JP2017149732A - Solution of plant extract containing piceatannol, and stabilization method of piceatannol comprised in solution thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide solutions of extract of plants, such as passion fruits, Rhodomyrtus tomentosa, and Callistemon speciosus; to provide stabilization methods of piceatannol which is included in the solution of the plant extract, has melanin generation inhibition, ultraviolet ray damage restorative effect, and MMP inhibiting action and the like, and is represented by the following left formula; and to provide methods of reducing scirpusin B (a dimer of piceatannol) included in the solutions of the plant extracts.SOLUTION: Disclosed is a method comprising blocking a solution of a plant extract from a gas containing oxygen. Preferably, the stabilization method further comprises blocking the solution from light.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a solution of a plant extract containing piceatannol and a method for stabilizing piceatannol contained in the solution.

Passion fruit is a fruit of the Passiflora family Passiflora. Passion fruit seed extract has the effect of suppressing the formation of melanin that causes pigmentation due to spots, buckwheat, sunburn, etc., and the active ingredient of this inhibitory effect is Piceatan contained in the seed extract of passion fruit It is reported to be a knoll (see Patent Document 1).
Tenninka is an evergreen shrub belonging to the genus Rhodomyrtus. Tenninka extract has a UV damage recovery effect, and it has been reported that the active ingredient of this recovery effect is piceatannol contained in the Tenninka extract (see Patent Document 2).
Brassica is an evergreen tree of the genus Callistemon. The extract of Callistemon rigidus has been shown to have an inhibitory action on MMP-2, and one of the active ingredients of this inhibitory action is piceatannol contained in the extract of the callaemon Has been reported (see Non-Patent Document 1).

JP 2009-102298 A JP 2012-46448 A

Takeo Sasaki et al., Tohoku Pharmaceutical University, 57, 61-65 (2010)

  An object of this invention is to provide the solution of the plant extract containing piceatannol, and the stabilization method of piceatannol contained in the solution.

The present inventors have found that by preventing the passion fruit seed extract solution from coming into contact with air, the piceatannol in the solution is converted into another compound and can be prevented from decaying. Further, in this case, it is generally assumed that the monomer exhibits the same behavior as that of the piceatannol. The dimer, skillpsin B, differs from the behavior of piceatannol. We found that it was converted to another compound more rapidly. The present invention has been completed based on these findings.

  The solution of the plant extract containing piceatannol according to the present invention is shielded from gas containing oxygen.

  It is preferable that the plant seed extract solution is further shielded from light.

The solvent of the solution is preferably water, ethanol, 1,3-butylene glycol, or a mixed solvent of two or more solvents selected from these.
The extract is preferably extracted from plant seeds using water, ethanol, 1,3-butylene glycol, or a mixed solvent of two or more solvents selected from these.

  The solution of the plant extract containing piceatannol contained in an airtight container according to the present invention has an oxygen barrier property, and there is no air layer made of a gas containing oxygen in the container. .

  It is preferable that the container further has a light shielding property. The container is preferably a composite paper container.

The solvent of the solution is preferably water, ethanol, 1,3-butylene glycol, or a mixed solvent of two or more solvents selected from these.
The extract is preferably extracted from a plant using water, ethanol, 1,3-butylene glycol, or a mixed solvent of two or more solvents selected from these as a solvent.

The method for stabilizing piceatannol contained in a solution of a plant extract according to the present invention includes a step of blocking the solution from a gas containing oxygen.
Moreover, the method of reducing the skillpsin B contained in the solution of the plant extract while stabilizing piceatannol contained in the solution of the plant extract according to the present invention, shuts off the solution from a gas containing oxygen. The process of carrying out is included.

  These methods preferably further comprise the step of shielding the solution from light.

  Any of the above plant extracts is preferably a passion fruit seed extract, a tenninka extract, or a brassica extract.

  According to the present invention, it is possible to provide a solution of a plant extract and a method for stabilizing piceatannol contained in the solution of the plant extract.

It is a graph which shows the change of the residual rate in case the container is a sampling tube based on one Embodiment of this invention. It is a graph which shows the change of the residual rate in case the container is a composite paper container based on one Embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described in detail with reference to examples. The objects, features, advantages, and ideas of the present invention will be apparent to those skilled in the art from the description of the present specification, and those skilled in the art can easily reproduce the present invention from the description of the present specification. it can. The embodiments and specific examples of the invention described below show preferred embodiments of the present invention, and are shown for illustration or explanation. It is not limited. It will be apparent to those skilled in the art that various modifications and variations can be made based on the description of the present specification within the spirit and scope of the present invention disclosed herein.

== Solution of plant extract, shielded from oxygen-containing gas ==
One embodiment of the invention is a solution of a plant extract containing piceatannol that is shielded from oxygen containing gases.
By making the plant extract solution containing piceatannol into such a configuration, the piceatannol contained in the extract solution is prevented from being converted into another compound and its stability is improved. Can be made. For this reason, the solution of the plant extract containing piceatannol can be stored for a long period of time while keeping piceatannol at a high concentration.
Further, by adopting such a configuration, it is possible to reduce Spicepsin B, which is a dimer of piceatannol, while suppressing the conversion of piceatannol into another compound. In a plant extract solution containing knoll and skillpsin B, skillpsin B that causes bitterness and color variation can be reduced while keeping piceatannol at a high concentration.

The gas containing oxygen is not particularly limited, but may be, for example, air or oxygen itself, and is preferably air. The state where the solution is shielded from the oxygen-containing gas may be any state as long as the surface of the solution is not in contact with the oxygen-containing gas. For example, the oxygen-containing gas is present in the solution. Even in the dissolved state, if the surface of the solution is not in contact with the oxygen-containing gas, it is said to be “cut off from the oxygen-containing gas”.
A method for bringing the target solution into a state in which the solution is blocked from a gas containing oxygen is not particularly limited, and a known method can be used. For example, the surface of the solution may be a gas not containing oxygen. May be contacted with a liquid that does not mix with the solution, or may be contacted with a solid that does not substantially permeate a gas containing oxygen (hereinafter also referred to as “having oxygen barrier properties”). Alternatively, or a combination thereof, the solution may be shielded from a gas containing oxygen. It should be noted that “blocking” a solution from an oxygen-containing gas means substantially or effectively blocking, that is, blocking a large part of the surface area of the solution from the oxygen-containing gas. 70% or more, preferably 80% or more, more preferably 90% or more, further preferably 95% or more, particularly preferably 98% or more, 100% % Is most preferred.
The gas not containing oxygen is not particularly limited, and examples thereof include nitrogen, carbon dioxide, argon, or a mixed gas of two or more gases selected from these. Although the liquid which does not mix with a solution changes with kinds of solvent of the solution of a plant extract, those skilled in the art can set such a liquid suitably. The solid having an oxygen barrier property is not particularly limited. For example, a metal such as aluminum, iron, stainless steel, or copper, glass, a resin having an oxygen barrier property such as Soarnol (registered trademark), or a GL film (registered trademark). Or a composite paper container coated with any one or more of such solids, or having one or more of such solids sandwiched therein, A composite resin container may be used.

  Although the solution of the plant extract which concerns on this embodiment is interrupted | blocked from the gas containing oxygen as mentioned above, it is preferable that it is further light-shielded. The method for shielding the solution from light is not particularly limited, and a known method can be used. However, the plant extract solution may be covered with a material that does not substantially transmit light, for example, paper coated with light shielding ink. May be covered with a resin or cloth, or a metal such as aluminum, iron, stainless steel or copper, or coated with any one or more of these, or a composite with any one or more of them sandwiched inside It may be covered with a paper container or a composite resin container.

The method for shielding the plant extract from the oxygen-containing gas and shielding it is not particularly limited, and a known method can be used. For example, the plant extract solution is shielded from the oxygen-containing gas. This method may be performed by combining the method of making it light-shielded and the method of making it light-shielded. As an example of this, a metallic container, composite paper container or composite resin having oxygen barrier properties and light-shielding properties. The container may be sealed after filling the container with a solution so that a gas layer composed of a gas containing oxygen is hardly or completely left in the container.
A person having ordinary skill in the art can appropriately select a container having an oxygen barrier property and a light-shielding property. Examples of such composite paper containers include the inside (solution side) to the outside (outside air side) of the container. Resin-paper-resin-metal (having oxygen barrier property and light shielding property) -resin, resin-metal (having oxygen barrier property and light shielding property) -resin-paper-resin or resin- A container having a multilayer structure of ceramic (having oxygen barrier property) -light-shielding ink (having light-shielding property) -resin-paper-resin may be used, but is not limited thereto. The resin used in the multilayer structure may not have an oxygen barrier property and / or a light shielding property, and such a resin can be appropriately selected by those skilled in the art. , Polypropylene, or PET. The shape of the composite paper container or the composite resin container is not particularly limited, and may be, for example, a cylindrical container, a cup container, a roof carton, a brick carton, or a triangular pyramid carton.

The plant extract used in the present invention contains a component extracted from a plant, preferably contains piceatannol as at least a part of this component, and preferably contains skillpsin B. If it is a plant extract containing the skillpsin B, this invention will become more effective from the difference in the decay rate of the piceatannol and the skillpsin B as mentioned above. The form of the plant extract is not particularly limited, and may be, for example, a solid form such as powder, an amorphous form, or an oil form, but the solvent used for the extraction is substantially removed.
The kind of plant for obtaining the plant extract is not particularly limited as long as it contains a piceatannol, and passion fruit (for example, Passiflora edulis, Passiflora alata, Passiflora amethystine, Passiflora antioquiensis, Passiflora biflora, Passiflora buonapartea, Passiflora) capsularis, Passiflora cearensis, Passiflora coccinea, Passiflora cochinchinesis, Passiflora filamentosa, Passiflora herbertiana, Passiflora laurifolia, Passiflora ligularis, Passiflora lunata, Passiflora lutea, Passiflora maliformis, Passiflora mixtaPassiflora mixta Passiflora parahypensis, Passiflora pedeta, Passiflora pinnatistipula, Passiflora popenovii, Passiflora quadrangularis, Passiflora riparia, Passiflora rubra, Passiflora serrate, Passiflora tiliaefolia, Passiflora tripartite, Passiflora villosa, Passiflora villosa, etc. , Tennin (eg, Rhodomyrtus tomentosa), brushwood (eg, Callistemon rigidus) (eg, stem), Caragana tibetica (eg, stem), Fallopia japonica (eg, root), peanut (Arachis hypogaea), grape (Vitaceae) (e.g. fruit), blueberry (Cyanococcus) (e.g. fruit), diaberry (Vaccinium stamineum) (e.g. fruit) and the like, for example, it is known to contain piceatannol in a high concentration, Passion fruit, tenninka or brushwood are preferred. In the case of a tenninka, it may be any part of the whole plant, for example, a fruit, a flower, a seed, a leaf, a branch, a bark, a trunk, a stem, or a root, Preferably there is. Moreover, it is more preferable if it is a plant containing Skillpsin B.
As a specific method for producing a plant extract, a known method can be used. For example, after crushing, crushing, or cutting a plant, an extract is obtained by extraction with a solvent, and further, The plant extract may be produced by distilling off the solvent from the extract.
The type of the solvent used for extraction can be appropriately selected by those skilled in the art. For example, water, methanol, ethanol, acetone, ethyl acetate, glycerin, propylene glycol, dipropylene glycol, 1,3-butylene glycol , Dimethyl sulfoxide, acetonitrile, N, N-dimethylformamide, 2-propanol, 1,4-dioxane, hexane, chloroform, cyclomethane, or a mixed solvent of two or more solvents selected from these, Water, ethanol, 1,3-butylene glycol, or a mixed solvent of two or more solvents selected from these is preferable, and water, ethanol, or a mixed solvent of water and ethanol is more preferable. When using a mixed solvent, the mixing ratio of each solvent is not particularly limited. For example, when using a mixed solvent of water and ethanol, the volume ratio of water to ethanol is 1:99 to 99: 1. The ratio is preferably 3:97 to 80:20, more preferably 5:95 to 50:50, and particularly preferably 10:90 to 40:60.
When water or a mixed solvent with water is used as the solvent, it is preferably hot water or a mixed solvent with hot water. Water or a mixed solvent with water may be a buffer containing a salt (buffer solution). The pH of the buffer is not particularly limited, and may be acidic, neutral, or alkaline, but is preferably acidic, more preferably acidic at pH 6 or lower, and acidic from pH 1 to pH 5. More preferably. The kind of salt used for the buffer is not particularly limited, and examples thereof include citrate, malate, phosphate, acetate, and carbonate.
The method for distilling off the solvent from the extract is not particularly limited, and a known method can be used. For example, vacuum distillation, freeze drying, or spray drying (spray drying) may be used, but freeze drying or spray drying is preferable, and spray drying is more preferable.
The shape of the plant extract is not particularly limited, and may be, for example, a solid form such as powder, an amorphous form, or an oil form, but the solvent used for the extraction is substantially removed.

The method for producing the solution of the plant extract is not particularly limited, and a known method can be used. For example, it may be produced by diluting the plant extract, or at least a part of the plant extract. You may manufacture by melt | dissolving with a solvent. Alternatively, the extract obtained in the process of producing the plant extract may be used as it is as a solution of the plant extract, or the extract obtained by diluting, concentrating, or concentrating and diluting the extract It may be used as a solution. Thus, the shape of the plant extract solution is not particularly limited as long as it substantially contains the plant extract and the solvent, for example, a clear solution, a solution (suspension) in which turbidity or precipitation occurs, or In this specification, even if it is a slurry form, it shall be contained in the solution of a plant extract.
The solvent for dissolving or diluting the plant extract or the type of solvent used for diluting the extract is not particularly limited. For example, water, methanol, ethanol, acetone, ethyl acetate, glycerin, propylene glycol, dipropylene Glycol, 1,3-butylene glycol, dimethyl sulfoxide, acetonitrile, N, N-dimethylformamide, 2-propanol, 1,4-dioxane, hexane, chloroform, cyclomethane, or two or more solvents selected from these It may be a mixed solvent, and is preferably water, ethanol, 1,3-butylene glycol, or a mixed solvent of two or more solvents selected from these, water, ethanol, or a mixture of water and ethanol More preferably, it is a solvent. When using a mixed solvent, the mixing ratio of each solvent is not particularly limited. Water or a mixed solvent with water may be a buffer containing a salt (buffer solution). The pH of the buffer is not particularly limited, and may be acidic, neutral, or alkaline, but is preferably acidic, more preferably acidic at pH 6 or lower, and acidic from pH 1 to pH 5. More preferably. The kind of salt used for the buffer is not particularly limited, and examples thereof include citrate, malate, phosphate, acetate, and carbonate.
The shape of the plant extract solution may be a solution (suspension) in which turbidity or precipitation occurs as described above. In this case, the precipitation or turbidity is, for example, filtered or centrifuged. Alternatively, it is preferably removed by a method such as decantation.
Moreover, the solution of a plant extract may contain the component extracted from plants other than piceatannol.
The solution of the plant extract may contain substances other than the plant extract as long as the stability of the contained piceatannol is not significantly impaired. For example, it is preferable that the solution of the plant extract does not contain viruses or living cells. When the plant is passion fruit, the plant extract solution may or may not contain the passion fruit pulp extract, but is preferably substantially free.
In addition to the piceatannol extracted from the plant from which the plant extract is derived, piceatannol separately extracted or synthesized may be added to the plant extract solution.

Although the usage method of the solution of the plant extract which concerns on this embodiment is not specifically limited, Since the solution contains piceatannol at a high concentration for a long period of time, the solution of piceatannol can be efficiently stored. Can do. The solution contains piceatannol at a high concentration for a long time, while the amount of skillpsin B decreases significantly with the passage of time. Therefore, bitterness and color variation caused by skillpsin B The solution of piceatannol can be stored efficiently while reducing
For this reason, these solutions can be used for foods, cosmetics, medicines, quasi-drugs, reagents, and the like for humans and non-human animals and their cells.
In addition, when using these solutions, the solutions may be further concentrated and diluted and / or semi-solid or solid such as jelly, pudding or cream. A person skilled in the art can appropriately determine the shape to be used.

== Method for stabilizing piceatannol contained in a solution of a plant extract ==
A method for stabilizing piceatannol contained in a solution of a plant extract according to an embodiment of the present invention includes the step of blocking the solution of the plant extract from a gas containing oxygen. Further, according to another embodiment of the present invention, a method for reducing skillpsin B while stabilizing piceatannol contained in a solution of a plant extract, the solution of the plant extract from a gas containing oxygen Including a step of blocking.
By setting it as such a structure, it can suppress that piceatannol contained in the solution of a plant extract is converted into another compound, and can improve the stability. Furthermore, while suppressing the conversion of piceatannol to another compound, it is possible to reduce the skillepsin B which is a dimer of piceatannol. Thereby, the solution of a plant extract which contains piceatannol at a high concentration but contains only skimpsin B at a low concentration can be easily produced.

The gas containing oxygen is not particularly limited, but may be air. The stabilization method preferably further includes a step of blocking the solution from light.
The method for realizing the stabilization method according to the present invention is not particularly limited. For example, the stabilization method according to the present invention is performed with reference to the above-mentioned column of “solution of plant extract shielded from oxygen-containing gas”. Can do.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further more concretely, the following Example is not described in order to limit the scope of the present invention.

Passion fruit (Passiflora edulis) seeds were crushed and extracted with hydrous ethanol (water: ethanol = 20: 80 (v / v)). The aqueous ethanol extract solution was concentrated to an appropriate amount and then spray dried to obtain a passion fruit seed extract as a powder. When the composition of the obtained extract was examined, it contained Piceatannol and Skillpsin B in a weight ratio of about 5: 1. The extract was dissolved in water at room temperature to obtain a 0.5% by weight aqueous solution of passion fruit seed extract.
Using this extract aqueous solution, the influence of the presence of air on piceatannol and skimpsin B was examined.

1 mL of the aqueous extract solution was added to an air-permeable 2 mL sampling tube BM20 (manufactured by BM Equipment Co., Ltd., material: polypropylene). Similarly, the aqueous extract solution is a composite paper container (manufactured by Morinaga Seika Co., Ltd., material: polyethylene-paper-polyethylene-aluminum foil-polyethylene in order from the inside to the outside). After filling the container so that no air layer remains inside, the container was sealed by crimping the opening to block intrusion of air from the outside.
That is, when the container was a sampling tube, the passion fruit seed extract solution was in contact with air, and when the container was a composite paper container, the solution was shielded from air.

  Two containers containing these aqueous extract solutions were warmed in a 50 ° C. incubator for 84 days. For the case where the container is a sampling tube, the amount of piceatannol and the amount of skillpsin B in the aqueous solution are as follows immediately before starting heating, and after 12 days, 14 days, and 18 days from the start of heating. Was measured by HPLC under the following conditions.

[HPLC conditions]
・ Column: Mightysil RP-18 GP250-10 Diameter 10 mm, Length 250 mm (Kanto Chemical Co., Ltd.)
・ Column temperature: 40 ℃
・ Elution conditions: Flow rate 3mL / min, 0% methanol 100% pure water → 30% methanol-70% pure water (gradient, 10 min)
・ UV detection: 280 nm

  In the case of the composite paper container, immediately before starting heating, and after 12 days, 20 days, 28 days, 32 days, 40 days, 47 days, 56 days, 56 days, 74 days, and 84 days after the start of heating, The aqueous solution was sampled so that air did not enter the container, and the amount of piceatannol and the amount of skillpsin B in the aqueous solution were measured by HPLC under the above-mentioned conditions.

Table 1 shows the results of measurement of the amount of piceatannol and the amount of skillpsin B in the aqueous solution when the container is a sampling tube, with the amount of piceatannol and the amount of skillpsin B immediately before starting heating being set to 100, respectively. And shown in FIG. Furthermore, Table 2 shows the results of calculating the decay rates of Piceatannol and Skillpsin B in the aqueous solution based on the following formula from the results of Table 1 and FIG.
Decay rate (% / day) = (100−remaining ratio of compound) / elapsed time

  In addition, when the container is a composite paper container, the measurement results of the amount of piceatannol and the amount of skillpsin B in the aqueous solution are set to 100 respectively for the amount of piceatannol and the amount of skillpsin B immediately before starting the heating. Table 3 and FIG. Furthermore, Table 4 shows the results of calculating the decay rates of Piceatannol and Skillpsin B in the aqueous solution based on the above formula from the results of Table 3 and FIG.

As shown in Tables 1 and 3, or the value of the residual rate of piceatannol in FIGS. 1 and 2 corresponding to these tables, the container is a composite paper container as opposed to the case where the container is a sampling tube. In some cases, piceatannol remained in the solution at a high concentration for a long time.
Specifically, for example, when the elapsed time is 12 days, when the container is a sampling tube, the residual rate of piceatannol is 67%, whereas the container is a composite paper container. In some cases, 95% remained. Furthermore, only 40% of piceatannol remained in the sampling tube with an elapsed time of 18 days, whereas 96% remained in the composite paper container with an elapsed time of 20 days.

  In addition, in the case where the container is a composite paper container, the stability of piceatannol in the solution is improved as compared with the case of the sampling tube. Table 5 shows values obtained by dividing the decay rate of piceatannol in the case of a sampling tube by the decay rate of piceatannol in the case of the composite paper container shown in Table 4.

  As Table 5 shows, the decay rate was significantly higher in the case of the sampling tube, regardless of the elapsed time between the composite paper container and the sampling tube. That is, when the container is a composite paper container, the stability of piceatannol contained in the solution is remarkably improved, regardless of the elapsed time since the solution was put in each container, as compared with the case of the sampling tube.

In addition, as shown in Tables 1 and 3, and both the residual rate of piceatannol and the residual rate of skillpsin B in FIGS. 1 and 2, when the container is a sampling tube, piceatannol is also Skillpsin B also decayed over time, whereas in the case of a composite paper container, piceatannol remained in the solution at a high concentration over a long period of time. A certain skillpsin B decayed over time, contrary to the behavior of piceatannol.
For example, in the case of a composite paper container, when the elapsed time was 32 days, 97% of piceatannol remained, whereas only 52% of skillpsin B remained. When the elapsed time was 56 days, 91% of piceatannol remained, whereas only 30% of skillpsin B remained. When the elapsed time was 84 days, 91% of piceatannol remained, whereas only 18% of skillpsin B remained.

  In order to compare this result also with the decay rate, Table 6 shows values obtained by dividing the decay rate of Skillpsin B by the decay rate of Piceatannol when the container shown in Table 2 is a sampling tube. Table 7 shows values obtained by dividing the attenuation rate of skimpsin B by the attenuation rate of piceatannol when the container shown in 4 is a composite paper container.

For example, when the elapsed time is 12 days, the damping speed ratio in Table 6 is compared with the damping speed ratio in Table 7, the damping speed ratio in the case of the composite paper container in Table 7 is the sampling tube in Table 6 It was about 2.7 times higher than the damping rate ratio. Further, when comparing the decay rate ratio of Table 6 when the elapsed time is 18 days and the decay rate ratio of Table 7 when the elapsed time is 20 days, the decay rate ratio in the case of the composite paper container of Table 7 is as shown in Table 6. It was about 6.7 times higher than the damping rate ratio in the case of the sampling tube.
That is, when the container was a composite paper container, it was shown that Skillpsin B was significantly attenuated while stabilizing piceatannol in the solution as compared with the case of the sampling tube.

Claims (15)

A solution of plant extract containing piceatannol that is shielded from oxygen-containing gases.   The solution according to claim 1, wherein the plant extract is a passion fruit seed extract, a tenninka extract, or a brassica extract.   The solution according to claim 1, wherein the solution is further shielded from light.   The solvent of the solution is water, ethanol, 1,3-butylene glycol, or a mixed solvent of two or more solvents selected from these, according to any one of claims 1 to 3. The solution described.   The extract is a product extracted from a plant using water, ethanol, 1,3-butylene glycol, or a mixed solvent of two or more solvents selected from these as a solvent. The solution according to any one of 1 to 4. A plant extract solution containing piceatannol in an airtight container,
The container has an oxygen barrier property;
A solution in a container in which there is no gas layer made of a gas containing oxygen in the container.   The solution in a container according to claim 6, wherein the plant extract is a passion fruit seed extract, a tenninka extract, or a brassica extract.   The solution in a container according to claim 6 or 7, wherein the container further has a light shielding property.   The solution in a container according to any one of claims 6 to 8, wherein the container is a composite paper container.   The solvent of the solution is water, ethanol, 1,3-butylene glycol, or a mixed solvent of two or more solvents selected from the above, according to any one of claims 6 to 9, The solution in the container as described.   The extract is a product extracted from a plant using water, ethanol, 1,3-butylene glycol, or a mixed solvent of two or more solvents selected from these as a solvent. The solution in a container as described in any one of 6-10.   A method for stabilizing piceatannol contained in a solution of a plant extract, comprising a step of blocking the solution from a gas containing oxygen.   A method for reducing skillpsin B contained in a solution of the plant extract while stabilizing piceatannol contained in the solution of the plant extract, comprising the step of blocking the solution from a gas containing oxygen Method.   The method according to claim 12 or 13, wherein the plant extract is a passion fruit seed extract, a tenninka extract, or a brassica extract.   15. The method according to any one of claims 12 to 14, further comprising the step of shielding the solution from light.

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