JPH05310776A - New flavonoids - Google Patents

Abstract

(57) [Abstract] [Purpose] It is an object of the present invention to provide flavonoids which are excellent in solubility and physiological activity and which are useful as a substance for expressing a plant growth promoting activity. [Structure] [Chemical 1] A new flavonoid represented by.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to flavonoids which are effective as a substance for expressing a plant growth promoting activity.

[0002]

BACKGROUND OF THE INVENTION Citrus peel contains flavanone glycosides mainly containing hesperidin and naringin, which are known to be pharmacologically active ingredients for stomach, antitussive, and inflammation. Hesperidin is also an active ingredient of vitamin P and is expected to have a wide range of uses. One of them is its use as a plant activator based on its antioxidant properties.

[0003]

However, since these flavonoids are glycosides and are poorly soluble in water, their use is limited and their activity is not sufficiently exerted. Therefore, it is necessary to improve the solubility without significantly changing the characteristics of flavonoids.

In view of such circumstances, an object of the present invention is to provide flavonoids useful as a plant growth promoting activity-expressing substance which is excellent in solubility and physiological activity.

[0005]

In order to achieve such an object, the novel flavonoids according to the present invention are represented by the formula 1 as described above.

[0006]

According to the above constitution, the glucose rhamnose group of hesperidin or naringin is substituted with two or more glucose groups, and the solubility is improved. Moreover, since it has a flavonoid skeleton, it has excellent physiological activity. The hesperetin glycosyltransferase, which is one of the flavonoids according to the present invention, is obtained by allowing hesperinase to act on hesperidin to give hesperetin-7 as shown in FIG.
-After producing glucoside, this hesperetin-7
-It can be obtained by allowing glucosyltransferase to act on glucoside. As shown in FIG. 2, the naringenin glycosyltransferase can be obtained by causing naringinase to act on naringin to produce naringenin monoglucoside, and then acting glucosyltransferase on the naringenin monoglucoside.

[0007]

EXAMPLES The present invention will be described in detail below with reference to its examples. (Example 1) 1 g of hesperidin isolated from citrus peel was suspended in 1 l of distilled water, 5 g of dextrin was added thereto, and hesperidin was dissolved in the autoclave for 10 minutes. Thereafter, the pH was adjusted to 4.5, and commercially available hesperidinase (Tanabe No. 2) was added and reacted at 60 ° C. for 10 hours to produce hesperetin-7-glucoside.
In addition, TLC (silica gel, developing agent:
Chloroform, methanol, water = 6: 6: 1, vanillin-hydrochloric acid reagent).

Since hesperetin (non-glycoside) and unreacted hesperidin are present in the reaction product, they were separated from each other by partitioning with ethyl acetate. And 300 ml of the obtained hesperetin-7-glucoside 250 mg
Suspended in water and added with 10 g of dextrin to homogenize them, and then add glucosyltransferase induced by Bacillus mase-rans IFO 3490 to adjust pH.
Hesperetin-7 was reacted for 12 hours at 6.0 and 45 ° C.
-The sugar of dextrin (glucose residue) was transferred to the sugar residue of glucoside to obtain a hesperetin glycosylated form. Example 2 A naringenin glycosyltransferase was obtained in the same manner as above by once converting it into purinine of monoglucoside by commercial naringinase (Tanabe) and then polysaccharifying with glycosyltransferase.

Since the transfer reaction solution contains proteins derived from the enzyme solution, amino acids and sugars such as dextrin, the synthetic adsorption resin Amberlite XA is used to remove them.
Purified using D-4. That is, the reaction solution is added to a column packed with this resin, the flavonoid glycoside is adsorbed on the resin, and then distilled water is developed to elute unreacted substances, and then adsorbed with 40% ethanol. The flavonoids were eluted and purified. Then, the eluent was concentrated under reduced pressure to form a syrup, and then powdered by a freeze dryer.

In the reaction product thus obtained, it was confirmed that about 2 to 6 glucose residues were rearranged and bonded (mainly about 2 to 3). Further, since the transferred component was positive for the vanillin-hydrochloric acid reagent, the presence of the flavonoid skeleton was confirmed in the transferred component. Furthermore, in order to confirm the structure of the sugar transfer component, the main component was isolated by column chromatography on silica gel (Wakogel C-300) (developing agent: chloroform-methanol system), and the separation component was identified by UV and UV. According to NMR, hesperetin and naringenin
^From the fact that it closely resembles the analysis value of flavonoid carbon in the ¹³ C-NMR spectrum and the number of appearance of sugar-carbon,
It was identified as hesperetin-7-maltotrioside and naringenin-7-maltotrioside. The sugar-binding site in each of the sugar-carbon (GC) GC-
4 and GC-4 'were shifted to a lower magnetic field as compared to GC-4 ", it was determined to be α-1,4-bond.

Both hesperidin and naringin have low solubility in water, which is an obstacle to practical use.
Further, from the aspect of activity evaluation, problems such as uptake into plants occur, but both the hesperetin glycotransfer and the naringenin glycotransfer obtained in Example 1 and Example 2 are 2
It was sufficiently dissolved in water even at a concentration of 000 ppm. Next, the results of the activity tests of the hesperetin glycosyltransferase and the naringenin glycosyltransferase obtained in Examples 1 and 2 will be described in detail with reference to Tables 1 to 3.

Table 1 shows the results of testing the effect of hesperetin glycosyltransferase on the growth of lettuce seedlings in comparison with the effects of hesperetin and hesperidin.
Numerical values are shown by the growth rate (%) with respect to the target plot (no additive plot).

[0013]

[Table 1]

As shown in Table 1, hesperidin promotes the elongation of the hypocotyl of lettuce seedlings and inhibits the elongation of radicles. , The activity was constantly promoted, and not only the hypocotyl length but also the cotyledon length was significantly promoted.
It can be seen that it shows an increase in fresh weight of%.

Table 2 shows the results of testing the effect of hesperetin glycosyltransferase on the growth of white clover seedlings in comparison with the effects of hesperetin and hesperidin.

[0016]

[Table 2]

The activity against white clover shows a tendency similar to that of lettuce, and as shown in Table 2, the hesperetin glycosyltransferase constantly promotes elongation to cotyledons, hypocotyls and radicles, and the 1000 ppm treatment group. Showed 81% increase in live weight. Table 3 shows the results of foliar treatment tests on the effects of hesperetin and naringenin and their glycosyl transferants on the growth of radish radish.

[0018]

[Table 3]

With respect to the foliar treatment of radish radish, as shown in Table 3, both the hesperetin glycotransfer and the naringenin glycotransfer showed an increase in the live weight of the roots. Particularly, the hesperetin glycosyltransferase showed an increase of 69% in the 500 ppm treatment group. In the seedling test, 10 seeds of lettuce and white clover seeds that had been germinated in advance were placed on a filter paper having a diameter of 5 cm, 2 ml of an appropriately adjusted test solution was added, and the mixture was cultured at 23 ° C. and 5000 lux for 7 days. The growth degree was measured. Also, in the case of radish of 20 days, it was sown directly in a pot with a diameter of 10 cm, and 3 individuals that were homogenized germinated were left. The first treatment was performed 10 days after germination, and then twice at 7-day intervals. The activity was evaluated by measuring the growth state 7 days after the final treatment. The growth conditions are 25 ° C and a glass room under natural light. The soil uses only vermiculite to reliably detect the effects of the active ingredients, and one of commercial liquid fertilizers (hyponex) is used to maintain the minimum growth.
A 000-fold aqueous solution was given every 10 days.

The results of investigations on the solubility of the hesperetin glycosylated form and the naringenin glycosylated form in water are shown in Table 4 in comparison with the solubility of hesperidin, hesperetin, naringin and naringenin.

[0021]

[Table 4]

As shown in Table 4, the hesperetin glycosyltransferase and the naringenin glycosyltransferase show superior solubility to hesperidin, hesperetin, naringin and naringenin.

[0023]

The novel flavonoids according to the present invention are
The solubility in water is improved as compared with hesperidin and naringin, and as a result, the incorporation of a sufficient amount of a component for expressing the growth promoting activity of plants can be easily progressed. Therefore, in a wide range of high concentration to low concentration treatment area,
It can promote early growth after germination.

[Brief description of drawings]

FIG. 1 is an explanatory view illustrating a process of synthesizing hesperetin glycosyl transfer compound, which is one of the growth promoting activity-expressing substances according to the present invention, from hesperidin.

FIG. 2 is an explanatory view illustrating a process of synthesizing a naringenin glycosyltransferase, which is one of the growth promoting activity-expressing substances according to the present invention, from naringin.

Claims (1)

[Claims] 1. Formula (1): A new flavonoid represented by.