A stable olea europaea leaf extract composition

Abstract

The present application provides a stable olive leaf extract composition. The composition is achieved by adding an amino acid derivative, oxothiazolidine carboxylic acid, to the olive leaf extract. In addition, the present application also provides the use of the olive leaf extract and the oxothiazolidine carboxylic acid composition in cosmetics, and a method for preparing the above-mentioned composition. Finally, the present application proves that the addition of oxothiazolidine carboxylic acid as an antioxidant can significantly improve the discoloration problem of the olive leaf extract, and the addition of oxothiazolidine carboxylic acid can slow down the degradation of the main active substance, oleuropein, in the olive leaf extract.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of cosmetics, and particularly relates to a stable olea europaea leaf extract composition. BACKGROUND

[0002] Olea europaea L. belongs to Oleaceae and is a evergreen tree originally from the Mediterranean coast. It is a famous woody oil tree species in the world. Olea europaea leaf contains rich active ingredients, including oleuropein, hydroxytyrosol, flavonoids and polyphenols, etc. Studies have found that olea europaea leaf extract has effects including antioxidant, anti-inflammatory, antibacterial, antiviral, etc., and is widely used in the fields of medicine and cosmetics. However, the main active substances in olea europaea leaf, such as oleuropein, have low stability, and external environmental changes such as light, temperature, pH, acid, base, enzyme, etc. can cause degradation, affecting the biological activity (Yuan Qiaoqiao et al., Research Progress of Biosynthesis of Hydroxytyrosol in Olea europaea and Its Derivatives, Forest Chemistry and Industry, Vol. 35, No. 2, 2015, 154-162). Specifically, the color of olea europaea leaf extract deepens, and the content of active substances decreases.

[0003] Patent CN102273623A “Preparation method of olea europaea leaf extract” improves the stability of olea europaea leaf extract by improving the extraction process. Patent CN115245483A “Immune cell preparation and preparation method thereof” improves the stability of oleuropein by forming a gel, and patent CN107019672A “Preparation method of long-circulating liposome of olea europaea polyphenol extract rich in hydroxytyrosol and verbascoside” improves the stability of olea polyphenol by forming a liposome. Although the above methods can improve the stability of active substances in olea europaea leaf extract, the processing is too complex, and the practical significance of application in cosmetic formulations is limited. Therefore, it is necessary to develop a simple method to improve the stability of olea europaea leaf extract and expand its application range in cosmetic formulations. SUMMARY

[0004] Previous studies have proposed methods to stabilize olea europaea leaf extract by forming gels or encapsulating bodies through physical methods to reduce the influence of external environment on active substances to increase their stability. This method increases the processing steps of raw materials and limits the application of olea europaea leaf extract in cosmetics. Adding antioxidants or light stabilizers can increase the stability of plant extracts, but the properties of antioxidants and light stabilizers and their effects on the formula need to be considered.

[0005] The present application introduces a combination of an amino acid derivative and olea europaea leaf extract, which has good water solubility, high safety, can slow down the color change of olea europaea leaf extract caused by environmental changes, and can reduce the degradation rate of the main active substance oleuropein in olea europaea leaf extract to a certain extent.

[0006] In one aspect, the present application provides a composition for stabilizing an Olea europaea leaf extract, comprising an Olea europaea leaf extract and an oxothiazolidine carboxylic acid. The composition is obtained by adding the oxothiazolidine carboxylic acid to the Olea europaea leaf extract. The oxothiazolidine carboxylic acid is an amino acid derivative with a chemical formula of C4H5NO3S, a structural formula of L-2-oxothiazole-4 carboxylic acid, and a structural formula as shown in Formula 1:

[0007]

[0008] Further, the Olea europaea leaf extract in the composition can be extracted by a method such as a soaking extraction method, an ultrasonic-assisted extraction method, a microwave-assisted extraction method, a supercritical carbon dioxide extraction method, and the like, and the extraction method is not particularly limited. The extract can be a solution or a solid, and the form is not particularly limited. The Olea europaea leaf used for extraction has an oleuropein content of greater than 5%, and is stored in a cool and ventilated place to avoid degradation of the active substances.

[0009] Preferably, the Olea europaea leaf extract is prepared by a soaking extraction method + membrane separation process.

[0010] Further, the Olea europaea leaf extract contains the following substances: oleuropein, hydroxytyrosol, verbascoside, osmanthus glycoside, apigenin, quercetin, rutin, and kaempferol, etc. The above active substances generally have phenolic hydroxyl groups and conjugated structures, and are easily affected by oxygen, free radicals, temperature, and the like, and are easily deteriorated. Changes in color and efficacy affect the application range thereof in cosmetics. The addition of an antioxidant can protect the active substances and increase the shelf life thereof.

[0011] Further, the main component in the Olea europaea leaf extract is oleuropein, and the content thereof is greater than 0.1%.

[0012] Preferably, the content of oleuropein in the Olea europaea leaf extract is greater than 0.6%.

[0013] Further, the ratio of the oxothiazolidine carboxylic acid to the oleuropein in the Olea europaea leaf extract is (0.01-10): 1.

[0014] Preferably, the ratio of the oxothiazolidine carboxylic acid to the oleuropein in the Olea europaea leaf extract is (0.1-5): 1.

[0015] Further preferably, the ratio of the oxothiazolidine carboxylic acid to the oleuropein in the Olea europaea leaf extract is (0.5-2): 1.

[0016] In another aspect, the present application provides a method for stabilizing an Olea europaea leaf extract, by adding an oxothiazolidine carboxylic acid to the Olea europaea leaf extract to improve the stability.

[0017] Further, the ratio of the oxothiazolidine carboxylic acid to oleuropein in the olive leaf extract is (0.01-10): 1.

[0018] Preferably, the ratio of the oxothiazolidine carboxylic acid to oleuropein in the olive leaf extract is (0.1-5): 1.

[0019] Further preferably, the ratio of the oxothiazolidine carboxylic acid to oleuropein in the olive leaf extract is (0.5-2): 1.

[0020] In another aspect, the present application provides the use of oxothiazolidine carboxylic acid for the manufacture of a preparation for inhibiting the degradation of oleuropein in an olive leaf extract.

[0021] In another aspect, the present application provides the use of oxothiazolidine carboxylic acid for the manufacture of a preparation for improving the oxidative discoloration problem of an olive leaf extract.

[0022] In another aspect, the present application provides a cosmetic comprising the above stable olive leaf extract composition.

[0023] Further, in the cosmetic, the content of the composition ranges from 0.01 to 30%.

[0024] The advantageous effects of the present application include:

[0025] 1. A stable olive leaf extract composition is provided, comprising an olive leaf extract and oxothiazolidine carboxylic acid.

[0026] 2. It is demonstrated that the addition of oxothiazolidine carboxylic acid can slow down the degradation of the main active substance, oleuropein, in an olive leaf extract.

[0027] 3. It is demonstrated that the addition of oxothiazolidine carboxylic acid can significantly improve the oxidative discoloration problem of an olive leaf extract.

[0028] 4. The application range of olive leaf extract in cosmetics is greatly increased. BRIEF DESCRIPTION OF DRAWINGS

[0029] Figure 1 Effect of different antioxidants on the stability of olive leaf extract in formulations (Groups 1-10)

[0030] Figure 2 Effect of 0.15% oxothiazolidine carboxylic acid on the stability of olive leaf extract (Groups 11-18)

[0031] Figure 3 Effect of 0.3% oxothiazolidine carboxylic acid on the stability of olive leaf extract (Groups 19-30) DETAILED DESCRIPTION

[0032] Example 1 Study the difference of different antioxidants on the improvement of the stability of olive leaf extract

[0033] First, compared with the common antioxidants on the market such as pentaerythritol tetra (bis-tert-butyl hydroxylated cinnamic acid) ester, glucorutin, (tris (tetramethyl hydroxyl piperidol) citrate, diethylhexyl aminobenzoic acid, can oxothiazolidine carboxylic acid improve the stability of olive leaf extract? Therefore, ten groups of samples numbered 1-10 were used to study the difference of different antioxidants on the improvement of the stability of olive leaf extract, and the component ratio is shown in Table 1. The emulsion samples were prepared according to the following formula by using the common method in the industry, and the content of oleuropein in the olive leaf extract was 0.6%.

[0034] Table 1: Component ratio of groups 1-10

[0035]

[0036]

[0037]

[0038] The antioxidants in groups 1-10 include different concentrations of oxothiazolidine carboxylic acid, pentaerythritol tetra (bis-tert-butyl hydroxylated cinnamic acid) ester, glucorutin, (tris (tetramethyl hydroxyl piperidol) citrate, diethylhexyl aminobenzoic acid and their combinations.

[0039] The color change of examples 1-10 after storage for 10 days under different temperature conditions (-18℃, 4℃, RT, 48℃, some samples were not tested at room temperature) was observed. The results showed that under high temperature conditions, groups 3-10 all showed significant color deepening, that is, pentaerythritol tetra (bis-tert-butyl hydroxylated cinnamic acid) ester, glucorutin, (tris (tetramethyl hydroxyl piperidol) citrate and diethylhexyl aminobenzoic acid cannot improve the stability problem of olive leaf extract. The color change of groups 1 and 2 under high temperature conditions is less than that of other groups, that is, oxothiazolidine carboxylic acid has a certain improvement effect on the stability of olive leaf extract. Figure 1 The color change of groups 1-10 after storage for 10 days under different temperature conditions is listed.

[0040] The conclusions are as follows:

[0041] Pentaerythritol tetra (bis-tert-butyl hydroxylated cinnamic acid) ester, glucorutin, (tris (tetramethyl hydroxyl piperidol) citrate and diethylhexyl aminobenzoic acid cannot improve the stability problem of olive leaf extract. But oxothiazolidine carboxylic acid has a certain improvement effect on the stability of olive leaf extract.

[0042] Example 2 Study on the effect of oxothiazolidine carboxylic acid on the stability of olive leaf extract

[0043] In order to further study the effect of oxothiazolidine carboxylic acid on the stability of olive leaf extract, groups 11-18 were used to study the effect of temperature (4°C and 40°C, respectively) and pH value of aqueous solution (5.5 and 6, respectively) on the color of the solution. The composition and proportion of each group are shown in Table 2. The content of oleuropein in the olive leaf extract is greater than 1%.

[0044] Table 2: Composition and proportion of groups 11-18

[0045]

[0046]

[0047] After adjusting the pH to the specified value with micro-arginine and citric acid, groups 11-18 were placed in the corresponding temperature refrigerator or oven. The color change of the solution was observed on the 7th day, 14th day, and 28th day. In the samples without the addition of antioxidant oxothiazolidine carboxylic acid, it was observed that the color of the solution deepened with the extension of time, the increase of temperature, and the rise of pH. The color of the sample with the addition of oxothiazolidine carboxylic acid was significantly lighter than that of the sample without the addition of oxothiazolidine carboxylic acid under the same treatment conditions, i.e. oxothiazolidine carboxylic acid had a certain protective effect on the olive leaf extract and could slow down its oxidation discoloration. Figure 2 The color change of groups 11-18 after being placed at different temperatures for 10 days is listed.

[0048] The conclusions are as follows:

[0049] With the extension of time, the increase of temperature, and the rise of pH, the color of the solution deepened faster. The color of the sample with the addition of oxothiazolidine carboxylic acid was significantly lighter than that of the sample without the addition of oxothiazolidine carboxylic acid under the same treatment conditions, i.e. oxothiazolidine carboxylic acid had a certain protective effect on the olive leaf extract and could slow down its oxidation discoloration.

[0050] Example 3 Study on the effect of oxothiazolidine carboxylic acid content on the stability of olive leaf extract

[0051] The color change of olive leaf extract with 0.3% oxothiazolidine carboxylic acid content was studied under different temperatures (4°C and 40°C) and pH values (5, 5.5, and 6) using a similar test method as in the above examples. The composition and proportion of each group are shown in Table 3, and the color change results are shown in Table 4. The content of oleuropein in the olive leaf extract is greater than 1%. Figure 3

[0052] Table 3: Composition and proportion of groups 19-30

[0053] ​

[0054]

[0055] In the samples without the addition of the antioxidant oxothiazolidine carboxylic acid, the color of the solution was observed to darken over time, with an increase in temperature and an increase in pH. The samples with the addition of oxothiazolidine carboxylic acid were significantly lighter in color than the samples without the addition of oxothiazolidine carboxylic acid under the same treatment conditions, i.e., oxothiazolidine carboxylic acid has a certain protective effect on the olive leaf extract and can slow down the oxidation discoloration thereof. Figure 3 The color changes of groups 19-30 after being placed at different temperatures for 10 days are listed.

[0056] The conclusions are as follows:

[0057] Comparison Figure 2 and Figure 3 It can be seen from the corresponding samples (group 14 and group 26, group 18 and group 30) in Examples 1-3 that increasing the concentration of oxothiazolidine carboxylic acid can further slow down the oxidation discoloration of the olive leaf extract.

[0058] Example 4: Study on the effect of oxothiazolidine carboxylic acid on the degradation of oleuropein

[0059] The main active ingredient in the olive leaf extract is oleuropein. Oleuropein is easily degraded under the influence of environmental changes such as light, acid, base, and enzymes, which affects its biological activity. The content changes of oleuropein in groups 11-18 within 14 days were tested by HPLC, and the results are shown in Table 4.

[0060] Table 4: Content changes of oleuropein in groups 11-18 within 14 days

[0061]

[0062] By comparing the degradation rates of oleuropein in groups 11-18 under different aqueous solution conditions, it can be seen that increasing the pH of the aqueous solution and increasing the temperature can increase the degradation rate of oleuropein. In groups 11-18, on the 7th day, the addition of oxothiazolidine carboxylic acid does not affect the degradation of oleuropein; on the 14th day, under low temperature conditions, the addition of oxothiazolidine carboxylic acid has no effect on the degradation rate of oleuropein, and under high temperature conditions, in the aqueous solutions with pH = 5.5 and pH = 6, oxothiazolidine carboxylic acid can reduce the degradation rate of oleuropein. That is, the degradation rate of oleuropein is mainly affected by the conditions of the aqueous solution, but under high temperature conditions, oxothiazolidine carboxylic acid can reduce the degradation rate of oleuropein to some extent.

[0063] The conclusions are as follows:

[0064] Oxothiazolidine carboxylic acid can significantly improve the discoloration problem of olive leaf extract, and can slow down the degradation of the main active substance oleuropein in olive leaf extract to a certain extent. The addition of oxothiazolidine carboxylic acid can improve the stability of olive leaf extract and increase its application range in cosmetic formulations.

[0065] The above is only a specific embodiment of the present application, but the protection scope of the present application is not limited thereto, and any skilled person in the art can easily think of various equivalent modifications or replacements within the technical range disclosed by the present application, which should be covered within the protection scope of the present application.

[0066] The efficacy and source of the drugs used in the examples are as follows:

[0067] The olive leaves come from Longnan, Gansu, and the olive leaf extract is extracted by extraction + membrane separation process. The extract is a solution, and the content of oleuropein is greater than 0.6%.

[0068] Oxothiazolidine carboxylic acid is an amino acid derivative, which is often used as a whitening active ingredient in cosmetics, and has good antioxidant effect. It is purchased from Nanjing Sbaike Biochemical Industry Co., Ltd.

[0069] Pentaerythritol tetra(bis-tert-butyl hydroxy cinnamic acid) ester is a cinnamic acid derivative, which is a good antioxidant. It is purchased from BASF (China) Co., Ltd.

[0070] Tris(tetramethyl hydroxypiperidinol) citrate is a derivative of tetramethyl piperidine, which is a good light stabilizer. It is purchased from BASF (China) Co., Ltd.

[0071] Glucosyl rutin is a derivative of rutin, which also has strong antioxidant effect. It is purchased from Xianting.

[0072] Diethylhexyl aminobenzoic acid ethyl ester is a light stabilizer, which is purchased from Merck Chemical Technology Co., Ltd.

Claims

1. Use of oxothiazolidine carboxylic acid for the preparation of a formulation for inhibiting the degradation of oleuropein in an olive leaf extract, for improving the problem of oxidative discoloration of an olive leaf extract, characterized in that, The ratio of the oxothiazolidine carboxylic acid to oleuropein in the olive leaf extract is (0.01-10):1, and the content of the oleuropein in the olive leaf extract is 0.6%.

2. A method for stabilizing an Olea europaea leaf extract, characterized in that, The stability is improved by adding oxothiazolidine carboxylic acid to the olive leaf extract, the ratio of the oxothiazolidine carboxylic acid to oleuropein in the olive leaf extract is (0.01-10):1, and the content of the oleuropein in the olive leaf extract is greater than 0.1%.

Images