensis; “Yeast Molds” for Candida Albicans; "tryptone soy broth" for Escherichia Coli; "medium" for Staphylococcus Aureus; and "middle" for Pseudomonas Aeruginosa. A dose of product to be tested according to Table 6 below, expressed as a weight/volume percentage, is then added to each test tube. For example, a percentage of 1.5% weight/volume means that for 100 mL of culture medium, 1.5 g of product to be tested are added. Then we homogenize carefully by suction-repression.

Test reference Product to test Series
"composition 40"
(% weight/volume) Series
"composition 43"
(% weight/volume) Witness Water 1.5 1.5 AT Gluconic acid solution 60/35 0.857 1.17 B Oramix CG110 0.585 0.3 VS Cymbopogon flexuosus lemongrass essential oil 0.059 0.03 D Gluconic acid solution 60/35 0.857 1.17 + Oramix CG110 + 0.585 +0.3 E Gluconic acid solution 60/35 0.857 1.17 + Cymbopogon flexuosus lemongrass essential oil +0.059 +0.03 F Oramix CG110 0.585 0.3 + Cymbopogon flexuosus lemongrass essential oil +0.059 +0.03 G Membership 40 1.50 - H Membership 43 - 1.5

Each test tube is inoculated with a known quantity of microorganism: 10^3 colony-forming units per milliliter of agar (denoted cfu/mL) for Aspergillus brasiliensis; 10^4 cfu/mL for Escherichia coli and Candida Albicans; 10^5 cfu/mL for Staphylococcus aureus and Pseudomonas aeruginosa. At the end of the inoculation, the inoculated media are again carefully homogenized by aspiration-discharge.

The samples inoculated with Aspergillus brasiliensis are incubated at 30°C (+/-2.5°C) for 48 hours. The samples inoculated with the two other strains are incubated at 37° C. (+/-2.5° C.) for 48 hours.

Samples and counts of microorganisms are taken at 30 minutes, 24 hours and 48 hours for each microorganism. The inoculated samples are taken, serially diluted in diluent (casein peptone 1g/L, sodium chloride 8.5g/L, pH 7) and deposited respectively on potato and dextrose agars for Aspergillus brasiliensis, trypto-casein-soya agars for Escherichia coli and Sabouraud dextrose agars for Candida albicans. The agars are incubated for 24 to 72 hours before counting the colonies present.

The measurements of microorganism populations carried out at each sampling time are expressed in cfu/mL. The detection limit of the test is 100 cfu/mL.

The results of the tests conducted are shown in Table 7 for Escherichia Coli, in Table 8 for Candida Albicans, in Table 9 for Aspergillus Brasiliensis, in Table 10 for Staphylococcus Aureus, and in Table 11 for Pseudomonas Aeruginosa.

[Table 7]: E.Coli Product reference to test Count (cfu/mL) 0 hours 0.5 hour 24 hours 48 hours Witness 3.5.10^4 3.5.10^4 5.6.10^8 4.0.10^8 AT 3.5.10^4 3.5.10^4 4.0.10^8 2.9.10^8 B 3.5.10^4 2.0.10^3 2.7.10^7 5.8.10^5 VS 3.5.10^4 3.0.10^3 4.1.10^7 7.0.10^4 D 3.5.10^4 6.0.10^2 3.2.10^6 1.8.10^6 E 3.5.10^4 3.7.10^4 1.0.10^8 1.7.10^7 F 3.5.10^4 1.0.10^2 1.0.10^2 1.0.10^1 G 3.5.10^4 1.0.10^2 1.0.10^2 1.0.10^1 H 3.5.10^4 4.0.10^2 1.0.10^2 1.0.10^1

[Table 8]: C. Albicans Product reference to test Count (cfu/mL) 0 hours 0.5 hour 24 hours 48 hours Witness 2.0.10^4 2.0.10^4 9.5.10^6 8.5.10^6 AT 2.0.10^4 2.4.10^4 9.3.10^6 5.9.10^6 B 2.0.10^4 1.9.10^4 4.7.10^5 4.3.10^5 VS 2.0.10^4 1.5.10^4 1.0.10^2 1.0.10^2 D 2.0.10^4 1.9.10^4 9.7.10^3 7.1.10^4 E 2.0.10^4 2.2.10^4 1.0.10^2 1.0.10^2 F 2.10^4 1.8.10^4 1.0.10^2 1.0.10^2 G 2.0.10^4 1.4.10^4 1.0.10^2 1.0.10^2 H 2.0.10^4 2.7.10^4 1.0.10^2 1.0.10^2

[Table 9]: A. Brasiliensis Product reference to test Count (cfu/mL) 0 hours 0.5 hour 24 hours 48 hours Witness 3.0.10^3 3.0.10^3 1.1.10^4 1.0.10^3 AT 3.0.10^3 6.4.10^3 2.5.10^3 1.0.10^3 B 3.0.10^3 5.1.10^3 4.0.10^2 8.0.10^2 VS 3.0.10^3 4.2.10^3 1.0.10^2 1.0.10^2 D 3.0.10^3 7.6.10^3 2.0.10^2 1.0.10^2 E 3.0.10^3 5.1.10^3 2.2.10^3 3.0.10^3 F 3.0.10^3 6.5.10^3 1.0.10^2 1.0.10^2 G 3.0.10^3 7.3.10^3 1.0.10^2 1.0.10^2 H 3.0.10^3 6.2.10^3 1.0.10^2 1.0.10^2

[Table 10]: S.Aureus Product reference to test Count (cfu/mL) 0 hours 0.5 hour 24 hours 48 hours Witness 8.6.10^4 7.1.10^4 1.3.10^8 2.9.10^8 AT 8.6.10^4 1.1.10^5 5.2.10^4 4.2.10^4 B 8.6.10^4 1.2.10^5 1.3.10^7 1.4.10^7 VS 8.6.10^4 1.3.10^5 3.4.10^5 1.2.10^6 D 8.6.10^4 9.4.10^4 2.0.10^2 1.0.10^2 E 8.6.10^4 4.4.10^4 1.0.10^2 1.0.10^2 F 8.6.10^4 5.1.10^4 2.0.10^2 1.0.10^2 G 8.6.10^4 n/a n/a n/a H 8.6.10^4 8.4.10^4 1.0.10^2 1.0.10^2

[Table 11]: P.Aeruginosa Product reference to test Count (cfu/mL) 0 hours 0.5 hour 24 hours 48 hours Witness 3.6.10^5 5.1.10^5 3.8.10^8 4.0.10^8 AT 3.6.10^5 5.6.10^5 8.7.10^6 4.8.10^8 B 3.6.10^5 1.2.10^6 1.6.10^7 1.5.10^7 VS 3.6.10^5 6.5.10^5 1.3.10^8 1.5.10^8 D 3.6.10^5 4.6.10^5 2.1.10^3 1.0.10^2 E 3.6.10^5 4.6.10^5 4.1.10^8 3.8.10^8 F 3.6.10^5 7.3.10^5 2.0.10^7 1.0.10^7 G 3.6.10^5 n/a n/a n/a H 3.6.10^5 3.7.10^5 6.7.10^3 4.0.10^2

The results in Table 7 show that it is the combination of Oramix® CG 110 and essential oil of lemongrass Cymbopogon flexuosus which kills the Escherichia coli bacteria and prevents their development. This antibacterial activity seems to be due to a synergy between Oramix CG 110 and the essential oil of lemongrass Cymbopogon flexuosus . Compositions 40 and 43 also have this antibacterial activity on Escherichia coli .

The results in Table 8 show that the combination of gluconic acid and essential oil, and the combination of Oramix® CG 110 and essential oil, have an antifungal activity on Candida albicans . Compositions 40 and 43 also have this antibacterial activity on Candida albicans .

The results in Table 11 show that it is the combination of gluconic acid/sodium gluconate and Oramix CG 110 which kills the Pseudomonas aeruginosa bacteria and prevents their development. This antibacterial activity seems to be due to a synergy between gluconic acid/sodium gluconate and Oramix® CG 110.

All these results show that compositions 40 and 43 have antibacterial and antifungal properties under in vitro culture conditions on agar-type medium, because they make it possible to microbiologically stabilize culture media inoculated with the reference bacteria and fungi on durations of up to 48 hours.

Example 5 : activation of preservatives at pH 6 in an oil-in-water emulsion

In this example, the ability of composition 43 prepared in example 3 to activate the bactericidal and fungicidal activity of preservatives at pH 6 in an oil-in-water emulsion is demonstrated. The preservatives are phenoxyethanol, benzyl alcohol, sodium benzoate, and potassium sorbate. They are listed in appendix 5 of regulation no. 1223/2009.

The cosmetic product used for this demonstration is an oil-in-water emulsion type cream, called “cotton cream”. Creams are prepared according to the composition of table 12, by adding sufficient quantities, denoted "Qs", of composition 43 and preservative according to the values of table 10. Antimicrobial protection efficacy tests are carried out on each cream of the table 13 for the five microorganisms of the ISO 11930 standard: Pseudomonas Aeruginosa, Staphylococcus Aureus, Escherichia Coli, Candida Albicans, Aspergillus Brasiliensis.

Phase Ingredient / Supplier INCI % by weight of emulsion AT Emulium delta / Cetyl Alcohol, Glyceryl Stearate, PEG-75 Stearate, Ceteth-20, Steareth-20 5.00 AT Caprylic/capric triglycerides 10.00 AT sweet almond oil 10.00 AT Cetyl alcohol 2.00 B Beauty by Roquette® ST 012 1.50 VS Demineralized Water Aqua Qsp 100 VS Xanthan gum 0.30 D Membership 43 - Qs according to test D Conservative - Qs according to test E Soda x %M Welded Qs pH 6

To prepare the cream of Table 9, all the ingredients of phase A are mixed separately and heated to 75°C. While maintaining at 75° C., phase B is added to phase A with gentle stirring (500-750 rpm; marine propeller), and the mixture is waited for to be homogeneous. Then phase A+B is added to phase C with emulsifying stirring (3000 rpm; deflocculating) for 10 minutes, maintaining at 75°C. The mixture is allowed to cool to 45° C., and phase D is added with moderate stirring (1500 rpm; marine propeller). The mixture is cooled to 25° C. with gentle stirring (500-750 rpm; marine propeller), then the pH is finally adjusted to 6 with phase E.

Cream No. Qs of composition 43
(% by weight of emulsion) Qs of curator
(% by weight of emulsion) 1 0% 0% 2 0% 1% Microcare® PM4 (Thor) 3 1% 0% 4 1.5% 0% 5 0% 0.4% phenoxyethanol 6 1% 0.4% phenoxyethanol 7 0% 0.4% benzyl alcohol 8 1% 0.4% benzyl alcohol 9 0% 0.4% sodium benzoate 10 1% 0.4% sodium benzoate 11 0% 0.4% potassium sorbate 12 1% 0.4% potassium sorbate

Each antimicrobial protection efficacy test is conducted according to the guidelines of the ISO 11930 standard. The results are provided in Tables 14 to 19. They are expressed as the logarithmic reduction in the number of colony-forming units per mL. A positive value corresponds to a decrease in the number of colony forming units. A negative value corresponds to an increase in the number of colony forming units.

Microorganism Time Cream 1: White without preservative Cream 2: 1% Microcare® PM4 (Thor) Pseudomonas Aeruginosa 7 days < - 0.63 0.68 14 days - 2.63 3.14 28 days - 0.26 3.75 Staphylococcus Aur e us 7 days 1.91 2.11 14 days 4.74 > 4.92 28 days > 4.92 > 4.92 Escherichia Coli 7 days < - 0.63 > 4.85 14 days - 0.16 > 4.85 28 days - 0.29 > 4.85 Candida Albicans 7 days < - 0.60 0.6 14 days - 1.67 1.41 28 days - 1.41 3.40 Aspergillus brasiliensis 14 days 0.27 0.35 28 days 0.17 1.36

The antimicrobial protection measure of Cream 1, which is a cream without any preservatives and without preservative activators, shows that Cream 1 is not protected against Pseudomonas Aeruginosa, Escherichia Coli, and Candida Albicans, but is protected against Staphylococcus Aureus and Aspergillus Brasiliensis (we speak of self-protection) beyond 14 days. This measurement is our negative control.

Cream 2's antimicrobial protection measure, which contains 1% by weight of Thor's Microcare® PM4 preservative, is protected against all five microorganisms. This measurement is our positive control.

Microorganism Time Cream 3:
1% composition 43 Cream 4:
1.5% composition 43 Pseudomonas Aeruginosa 7 days 0.74 < - 0.63 14 days - 1.38 - 1.6 28 days - 0.84 - 0.95 Staphylococcus aureus 7 days 2.26 > 4.92 14 days > 4.92 > 4.92 28 days > 4.92 > 4.92 Escherichia Coli 7 days 0.2 < - 0.63 14 days 2.33 - 1.14 28 days > 4.85 > 4.85 Candida Albicans 7 days < - 0.60 < - 0.60 14 days - 2.16 - 1.65 28 days - 1.72 - 2.19 Aspergillus brasiliensis 14 days 0.47 0.15 28 days 0.15 0.06

The antimicrobial protection measurements of Creams 3 and 4, which contain 1% and 1.5% of Composition 43, respectively, and no preservatives, show that neither of these creams is protected against Pseudomonas Aeruginosa and Candida Albicans . Self-protection against Staphylococcus Aureus and Aspergillus Brasiliensis is maintained. Concerning Escherichia Coli , protection is observed from 28 days. Composition 43 does not make it possible to protect the cream against microbial growth. It is however notable that composition 43 does not degrade the self-protection of the cream against Staphylococcus Aureus and Aspergillus Brasiliensis .

Microorganism Time Cream 5:
0.4% phenoxyethanol Cream 6:
1% composition 43
+ 0.4% phenoxyethanol Pseudomonas Aeruginosa 7 days - 0.05 2.69 14 days 0.96 4.01 28 days Staphylococcus aureus 7 days 1.38 > 4.92 14 days 2.33 > 4.92 28 days Escherichia Coli 7 days 2.11 > 4.88 14 days 2.89 > 4.88 28 days Candida Albicans 7 days < - 0.64 < - 0.64 14 days - 0.87 - 0.85 28 days Aspergillus brasiliensis 14 days 0.46 2.20 28 days

Concerning cream 5, the microbial protection conferred by 0.4% by weight of phenoxyethanol makes it possible to protect the cream but insufficiently, in particular vis-à-vis Candida albicans , and less than the positive control.

Concerning cream 6, which contains 0.4% by weight of phenoxyethanol and 1% by weight of composition 43, it is noted that the microbial protection against Pseudomonas Aeruginosa , Escherichia Coli , and Aspergillus brasiliensis is much better than that of cream 5, and equivalent to the positive control. Indeed, from 7 days, or 14 days for A.brasiliensis, strong logarithmic reductions are measured, and are greater than the reductions measured on cream 5 by at least 2 log. These reductions continue to 14 days. Self-protection against Staphylococcus aureus is maintained. However, Cream 6 is not protected against Candida albicans , which continues to grow there. Composition 43 therefore makes it possible to activate the preservative power of phenoxyethanol with respect to Pseudomonas Aeruginosa , Escherichia Coli , and Aspergillus brasiliensis .

Microorganism Time Cream 7:
0.4% benzyl alcohol Cream 8:
1% composition 43
+ 0.4% benzyl alcohol Pseudomonas Aeruginosa 7 days - 0.1 3.22 14 days 0.72 > 4.92 28 days Staphylococcus aureus 7 days 1.36 > 4.92 14 days 2.42 > 4.92 28 days Escherichia Coli 7 days 0.27 1.19 14 days 0.94 4.88 28 days Candida Albicans 7 days < - 0.64 < - 0.64 14 days - 0.89 - 1.29 28 days Aspergillus brasiliensis 14 days 0.01 0.46 28 days

Concerning cream 7, the microbial protection conferred by 0.4% by weight of benzyl alcohol does not protect the cream. Benzyl alcohol strongly degrades (by more than 2 log) the self-protection of cotton cream against Staphylococcus aureus.

Concerning cream 8, which contains 0.4% by weight of benzyl alcohol and 1% by weight of composition 43, it is noted that the microbial protection against Pseudomonas Aeruginosa , Escherichia Coli , and Aspergillus brasiliensis is much better than that of cream 7, and equivalent to the positive control. Indeed, from 7 days, or 14 days for A.brasiliensis, significant or strong logarithmic reductions are measured, and are greater than the reductions measured on cream 7 by at least 2 log. These reductions continue to 14 days. Self-protection against Staphylococcus aureus is maintained. However, Cream 8 is not protected against Candida albicans , which continues to grow there. Composition 43 therefore makes it possible to activate the preservative power of benzyl alcohol against Pseudomonas Aeruginosa , Escherichia Coli , and Aspergillus brasiliensis .

Microorganism Time Cream 9:
0.4% sodium benzoate Cream 10:
1% composition 43
+ 0.4% sodium benzoate Pseudomonas Aeruginosa 7 days 1.38 3.21 14 days 1.69 4.92 28 days Staphylococcus aureus 7 days 1.02 3.52 14 days 3.28 4.92 28 days Escherichia Coli 7 days 0.78 1.06 14 days 1.23 4.88 28 days Candida Albicans 7 days < - 0.64 0.82 14 days - 0.96 1.24 28 days Aspergillus brasiliensis 14 days 0.48 1.14 28 days

Concerning cream 9, the microbial protection conferred by 0.4% by weight of sodium benzoate allows the cream to be poorly protected, except against Candida albicans . Sodium benzoate slightly degrades the self-protection of cotton cream against Staphylococcus aureus .

Concerning cream 10, which contains 0.4% by weight of sodium benzoate and 1% by weight of composition 43, it is noted that the microbial protection against Pseudomonas Aeruginosa , Escherichia Coli , Aspergillus brasiliensis and Candida albicans is much better than that of cream 9, and equivalent to the positive control. Indeed, from 7 days, or 14 days for A.brasiliensis , significant or strong logarithmic reductions are measured, and are greater than the reductions measured on cream 7 by at least 2 log. These reductions continue to 14 days. Self-protection against Staphylococcus aureus is maintained. It is noteworthy that the cream 10 here presents sufficient protection against Candida albicans . Composition 43 therefore makes it possible to activate the preservative power of benzyl alcohol against Pseudomonas Aeruginosa , Escherichia Coli , Aspergillus brasiliensis , and Candida albicans . Composition 43 also makes it possible to maintain the self-protection of the cotton cream against Staphylococcus aureus .

Microorganism Time Cream 11:
0.4% potassium sorbate Cream 12:
1% composition 43
+ 0.4% potassium sorbate Pseudomonas Aeruginosa 7 days 1.78 4.92 14 days - 0.56 4.92 28 days Staphylococcus aureus 7 days 2.74 4.92 14 days 4.92 4.92 28 days Escherichia Coli 7 days 1.19 4.88 14 days 3.67 4.88 28 days Candida Albicans 7 days 0.86 2.24 14 days 1.23 3.84 28 days Aspergillus brasiliensis 14 days 0.96 3.82 28 days

Concerning cream 11, the microbial protection conferred by 0.4% by weight of potassium sorbate makes it possible to protect the cream in an equivalent manner to the positive control, except against Pseudomonas aeruginosa .

Concerning cream 12, which contains 0.4% by weight of potassium sorbate and 1% by weight of composition 43, it is noted that the microbial protection against Pseudomonas Aeruginosa , Escherichia Coli , Candida Albicans and Aspergillus brasiliensis is much better than that of cream 11, and even better than that of positive control cream 2 (containing 1% of Microcare® PM4). Indeed, from 7 days, or 14 days for Aspergillus Brasiliensis , strong logarithmic reductions are measured, and are greater than the reductions measured on cream 11 by at least 2 log. These reductions are maintained or continue at 14 days. Composition 43 therefore makes it possible to activate the preservative power of potassium sorbate against Pseudomonas Aeruginosa , Escherichia Coli, Candida Albicans and Aspergillus brasiliensis .

Example 6 : activation of preservatives at pH 4.5 in an oil-in-water emulsion

In this example, the procedure is identical to Example 5, with the only difference that the “cotton cream” is adjusted to pH 4.5. The antibacterial activity of composition 43 alone is tested here according to Table 20. Table 21 presents the results expressed as log reduction.

Cream No. Qs of composition 43
(% by weight of emulsion) 13 0% 14 1% 15 1.5%

Microorganism Time Cream 13:
White without preservative Cream 14:
1% composition 43 Cream 15: 1.5% composition 43 Pseudomonas aeruginosa 7 days - 0.11 > 4.98 > 4.98 14 days - 0.82 > 4.98 > 4.98 28 days Staphylococcus aureus 7 days 0.95 3.57 > 4.94 14 days > 4.94 > 4.94 > 4.94 28 days Escherichia Coli 7 days 0.79 3.49 > 4.95 14 days 0.00 3.48 > 4.95 28 days

Cream 13 is not protected against Pseudomonas Aeruginosa , Escherichia Coli , but is protected against Staphylococcus Aureus, by self-protection.

Cream 14, which contains 1% composition 43, exhibits microbial protection against Pseudomonas Aeruginosa and Escherichia Coli , which Cream 13 does not have. The self-protection of cream 14 against Staphylococcus Aureus is improved compared to cream 13: the logarithmic reduction is greater by more than 2 log.

Concerning cream 15, which contains 1.5% of composition 43, we observe the same protection as that of cream 14.

Composition 43 therefore does not provide sufficient antibacterial protection for cotton cream at pH 4.5.

Example 7 : products cosmetic s comprising the composition " preservative activator » and a curator

Product 2: shampoo

Phase Ingredient / Supplier INCI % by weight of emulsion AT Aqua Qsp 100 AT Xanthan gum 1.00 B Coco-Glucoside and aqua 28.80 B Glyceryl Oleate 1.00 B PEG-12 Dimethicone 1.00 VS Membership 43 - 1.00 VS Potassium sorbate 0.40 D citric acid SQ pH 4.5-6

A shampoo is prepared according to the composition of table 22:

The xanthan gum is added to the water with moderate agitation until a homogeneous gel is obtained, approximately after 20 minutes of agitation. At a temperature of 20-22° C., the ingredients of phase B are successively added, with moderate stirring. Phase C is then added, still with gentle stirring. Then the pH is adjusted to 4.8 with citric acid, still with gentle stirring.

A fluid, transparent and foaming gel is obtained. The Brookfield viscosity at 20 rpm 20° C. for 1 minute (with the RV M04 spindle) is 3200 mPa.s +/-500. Composition 43 is therefore indeed highly compatible with the ingredients of the shampoo.

Claims (18)

Antimicrobial liquid composition comprising:
- from one to four essential oils,
- from one to four nonionic surfactants,
- from one to four carboxylic acids in free form,
- some water. A liquid antimicrobial composition according to claim 1, further comprising from one to four carboxylic acid salts. Antimicrobial liquid composition according to Claim 1 or 2, characterized in that the essential oil or oils is or are chosen from the essential oils of clove, lemongrass, Bourbon geranium, geranium grass, gingergrass, noble laurel, lemongrass, west indian lemongrass, east indian lemongrass, lemongrass, lemon balm, palmarose, chili pepper, crown pepper, oregano, lemon tree tea, thyme, lemongrass. Antimicrobial liquid composition according to Claim 3, characterized in that the essential oil or oils is or are chosen from essential oils of citronella, and essential oils of lemongrass from western India, lemongrass from eastern India, and preferably the essential oil or oils is or are chosen from the essential oils of species of the Cymbopogon genus. Antimicrobial liquid composition according to one of Claims 1 to 4, characterized in that the nonionic surfactant(s) is or are chosen from polyethoxylated or polypropoxylated or polyglycerolated alcohols, alpha-diols and alkyl (C1-C20)phenols, condensates ethylene oxide and propylene oxide on fatty substances, polyethoxylated fatty amides, ethoxylated sorbitan fatty acid esters, sucrose fatty esters, polyethoxylated fatty acid esters, derivatives of N -(C6-C24 alkyl)glucamine, amine oxides, alkyl(poly)glycosides, preferably, said nonionic surfactant(s) is or are chosen from sucrose fatty esters, alkyl(poly)glycosides, and most preferably said nonionic surfactant(s) is or are chosen from alkyl(poly)glycosides, and even more preferably said nonionic surfactant(s) is or are chosen from alkyl(poly)glucosides. Antimicrobial liquid composition according to one of the preceding claims, characterized in that the ratio of the total dry mass of nonionic surfactants to the total dry mass of essential oils is greater than or equal to 2, preferably greater than or equal to 3, plus preferably greater than or equal to 4, and most preferably greater than or equal to 5. Antimicrobial liquid composition according to one of the preceding claims, characterized in that the total amount of nonionic surfactants is greater than or equal to 1% by dry weight, preferably greater than or equal to 5% by dry weight, more preferably greater than or equal to 7.5% by dry weight, and most preferably greater than or equal to 10% by dry weight, relative to the total weight of said liquid antimicrobial composition. Antimicrobial liquid composition according to one of the preceding claims, characterized in that the carboxylic acid(s) in free form is or are chosen from monocarboxylic acids and polycarboxylic acids, and preferably from monocarboxylic acids, dicarboxylic acids, tricarboxylic acids, and most preferably from monocarboxylic acids and dicarboxylic acids. Antimicrobial liquid composition according to one of the preceding claims, characterized in that the carboxylic acid or acids is or are chosen from gluconic acid, glucuronic acid, maltobionic acid, succinic acid, glucaric acid, and glutaric acid, and preferably the carboxylic acid or acids is or are chosen from gluconic acid and succinic acid, and most preferably the carboxylic acid is gluconic acid. Antimicrobial liquid composition according to one of Claims 2 to 9, characterized in that the carboxylic acid salt(s) is or are chosen from sodium, magnesium, zinc, calcium, potassium, iron, of lithium. Antimicrobial liquid composition according to one of Claims 2 to 10, characterized in that the carboxylic acid salt(s) is or are chosen from sodium, magnesium, zinc, calcium, potassium, iron, or lithium, gluconic acid or succinic acid, and preferably the carboxylic acid salt(s) is or are chosen from sodium gluconate and sodium succinate, and most preferably the carboxylic acid salt is sodium gluconate. Cosmetic product comprising at least one antimicrobial liquid composition according to claims 1 to 11, and at least one preservative chosen from: benzoic acid, sodium benzoate, salicylic acid and its salts, sorbic acid, calcium sorbate, sodium sorbate, potassium, dehydroacetic acid, sodium dehydroacetate, undecylenic acid, calcium undecylenate, potassium undecylenate, sodium undecylenate, phenoxyethanol, 1,2-Dimethylol-5,6-dimethylhydantoin, benzyl alcohol, chlorhexidine, chlorhexidine diacetate, chlorhexidine digluconate , chlorhexidine dihydrochloride, behentrimonium chloride, cetrimonium chloride, cetrimonium bromide, laurtrimonium chloride, laurtrimonium bromide, steartrimonium chloride, steartrimonium bromide, hexamidine, hexamidine diisethionate, chlorphenesin, benzalkonium chloride, benzalkonium bromide, benzalkonium saccharinate, ethyl lauroyl arginate. Cosmetic product according to Claim 12, characterized in that the preservative is chosen from benzoic acid and its salts, sorbic acid and its salts, phenoxyethanol, benzyl alcohol and its salts. Cosmetic product according to Claim 12 or 13, characterized in that the cosmetic product comprises:
- up to 2.5% by gross weight, preferably up to 1.5% by gross weight, more preferably up to 1% by gross weight, preferably up to 0.7% by gross weight, and even more preferably up to 0.6% by gross weight, of said at least one preservative,
- and at least 0.1% by gross weight, preferably at least 0.5% by gross weight, more preferably at least 0.75% by gross weight, preferably at least 1% by gross weight, and even more more preferably at least 1.5% by gross weight, of said at least one antimicrobial liquid composition,
relative to the total weight of the cosmetic product. Cosmetic product according to the preceding claim, characterized in that it comprises a single and single preservative and a single and single antimicrobial liquid composition. Cosmetic product according to one of Claims 12 to 15, characterized in that it is in the form of an oil-in-water emulsion, or of a water-in-oil emulsion, or of an aqueous suspension, or of an aqueous foam, or a true aqueous solution, or a micellar solution, or a hydroalcoholic solution, or a paste, or a gel, or a powder, or a tablet , or a wipe. Use of an antimicrobial liquid composition according to claims 1 to 11 to activate the preservatives of cosmetic products, preferably those chosen from: benzoic acid, sodium benzoate, salicylic acid and its salts, sorbic acid, calcium sorbate, sodium sorbate, potassium sorbate, dehydroacetic acid, sodium dehydroacetate, undecylenic acid, calcium undecylenate, potassium undecylenate, sodium undecylenate, phenoxyethanol, 1,2-Dimethylol-5,6-dimethylhydantoin, benzyl alcohol, chlorhexidine, chlorhexidine diacetate, digluconate chlorhexidine, chlorhexidine dihydrochloride, behentrimonium chloride, cetrimonium chloride, cetrimonium bromide, laurtrimonium chloride, laurtrimonium bromide, steartrimonium chloride, steartrimonium bromide, hexamidine, hexamidine diisethionate, chlorphenesin, benzalkonium chloride, benzalkonium, benzalkonium saccharinate, ethyl lauroyl arginate. Use of an antimicrobial liquid composition according to Claim 17, characterized in that the cosmetic product preservatives are chosen from benzoic acid and its salts, sorbic acid and its salts, phenoxyethanol, benzyl alcohol and its salts.