Application of curcumin derivative in whitening aspect

Abstract

The invention belongs to the technical field of whitening products, and discloses application of curcumin derivatives in whitening. The invention discovers that dimethyl curcumin has the whitening-related effects for the first time, specifically, the dimethyl curcumin can inhibit melanogenesis and tyrosinase activity, is good in inhibition effect, low in onset concentration and non-irritant to red blood cells, and shows that the dimethyl curcumin has certain safety and has huge potential of being applied to whitening products; meanwhile, the invention also finds that after the dimethyl curcumin is combined with other curcumin derivatives (one or more of tetrahydrocurcumin, hexahydrocurcumin, octahydrocurcumin, demethoxycurcumin and tetramethyl curcumin), the dimethyl curcumin and other curcumin derivatives show a synergistic interaction effect on the in-vitro whitening effect, so that the whitening effect is further improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of whitening products, and particularly relates to the application of curcumin derivatives in whitening. Background Art

[0002] Melanin is mainly synthesized by melanocytes. Under the catalysis of related enzymes such as tyrosinase (TYR), tyrosinase-related protein 1 / 2 (TRP1 / 2), etc., through a series of oxidation synthesis reactions, a high-molecular compound is generated, and its content and distribution determine the color presented by human skin. Once melanin undergoes abnormal synthesis, metabolism, and accumulation in the body, it will lead to some common pigmentation disorders, such as solar lentigines, melasma, and post-inflammatory hyperpigmentation, which may even become an inducing factor for the occurrence of melanoma, posing serious aesthetic and health problems to people. At present, the only registered whitening agent ingredient approved and recognized by the drug administration in China is phenethyl resorcinol. Over the years, the development process of whitening agents has been relatively slow, while the market share and demand of the whitening market are gradually expanding. The existing number and categories of whitening agents are difficult to meet the development needs of the current whitening market. The existing whitening ingredients include various forms such as natural, synthetic monomer ingredients, extracts, etc. Small molecule compounds usually have good transdermal absorbability, and they often have stronger whitening effects compared to macromolecular polypeptides, plant extracts, and other raw material ingredients. They occupy a major position in the raw materials for whitening cosmetics at present. However, some synthetic small molecules have limitations in the application of whitening cosmetics due to their certain irritation and poor safety. For example, azelaic acid, kojic acid, etc. Natural plant-derived small molecule compounds usually have higher safety compared to some artificial and chemically synthesized ingredients. In addition, modern whitening is based on the concept of "returning to nature", and in order to better solve the shortcomings of individual existing whitening ingredients being prone to irritation and allergies, screening safe, efficient, and mild whitening ingredients from natural products has become a research hotspot in cosmetics development.

[0003] Dimethylcurcumin (CAS: 52328-98-0), also known as ASC-J9, is an androgen receptor degradation enhancer that can effectively inhibit the proliferation and invasion of drug-resistant prostate cancer cells (the reference is PMID: 22355276). At the same time, it also has a certain inhibitory effect on other types of tumors, such as liver cancer and renal cell carcinoma (the references are PMID: 27668844, PMID: 24924778), can improve spinal and bulbar muscular atrophy (the reference is PMID: 17334372), and has a certain protective effect on the heart (the reference is PMID: 28246012). The existing public patents related to dimethylcurcumin mainly focus on its application in the technical fields of drug delivery systems and biopharmaceuticals. For example, the existing patented technologies disclose that dimethylcurcumin can be applied to the treatment of renal failure in pets (publication number: CN118743679A), and the killing of tumor cells such as prostate cancer cells (publication numbers: CN111973756A, CN118403011A). There is no report on the application of dimethylcurcumin in the field of whitening. Summary of the Invention

[0004] The present invention aims to solve at least one of the technical problems existing in the above-mentioned prior art. For this purpose, the present invention provides the application of curcumin derivatives in whitening. The present invention discovers for the first time that dimethylcurcumin has the effects of inhibiting melanogenesis and inhibiting tyrosinase activity, with good inhibitory effects, low effective concentrations, and low irritation, and has great potential for application in whitening products.

[0005] In the first aspect of the present invention, there is provided the application of curcumin derivatives in the preparation of products with whitening efficacy, wherein the curcumin derivatives include dimethylcurcumin or one or more of its pharmaceutically acceptable acids, bases, salts, esters, solvates, stereoisomers, and tautomers.

[0006] In some embodiments of the present invention, the curcumin derivatives further include one or more of tetrahydrocurcumin, hexahydrocurcumin, octahydrocurcumin, demethoxycurcumin, and tetramethylcurcumin.

[0007] In some embodiments of the present invention, the whitening efficacy includes inhibiting tyrosinase activity and / or inhibiting melanogenesis.

[0008] In some embodiments of the present invention, the addition amount of the curcumin derivatives in the product is ≤ 10 wt%, preferably ≤ 5 wt%, and more preferably ≤ 1 wt%.

[0009] In some embodiments of the present invention, the addition amount of the curcumin derivative in the product is 0.0000004 wt% (0.004 ppm) - 1 wt%, preferably 0.00004 wt% (0.4 ppm) - 1 wt%, and more preferably 0.0001 wt% (1 ppm) - 1 wt%.

[0010] In some embodiments of the present invention, the addition amount of the curcumin derivative in the product is 0.001 wt% - 1 wt%, preferably 0.01 wt% - 1 wt%, more preferably 0.01 wt% - 0.5 wt%, and even more preferably 0.01 wt% - 0.2 wt%.

[0011] In some embodiments of the present invention, the product includes cosmetics and / or topical skin preparations.

[0012] In a second aspect of the present invention, there is provided a whitening cosmetic, which includes dimethylcurcumin or one or more of its pharmaceutically acceptable acids, bases, salts, esters, solvates, stereoisomers, and tautomers.

[0013] In some embodiments of the present invention, the whitening cosmetic further includes one or more of tetrahydrocurcumin, hexahydrocurcumin, octahydrocurcumin, demethoxycurcumin, and tetramethylcurcumin.

[0014] In some embodiments of the present invention, the dosage form of the whitening cosmetic includes any one of aqueous solutions, emulsions, sprays, creams, essences, or masks.

[0015] In a third aspect of the present invention, there is provided a whitening topical skin preparation, which includes dimethylcurcumin or one or more of its pharmaceutically acceptable acids, bases, salts, esters, solvates, stereoisomers, and tautomers.

[0016] In some embodiments of the present invention, the whitening topical skin preparation further includes one or more of tetrahydrocurcumin, hexahydrocurcumin, octahydrocurcumin, demethoxycurcumin, and tetramethylcurcumin.

[0017] In a fourth aspect of the present invention, there is provided any one of the methods in 1) - 2), including the following steps: treating cells with a curcumin derivative, which includes dimethylcurcumin or one or more of its pharmaceutically acceptable acids, bases, salts, esters, solvates, stereoisomers, and tautomers;

[0018] 1) A method for non - therapeutically inhibiting tyrosinase activity in vitro;

[0019] 2) A method for non - therapeutically inhibiting melanogenesis in vitro.

[0020] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0021] The present invention firstly discovers that dimethylcurcumin has whitening-related effects, specifically manifested as the ability to inhibit melanin production and tyrosinase activity, with good inhibitory effects, low effective concentrations, and no irritation to red blood cells, indicating its certain safety and great potential for application in whitening products; at the same time, the present invention also discovers that after combining dimethylcurcumin with other curcumin derivatives (one or several of tetrahydrocurcumin, hexahydrocurcumin, octahydrocurcumin, demethoxycurcumin, tetramethylcurcumin), a synergistic effect is shown in the in vitro whitening effect, further improving the whitening effect. Detailed implementation manners

[0022] In order to make those skilled in the art more clearly understand the technical solutions of the present invention, the following examples are listed for illustration. It should be noted that the following examples do not limit the protection scope required by the present invention.

[0023] The sources of the raw material components used in the following examples and comparative examples are as follows:

[0024] Resveratrol (CAS: 501-36-0), tranexamic acid (CAS: 1197-18-8), 4-butylresorcinol (CAS: 18979-61-8), hydroquinone (CAS: 123-31-9), and niacinamide (CAS: 98-92-0) are all purchased from Shanghai Aladdin;

[0025] Dimethylcurcumin (CAS: 52328-98-0), octahydrocurcumin (CAS: 36062-07-4), hexahydrocurcumin (CAS: 36062-05-2), demethoxycurcumin (CAS: 22608-11-3), tetrahydrocurcumin (CAS: 36062-04-1), and tetramethylcurcumin (CAS: 52328-97-9) are all purchased from Shanghai TargetMol.

[0026] Example 1

[0027] This example provides a methyl derivative of curcumin, dimethylcurcumin (CAS: 52328-98-0).

[0028] It is dissolved with dimethyl sulfoxide (DMSO) as the solvent to prepare sample solutions with different concentrations for subsequent experimental tests.

[0029] Example 2

[0030] This embodiment provides a curcumin derivative composition, which consists of dimethylcurcumin (CAS: 52328-98-0) and octahydrocurcumin (CAS: 36062-07-4).

[0031] Dissolve it with DMSO as the solvent to prepare sample solutions with different concentrations for subsequent experimental tests.

[0032] Example 3

[0033] This embodiment provides a curcumin derivative composition, which consists of dimethylcurcumin (CAS: 52328-98-0) and tetrahydrocurcumin (CAS: 36062-04-1).

[0034] Dissolve it with DMSO as the solvent to prepare sample solutions with different concentrations for subsequent experimental tests.

[0035] Example 4

[0036] This embodiment provides a curcumin derivative composition, which consists of dimethylcurcumin (CAS: 52328-98-0) and hexahydrocurcumin (CAS: 36062-05-2).

[0037] Dissolve it with DMSO as the solvent to prepare sample solutions with different concentrations for subsequent experimental tests.

[0038] Example 5

[0039] This embodiment provides a curcumin derivative composition, which consists of dimethylcurcumin (CAS: 52328-98-0) and demethoxycurcumin (CAS: 22608-11-3).

[0040] Dissolve it with DMSO as the solvent to prepare sample solutions with different concentrations for subsequent experimental tests.

[0041] Example 6

[0042] This embodiment provides a curcumin derivative composition, which consists of dimethylcurcumin (CAS: 52328-98-0) and tetramethylcurcumin (CAS: 52328-97-9).

[0043] Dissolve it with DMSO as the solvent to prepare sample solutions with different concentrations for subsequent experimental tests.

[0044] Example 7

[0045] This example provides a curcumin derivative composition, which consists of dimethylcurcumin (CAS: 52328-98-0), tetramethylcurcumin (CAS: 52328-97-9), and octahydrocurcumin (CAS: 36062-07-4).

[0046] Using DMSO as a solvent for dissolution, sample solutions with different concentrations are prepared for subsequent experimental tests.

[0047] Example 8

[0048] This example provides a curcumin derivative composition, which consists of dimethylcurcumin (CAS: 52328-98-0), tetrahydrocurcumin (CAS: 36062-04-1), and octahydrocurcumin (CAS: 36062-07-4).

[0049] Using DMSO as a solvent for dissolution, sample solutions with different concentrations are prepared for subsequent experimental tests.

[0050] Example 9

[0051] This example provides a curcumin derivative composition, which consists of dimethylcurcumin (CAS: 52328-98-0), hexahydrocurcumin (CAS: 36062-05-2), and octahydrocurcumin (CAS: 36062-07-4).

[0052] Using DMSO as a solvent for dissolution, sample solutions with different concentrations are prepared for subsequent experimental tests.

[0053] Example 10

[0054] This example provides a curcumin derivative composition, which consists of dimethylcurcumin (CAS: 52328-98-0), demethoxycurcumin (CAS: 22608-11-3), and octahydrocurcumin (CAS: 36062-07-4).

[0055] Using DMSO as a solvent for dissolution, sample solutions with different concentrations are prepared for subsequent experimental tests.

[0056] Example 11

[0057] This example provides a curcumin derivative composition, which consists of dimethylcurcumin (CAS: 52328-98-0), tetramethylcurcumin (CAS: 52328-97-9), and octahydrocurcumin (CAS: 36062-07-4).

[0058] Using DMSO as a solvent for dissolution, sample solutions with different concentrations are prepared for subsequent experimental tests.

[0059] Example 12

[0060] This example provides a curcumin derivative composition, which consists of dimethylcurcumin (CAS: 52328-98-0), tetramethylcurcumin (CAS: 52328-97-9), and tetrahydrocurcumin (CAS: 36062-04-1).

[0061] Dissolve it with DMSO as the solvent to prepare sample solutions with different concentrations for subsequent experimental tests.

[0062] Example 13

[0063] This example provides a curcumin derivative composition, which consists of dimethylcurcumin (CAS: 52328-98-0), tetramethylcurcumin (CAS: 52328-97-9), and hexahydrocurcumin (CAS: 36062-05-2).

[0064] Dissolve it with DMSO as the solvent to prepare sample solutions with different concentrations for subsequent experimental tests.

[0065] Example 14

[0066] This example provides a curcumin derivative composition, which consists of dimethylcurcumin (CAS: 52328-98-0), tetramethylcurcumin (CAS: 52328-97-9), and demethoxycurcumin (CAS: 22608-11-3).

[0067] Dissolve it with DMSO as the solvent to prepare sample solutions with different concentrations for subsequent experimental tests.

[0068] Example 15

[0069] This example provides a curcumin derivative composition, which consists of dimethylcurcumin (CAS: 52328-98-0), tetrahydrocurcumin (CAS: 36062-04-1), and hexahydrocurcumin (CAS: 36062-05-2).

[0070] Dissolve it with DMSO as the solvent to prepare sample solutions with different concentrations for subsequent experimental tests.

[0071] Comparative Example 1

[0072] This comparative example provides a phenolic structure compound, resveratrol (CAS: 501-36-0).

[0073] Dissolve it with DMSO as the solvent to prepare sample solutions with different concentrations for subsequent experimental tests.

[0074] Comparative Example 2

[0075] This comparative example provides a phenolic structural compound, hydroquinone (CAS: 123-31-9).

[0076] Dissolve it with DMSO as the solvent to prepare sample solutions with different concentrations for subsequent experimental tests.

[0077] Comparative Example 3

[0078] This comparative example provides a phenolic structural compound, 4-butylresorcinol (CAS: 18979-61-8).

[0079] Dissolve it with DMSO as the solvent to prepare sample solutions with different concentrations for subsequent experimental tests.

[0080] Comparative Example 4

[0081] This comparative example provides a lysine synthetic derivative, tranexamic acid (CAS: 1197-18-8).

[0082] Dissolve it with deionized water as the solvent to prepare sample solutions with different concentrations for subsequent experimental tests.

[0083] Comparative Example 5

[0084] This comparative example provides an amide derivative, nicotinamide (CAS: 98-92-0).

[0085] Dissolve it with deionized water as the solvent to prepare sample solutions with different concentrations for subsequent experimental tests.

[0086] Comparative Example 6

[0087] This comparative example provides a phenolic curcumin hydrogenated derivative, hexahydrocurcumin (CAS: 36062-05-2).

[0088] Dissolve it with DMSO as the solvent to prepare sample solutions with different concentrations for subsequent experimental tests.

[0089] Comparative Example 7

[0090] This comparative example provides a curcumin methyl derivative, demethoxycurcumin (CAS: 22608-11-3).

[0091] Dissolve it with DMSO as the solvent to prepare sample solutions with different concentrations for subsequent experimental tests.

[0092] Comparative Example 8

[0093] This comparative example provides a phenolic curcumin hydrogenated derivative, octahydrocurcumin (CAS: 36062-07-4).

[0094] Dissolve it with DMSO as the solvent to prepare sample solutions with different concentrations for subsequent experimental tests.

[0095] Comparative Example 9

[0096] This comparative example provides a phenolic curcumin hydrogenated derivative, tetrahydrocurcumin (CAS: 36062-04-1).

[0097] Dissolve it with DMSO as the solvent to prepare sample solutions with different concentrations for subsequent experimental tests.

[0098] Comparative Example 10

[0099] This comparative example provides a curcumin methyl derivative, tetramethylcurcumin (CAS: 52328-97-9).

[0100] Dissolve it with DMSO as the solvent to prepare sample solutions with different concentrations for subsequent experimental tests.

[0101] Comparative Example 11

[0102] This example provides a curcumin derivative composition composed of tetrahydrocurcumin (CAS: 36062-04-1) and octahydrocurcumin (CAS: 36062-07-4).

[0103] Dissolve it with DMSO as the solvent to prepare sample solutions with different concentrations for subsequent experimental tests.

[0104] Comparative Example 12

[0105] This example provides a curcumin derivative composition composed of hexahydrocurcumin (CAS: 36062-05-2) and octahydrocurcumin (CAS: 36062-07-4).

[0106] Dissolve it with DMSO as the solvent to prepare sample solutions with different concentrations for subsequent experimental tests.

[0107] Comparative Example 13

[0108] This example provides a curcumin derivative composition composed of demethoxycurcumin (CAS: 22608-11-3) and octahydrocurcumin (CAS: 36062-07-4).

[0109] Dissolve it with DMSO as the solvent to prepare sample solutions with different concentrations for subsequent experimental tests.

[0110] Comparative Example 14

[0111] This example provides a curcumin derivative composition, which consists of tetramethylcurcumin (CAS: 52328-97-9) and octahydrocurcumin (CAS: 36062-07-4).

[0112] Dissolve it with DMSO as the solvent to prepare sample solutions with different concentrations for subsequent experimental tests.

[0113] Comparative Example 15

[0114] This example provides a curcumin derivative composition, which consists of tetrahydrocurcumin (CAS: 36062-04-1) and demethoxycurcumin (CAS: 22608-11-3).

[0115] Dissolve it with DMSO as the solvent to prepare sample solutions with different concentrations for subsequent experimental tests.

[0116] Comparative Example 16

[0117] This example provides a curcumin derivative composition, which consists of hexahydrocurcumin (CAS: 36062-05-2) and demethoxycurcumin (CAS: 22608-11-3).

[0118] Dissolve it with DMSO as the solvent to prepare sample solutions with different concentrations for subsequent experimental tests.

[0119] Comparative Example 17

[0120] This example provides a curcumin derivative composition, which consists of tetrahydrocurcumin (CAS: 36062-04-1), hexahydrocurcumin (CAS: 36062-05-2) and octahydrocurcumin (CAS: 36062-07-4).

[0121] Dissolve it with DMSO as the solvent to prepare sample solutions with different concentrations for subsequent experimental tests.

[0122] Comparative Example 18

[0123] This example provides a curcumin derivative composition, which consists of hexahydrocurcumin (CAS: 36062-05-2), octahydrocurcumin (CAS: 36062-07-4) and demethoxycurcumin (CAS: 22608-11-3).

[0124] Dissolve it with DMSO as the solvent to prepare sample solutions with different concentrations for subsequent experimental tests.

[0125] Comparative Example 19

[0126] This embodiment provides a curcumin derivative composition, which is composed of tetrahydrocurcumin (CAS: 36062-04-1), demethoxycurcumin (CAS: 22608-11-3), and tetramethylcurcumin (CAS: 52328-97-9).

[0127] It is dissolved with DMSO as a solvent to prepare sample solutions with different concentrations for subsequent experimental tests.

[0128] Test Example 1 Experiment on Inhibition of Melanin Synthesis and Tyrosinase Activity

[0129] 1.1 Sample Solution

[0130] The sample solutions prepared in Examples 1-15 and Comparative Examples 1-19 were tested, and the specific concentrations are shown in Tables 1-3.

[0131] 1.2 Experimental Principle

[0132] Melanin is a biological pigment synthesized and secreted by melanocytes. Inside melanocytes, tyrosine is catalyzed by tyrosinase and undergoes a series of reactions to finally form melanin.

[0133] B16-F10 mouse melanoma cells are widely used as test cells for the determination of the efficacy of whitening chemicals. α-MSH is α-melanocyte-stimulating hormone, which can promote the secretion of melanin by B16-F10 and enhance the activity of tyrosinase in cells. By inducing B16-F10 with α-MSH, the inhibitory effect of the test substance on melanin synthesis and the inhibitory effect on tyrosinase activity are determined.

[0134] 1.3 Experimental Method

[0135] (1) Cell Culture and Treatment

[0136] B16-F10 cells are cultured in a 1640 complete medium (1640 medium + 10% volume fraction of FBS + double antibodies) in a carbon dioxide incubator at 37°C and 5% CO2, and passaged every 2-3 days.

[0137] (2) Determination of Intracellular Melanin Content

[0138] Select B16-F10 cells in the logarithmic growth phase. After digestion with 0.25% trypsin, inoculate them into a 6-well culture plate with 2 mL of medium per well and place them in an incubator at 37°C and 5% CO2. On the second day after inoculation, add media containing different concentrations of the test substance and α-MSH (1 μM), and set up a control group (containing only 1 μM of α-MSH), 2 mL per well, with 3 parallels for each concentration. After incubation at 37°C and 5% CO2 for 48 h, discard the supernatant. Add 0.5 mL of 0.25% trypsin digestion solution to each well and digest at room temperature for 1 min. Add 1 mL of medium to stop the digestion and pipette into a single-cell suspension. Take 20 μL for cell counting, take 0.7 mL of the cell suspension and centrifuge at 2000 r / min for 5 min. Discard the supernatant, add 1 mL of 1 mol / L NaOH solution (containing 10% DMSO by mass fraction), and incubate in a water bath at 80°C for 30 min. Then measure the absorbance at 490 nm using an enzyme-linked immunosorbent assay (ELISA) reader.

[0139] (3) Determination of intracellular tyrosinase activity

[0140] For the cells treated with the above drugs, after trypsin digestion and counting (the specific steps are the same as in 1.3-(2)), take 0.7 mL of the cell suspension and centrifuge at 2000 r / min for 5 min. Discard the supernatant, add 1 mL of 0.5% sodium deoxycholate solution by mass fraction, and incubate in an ice bath for 15 min to lyse the cells to prepare an extract containing tyrosinase. After pre-warming at 37°C, add 0.5 mL of 0.3% dopa solution, react at 37°C for 10 min, and then measure the absorbance at 475 nm using an ELISA reader.

[0141] (4) Result statistics

[0142] Calibrate the measured OD value with the cell count.

[0143] Melanin production inhibition rate (%) = [1 - (As / Ds) / (Ac / Dc)] × 100;

[0144] Tyrosinase activity inhibition rate (%) = [1 - (As / Ds) / (Ac / Dc)] × 100;

[0145] Where: As is the absorbance value of the sample group, Ac is the absorbance value of the control group, Ds is the cell concentration of the sample group, and Dc is the cell concentration of the control group.

[0146] 1.4 Experimental results

[0147] The results are shown in Table 1-3.

[0148] Table 1

[0149]

[0150]

[0151] It is understandable that melanin is mainly produced by melanocytes. The level of melanin content in the skin is closely related to problems such as the depth, dullness, skin spots, and uneven pigmentation of human skin color. Tyrosinase is the key enzyme that catalyzes the synthesis of melanin. Therefore, the whitening effect of the test substance can be judged by evaluating the melanin content and tyrosinase activity using melanocytes.

[0152] Resveratrol with a phenolic structure (Comparative Example 1), hydroquinone (Comparative Example 2), 4-butylresorcinol (Comparative Example 3), and amino acid and amide derivative tranexamic acid (Comparative Example 4), nicotinamide (Comparative Example 5) are all recognized raw material components for cosmetics with good whitening effects. From the results in Table 1, it can be seen that Example 1 (dimethylcurcumin) showed an obvious effect of inhibiting tyrosinase activity. At micromolar concentrations (2 μM, 1 μM), its tyrosinase inhibition rates can reach 67.20% and 34.02% respectively. The tyrosinase inhibition effect of Example 1 is significantly better than that of Comparative Examples 1-5.

[0153] In addition, Comparative Examples 6-8, which are also curcumin derivatives, showed relatively weak inhibitory effects on tyrosinase activity, significantly weaker than that of Example 1. Comparative Examples 9-10 showed the presence of tyrosinase inhibitory effects, but the inhibitory effect of Example 1 was significantly better than that of Comparative Example 9; at a concentration of 2 μM, the effect of Example 1 was slightly better than that of Comparative Example 10.

[0154] Table 2

[0155]

[0156]

[0157]

[0158]

[0159] From the results in Table 2, it can be seen that Examples 2 (dimethylcurcumin + octahydrocurcumin) with different concentrations and ratios showed strong inhibitory effects on tyrosinase, which were better than the effects of their single components at their respective concentrations. Taking Example 2 (dimethylcurcumin 1 μM + octahydrocurcumin 1 μM) as an example, its tyrosinase activity inhibition rate was 57.44%, which was better than that of Example 1 (34.02%) at 1 μM and Comparative Example 8 (≤0) at 1 μM. Examples 3-5, 7-14 (combinations of dimethylcurcumin with different curcumin derivatives to form two-component or three-component combinations) all showed better inhibitory effects on tyrosinase than their single components at their respective concentrations. Comparative Examples 11-14 showed that not any combination of curcumin derivatives could exhibit synergy in tyrosinase activity inhibition.

[0160] Table 3

[0161]

[0162]

[0163]

[0164] As can be seen from the results in Table 3, Example 1 (dimethylcurcumin) has a significantly stronger inhibitory effect on melanogenesis compared to Comparative Examples 6-9 (other curcumin derivative monomers), and the compositions formed by combining dimethylcurcumin with other curcumin derivatives (Examples 3 / 4 / 6 / 11 / 14 / 15) exhibit a better inhibitory effect on melanogenesis, which is superior to its single component. The results of Comparative Examples 6-9, 11-12, and 15-19 show that not any combination of curcumin derivatives can achieve a significantly stronger inhibitory effect on melanogenesis.

[0165] Based on the above results, dimethylcurcumin shows a strong whitening effect in vitro, specifically manifested as inhibiting melanogenesis and tyrosinase activity. At the same time, when dimethylcurcumin is compounded with other curcumin derivatives, such as one or several of tetrahydrocurcumin, hexahydrocurcumin, octahydrocurcumin, demethoxycurcumin, and tetramethylcurcumin, a better whitening effect in vitro can be shown.

[0166] Test Example 2 Erythrocyte Hemolysis Test

[0167] 1.1 Experimental Principle

[0168] Eye irritants can denature proteins or dissolve cell membranes. The test substance is applied to red blood cells to detect whether hemolysis occurs and whether it has a denaturing effect on the hemoglobin released from the cells. The degree of damage to the cell membrane by the test substance is evaluated by measuring the amount of leaked hemoglobin and its denaturation degree, and it is speculated whether it may have eye irritation. The erythrocyte hemolysis experiment simulates a damage effect similar to that of the cornea.

[0169] 1.2 Experimental Method (refer to EURL ECVAM DB-ALM Protocol No.99 and EURL ECVAM DB-ALMProtocol No.37)

[0170] (1) The test substances - Examples 1-4, 6, 11, 14-15 and Comparative Examples 1, 4-5, 9 were respectively prepared into suspensions with a series of gradients of 0.001%, 0.01%, 0.1%, 1%, 10%, 20%, 30%, 40%, etc. in mass fraction using normal saline as a solvent, mixed with the red blood cell suspension in an equal volume ratio, centrifuged after culturing at 37°C for 3 h to obtain the supernatant, and the absorbance was measured at 410 nm, 540 nm, and 575 nm with an enzyme-linked immunosorbent assay (ELISA) reader, and the results were statistically analyzed. Normal saline was used as a negative control (i.e., no hemolysis at all), and 0.1% SDS solution was used as a positive control (i.e., complete hemolysis).

[0171] (2) Result statistics

[0172] Hemolysis rate (%) = (A 410nm - C 410nm ) / (B 410nm - C 410nm ) × 100;

[0173] Protein denaturation index DI (%) = (A 575nm / A 540nm ) / (B 575nm / B 540nm ) × 100;

[0174] In the formula, A is the test sample, B is the positive control, and C is the average absorbance of the negative control, where the average absorbance value of the A / B sample at a concentration of 1% is used in the calculation of DI%.

[0175] With the sample concentration as the abscissa and the hemolysis rate as the ordinate, a curve is plotted, and the test substance concentration HC50 (mg / L) that causes 50% hemolysis of red blood cells by the test substance is determined according to the regression equation.

[0176] (3) Result determination

[0177] The L / D value of the sample is calculated according to the HC50 value and the DI value: L / D = HC50 / DI;

[0178] According to the RBC experiment grading standard of the European Centre for the Validation of Alternative Methods (ECVAM), the irritation degree of cosmetics is graded, and the grading standard is shown in Table 4.

[0179] Table 4

[0180] L / D Classification ﹥100 Non-irritating 10 < L / D ≤ 100 Slightly irritating 1 < L / D ≤ 10 Mildly irritating 0.1 < L / D ≤ 1 Moderately irritating L / D ≤ 0.1 Severely irritating

[0181] 1.3 Experimental results

[0182] The results are shown in Table 5.

[0183] Table 5

[0184]

[0185]

[0186] Comparative Examples 1, 4 - 5 are all raw material components of cosmetics with good effects and relatively popular in the current whitening field. It has been reported that Comparative Example 9 has certain in vitro whitening effects. From the results in Table 5, it can be seen that by comparing the irritation of different samples to red blood cells, Examples 1 - 4, 6, 11, 14 - 15 all showed no irritation and were relatively mild, which is similar to Comparative Examples 1, 4 - 5, 9. Therefore, from the perspective of safety, dimethylcurcumin and its complex formed with other curcumin derivatives (one or several of tetrahydrocurcumin, hexahydrocurcumin, octahydrocurcumin, demethoxycurcumin, tetramethylcurcumin) have the potential to be applied in the field of cosmetics.

[0187] Although dimethylcurcumin and the combination of curcumin derivatives containing it are not currently in the catalog of raw materials available for cosmetics, their irritation is relatively low and they have good whitening effects. The above characteristics provide good data support for their application in the field of cosmetics, especially in products with whitening effects.

[0188] Application Example 1

[0189] A composition consists of 5 wt% dimethylcurcumin and the balance solvent.

[0190] Application Example 2

[0191] A composition consists of 1 wt% dimethylcurcumin and the balance solvent.

[0192] Application Example 3

[0193] A composition consists of 0.01 wt% dimethylcurcumin and the balance solvent.

[0194] Application Example 4

[0195] A composition consists of 1 ppm dimethylcurcumin and the balance solvent.

[0196] Application Example 5

[0197] A composition consists of 0.4 ppm dimethylcurcumin and the balance solvent.

[0198] Application Example 6

[0199] A lotion consists of the following components in mass percentage:

[0200] Glycerol 6%, sodium hyaluronate 0.08%, xanthan gum 0.05%, p - hydroxyacetophenone 0.4%, 1,2 - hexanediol 1%, dimethylcurcumin 5% and the balance water.

[0201] Application Example 7

[0202] A facial mask is composed of the following components by mass percentage:

[0203] Glycerin 6%, disodium EDTA 0.02%, sodium hyaluronate 0.08%, xanthan gum 0.05%, carbomer 0.15%, hydroxyacetophenone 0.4%, 1,2 - hexanediol 1%, dimethylcurcumin 1% and the balance being water.

[0204] Application Example 8

[0205] An emulsion is composed of the following components by mass percentage:

[0206] Glycerin 10%, disodium EDTA 0.01%, acryloyldimethyltaurate / VP copolymer 0.1%, sodium hyaluronate 0.05%, hydroxyacetophenone 0.4%, 1,2 - hexanediol 1%, squalane 1.5%, dimethylcurcumin 0.01% and the balance being water.

[0207] Application Example 9

[0208] An emulsion is composed of the following components by mass percentage:

[0209] Glycerin 10%, disodium EDTA 0.01%, acryloyldimethyltaurate / VP copolymer 0.1%, sodium hyaluronate 0.05%, hydroxyacetophenone 0.4%, 1,2 - hexanediol 1%, squalane 1.5%, dimethylcurcumin 1 ppm and the balance being water.

[0210] Application Example 10

[0211] A serum is composed of the following components by mass percentage:

[0212] Carbomer 0.3%, aminomethylpropanol 0.1%, dipotassium glycyrrhizinate 0.3%, trehalose 0.6%, 1,2 - hexanediol 0.5%, hydroxyacetophenone 0.4%, ethanol 8%, dimethylcurcumin 0.4 ppm and the balance being water.

[0213] It can be understood that the compositions of Application Examples 1 - 5 of the present invention and the cosmetics of Application Examples 6 - 10 have good whitening effects because they contain dimethylcurcumin of the present invention respectively.

[0214] The above has specifically described the preferred embodiments of the present invention, but the present invention is not limited to the above - mentioned embodiments. Those skilled in the art can also make various equivalent variations or substitutions without departing from the spirit of the present invention, and these equivalent variations or substitutions are all included within the scope defined by the claims of this application.

Claims

1. Use of curcumin derivatives in the preparation of products with whitening effect, characterized in that, The curcumin derivatives include one or more of dimethylcurcumin or its pharmaceutically acceptable acids, bases, salts, esters, solvates, stereoisomers, and tautomers.

2. The application according to claim 1, wherein The curcumin derivatives further include one or more of tetrahydrocurcumin, hexahydrocurcumin, octahydrocurcumin, demethoxycurcumin, and tetramethylcurcumin.

3. The application according to claim 1, characterized in that The whitening effect includes inhibiting tyrosinase activity and / or inhibiting melanin production.

4. The application according to claim 1, characterized in that, The product includes cosmetics and / or topical skin preparations.

5. A whitening cosmetic, characterized in that, The whitening cosmetics include one or more of dimethylcurcumin or its pharmaceutically acceptable acids, bases, salts, esters, solvates, stereoisomers, and tautomers.

6. The whitening cosmetic according to claim 5, characterized in that, The whitening cosmetics further include one or more of tetrahydrocurcumin, hexahydrocurcumin, octahydrocurcumin, demethoxycurcumin, and tetramethylcurcumin.

7. The whitening cosmetic according to claim 5, characterized in that, The dosage form of the whitening cosmetics includes any one of aqueous solutions, emulsions, sprays, creams, essences, or masks.

8. A whitening topical skin preparation, characterized in that, The whitening topical skin preparation includes one or more of dimethylcurcumin or its pharmaceutically acceptable acids, bases, salts, esters, solvates, stereoisomers, and tautomers.

9. The whitening topical skin preparation according to claim 8, characterized in that, The whitening topical skin preparation further includes one or more of tetrahydrocurcumin, hexahydrocurcumin, octahydrocurcumin, demethoxycurcumin, and tetramethylcurcumin. Any one of the methods in 10.1) to 2) includes the following steps: Treating cells with curcumin derivatives, the curcumin derivatives include one or more of dimethylcurcumin or its pharmaceutically acceptable acids, bases, salts, esters, solvates, stereoisomers, and tautomers; 1) A method for non-therapeutically inhibiting tyrosinase activity in vitro; 2) A method for non-therapeutically inhibiting melanin production in vitro.

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