CN109966216B

CN109966216B - Chinese iris extract and new application thereof

Info

Publication number: CN109966216B
Application number: CN201711457399.6A
Authority: CN
Inventors: 章漳; 李慧; 张佳伟; 宋肖洁; 席淑云; 陈明华
Original assignee: Jala Group Co
Current assignee: Shanghai Natural Hall Group Co ltd
Priority date: 2017-12-28
Filing date: 2017-12-28
Publication date: 2022-11-15
Anticipated expiration: 2037-12-28
Also published as: CN109966216A

Abstract

The present invention provides an iris lactea extract and a new application thereof, wherein the iris lactea extract has good whitening and anti-aging effects, can be used in the fields of cosmetics, health foods and medicines, and especially can be applied to cosmetics.

Description

Chinese iris extract and new application thereof

Technical Field

The invention belongs to the field of natural product chemistry, and particularly relates to an iris lactea extract and a new application thereof.

Background

Whitening and anti-aging cosmetics are always pursued and aimed by women and are also a permanent topic of research in the beauty community. In recent years, with the development of socioeconomic and the progress of science and technology, the demand of people for cosmetics has been increased.

The color of human skin is related to the type and amount of pigment present in the skin, with melanin having the greatest effect on skin color. Regarding the formation of melanin in the skin, studies have been conducted to show that it is mainly caused by biochemical reactions in melanocytes, i.e., tyrosine generates dopaquinone under the action of tyrosinase as a catalyst, and then melanin is formed by enzymatic catalysis or non-enzymatic oxidation. As for the whitening active substance for inhibiting the production of melanin, inhibition of tyrosinase activity is generally a major target. Tyrosinase inhibitors derived from plant extracts are expected to be a potential whitening active substance, and have safety and low skin irritation, and various developments have been reported.

The skin is exposed to external environments such as ultraviolet rays, active oxygen generated by the ultraviolet rays and active oxygen in other external environments generate various free radicals in the skin, so that the skin is damaged by oxidative stress, skin diseases such as skin inflammation can be induced in a short term, and skin aging can be caused in a long term. The antioxidant is a substance having an ability to capture free radicals, and can scavenge active free radicals in the skin, and relieve oxidative stress damage of the skin caused by free radicals, thereby improving skin aging caused by oxidative stress and the like. Free radical scavenging antioxidants in vivo, such as vitamin E and vitamin C, are known, and plant-derived antioxidants, such as extracts of lotus flowers and plum fruits, have also been reported.

The causes of skin aging can be divided into photoaging and intrinsic aging, and photoaging caused by UV exposure causes increased activity of skin elastase. Elastase (Elastase) is distributed in various tissues and cells, and the increase of Elastase activity can cause the hydrolysis of skin elastic fibers, thereby accelerating the decomposition of collagen and elastin in dermis, leading the skin to lose elasticity, and causing skin aging phenomena such as wrinkles and the like. It is known that plant-derived anti-aging actives, such as Polygonum tinctorium, sweet pea, etc., have elastase inhibitory effects.

Iris lactea, also known as Iris lactea, iris lactea and Iris lactea, is a perennial herbaceous plant of Iris (Iris lactea pall. Var. Chinensis (fisch.) koidz.) of the family iridaceae, and grows on the beach, trench or dam of saline soil, saline-alkali soil or salinized soil in the temperate or cold temperature zone with an altitude of 50-3900 m. The high-stress resistance, particularly the salt and alkali resistance, is a group-building grass seed of a salinized meadow, and is used for saline-alkali soil improvement, industrial waste land reconstruction and desertification treatment. In addition, due to the developed root system, the leaves are early green, long in greenness and light and beautiful in color, and the plant leaf tea is used for water retention slope protection and landscaping. The root, flower and seed of Chinese iris can be used as medicine. Iris lactea root, sweet in taste and neutral in nature, has the efficacy of clearing heat and removing toxicity, and is used for treating acute swelling and sore throat, viral hepatitis, hemorrhoids, toothache and other symptoms.

In combination with the recent research progress, no report of iris lactea in the cosmetic field is found.

Disclosure of Invention

The invention aims to: provides an iris lactea extract and a new application thereof, aiming at applying the iris lactea extract in a skin external preparation to play a role in beautifying and protecting the skin.

The purpose of the invention is realized as follows:

an Iris lactea extract is prepared by pulverizing Iris lactea, extracting with organic solvent, and filtering to obtain Iris lactea crude extract; dissolving the crude extract in organic solvent, adsorbing with macroporous resin column, eluting with water and organic solvent, and distilling under reduced pressure to remove solvent.

The organic solvent refers to an organic solvent containing a polar group such as a hydroxyl group or a carbonyl group, and examples thereof include: formamide, dimethylformamide, hexamethylphosphoramide, tetramethylethylenediamine, triethylamine, tributylamine, acetic acid, trifluoroacetic acid, acetonitrile, methyl formate, ethyl acetate, dimethyl carbonate, dimethyl sulfoxide, acetone, methyl ethyl ketone, dioxane, pyridine, tetrahydrofuran, methanol, ethanol, chloroform, glycerol, propylene glycol, isopropanol, n-hexane, n-butanol, diethyl ether and the like, wherein one or more of ethanol aqueous solution, n-hexane, ethyl acetate or n-butanol is preferred.

According to tests, the Chinese iris extract has good effects in whitening, inhibiting tyrosinase and resisting aging, and can be used as an active ingredient to be added into a cosmetic formula, wherein the active ingredient can provide one or more than one effect under certain conditions.

The active ingredients in the invention can also be panthenol, dipotassium glycyrrhizinate, allantoin, nicotinamide, sodium ascorbyl phosphate, pansy extract, sodium hyaluronate, tocopheryl acetate, undecylenoyl phenylalanine and the like. Moreover, such descriptions are provided to facilitate understanding and are not intended to limit the components to the specifically identified applications or listed applications.

The Iris lactea extract can be applied to skin external agent, health food and medicine, especially can be applied to cosmetics, and different dosage can be added according to different types of preparation.

The composition for external preparation for skin is a general concept of all ingredients generally used for the external part of skin, and may be, for example, a cosmetic composition or a pharmaceutical composition. The cosmetic composition may be a basic cosmetic, a face makeup cosmetic, a body cosmetic, a hair care cosmetic, etc., and the formulation thereof is not particularly limited and may be appropriately selected depending on the purpose.

The cosmetic composition also contains different cosmetically acceptable media or matrix excipients according to different formulations and purposes.

The cosmetically, dermatologically or pharmaceutically acceptable vehicle that can be used in the composition for external application to skin of the present invention may be in the form of a water phase, an oil phase, a gel, a wax-in-water type emulsion, an oil-in-water type emulsion or a water-in-oil type emulsion. The aqueous phase is a mixture of one or more water-soluble or dispersible components, which may be liquid, semi-solid, or solid at room temperature. The vehicle includes or may be in the form of a suspension, dispersion or solution in an aqueous or hydro-alcoholic vehicle, which may contain a thickening or gelling agent. The person skilled in the art can select suitable product forms, the components contained therein, based on the knowledge of the person skilled in the art.

The composition may comprise an aqueous phase which may contain water or a mixture of water and at least one hydrophilic organic solvent such as an alcohol, in particular a linear or branched lower monohydric alcohol containing from 2 to 5 carbon atoms, such as ethanol or propanol; polyols, such as propylene glycol, sorbitol, glycerol, panthenol or polyethylene glycols and mixtures thereof.

When the composition of the invention is in the form of an emulsion, the composition may also optionally comprise a surfactant.

The composition may also comprise film-forming polymers such as polyurethanes, polyacrylic acid homo-or copolymers, polyesters, hydrocarbon-based resins and/or silicone resins. The polymer may be dissolved or dispersed in a cosmetically acceptable vehicle and optionally combined with a plasticizer.

The compositions of the present invention may also comprise an oil phase containing oil-soluble or oil-dispersible components that are liquid at room temperature and/or materials that are oily or waxy at room temperature, such as waxes, semisolids, gums, and mixtures thereof. The oil phase may also contain an organic solvent.

Typically liquid at room temperature, suitable oily substances include: hydrocarbon-based oils of animal origin, such as perhydrosqualene; hydrocarbon-based vegetable oils, such as liquid triglycerides of C4-10 fatty acids, e.g. heptanoic acid or octanoic acid triglycerides, or oils, e.g. sunflower oil, corn oil, soybean oil, grapeseed oil, castor oil, avocado oil, octanoic/decanoic acid triglycerides, jojoba oil; linear or branched hydrocarbons of mineral or synthetic origin, such as liquid paraffin and its derivatives, vaseline; synthetic esters and ethers, in particular esters of fatty alcohols, such as isopropyl myristate, 2-ethylhexyl palmitate, 2-octyldodecyl stearate, isostearyl isostearate; hydroxylated esters, such as isostearyl lactate, octyl hydroxystearate, octyl dodecyl hydroxystearate, heptanoates, octanoates and decanoates of fatty alcohols; polyol esters such as propylene glycol dicaprylate, neopentyl glycol diheptanoate, diethylene glycol diisononanoate, and pentaerythritol esters; c12-26-containing fatty alcohols, such as octyldodecanol, 2-butyloctanol, 2-hexyldecanol, 2-undecylpentadecanol, oleyl alcohol; fluoro and/or fluorosilicone oils based in part on hydrocarbons, silicone oils, volatile or non-volatile linear or cyclic polymethylsiloxanes which are liquid or semi-solid at room temperature, such as cyclic polydimethylsiloxanes and polydimethylsiloxanes, optionally containing phenyl groups, such as phenyltrimethicones, silicones and mixtures thereof.

The composition of the present invention may further comprise any component commonly used in the cosmetic field. These components include preservatives, aqueous phase thickeners (extract biopolymers, synthetic polymers) and fatty phase thickeners, fragrances, hydrophilic and lipophilic active agents and mixtures thereof.

The compositions of the invention may also comprise an additional particulate phase, which may be a pigment and/or a pearlescent agent and/or a filler used in cosmetic compositions.

Pigments may be present in the composition, suitable inorganic pigments include titanium oxide, zirconium oxide and cerium oxide as well as zinc oxide, iron oxide and ferric blue; suitable organic pigments include barium, strontium, calcium and aluminum lakes and carbon black.

Pearling agents may be present in the composition, suitable pearling agents include mica coated with titanium oxide, iron oxide or natural pigments.

Fillers may be present in the composition, suitable fillers include talc, silica, zinc stearate, mica, kaolin, nylon powder, polyethylene powder, teflon, starch, boron nitride, copolymer microspheres, such as silicone resin microbeads.

The oil phase of the compositions of the present invention may comprise one or more waxes, gums or mixtures thereof. Waxes include hydrocarbon-based waxes, fluoro waxes, and/or silicone waxes, and may be derived from vegetable, mineral, animal, and/or synthetic sources. Suitable waxes include beeswax, carnauba wax, candelilla wax, paraffin wax, microcrystalline wax, ozokerite; synthetic waxes include polyethylene waxes, silicone waxes containing C16-45. Gums are generally polydimethylsiloxanes or sodium carboxymethylcellulose or extracts, and semisolid substances are generally hydrocarbon-based compounds, such as lanolin and its derivatives.

The compositions of the present invention may be formulated into any suitable product form. Such product forms include, but are not limited to, aerosol sprays, creams, lotions, solids, liquids, dispersions, foams, gels, lotions, mousses, ointments, powders, patches, pomades, solutions, hand pump sprays, sticks, masks and towelettes. The compositions of the present invention may be conveniently used to prepare or as cosmetic, dermatological or pharmaceutical topical products by various methods well known in the art.

The composition for external skin preparations of the present invention may include one or more of the following ingredients: anti-allergic agents, antimicrobial agents, antioxidants, chelating agents, colorant depigmenting agents, emollients, emulsifiers, exfoliants, film formers, fragrances, humectants, insect repellents, lubricants, pharmaceutically active agents, moisturizers, light stabilizers, preservatives, skin protectants, skin penetration enhancers, sunscreens, stabilizers, surfactants, thickeners, viscosity modifiers, vitamins, or any combination thereof.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail with reference to the following embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and do not limit the invention.

Example 1 preparation of Iris lactea extract

(1) 4500g of the crushed Chinese iris is weighed, 20L of 70v/v% ethanol solution is added, and the cold soaking is carried out for 12 hours until the solvent fully soaks the materials. Heating to 60 deg.C, extracting for 2 hr, filtering, collecting extractive solution, and extracting for 3 times. Mixing the three extractive solutions, and vacuum drying under reduced pressure to obtain 100g of crude extract of Iris lactea.

(2) Weighing 10g of the Chinese iris crude extract, dissolving with DMSO, passing through macroporous adsorbent resin AB-8, eluting with 1 column volume of deionized water, and discarding the water washing solution. Then eluting with 5 times column volume of 30v/v% ethanol solution and 70v/v% ethanol solution sequentially, mixing eluates, concentrating, and evaporating to dryness to obtain 0.6g of 30v/v% ethanol solution elution part and 0.5g of 70v/v% ethanol solution elution part.

Example 2 antioxidant Activity study of Iris lactea extract

1,1-Diphenyl-2-trinitrophenylhydrazine (DPPH) is a stable nitrogen-centered organic radical. The DPPH method was proposed in 1958 and widely used to quantitatively determine the anti-aging ability of biological samples, classified substances and foods. The method is based on the characteristic that DPPH free radical has single electron, strong absorption is provided at 517nm, and alcoholic solution is purple. When the free radical scavenger exists, the absorption of the free radical scavenger disappears gradually due to the pairing with a single electron of the free radical scavenger, and the quantity of electrons forms a quantitative relation with the fading degree and the acceptance of the fading degree, so that a spectrophotometer can be used for carrying out rapid quantitative analysis to detect the free radical scavenging condition, and the anti-aging capability of a sample is evaluated.

Taking the iris lactea crude extract prepared in the example 1 and the elution part of each ethanol solution, preparing the mixture into 0.1mg/mL by DMSO, adding 2mL of sample solution into a test tube, adding 2mL of 76 mu M DPPH ethanol solution, uniformly mixing, reacting in the dark for 30min in the dark at room temperature, and measuring absorbance Abs at 525 nm; the clearance was calculated according to the following formula, and the results are shown in Table 1.

Clearance I (%) = [1- (T-T0)/(C-C0) ]. Times.100%

In the formula: t0: absorbance of 0.1ml DMSO plus 2ml DPPH solution;

t: absorbance of 0.1ml sample plus 2ml DPPH solution;

c0: absorbance of 0.1ml DMSO plus 2ml 95% ethanol;

c: absorbance of 0.1ml sample solution with 2ml 95% ethanol. ,

TABLE 1

As can be seen from table 1, the irisquinone extract has excellent radical scavenging action and is useful as an effective antioxidant, and the irisquinone extract can be used as an antioxidant active substance for preventing skin aging and maintaining a young and healthy skin state by being incorporated into an external preparation.

Example 3 Elisa iris extract-inhibiting elastase action study

Elastase (Elastase) is a proteolytic enzyme characterized by the breakdown of insoluble proteins, which excessively degrades the elastin that supports the skin structure in the dermis of the skin, causing the skin to develop signs of aging such as wrinkles, sagging skin, and inelasticity. The protease inhibitor can effectively inhibit the activity of elastase, thereby playing roles in enhancing skin elasticity, reducing wrinkles and pigmentation, delaying skin aging and the like.

The irisquinone extract prepared in example 1 was prepared to 6 mg/mL, and the inhibitory effect of elastase was determined by the following method. And setting a sample tube and a sample solvent control tube, and setting a blank control and a blank solvent control. mu.L of each of the sample solutions of different concentrations was added to the sample tube and the sample solvent control tube, and the blank control and the blank solvent control tube were replaced with 10. Mu.L of 0.1M Tris-HCl buffer solution (pH 8.0) buffer. mu.L of 0.1M Tris-HCl buffer (pH 8.0) containing 1.015mM of the reaction substrate Succ-Ala-Ala-Ala-p-nitroanilide, mixed well and incubated at 25 ℃ for 5 minutes. mu.L of elastase solution (0.5U/mL) was added to the sample and blank control tubes, the sample solvent control and blank solvent control tubes were replaced with 10. Mu.L of 0.1M Tris-HCl buffer (pH 8.0), all tubes were shaken and incubated at 25 ℃ for 30min. The absorbance was immediately measured at 410 nm. The inhibition ratio was calculated according to the following formula, and the calculation results are shown in table 2.

Inhibition ratio I (%) = [1- (T-T0)/(C-C0) ]. Times.100%

In the formula: t0: sample solvent control; t: a sample control; c: blank control; c0: blank solvent control.

TABLE 2

As is clear from table 2, the iris lactea extract, the iris lactea crude extract, the iris lactea 30v/v% ethanol solution elution portion and the iris lactea 70v/v% ethanol solution elution portion all had excellent elastase inhibitory activity, and the iris lactea extract was blended with an external preparation and used as an anti-aging agent for preventing skin aging and maintaining a young and healthy skin state.

Example 4 study of anti-aging Activity of Iris lactea extract

The iris lactea extract prepared according to example 1 was prepared into a 0.02% solution with DMSO, and added to the culture solution of human fibroblasts, with DMSO without sample as a blank. After 48 hours of culture, after staining the cells by MTT method, measuring the absorbance at 490nm by a microplate reader, evaluating the proliferation effect on human fibroblasts, wherein the proliferation rate of the blank control is 100%, and the proliferation rate higher than 100% is the proliferation effect on the cells. Taking cell supernatant sample, and determining collagen production with type I collagen determination kit, wherein the increase rate of blank control is 100%, and the increase rate is more than 100% for promoting collagen production. The test results are shown in table 3.

TABLE 3

	Fibroblast proliferation Rate (%)	Type I collagen Synthesis Rate (%)
			Crude extract	100.12±1.89	103.02±2.76
Elution site with 30v/v% ethanol solution	106.12±2.34	104.02±1.56
			70v/v% ethanol solution elution part	129.44 ± 9.96	155.66 ±8.64

As can be seen from table 3, a statistically significant difference was observed between the blank control and the iris lactea extract, indicating that the iris lactea extract has a good proliferation effect on human fibroblasts and an activity of promoting the production of type I collagen. Therefore, the iris lactea extract can be blended with a skin external preparation to be used as an anti-aging agent for preventing skin aging and maintaining a young and healthy skin state.

Example 5 tyrosinase activity inhibition study of Iris lactea extract

The crude extract of Iris lactea and each part were mixed with DMSO to give 0.5 mg/mL, and tyrosinase inhibitory effect was measured by the following method. And setting a sample tube and a sample solvent control tube, and setting a blank control and a blank solvent control. 80 μ L of each sample solution was added to the sample tube and the sample solvent control tube, and the blank control and the blank solvent control tube were replaced with 80 μ L of phosphate buffer. 80 μ L of 1.66mM tyrosine solution was added, mixed well, and incubated in a constant temperature water bath at 37 ℃ for 5 minutes. Mu.l tyrosinase solution (enzyme activity unit 125 u/ml) was added to the sample and blank control tubes, the sample solvent control and blank solvent control tubes were replaced with 10. Mu.l phosphate buffer (pH = 6.8), all tubes were shaken and incubated in a 37 ℃ water bath for 10 minutes. The absorbance was immediately measured at 475 nm. The inhibition ratio was calculated according to the following formula, and the calculation results are shown in Table 4.

Inhibition ratio I (%) = [1- (T-T0)/(C-C0) ]. Times.100%

TABLE 4

As is clear from table 4, all of the above three types of iris lactea extracts have tyrosinase activity inhibitory activity, and can be used as a whitening active substance for preventing skin pigmentation by blending the iris lactea extract into an external preparation.

Example 6 study of Iris lactea extract on inhibition of tyrosinase and melanin synthesis in mouse B16 melanoma cells

The inhibition effect of the iris lactea crude extract and the active site on tyrosinase is measured by an L-Dopa oxidation method, and the test concentration is 0.1 mg/mL. B16 melanocytes at 1 × 10 ⁵ Culturing in 96-well plate at a density of 24 hr, changing the solution, adding the extract solution, culturing for 48 hr, adding 90 μ L of 1% TritonX-100-containing PBS buffer solution into each well, and adding 10 μ L of 1.0 mg. ML ^-1 L-DOPA, ultrasonic 30s,30 ℃ for 30min, and then measuring the absorbance of 475 nm. The enzyme activity was calculated as follows: tyrosinase inhibition = [1- (experimental OD value/experimental cell density)/(control OD value/control cell density)]X 100%, the calculation results are shown in Table 5.

The inhibition effect of the iris lactea crude extract and the active site on melanin is measured by adopting an improved method such as Hosoi, and the test concentration is 0.1 mg/mL. B16 melanocytes at 1 × 10 ⁵ Culturing in 96-well plate at a density, changing solution after 24 hr, adding extract solution, culturing for 72 hr, washing with PBS twice, air drying the sample, dissolving in 200 μ l 1N NAOH, heating to 80 deg.C for 1 hr, cooling, and reading absorbance at 475nm wavelength on ELISA. Calculating the melanin content inhibition rate according to the formula: melanin content inhibition = [1- (experimental OD value/experimental cell density)/(control OD value/control cell density)]X 100%, the calculation results are shown in Table 5.

TABLE 5

	Tyrosinase inhibition (%)	Melanin content inhibition (%)
			Crude extract	1.03±0.64	1.98±2.65
Elution site with 30v/v% ethanol solution	12.54±3.57	2.23±1.09
			70v/v% ethanol solution elution part	89.12±8.19	16.15±3.73

As shown in table 5, the three types of iris lactea extracts have excellent inhibitory effects on melanin proliferation and melanin synthesis of B16 cells.

Example 7 skin external preparation containing Iris lactea extract

The iris lactea extract prepared in the example 1 was used for preparing a skin external preparation. The skin external preparation is preferably a cosmetic composition such as a lotion, essence, cream, etc. The weight percentage of the Iris lactea extract in the skin external preparation is 0.0001-3, preferably 0.5-3. The following are examples of specific applications of the iris lactea extract in the skin external preparation. In the tables, "-" indicates no addition.

Example 8 cosmetic water containing Iris lactea extract

The iris lactea extract is used for preparing the toning lotion with the functions of resisting aging and whitening, and the toning lotion comprises the following components in a table 6:

TABLE 6

Example 9 essence containing Iris lactea extract

The iris lactea extract is used for preparing the essence with the functions of resisting aging and whitening, and the essence contains the following components as shown in a table 7:

TABLE 7

Example 10 emulsion/cream containing Iris lactea extract

The iris lactea extract is used for preparing the emulsion/cream with the effects of resisting aging and whitening, and the emulsion/cream contains the following components as shown in a table 8:

TABLE 8

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents and improvements made within the spirit and principle of the present invention are intended to be included within the scope of the present invention.

Claims

1. The use of the iris lactea extract as an active ingredient for inhibiting tyrosinase activity and/or inhibiting elastase activity and/or promoting human fibroblast proliferation and/or promoting type I collagen production in the preparation of a skin external preparation,

the Chinese iris extract is prepared by the following method:

step 1, crushing Chinese iris, adding an ethanol water solution for extraction, carrying out solid-liquid separation to obtain a filtrate, and removing ethanol and water from the filtrate to obtain a Chinese iris crude extract;

step 2, dissolving the Chinese iris crude extract by adding a solvent, loading the sample to macroporous adsorption resin, performing gradient elution by using deionized water and ethanol solution with gradient concentration from low to high in sequence, respectively collecting the ethanol-eluted eluent, and removing ethanol and water to obtain the Chinese iris extract; the ethanol solution with gradient concentration from low to high in the step 2 is a gradient concentration ethanol solution consisting of 30v/v% ethanol solution and 70v/v% ethanol solution.

2. The use according to claim 1, wherein the mass-to-volume ratio of the iris lactea to the ethanol aqueous solution in the step 1 is 1 g; the concentration of the ethanol water solution is 65-75 v/v%.

3. The use according to claim 1, wherein the macroporous adsorbent resin is an AB-8 type macroporous adsorbent resin.

4. The application of claim 1, wherein the extraction manner of step 1 is: pulverizing Chinese iris, adding ethanol water solution, and cold soaking for 11-13 hr; heating, extracting at 55-65 deg.C for 1-3 hr, filtering, collecting extractive solution, heating for 1-3 times, mixing extractive solutions, and removing ethanol and water to obtain Chinese iris crude extract.

5. The use of claim 1, wherein the gradient elution in step 2 is performed by using 5 times of the volume of the adsorption column per elution of the ethanol solution.

6. The use of any one of claims 1 to 5, wherein the Iris lactea extract is present in the external composition for skin in an amount of 0.0001 to 3 wt%.

7. The use according to claim 6, wherein the weight percentage of the Iris lactea extract in the skin external composition is 0.5-3.