JP2013249265A - Whitening agent and skin cosmetic - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide: a whitening agent in which a material having a whitening action is found from among natural products with high safety, and is used as an active ingredient; and a skin cosmetic that combines a natural product having a whitening action.SOLUTION: A whitening agent includes flavonoid A and/or an extract obtained by extracting bran of rice having a pigment by an acidic solvent as active ingredients. Moreover, a skin cosmetic combines the flavonoid A and/or the extract obtained by extracting the bran of the rice having a pigment by the acidic solvent. It is desirable that the skin cosmetic is used for bleaching application.

Description

  The present invention relates to a whitening agent and a skin cosmetic.

  Melanin also plays a role in protecting the body from ultraviolet rays in the skin, but overproduction and uneven accumulation cause skin darkening and spots. In general, melanin is converted from tyrosine to dopa and from dopa to dopaquinone by the action of the enzyme tyrosinase biosynthesized in pigment cells, and then formed through intermediates such as 5,6-dihydroxyindophenol. ing. Therefore, in order to prevent, treat, or improve skin darkness (skin pigmentation), spots, freckles, etc., it is conceivable to suppress the production of melanin.

  Conventionally, for the prevention, treatment or improvement of skin pigmentation, stains, buckwheat, etc., a treatment using a whitening agent containing a chemically synthesized product such as hydroquinone as an active ingredient has been performed. However, chemically synthesized products such as hydroquinone may cause side effects such as skin irritation and allergies. Therefore, development of a whitening agent containing a highly safe natural raw material as an active ingredient is desired. Examples of those having a melanin inhibitory action include, for example, an extract from a root of castor bean (see Patent Document 1), south urea ( Extracts from plants belonging to the genus Saussurea) (see Patent Document 2) and the like are known.

JP 2001-213757 A JP 2002-201222 A

  It is an object of the present invention to find a whitening agent having a whitening effect from among highly safe natural products, and to provide a whitening agent containing the same as an active ingredient, and a skin cosmetic containing the natural product having a whitening effect. To do.

  In order to solve the above-mentioned problems, the whitening agent of the present invention contains, as an active ingredient, a compound represented by the following formula (I) and / or an extract obtained by extraction of pigmented rice bran with an acidic solvent. It is characterized by doing.

  The skin cosmetic of the present invention is characterized by blending an extract obtained by extracting a compound represented by the above formula (I) and / or pigmented rice bran with an acidic solvent. The skin cosmetic of the present invention is preferably used for whitening.

  According to the present invention, it is possible to provide a whitening agent and a skin cosmetic that have an excellent whitening action and are highly safe.

Embodiments of the present invention will be described below.
[Whitening agent]
The whitening agent of this embodiment contains, as an active ingredient, an extract obtained by extracting a compound represented by the following formula (I) and / or pigmented rice bran with an acidic solvent.

  In the present embodiment, the compound represented by the formula (I) is referred to as “flavonoid A”. Further, an extract obtained by extracting colored rice bran with an acidic solvent may be simply referred to as “pigmented rice bran acidic extract”.

  In the “extract obtained by extracting pigmented rice bran with an acidic solvent” in the present embodiment, the extract obtained by extracting the pigmented rice bran as an extraction material with an acidic solvent, the extract Any of these diluted solutions or concentrated solutions, dried products obtained by drying the extract, or crudely purified products or purified products thereof are included.

  Here, “pigmented rice” means rice (Oryza sativa) belonging to the family Gramineae with a pigment (for example, a tannin-based red pigment, If you have anthocyanin-based purple pigment), and if you have pigment in the cocoon layer, subtypes such as japonica (Oryza sativa subsp. Japonica), indica (Oryza sativa subsp. Indica) There is no particular limitation. Further, “pigmented rice bran” means a powdery mixture such as pericarp, seed coat, and external endosperm that is produced when fertilizing pigmented rice.

  As described above, the cocoon layer of pigmented rice contains tannin-based red pigment, anthocyanin-based purple pigment, etc., so pigmented rice in a state having a cocoon layer (for example, brown rice) It can be easily distinguished from the brown rice of general white rice that exhibits light red to purple black and brown. In addition, koji produced when scouring pigmented rice can be easily distinguished from general white rice koji by its appearance.

  There are various types of pigmented rice such as red rice, red rice, purple rice, and black rice, each with various varieties and production areas. In the whitening agent of the present embodiment, pigmented rice of any kind, variety, production area or the like may be used as an extraction raw material, but among them, red rice bran is preferably used.

  The cultivar of red rice that can be used in the present embodiment is not particularly limited, but red dyed rice cake, Saikai rice cake No. 197, Himikomochi, hachi red 124, Beniroman, evening rice cake, Soja red rice, Tsushima red rice, Tanegashima red rice, cold water, akamuro, tokon, horsetail red rice cake, red potato, red incense, red robe, Saikaikan No. 246 and the like can be suitably used.

  In addition, the “acidic solvent” used in the present embodiment refers to acidic water adjusted to pH 6.5 or less, preferably 4.5 to 1.5, or a mixed solvent of the acidic water and a hydrophilic organic solvent. Means.

  Here, the water that can be used for the preparation of the acidic water includes pure water, tap water, well water, mineral spring water, mineral water, hot spring water, spring water, fresh water, etc., and those subjected to various treatments. It is. The treatment applied to water includes, for example, purification, heating, sterilization, filtration, ion exchange, osmotic pressure adjustment, buffering, etc., in addition to pH adjustment described later. Therefore, the water that can be used as the extraction solvent in this embodiment includes purified water, hot water, ion-exchanged water, physiological saline, organic acid buffer, organic acid buffered saline, and the like.

  In the present embodiment, acidic water whose pH is adjusted is used. Acidic water may be an inorganic acid such as hydrochloric acid, sulfuric acid, phosphoric acid, etc .; an acid such as acetic acid, lactic acid, malic acid, citric acid, etc. added to water to adjust the pH. Anodized water generated by electrolysis of water may be used.

  Examples of hydrophilic organic solvents that can be used for mixing with acidic water include lower aliphatic alcohols having 1 to 5 carbon atoms such as methanol, ethanol, propyl alcohol, and isopropyl alcohol; lower aliphatic ketones such as acetone and methyl ethyl ketone; Examples thereof include polyhydric alcohols having 2 to 5 carbon atoms such as 3-butylene glycol, propylene glycol and glycerin, and these may be used in combination.

  When a mixed solvent of acidic water and a hydrophilic organic solvent is used as the extraction solvent, the mixing ratio can be adjusted as appropriate. For example, when using a mixed solution of acidic water and lower aliphatic alcohol, it is preferable to mix 1 to 90 parts by volume of lower aliphatic alcohol with 10 parts by volume of acidic water. When using a mixed solution with a ketone, it is preferable to mix 1 to 40 parts by volume of a lower aliphatic ketone with 10 parts by volume of acidic water, and when using a mixed solution of acidic water and a polyhydric alcohol. It is preferable to mix 10 to 90 parts by volume of polyhydric alcohol with 10 parts by volume of acidic water.

  The method for extracting pigmented rice bran with an acidic solvent is not particularly limited, and can be performed according to a conventional method. For example, after drying pigmented rice bran as an extraction raw material, it is subjected to extraction with an acidic solvent. Drying may be performed in the sun or using a commonly used dryer. Moreover, after performing pretreatment, such as degreasing, with a nonpolar solvent such as hexane, it may be used as an extraction raw material. By performing pretreatment such as degreasing, extraction treatment of pigmented rice bran with an acidic solvent can be performed efficiently.

  The extraction treatment is not particularly limited as long as the soluble component contained in the extraction raw material can be eluted in the extraction solvent, and can be performed according to a conventional method. For example, the extraction raw material is immersed in an extraction solvent in an amount of 5 to 15 times (mass ratio) of the extraction raw material, and the soluble component is extracted at room temperature or under reflux heating. The extraction temperature is preferably room temperature or a temperature not higher than the boiling point of the solvent. An extract can be obtained by filtering the soluble component thus obtained to remove the extraction residue. When the solvent is distilled off from the obtained extract, a paste-like concentrate is obtained, and when this concentrate is further dried, a dried product is obtained.

  Since the pigmented rice bran acidic extract obtained as described above has an excellent whitening action, it can be used as an active ingredient of a whitening agent.

  On the other hand, since the flavonoid A according to this embodiment also has an excellent whitening action, it can be used as an active ingredient of a whitening agent. Flavonoid A can be isolated from, for example, pigmented rice straw such as red rice, but it only needs to contain a cocoon layer (fruit skin, seed coat, outer endosperm, etc.), and pigmented rice before fertilization. Brown rice may be used. Organic pigmented rice flavonoids may also be present in other components of pigmented rice, rice other than pigmented rice, and other plants. Therefore, the source of flavonoid A isolation is not limited to pigmented rice bran, and any plant containing flavonoid A may be used.

  Flavonoid A is, for example, obtained by subjecting a plant extract containing flavonoid A to a purification process effective for isolating flavonoid compounds such as liquid-liquid partition extraction, various chromatography, membrane separation, and recrystallization. It can be obtained by performing liquid chromatography using octadecylsilylated silica gel (ODS) or the like as a stationary phase.

  As the plant containing flavonoid A, pigmented rice can be exemplified, and among them, red rice is preferable. When flavonoid A is isolated from pigmented rice, it is preferable that the pigmented rice used as an extraction raw material contains a straw layer. As an extraction solvent for obtaining an extract from these plants, it is preferable to use a polar solvent, for example, water, a hydrophilic organic solvent, etc., and these may be used alone or in combination of two or more at room temperature. Or it is preferable to use at the temperature below the boiling point of a solvent. Here, when water or a mixed liquid of water and a hydrophilic organic solvent is used as the extraction solvent, the liquidity of the water is not particularly limited, but is preferably neutral or acidic. That is, the pigmented rice bran acidic extract is one of the suitable extracts for isolating flavonoid A.

  When water is used as the extraction solvent, examples of water that can be used include those similar to the water used in the preparation of the acidic water described above, and the hydrophilic organic solvent also includes the acidic water described above. The thing similar to the hydrophilic organic solvent which can be used for these mixed solvents can be illustrated. When a mixed solvent of water and a hydrophilic organic solvent is used as the extraction solvent, the mixing ratio may be adjusted as appropriate, similar to the mixing ratio of the acidic water and the hydrophilic organic solvent described above.

  The extraction treatment is not particularly limited as long as the soluble component contained in the extraction raw material can be eluted in the extraction solvent, and can be performed according to a conventional method. For example, similarly to the pigmented rice bran acidic extract described above, a plant containing flavonoid A is dried and subjected to pretreatment such as degreasing as necessary to obtain an extraction raw material. The obtained extraction raw material is immersed in 5 to 15 times amount (mass ratio) of extraction solvent to extract soluble components at room temperature or under reflux, and then filtered to remove the extraction residue to obtain an extract. be able to. When the solvent is distilled off from such an extract, a paste-like concentrate is obtained, and when this concentrate is further dried, a dry product is obtained.

  Examples of the method for purifying flavonoid A from the extract thus obtained include liquid-liquid partition extraction, various chromatographies, membrane separation, and recrystallization. Among them, it is preferable to use in combination an adsorption chromatography using a column packed with a synthetic adsorbent and a gel filtration chromatography using a column packed with a porous carrier.

  Finally, flavonoid A is isolated from the purified product or purified fraction obtained by the purification treatment by liquid chromatography. The fractionation method by liquid chromatography is not particularly limited. For example, reverse phase chromatography using octadecylsilyl silica gel (ODS) or the like as the stationary phase, normal phase chromatography using silica gel or the like as the stationary phase, Size exclusion chromatography using a porous polymer or the like can be used alone or in combination.

  The whitening agent according to this embodiment contains the pigmented rice bran acidic extract and / or flavonoid A as an active ingredient. The whitening agent of this embodiment can be used for a wide range of uses such as pharmaceuticals, quasi drugs, and cosmetics. Here, flavonoid A is particularly preferable as an active ingredient of a whitening agent because it exhibits a stronger whitening effect as compared with pigmented rice bran acidic extract.

  In the present embodiment, any one of flavonoid A or pigmented rice bran acidic extract may be used as the active ingredient, or these may be mixed and used as the active ingredient. When flavonoid A or pigmented rice bran acidic extract is mixed and used as the active ingredient, the blending ratio may be appropriately adjusted depending on the degree of whitening action of flavonoid A or pigmented rice bran acidic extract.

  The whitening agent of the present embodiment may be composed only of flavonoid A, pigmented rice bran acidic extract or a mixture thereof, or may be formulated from flavonoid A, pigmented rice bran acidic extract or a mixture thereof.

  The whitening agent of the present embodiment is an arbitrary dosage form such as powder, granule, tablet, liquid, etc. according to a conventional method using a pharmaceutically acceptable carrier such as dextrin and cyclodextrin and any other auxiliary agent. Can be formulated. In this case, as an auxiliary agent, for example, an excipient, a binder, a disintegrant, a lubricant, a stabilizer, a flavoring / flavoring agent, and the like can be used. The whitening agent can be used by blending with other compositions (for example, external preparations for skin, cosmetic foods and drinks, etc.), and can also be used as an ointment, a solution for external use, a patch, and the like.

  When the whitening agent of the present embodiment is formulated, the content of the flavonoid A, the pigmented rice bran acidic extract or a mixture thereof is not particularly limited, and can be appropriately set according to the purpose.

  In addition, the whitening agent of the present embodiment may be used as an active ingredient by blending other natural extracts having a whitening action with flavonoid A, pigmented rice bran acidic extract or a mixture thereof as necessary. it can.

  Examples of the method for administering the whitening agent of this embodiment to a patient include transdermal administration, oral administration, and the like. A suitable method for the prevention / treatment or the like may be appropriately selected according to the type of disease. In addition, the dosage of the whitening agent of this embodiment may be appropriately increased or decreased depending on the type of disease, severity, individual differences among patients, administration method, administration period, and the like.

  The whitening agent of this embodiment suppresses the production of melanin in pigment cells through the melanin production inhibitory action of flavonoid A or pigmented rice bran acidic extract, and prevents or improves spots, buckwheat, skin pigmentation, etc. And a whitening effect can be obtained. However, the whitening agent of the present embodiment can be used for all uses other than these uses that are meaningful for exhibiting a melanin production inhibitory effect.

  Moreover, since the whitening agent of this embodiment has the outstanding whitening effect | action, it is suitable for mix | blending with a skin external preparation, for example. In this case, flavonoid A, pigmented rice bran acidic extract or a mixture thereof may be blended as they are, or a whitening agent formulated from flavonoid A, pigmented rice bran acidic extract or a mixture thereof may be blended. Good.

  Here, the external preparation for skin is not limited in its category, and includes a wide range of quasi-drugs and pharmaceuticals used transdermally, in addition to the skin cosmetics described below.

  Moreover, since the whitening agent of this embodiment has the outstanding whitening effect | action, it can be utilized suitably also as a reagent for the research relevant to the melanin production | generation mechanism in a pigment cell, for example.

[Skin cosmetic]
Flavonoid A, pigmented rice bran acidic extract and a mixture thereof are suitable for blending into skin cosmetics because they have an excellent whitening effect. In this case, flavonoid A, pigmented rice bran acidic extract or a mixture thereof may be blended as they are, or a whitening agent formulated from flavonoid A, pigmented rice bran acidic extract or a mixture thereof may be blended. . By blending flavonoid A, pigmented rice bran acidic extract or a mixture thereof or the above-described whitening agent into the skin cosmetic, a whitening action can be imparted to the skin cosmetic.

  Skin cosmetics that can be blended with flavonoid A, pigmented rice bran acidic extract or a mixture thereof, or the above-described whitening agent are not particularly limited. For example, ointments, creams, emulsions, lotions, packs, foundations, lips Creams, bath salts, hair nicks, hair lotions, soaps, body shampoos and the like.

  When flavonoid A, pigmented rice bran acidic extract or a mixture thereof is blended in skin cosmetics, the blending amount can be appropriately adjusted according to the type of skin cosmetic, but the preferred blending ratio is about 0. 0.0001 to 10% by mass, and a particularly preferable blending ratio is about 0.001 to 1% by mass.

  As long as the skin cosmetic of this embodiment does not interfere with the whitening action of flavonoid A, pigmented rice bran acidic extract and mixtures thereof, the main agent, auxiliary agent or other components used in the production of ordinary skin cosmetics, For example, astringents, bactericides / antibacterial agents, whitening agents, UV absorbers, moisturizers, cell activators, anti-inflammatory / antiallergic agents, antioxidant / active oxygen scavengers, fats and oils, waxes, hydrocarbons, fatty acids , Alcohols, esters, surfactants, fragrances and the like can be used in combination. When used in combination, it becomes a more general product, and a synergistic effect with other active ingredients used in combination may lead to an excellent effect that is more than normally expected.

  The skin cosmetic of this embodiment suppresses the production of melanin in pigment cells through the melanin production inhibitory action of flavonoid A or pigmented rice bran acidic extract, and prevents or improves spots, buckwheat, skin pigmentation, etc. And a whitening effect can be obtained.

  The whitening agent and skin cosmetic of the present embodiment are preferably applied to humans. However, as long as the respective effects are exhibited, animals other than humans (for example, mice, rats, hamsters). , Dogs, cats, cows, pigs, monkeys, etc.).

  Hereinafter, although a manufacture example and a test example are shown and this invention is demonstrated concretely, this invention is not restrict | limited to each following example at all.

[Example 1] Preparation of red rice defatted bran acid extract 12 kg of red rice (red dyed rice cake, 2010, manufactured by Ehime Prefecture, manufactured by Aguri Co., Ltd.) was obtained after rice milling using a rice mill (BR-EA35, manufactured by ZOJIRUSHI). After immersing 1.2 kg of red rice bran in 4 L of n-hexane (manufactured by Nacalai Tesque) for 0.5 hour, the mixture was filtered with double gauze to remove the hexane-soluble fraction. Degreasing with n-hexane was performed a total of 5 times, and the last one was sonicated for 15 minutes. The residue excluding the hexane-soluble fraction was air-dried in a fume hood to remove n-hexane, and 885 g of red rice defatted koji was obtained.

  BG (1,3-butylene glycol, high sugar cane BG, manufactured by Higher Alcohol Industry Co., Ltd.) and acidic water having a pH of 3.1 (manufactured by an alkali ion water conditioner manufactured by Panasonic) were mixed in an equal amount and 50% ( v / v) Acidic BG was prepared. 200 g of 50% (v / v) acidic BG was mixed with 20 g of the above-described red rice defatted koji, and immersed for a whole day and night. After mesh filtration, the supernatant was collected by centrifugation (15000 rpm, 10 minutes, 4 ° C.) to obtain a red rice defatted and acidic extract (124 g).

[Example 2] Preparation of flavonoids from red rice defatted rice cake After using 447 g of red rice defatted rice cake obtained in the preparation process of Example 1 and immersing in 3 L of 50% (v / v) ethanol for 0.5 hour, Filtration through double gauze gave an extract. The filtered residue was further extracted with 50% (v / v) ethanol in the same manner, and the extract obtained by a total of three extraction operations was filtered through Celite (No. 545, manufactured by Wako Pure Chemical Industries, Ltd.) The filtrate was concentrated with a rotary evaporator (R-200, manufactured by Shibata Kagaku).

  Concentrated red rice defatted koji 50% (v / v) ethanol extract is applied to a separation and purification resin column (Diaion HP20, 1.5L, manufactured by Mitsubishi Chemical Corporation), distilled water, 10% (v / v) After eluting with methanol, 20% (v / v) methanol, 30% (v / v) methanol, 50% (v / v) methanol, and methanol in 4.5 L each, and concentrating each fraction, freeze dryer (DC-41B, manufactured by Yamato Scientific Co.) was freeze-dried.

  A 10% (v / v) methanol fraction (1.37 g) was dissolved in a small amount (4 to 5 mL) of distilled water, applied to a gel filtration resin column (TOYOPER HW-40C, manufactured by Tosoh Corporation), and similarly distilled. Elution with water, 10% (v / v) methanol, 20% (v / v) methanol, 30% (v / v) methanol, 50% (v / v) methanol, and methanol sequentially, followed by fraction collector (DC- 1000, manufactured by EYELA). Using an HPLC apparatus (La Chrom Elite, manufactured by Hitachi High-Tech), the injection sample (fraction) was sequentially switched while confirming the peak under the conditions shown below, and fractionated by high performance liquid chromatography. The eluate was collected for each similar peak shape, concentrated and lyophilized.

<High performance liquid chromatography conditions>
Stationary phase: Inert Sustain C18 (manufactured by GL Sciences Inc.)
Column diameter: 4.6 mm
Column length: 150mm
Column oven: 40 ° C
Mobile phase: 10 mM phosphate buffer: acetonitrile = 92: 8
Flow rate: 1.0 mL / min
Detection: 280nm

  The fr. 81-100 (0.0185 g) fraction and fr. 101-120 (0.0124 g) fractions were combined and applied to a silica-based filler column (YMC-gel ODS-AQ12S50, ф1.8 cm × 18 cm, manufactured by YMC Co., Ltd.), and similarly distilled water, 10% (v / v ) Elution with methanol, 20% (v / v) methanol, 30% (v / v) methanol, 50% (v / v) methanol, and methanol and collected in a fraction collector. Under the same HPLC conditions as described above, the injection sample (fraction) was switched and fractionated while confirming the peak, and the purified product (0.0031 g) was isolated.

  The purified product obtained as described above was subjected to mass spectrum analysis (micrOTOF-Q, manufactured by BRUKER) and NMR (nuclear magnetic resonance spectroscopy) spectrum analysis (AVANCE500, manufactured by BRUKER). The results are shown below.

<Mass spectrum (ESI-MS)>
[M−H] ⁻ m / z 315.0489 (theoretical value: C ₁₆ H ₁₂ O ₇ −H = 315.0510)

< ¹ H-NMR chemical shift δ>
7.06 (1H, s), 6.64 (1H, s), 5.87 (1H, d, J = 2.0 Hz), 5.69 (1H, d, J = 2.0 Hz), 5.02 (1H, dd, J = 2.0, 2.5 Hz ), 4.25 (1H, dd, J = 2.0, 2.5 Hz), 3.87 (2H, m)

From the above results, it was confirmed that the compound isolated from the red rice bran extract has the molecular formula C ₁₆ H ₁₂ O ₇ and is a flavonoid represented by the following formula (I).

[Comparative Example 1] Preparation of plain rice defatted bran acidic extract Same as Example 1 except that plain rice (Kinuhikari, 2010, produced in Ehime Prefecture, manufactured by Nomin Co., Ltd.) was used instead of red rice as an extraction raw material To obtain a regular rice defatted cocoon acid extract (132.6 g).

[Comparative Example 2] Preparation of red rice defatted koji neutral extract As an extraction solvent, instead of 50% (v / v) acidic BG, BG (1,3-butylene glycol, high sugar cane BG, manufactured by Higher Alcohol Industry Co., Ltd.) ) And neutral water of pH 7.3 (manufactured by an ultrapure water production apparatus manufactured by Millipore) and 50% (v / v) neutral BG prepared by mixing equal amounts, and Example 1 A red rice defatted koji neutral extract was obtained in the same manner (144.6 g).

[Test Example 1] Melanin production inhibitory test-1
About the red rice defatted koji acidic extract (Example 1), the ordinary rice defatted koji acidic extract (Comparative Example 1) and the red rice defatted koji neutral extract (Comparative Example 2) obtained as described above, The melanin production inhibitory action was tested.

B16 melanoma 4A5 cells were cultured at 37 ° C. and 5% CO ₂ -95% air using DMEM (Dulbecco's modified minimum essential medium, Gibco) medium containing 10% FBS (Fetal Bovine Serum, Gibco). The cells were collected by treatment with 0.25% trypsin (manufactured by Sigma). The collected cells were diluted with 10% FBS-containing DMEM medium to a concentration of 3 × 10 ⁴ cells / mL, and then seeded at 5 mL each in a T25 flask (manufactured by Sumitomo Bakelite). After culturing at 37 ° C. under 5% CO ₂ -95% air for 2 hours, a test sample (Example 1, Comparative Examples 1 and 2, see Table 1 below for sample concentration) was added to the medium, and the culture was continued for 4 days. Cultured. After completion of the culture, the cells were collected in 10 mL sterilized spitz by 0.25% trypsin treatment, a pellet was prepared by centrifugation (1500 rpm, 10 minutes), and the melanin production inhibitory action was determined according to the pellet determination criteria shown below. The results are shown in Table 1.

= Pellets criteria =
-: Same as untreated control ±: Slight lightening (reduction) action +: Remarkable lightening (reduction) action

  As shown in Table 1, the red rice defatted koji acidic extract (Example 1) is compared with not only the regular rice defatted koji acidic extract (Comparative Example 1) but also the red rice defatted koji acidic extract (Comparative Example 2). However, it was confirmed to have an excellent melanin production inhibitory action.

[Test Example 2] Melanin production inhibitory test-2
About the flavonoid A obtained as described above (Example 2, for sample concentration, see Table 2 below), the melanin production inhibitory action was tested in the same manner as in Test Example 1. As a comparative example, kojic acid (Comparative Example 3, manufactured by Nacalai Tesque, see Table 2 below for sample concentration) was used. The results are shown in Table 2.

  As shown in Table 2, flavonoid A (Example 2) has an excellent melanin production inhibitory effect equivalent to or better than kojic acid (Comparative Example 3), which is known to have a melanin production inhibitory effect. It was confirmed to have.

[Formulation Example 1]
A milky lotion was produced by a conventional method according to the following composition.
Flavonoid A (Example 2) 0.01 g
Jojoba oil 4.00 g
1,3-butylene glycol 3.00 g
Arbutin 3.00g
Polyoxyethylene cetyl ether (20E.O.) 2.50g
2.00 g of olive oil
Squalane 2.00g
Cetanol 2.00g
Glyceryl monostearate 2.00g
Oleic acid polyoxyethylene sorbitan (20E.O.) 2.00g
Methyl paraoxybenzoate 0.15g
Stearyl glycyrrhizinate 0.10g
Twilight extract 0.10g
Dipotassium glycyrrhizinate 0.10g
Ginkgo biloba extract 0.10g
Conchiolin 0.10g
Oat extract 0.10g
Chamomile extract 0.10g
Fragrance 0.05g
Purified water remainder (total amount is 100 g)

[Formulation Example 2]
A cream having the following composition was produced by a conventional method.
Red rice defatted koji acidic extract (Example 1) 0.05 g
Kujin extract 0.1g
Ogon Extract 0.1g
Liquid paraffin 5.0g
Salami beeswax 4.0g
Squalane 10.0g
Cetanol 3.0g
Lanolin 2.0g
Stearic acid 1.0g
Oleic acid polyoxyethylene sorbitan (20E.O.) 1.5g
3.0 g glyceryl monostearate
Oil soluble licorice extract 0.1g
1,3-butylene glycol 6.0 g
1.5 g of methyl paraoxybenzoate
Fragrance 0.1g
Purified water remainder (total amount is 100 g)

[Composition Example 3]
A serum having the following composition was produced by a conventional method.
Flavonoid A (Example 2) 0.01 g
Chamomile extract 0.1g
Carrot extract 0.1g
Xanthan gum 0.3g
Hydroxyethylcellulose 0.1g
Carboxyvinyl polymer 0.1g
1,3-butylene glycol 4.0 g
0.1g dipotassium glycyrrhizinate
Glycerin 2.0g
Potassium hydroxide 0.25g
Fragrance 0.01g
Preservative (Methyl paraoxybenzoate) 0.15g
Ethanol 2.0g
Purified water remainder (total amount is 100 g)

  The whitening agent and skin cosmetic of the present invention can greatly contribute to the prevention or improvement of stains, buckwheat, skin pigmentation and the like due to its excellent melanin production inhibitory action.

Claims (5)

A whitening agent comprising a compound represented by the following formula (I) as an active ingredient.

  A whitening agent characterized by containing, as an active ingredient, an extract obtained by extracting rice bran of pigmented rice with an acidic solvent. A skin cosmetic comprising a compound represented by the following formula (I):

  A skin cosmetic characterized by containing an extract obtained by extracting colored rice bran with an acidic solvent.   The skin cosmetic according to claim 3 or 4, which is used for whitening.