JP2018145345A - Method for increasing amount of secondary metabolite contained in flowers - Google Patents

Abstract

A method for increasing the amount of secondary metabolites contained in a flower of a dicotyledonous plant is provided.
A dicotyledonous plant is harvested with flowers, leaves and stems, and has blue light having a peak wavelength in a wavelength region of 400 to 500 nm and red light having a peak wavelength in a wavelength region of 600 to 700 nm. A method for increasing the amount of a secondary metabolite contained in a flower of a dicotyledon after harvesting, comprising a step of drying while irradiating any one or more lights.
[Selection figure] None

Description

  The present invention relates to a method for increasing the amount of secondary metabolites contained in a flower, in particular a flower of a dicotyledon after harvesting.

  Secondary metabolites produced by plants are derived from primary metabolites and are widely used as foodstuffs, pharmaceuticals, fragrances (essential oils) and the like. In particular, dicotyledonous flowers are the main organs that accumulate aroma components, and many perfumes (essential oils) are extracted from dicotyledonous flowers. Secondary metabolites contained in essential oils are substances that have been produced in other organs such as leaf blades during reproductive growth, when flowers are formed. It accumulates via. When extracting essential oil from flowers, contaminants derived from leaves, stems, etc. interfere with extraction, and the quality of the essential oil is reduced, so only flowers are collected (harvested) from the plant body and carefully separated. . In some cases, the flowers are dried in advance as a pretreatment for extraction.

It is known that the composition and production amount of secondary metabolites in plants are greatly influenced by plant cultivation conditions, etc., and technology development for obtaining a desired secondary metabolite stably has been conducted. It has been broken. For example, Patent Document 1 discloses that, in hydroponic cultivation of licorice plants, low temperature cultivation is performed before harvesting, and after harvesting, root parts of the licorice plants are collected, stored under specific conditions, and dried. A method for improving the concentration of medicinal components in the root of a genus plant has been reported.
In addition, as techniques for irradiating light in a specific wavelength region during plant cultivation or after harvesting, Patent Documents 2 and 3 include plant cells and plant tissues containing chlorophyll such as Chinese cabbage (green beans) and green broccoli, or chlorophyll. A method for increasing the concentration of ascorbic acid, glutathione, etc. in the plant cell or tissue by irradiating the collected plant cell or plant tissue containing light with a desired wavelength such as red light has been reported. ing. Furthermore, Patent Document 4 cultivates chamomile by irradiating it with light having a photosynthetic photon flux density (PPFD) ratio in the wavelength range of 400 to 515 nm and 570 to 730 nm of 1: 4 to 1: 2, and about 60 after harvesting. A method for enhancing the anti-oxidation effect and the like of a chamomile extract that has been dried by hot air at ℃ has been reported.

JP 2014-233202 A Special table 2007-511202 gazette Special table 2009-524423 JP2015-212232A

However, so far, no method has been reported to increase the accumulation of secondary metabolites in harvested dicotyledonous flowers. If the amount of secondary metabolites contained in the flowers of dicotyledonous plants can be increased, the amount of extraction will also increase, and a stable supply of fragrance (essential oil) is expected.
In view of such circumstances, the present invention intends to provide a method for increasing the amount of secondary metabolites contained in dicotyledonous flowers.

  In view of the above-mentioned problems, the present inventor has intensively studied focusing on the treatment of dicotyledonous flowers, and when extracting essential oil, only the flowers are not harvested and dried as in the prior art. In addition, it was found that the amount of secondary metabolites contained in the flower increased by harvesting the leaves while being connected to the stem without being cut, and performing drying while irradiating with predetermined light.

  That is, the present invention harvests dicotyledonous plants in a state having flowers, leaves and stems, blue light having a peak wavelength in a wavelength region of 400 to 500 nm, and red having a peak wavelength in a wavelength region of 600 to 700 nm. The present invention provides a method for increasing the amount of secondary metabolites contained in a flower of a dicotyledon after harvesting, which comprises a step of drying while irradiating at least one light of light.

  ADVANTAGE OF THE INVENTION According to this invention, the amount of secondary metabolites contained in the dicotyledonous flower after harvest can be increased. Therefore, secondary metabolites useful as perfumes (essential oils) and the like can be stably obtained from dicotyledonous flowers.

  The method of increasing the amount of secondary metabolites contained in dicotyledonous flowers after harvesting according to the present invention is to harvest dicotyledonous plants with flowers, leaves and stems, and peak in the wavelength region of 400 to 500 nm. It is a method including a step of performing drying while irradiating at least one of blue light having a wavelength and red light having a peak wavelength in a wavelength region of 600 to 700 nm.

(Dicotyledonous plant)
Dicotyledonous plants are one of the taxonomic groups of angiosperms and are also called dicotyledons.
The dicotyledonous plants are preferably those of the Asteraceae group in the plant classification system based on APG (Angiosperm Phylogeny Group Angiosperm Lineage Research Group). The Oleaceae group includes, for example, Ilex (Alexaceae, etc.), Escalonia (Aesconiaceae), Asteraceae (Asteraceae, Aedesaceae, etc.), Ceramidae (Aceraceae, Argiaceae) and the like. Among them, plants of the order of Asterales are preferable, and plants of the family Asteraceae are more preferable.
Examples of the Asteraceae plants include, but are not limited to, Sikagiku (german chamomile, etc.), Camomile (roman chamomile, etc.), Gerbera (gerbera, etc.), Chrysanthemum (chrysanthemum), sunflower (sunflower, etc.), Preferred is Matricaria, and more preferred is German chamomile (Matricaria recutita L.).

The cultivation of dicotyledonous plants is not particularly limited, and can be performed by soil cultivation or hydroponics. Hydroponics is preferable because the risk of contamination by microorganisms is low.
Cultivation is preferably performed under conditions where temperature, relative humidity, light, light / dark cycle, carbon dioxide concentration, and the like are controlled. The cultivation conditions can be appropriately set depending on the type of dicotyledonous plant.

After cultivation, harvest with flowers, leaves and stems. Here, harvesting means separation from the plant growth environment. The dicotyledonous plant having flowers, leaves and stems may be in a state where the flowers and leaves are connected to the stems without being cut.
The dicotyledonous plants having flowers, leaves and stems are preferably plant parts obtained by cutting stem portions having roots from dicotyledonous plants at the time of growth. Plant bodies having roots separated from flowers, leaves and stems can be continuously used for regeneration cultivation.
Dicotyledonous plants may be harvested at an appropriate time after flowering. For example, in the case of chamomile, it is preferable that most of the buds attached to one stem are flowered so that the petals are horizontal.

(Drying process)
In the present invention, dicotyledonous plants having flowers, leaves and stems after harvesting are either blue light having a peak wavelength in the wavelength region of 400 to 500 nm and red light having a peak wavelength in the wavelength region of 600 to 700 nm. Drying is performed while irradiating one or more lights. In general, when obtaining perfume (essential oil) from dicotyledonous flowers, only the flowers are harvested from the plant and dried, and the flowers and leaves are connected to the stem without being cut. By harvesting and drying in this state, the amount of secondary metabolites contained in the dried flowers can be increased. The reason for the increase in the amount of secondary metabolites is not clear, but post-harvest light irradiation promotes the production of secondary metabolites in organs other than flowers and their movement through leaves and stems, resulting in accumulation in flowers. It is thought that the amount of secondary metabolites produced increases.
The drying step is preferably performed immediately after harvesting the dicotyledonous plants with flowers, leaves and stems.

(Light irradiation)
The light irradiated to the dicotyledonous plants having flowers, leaves and stems after harvesting is either blue light having a peak wavelength in the wavelength region of 400 to 500 nm or red light having a peak wavelength in the wavelength region of 600 to 700 nm. One or more lights.
Examples of the light source include a laser and a light emitting diode (LED), and a light emitting diode (LED) is preferable. The light source is preferably installed in the upward, obliquely upward, and lateral directions of the plant so that the entire dicotyledonous plant having flowers, leaves, and stems is irradiated with light.

The amount of light is expressed as a photosynthetic effective photon flux density (PPFD). Photosynthetic photon flux density of the irradiation light from the point to promote the metabolism of plants, preferably 50~250μmol m ^-2 s ^-1, more preferably 100~200μmol m ^-2 s ^-1. In addition, when irradiating combining blue light and red light, the total light quantity is meant.

  When irradiating in combination with blue light and red light, the blue: red light amount ratio (PPFD ratio) is preferably 1: 4 to 4: 1, more preferably 1: 3 to 2: 1.

  The irradiation time may be 24 hours a day (24 hours day length) with a period of 24 hours per day, but a light / dark cycle can also be set. When setting a dark period, 4-8 hours are preferable and 6-8 hours are more preferable. From the viewpoint of production of secondary metabolites, the light irradiation time is preferably 16 to 20 hours, more preferably 16 to 18 hours continuously. The light irradiation is preferably performed during the drying step, more preferably continuously for 1 day or more, and more preferably for 2 days or more.

(Drying method)
Examples of the drying method include stationary drying and warm air drying. When performing warm air drying, it is preferable to carry out at 40 degrees C or less from the point which suppresses the fall of the essential oil amount extracted from a dicotyledonous plant, and the fall of quality. The drying method is preferably stationary drying. Here, stationary drying is a method of naturally drying dicotyledonous plants having flowers, leaves, and stems after harvesting, and can be performed by, for example, a shelf dryer.
The drying conditions are preferably a drying temperature of 4 to 35 ° C., more preferably 15 to 25 ° C., preferably a relative humidity of 20 to 80%, more preferably 45 to 60%, and a drying period of 1 to 20 days. It is preferable that the weight of the plant body after drying is 1/5 or less as compared with that immediately after harvesting. Furthermore, from the viewpoint of increasing the amount of secondary metabolites, the carbon dioxide concentration in the drying chamber is preferably 200 to 2000 ppm.

(UV irradiation treatment)
In the present invention, ultraviolet irradiation may be performed prior to irradiating the dicotyledonous plants having flowers, leaves and stems after harvesting with the predetermined light. By performing the ultraviolet irradiation treatment in advance, the amount of secondary metabolites contained in the dried flowers can be further increased.
Ultraviolet rays are classified into A region (UV-A; wavelength 315 to 400 nm), B region (UV-B; wavelength 280 to 315 nm), and C region (UV-C; wavelength 100 to 280 nm) depending on the wavelength. The ultraviolet rays used in the present invention are preferably in the A region (UV-A; wavelength 315 to 400 nm).
For irradiation with ultraviolet rays, a known light source such as a xenon lamp, a xenon-mercury lamp, a metal halide lamp, a high-pressure mercury lamp, a low-pressure mercury lamp, or an LED can be used.
The illuminance of ultraviolet light is preferably 1 to 5 W m ⁻² . The irradiation time is preferably 5 minutes or more and 16 hours or less from the viewpoint of increasing accumulation of secondary metabolites.

In the present invention, the light irradiation is preferably performed such that the integrated energy amount of light is in the range of 0.5 to 55 MJm ⁻² , and more preferably in the range of 1.6 to 50 MJm ⁻² . Here, the cumulative energy amount of light is the amount of the ultraviolet light combined with one or more of the blue light and red light when the ultraviolet irradiation treatment is performed, and when the ultraviolet irradiation treatment is not performed, This is an accumulated energy amount of at least one of the blue light and the red light.

Thus, the amount of secondary metabolites contained in the dicotyledonous flowers after harvest can be increased.
The amount of secondary metabolite contained in the dicotyledonous flower obtained by the method of the present invention is preferably 10% or more, and further increased by 20% or more, compared to the flower obtained by drying under dark conditions without light irradiation. To do.
The secondary metabolite includes an aroma component, although it varies depending on the type of dicotyledonous plant. Examples of aroma components include hydrocarbons, alcohols, phenols, aldehydes, acetals, ketones, ethers, esters, lactones, acids, furans, pyrans, nitrogen-containing compounds, sulfur-containing compounds And heterocyclic compounds. Of these, hydrocarbons are preferable, and monoterpenes and sesquiterpenes are more preferable.
Taking chamomile as an example, the secondary metabolites are (-)-α-bisabolol and its oxide, bisabolol oxide (“Camomile Encyclopedia-Efficacy as Herb, Research and Development to Industry Application” There are monocyclic sesquiterpenoids such as Fragrance Journal, 2007, p.80), matricin, and sesquiterpenoid derivatives such as camazulene, which are decomposition products thereof.

  Extraction of secondary metabolites from dicotyledonous flowers after drying can be performed by a known extraction method such as steam distillation or solvent extraction after fractionating the flowers from the leaves and stems.

Test example Chamomile cultivation test [test method]
Test area 1-4
A plastic tray with a tissue soaked in water was prepared, and dried seeds of German chamomile (Matricaria recutita L.) were sown on the tissue. The tray was wrapped with a plastic film so that the water did not evaporate, and stored in a cultivation room at a temperature of 23 ± 2 ° C. for 1 week. Seedlings that germinate from about 3 days after seeding and have been stored for one week and have the same root length are placed one by one in a urethane medium for hydroponics (size: 3 cm x 3 cm x 3 cm cube shape). After transplanting and transplanting under the following environmental conditions, seedlings were raised in a cultivation room for about 3 weeks.
<Seedling environmental conditions>
Light source: Daylight white fluorescent lamp (Panasonic FHF32EX-N-H)
Light quantity (photosynthetic photon flux density PPFD): 100 ± 10 μmolm ⁻² s ⁻¹
Light / dark cycle: 16 hours / 8 hours Cultivation solution: OAT house A prescription (OAT house 1 and 2 mixed in 3: 2)
Electrical conductivity (EC) of hydroponic liquid: 1.0 ± 0.5 dS m ⁻¹
PH of hydroponic solution: 6.0 ± 0.5

From the seedlings that have been nurtured, those having a uniform growth state (plant height of about 0.5 to 2 cm) are selected and further transplanted to a thin-film hydroponic cultivation apparatus with LED illumination, and the following cultivation environment conditions are set to 12 to 15 Growing weekly.
<Cultivation environmental conditions>
Light source: Warm white fluorescent lamp (HITACHI FHF32EX-WW-J)
Light quantity (photosynthetic photon flux density: PPFD): 150 ± 10 μmol m ⁻² s ⁻¹
Light / dark cycle: 16 hours / 8 hours Cultivation room temperature: 23 ± 2 ° C
Cultivation room relative humidity: 65 ± 10%
Cultivation chamber carbon dioxide concentration: lower limit 1000ppm
Cultivation solution: OAT House A prescription (OAT House No. 1 and No. 2 mixed at 3: 2)
Electrical conductivity (EC) of hydroponic liquid: 1.5 ± 0.5 dS m ⁻¹
PH of hydroponic solution: 6.0 ± 0.5

German chamomile seedlings that are approximately the same height, 7 to 14 days after flowering, and have petals leveled and almost in full bloom, with stems and flowers and leaves attached to the stems The sample was cut at a height of 30 cm from the upper surface. Immediately after collection, German Chamomile with flowers, leaves and stems is subjected to light irradiation under the following conditions in Test Zones 2 to 4 for 14 days continuously against Test Zone 1 which was allowed to stand and dry for 14 days under dark conditions. While standing, drying was carried out in the cultivation room. LEDs (Showa Denko Aluminum Sales Co., Ltd.) were used as blue and red light sources.
<Light irradiation treatment conditions>
Cultivation room temperature: 23 ± 2 ° C
Cultivation room relative humidity: 65 ± 10%
Cultivation chamber carbon dioxide concentration: lower limit 1000ppm
Light quantity (photosynthetic photon flux density PPFD): 150 ± 10 μmol m ⁻² s ⁻¹
Light source and irradiation time: Table 1 below

Test area 5-9
German chamomile (Matricaria recutita L.) was cultivated in the same manner as in the above test groups 1 to 4.
For German chamomile with flowers, leaves, and stems just collected in the same growth and flowering state as in Test Zones 1 to 4, static drying was performed in the cultivation room while performing light irradiation under the following conditions for 14 days continuously. It was. With test group 5 as a reference, test groups 6 and 7 were irradiated with UV-A for 5 minutes or 30 minutes as a pretreatment, and then irradiated with red light in the same manner as test group 5. The illuminance of ultraviolet light was 3 W / m ² .

In addition, as test plots 8 and 9, German chamomile in the same growth and flowering state as in test plots 1 to 7 was collected by cutting only flower parts from seedlings having almost the same height, and 14 under dark conditions. Drying was carried out by standing still for days (test group 8), or by performing blue light irradiation under the following conditions for 14 days immediately after harvesting (test group 9).
<Light irradiation treatment conditions>
Cultivation room temperature: 23 ± 2 ° C
Cultivation room relative humidity: 65 ± 10%
Cultivation chamber carbon dioxide concentration: lower limit 1000ppm
Light quantity (photosynthetic photon flux density PPFD): 150 ± 10 μmol m ⁻² s ⁻¹
Light source and irradiation time: Table 2 or 3 below

  The dried stems of German chamomile were green in Test Zone 1 stored under dark conditions, whereas those irradiated with blue light turned white and those irradiated with red light became wheat-colored. It was discolored.

[Extraction of secondary metabolites]
The flowers in test groups 1 to 9 were separated and solvent extraction was performed from the flowers. As an extraction solvent, 15 [mL / g-flower dry mass] of n-hexane was used, and immersion extraction was performed at room temperature for 3 days.
After extraction, it was filtered with a membrane filter (Millex (registered trademark) -GV 0.22 μm; manufactured by Millipore), and components contained in the obtained extract were subjected to gas chromatograph mass spectrometry under the following conditions.
<Gas chromatographic analysis conditions>
GC system: Agilent 6890N (Agilent Technologies)
Analysis column: DB-1; 60.0 m × 250 μm id × 0.25 μm
Carrier gas: helium Column head pressure: 116.5 kPa, linear velocity: 1.1 mL / min
Analysis column heating program: Initial: 40 ° C. (2 min hold) → 6 ° C./min→60° C. → 2 ° C./min→300° C. (30 min hold)
Analytical sample injection volume: 2 μL (splitless)
Mass spectrometer: Agilent 5975B GC / MSD (Agilent Technologies)

  Tables 4 to 6 show the amount of secondary metabolite (average value ± standard error) and the rate of increase of the amount of secondary metabolite (when test zone 1, 5 or 8 is used as a reference) by GC analysis.

As is clear from Table 4, the flowers in the test groups 2 to 4 which were dried while being irradiated with blue light, red light or a mixed light thereof were secondary compared to the test group 1 dried in the dark condition. The amount of accumulated metabolite was increasing. Moreover, from Table 5, in the test groups 6 and 7 in which UV-A pretreatment was irradiated for 5 minutes or 30 minutes before irradiation with red light, secondary metabolism was compared with test group 5 in which only red light was irradiated. The amount of accumulated substances was increasing.
On the other hand, as apparent from Table 6, the test group 9 in which only the flower part was harvested and dried while irradiating with blue light had the same amount of α-bisabolol as the test group 8 dried in the dark condition. There was no increase in the accumulation of secondary metabolites.
From these results, the secondary metabolite contained in the flower increases when it is dried while irradiating it with flowers and leaves on the stem, but it is secondary only by cutting the flower and irradiating it with light. Metabolites were confirmed not to increase.

Claims (8)

  Dicotyledonous plants are harvested in a state having flowers, leaves and stems, and any one or more of blue light having a peak wavelength in the wavelength region of 400 to 500 nm and red light having a peak wavelength in the wavelength region of 600 to 700 nm A method for increasing the amount of secondary metabolites contained in the flowers of dicotyledonous plants after harvesting, comprising a step of drying while irradiating the light. The method for increasing the amount of secondary metabolites contained in a dicotyledonous flower after harvesting according to claim ¹ , wherein the photosynthesis effective photon flux density of the irradiated light is 50 to 250 μmol m ⁻² s ⁻¹ .   The secondary metabolite contained in the flower of the dicotyledon after harvesting according to claim 1 or 2, wherein the light irradiation time is 16 to 20 hours as 24 hours a day, and irradiation is continuously performed for 2 days or more. How to increase the amount.   Including a step of performing ultraviolet irradiation treatment before irradiating at least one of blue light having a peak wavelength in a wavelength region of 400 to 500 nm and red light having a peak wavelength in a wavelength region of 600 to 700 nm. The method of increasing the amount of secondary metabolites contained in the flower of the dicotyledon after harvesting of any one of Claims 1-3.   The method for increasing the amount of secondary metabolites contained in the dicotyledonous flowers after harvesting according to claim 4, wherein the ultraviolet rays are UV-A, and the irradiation time of UV-A is 5 minutes or more and 16 hours or less. 6. The method for increasing the amount of secondary metabolites contained in a flower of a dicotyledon after harvesting according to any one of claims 1 to 5, wherein the integrated energy amount of the irradiated light is 0.5 to 55 MJm- ² .   The method for increasing the amount of secondary metabolites contained in a flower of a dicotyledon after harvesting according to any one of claims 1 to 6, wherein the dicotyledonous plant is a member of the family Asteraceae.   The method for increasing the amount of secondary metabolites contained in a dicotyledonous flower according to any one of claims 1 to 6, wherein the dicotyledonous plant is chamomile.