Plant raw material with sunscreen effect and preparation method thereof

Abstract

The preparation method comprises the following steps: S1) extracting lignin in ginkgo leaves by using an alkali dissolution and acid precipitation method, performing rough filtration to filter impurities, centrifuging the filtrate to obtain a precipitate, washing the filtrate for multiple times by using deionized water, then performing centrifugation again to obtain a precipitate, and drying the precipitate to obtain a crude extract; uniformly mixing the lignin precipitate with deionized water in proportion to obtain a lignin extracting solution; s2) soaking basil seeds in water, enabling basil fibers to fully absorb water and swell, stirring and extracting at a high speed, and filtering to obtain a basil fiber extracting solution; s3) mixing and heating the lignin extracting solution and the basil fiber extracting solution, keeping the temperature and homogenizing until the solution state is stable and uniform; s4) homogenizing the coarse homogenized liquid in a micro-jet homogenizer; and S5) sterilizing the homogenized liquid at high temperature and high pressure to obtain the plant sunscreen raw material.

Description

Technical Field

[0001] The invention belongs to the technical field of sunscreen, and in particular relates to a plant raw material with sunscreen efficacy and a preparation method thereof. Background Art

[0002] The main source of ultraviolet rays is sunlight. Long-term exposure to ultraviolet rays can cause damage to human skin, so sun exposure is one of the important factors leading to skin aging. Studies have shown that ultraviolet rays are divided into three types: ultra-short ultraviolet rays UVC (100-290nm), far ultraviolet rays UVB (290-320nm) and near ultraviolet rays UVA (320-400nm). Among them, UVC is almost completely absorbed by the atmosphere; ultraviolet rays in the UVB band can pass through the stratum corneum and epidermis, causing skin erythema and DNA damage; ultraviolet rays in the UVA band can reach the dermis and are an important factor in causing melanoma.

[0003] Research has found that sunscreens can effectively absorb or reflect ultraviolet rays, and have a wide spectrum of protection. The existing sunscreens on the market are generally divided into two categories: physical and chemical. Physical sunscreens, such as inorganic particles such as titanium dioxide and zinc oxide, can reflect or scatter ultraviolet radiation; chemical sunscreens are generally organic synthetic small molecule compounds that can selectively absorb ultraviolet rays. Different molecular structures have different selective absorption bands of ultraviolet rays, such as trimethyl salicylate, 2-hydroxy-4-methoxyphenyl-phenyl ketone, and butyl methoxydibenzoylmethane.

[0004] The common feature of the molecular structure of chemical sunscreens is that they all contain benzene rings or conjugated structures. This is because the benzene rings and conjugated structures in the molecules have a good absorption effect on ultraviolet rays. In plants, secondary metabolites such as flavonoids, phenylpropanoids, polyphenols and lignin also have benzene rings or conjugated structures. Therefore, they also have obvious ultraviolet absorption characteristics and are considered to be natural sunscreens. At the same time, the sunscreen ingredients in plant extracts also have a certain protective effect on skin sunburn and photoaging caused by ultraviolet rays. For example: proanthocyanidins, plant polyphenols, bearberry extracts, rhodiola rosea, etc., are all popular natural sunscreens in recent years.

[0005] There are two main types of sunscreens on the market: physical sunscreens and chemical sunscreens. Physical sunscreens are mainly in the form of small molecule particles. Although they can effectively reflect ultraviolet rays, they are not very compatible with the skin and can easily clog pores, causing inflammation of the skin or increased inflammatory symptoms. Existing chemical sunscreens are prone to photodegradation, resulting in a gradual decrease in the ability to absorb ultraviolet rays, and cannot achieve long-term sun protection. At the same time, some chemical sunscreens are easy to irritate the skin, and long-term use has the risk of increasing skin sensitivity. Relevant animal experimental studies have shown that this type of organic matter poses a potential threat to the health of organisms. Plant extracts with sunscreen effects, such as proanthocyanidins and plant polyphenols, have the disadvantages of low stability and a narrow absorption spectrum.

[0006] Natural lignin is generally a complex macromolecular polymer formed by three basic structural units, namely guaiacyl, syringyl and p-hydroxyphenyl, linked by different carbon-oxygen bonds, carbon-carbon bonds and the like. The aromatic, phenolic hydroxyl, ketone, carboxyl and other functional group structures in the lignin molecule, as well as the intramolecular hydrogen bonds and conjugation, determine that it can not only absorb ultraviolet rays, but also has the function of scavenging free radicals. It is a safe, green and natural light stabilizer, ultraviolet absorber and antioxidant. Under certain conditions, lignin and cellulose can form a stable membrane interface through mutual synergy, which can block ultraviolet rays from directly acting on the skin and absorb ultraviolet rays, and can meet the sun protection needs of both physical and chemical sun protection.

[0007] Studies have found that ginkgo leaves also contain lignin, which can be prepared into a plant extract with sunscreen effect by combining it with basil fibers extracted from basil seeds after they are soaked in water and swell into a ball. This plant extract has a wider application prospect in the cosmetics field. Summary of the invention

[0008] The purpose of the present invention is to provide a plant material with sunscreen effect and a preparation method thereof in view of the problems existing in the prior art.

[0009] To achieve the above object, the present invention provides the following technical solutions:

[0010] A method for preparing a plant raw material with sunscreen effect, comprising the steps of:

[0011] S1) extracting lignin from ginkgo leaves by alkali dissolution and acid precipitation, filtering impurities by coarse filtration, centrifuging the filtrate to obtain a precipitate, washing with deionized water for multiple times and centrifuging again to obtain a precipitate, and mixing the lignin precipitate with deionized water in a proportion to obtain a lignin extract;

[0012] S2) soaking basil seeds in water to allow basil fibers to fully absorb water and swell, extracting by high-speed stirring, and filtering to obtain a basil fiber extract;

[0013] S3) mixing and heating the lignin extract and the basil fiber extract, and maintaining the temperature to homogenize until the solution is stable and uniform;

[0014] S4) homogenizing the crude homogenate in a microfluidizer;

[0015] S5) sterilizing the homogenized liquid under high temperature and high pressure to obtain the plant sunscreen raw material.

[0016] Preferably, in step S1, the ginkgo leaves are crushed into powder, the alkaline solution used is a 5% sodium hydroxide aqueous solution, and the acid solution is a 1% hydrochloric acid solution;

[0017] The alkaline dissolution and acid precipitation method comprises the following steps: mixing the solid-liquid mixture in a solid-liquid ratio of 1:4, extracting the mixture in a water bath at 80° C. with stirring for 1-2 hours, dripping a 1% hydrochloric acid solution into the alkaline solution until the pH value is 2.0±0.5, filtering the mixture through a 100-mesh sieve to remove large particle impurities, centrifuging the filtrate at 4000 rpm for 5 minutes, discarding the supernatant and taking the precipitate, washing the precipitate twice with deionized water, and then centrifuging the mixture at 4000 rpm for 5 minutes, and uniformly mixing the precipitate and deionized water at a ratio of 1:5.

[0018] Preferably, in step S2, basil seeds are soaked in water at a solid-liquid ratio of 1:5 for 1 hour, so that the basil fibers fully absorb water and swell, and then the extraction is carried out by stirring at 500 rpm for 30 minutes, then at 1000 rpm for 30 minutes, and finally the stirring is reduced to 500 rpm for 30 minutes, and the basil fiber extract is filtered and removed with a 100-mesh sieve to obtain the basil fiber extract.

[0019] Preferably, in step S3, the lignin solution and the basil fiber extract are mixed in a ratio of 1-5:1, heated to 60-80°C in a water bath, and homogenized at 3krpm for 30-60min until the solution is stable and uniform.

[0020] Preferably, in step S4 of the present invention, the microfluidizer is set to a pressure of 1000 bar, and the number of cycles is 1-3 times.

[0021] Preferably, in step S5 of the present invention, the sterilization conditions are: high pressure sterilization at 121° C. for 15 min.

[0022] In summary, the beneficial effects of the present invention are as follows:

[0023] The plant raw material with sunscreen effect prepared by the method has good light stability;

[0024] The plant raw material with sunscreen effect prepared by the method has a broad-spectrum absorption effect on ultraviolet rays;

[0025] (1) The plant raw material with sunscreen effect prepared by the method can synergistically enhance the effect when compounded with other sunscreen agents;

[0026] (4) The plant raw material with sunscreen effect prepared by the method has a certain antioxidant effect and can effectively remove free radicals generated by photo-oxidation.

[0027] A plant extract with the above characteristics is used as a cosmetic raw material with sunscreen effect. Compared with traditional sunscreens, it has the advantages of being natural and renewable, green and pollution-free, degradable, and highly safe. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 1 g of the plant sunscreen raw material made of lignin and basil fiber is diluted to a concentration of 10%, and the spectrum is scanned between a wavelength of 200 nm and 400 nm to obtain an ultraviolet spectrum.

[0029] Figure 2 It is a comparison chart of the DPPH radical scavenging rate of the raw materials obtained in each embodiment and the comparative example. DETAILED DESCRIPTION

[0030] The technical solution of the present invention is further specifically described below through embodiments.

[0031] Embodiment 1, a method for preparing a plant extract having sunscreen effect, comprising the following process steps:

[0032] S1) Ginkgo leaves were crushed into powder, and lignin in the ginkgo leaves was extracted by alkali dissolution and acid precipitation method, 5% sodium hydroxide solution and ginkgo leaf powder were mixed at a solid-liquid ratio of 1:4, and extracted with stirring in a water bath at 80°C for 1 hour, 1% hydrochloric acid solution was added dropwise to the alkaline solution until the pH value was 2.0±0.5, and large particles of impurities were removed by filtering with a 100-mesh sieve, and the filtrate was centrifuged at 4000 rpm for 5 min, the supernatant was discarded, and the precipitate was washed with deionized water twice and then centrifuged at 4000 rpm for 4 min, and the precipitate and deionized water were mixed at a ratio of 1:5 to obtain a lignin extract;

[0033] S2) basil seeds were soaked in water at a solid-liquid ratio of 1:5 for 1 h, and basil fiber was fully swollen by water absorption, first at 500 rpm for 30 min, then at 1000 rpm for 30 min, and finally reduced to 500 rpm for 30 min, filtered with a 100 mesh screen to remove impurities, and obtained basil fiber extract;

[0034] Basil cellulose of different chain types can be extracted by gradient stirring extraction of basil seeds. The mechanical shear force is used to decompose and repolymerize into stable short-chain cellulose at varying stirring speeds, which facilitates the interaction with lignin.

[0035] S3) mixing the lignin extract and the basil fiber extract in a ratio of 1:1, heating in a water bath to 60°C, and homogenizing at 3krpm for 30min until the solution is stable and uniform;

[0036] The self-aggregation of lignin and the solvation of cellulose hinder the interaction between the two. The degree of self-aggregation of lignin and the solvation of cellulose can be reduced by increasing the temperature and applying mechanical external force, thereby enhancing the interaction between the two. Lignin quickly precipitates on the hydrophobic cellulose surface to form an interfacial film that can absorb and reflect ultraviolet light.

[0037] S4) the microfluidizer is set to a pressure of 1000 bar and a homogenization cycle of 1 time to homogenize the coarse homogenate;

[0038] To improve skin feel and fluidity, a microfluidizer is used to homogenize the product into uniform interface film particles, which further improves stability. The microfiltration particles composed of lignin and cellulose can also effectively block solid particles or bacteria, providing a natural protective shield for the skin.

[0039] S5) The homogenized liquid is sterilized by high pressure at 121° C. for 15 min, and cooled to obtain the plant sunscreen raw material.

[0040] Lignin is a high molecular weight aromatic compound containing hydroxyl and methoxy groups. Lignin has strong absorption in the ultraviolet band. General lignin has two absorption peaks at 200-208nm and around 268-287nm, and two shoulder peaks at 227-233nm and 330-340nm. It is speculated that the ultraviolet absorption band can be wider after mixing with basil fiber.

[0041] Take 1g of plant sunscreen raw material made of lignin and basil fiber, dilute it to a concentration of 10%, and scan the spectrum between wavelengths of 200nm-400nm to obtain Figure 1 , it can be seen that there are two absorption peaks between 200-208nm and 268-287nm, indicating that the lignin extraction is successful; after mixing and homogenizing with basil fiber, it still maintains a high absorption rate at 400nm, proving that the plant sunscreen raw material has a broad-spectrum sunscreen effect.

[0042] Example 2, a method for preparing a plant extract having sunscreen effect, comprising the following process steps:

[0043] S1) Ginkgo leaves were crushed into powder, and lignin in the ginkgo leaves was extracted by alkali dissolution and acid precipitation method, 5% sodium hydroxide solution and ginkgo leaf powder were mixed at a solid-liquid ratio of 1:4, and extracted with stirring in a water bath at 80°C for 2h, 1% hydrochloric acid solution was added dropwise to the alkaline solution until the pH value was 2.0±0.5, and large particles of impurities were removed by filtering with a 100-mesh sieve, and the filtrate was centrifuged at 4000rpm for 5min, the supernatant was discarded, and the precipitate was washed with deionized water twice and then centrifuged at 4000rpm for 4min, and the precipitate and deionized water were mixed at a ratio of 1:5 to obtain a lignin extract;

[0044] S2) basil seeds were soaked in water at a solid-liquid ratio of 1:5 for 1 h, and basil fiber was fully swollen by water absorption, first at 500 rpm for 30 min, then at 1000 rpm for 30 min, and finally reduced to 500 rpm for 30 min, filtered with a 100 mesh screen to remove impurities, and obtained basil fiber extract;

[0045] S3) mixing the lignin extract and the basil fiber extract in a ratio of 2:1, heating to 80°C in a water bath, and homogenizing at 3krpm for 30min until the solution is stable and uniform;

[0046] S4) the pressure of the microfluidizer is set to 1000 bar, the homogenization cycle number is 2, and the coarse homogenized liquid is homogenized;

[0047] S5) The homogenized liquid is sterilized by high pressure at 121° C. for 15 min, and cooled to obtain the plant sunscreen raw material.

[0048] Embodiment 3, a method for preparing a plant extract having sunscreen effect, comprising the following process steps:

[0049] S1) Ginkgo leaves were crushed into powder, and lignin in the ginkgo leaves was extracted by alkali dissolution and acid precipitation method, 5% sodium hydroxide solution and ginkgo leaf powder were mixed at a solid-liquid ratio of 1:4, and extracted with stirring in a water bath at 80°C for 2h, 1% hydrochloric acid solution was added dropwise to the alkaline solution until the pH value was 2.0±0.5, and large particles of impurities were removed by filtering with a 100-mesh sieve, and the filtrate was centrifuged at 4000rpm for 5min, the supernatant was discarded, and the precipitate was washed with deionized water twice and then centrifuged at 4000rpm for 4min, and the precipitate and deionized water were mixed at a ratio of 1:5 to obtain a lignin extract;

[0050] S2) basil seeds were soaked in water at a solid-liquid ratio of 1:5 for 1 h, and basil fiber was fully swollen by water absorption, first at 500 rpm for 30 min, then at 1000 rpm for 30 min, and finally reduced to 500 rpm for 30 min, filtered with a 100 mesh screen to remove impurities, and obtained basil fiber extract;

[0051] S3) mixing the lignin extract and the basil fiber extract in a ratio of 5:1, heating to 80°C in a water bath, and homogenizing at 3krpm for 60min until the solution is stable and uniform;

[0052] S4) the microfluidizer was set to a pressure of 1000 bar and the homogenization cycle was repeated 3 times to homogenize the coarse homogenate;

[0053] S5) The homogenized liquid is sterilized by high pressure at 121° C. for 15 min, and cooled to obtain the plant sunscreen raw material.

[0054] Comparative Example 1 was introduced into the experiment. Compared with Example 3, only lignin was extracted in Comparative Example 1;

[0055] Example 3 and Comparative Example 1 were mixed with a commercially available sunscreen with a sun protection index SPF=15 at an addition amount of 10%, and mixed with an emulsion containing no sunscreen substances for comparison. The determination method of the sun protection index SPF was carried out in accordance with the "Technical Specification for Safety of Cosmetics" (2015 edition), and Table 1 was obtained.

[0056] SPF Blank group Example 3 Comparative Example 1 Commercially available 14.68 64.50 37.66 Contains no sunscreen 41.54 22.31

[0057] Table 1

[0058] Compared with the blank group, the sun protection index of the plant sunscreen raw material made of lignin and basil fiber was greatly improved, increasing by 49.82; the sun protection index of adding only lignin also increased by 22.98; compared with the sun protection index of the control group, it can be seen that the sun protection index of the plant sunscreen raw material made of lignin and basil fiber combined with other sunscreens is better, indicating that it has a certain synergistic effect, which is not achieved by adding lignin alone.

[0059] The emulsions containing no sunscreen substances were mixed with Example 3 and Comparative Example 1 at an addition amount of 10%, and the sun protection index SPF was measured before and after 8 hours of illumination. The measurement method was carried out in accordance with the "Technical Specification for Safety of Cosmetics" (2015 edition), and Table 2 was obtained.

[0060] SPF Example 3 Comparative Example 1 Light 0h 41.54 22.31 Light 8h 45.59 17.48

[0061] Table 2

[0062] After 8 hours of illumination, the sun protection index of the sunscreen lotion with added lignin alone decreased, indicating that the structure of lignin was damaged; while the sun protection index of the sunscreen lotion made of plant sunscreen raw materials made of lignin and basil fiber did not decrease, but increased slightly, indicating that after mixing and homogenizing with basil fiber, the lignin component can be effectively protected, the stability can be improved, and the action time of the sunscreen can be extended.

[0063] Comparative Example 2 was introduced into the experiment. Compared with Example 3, Comparative Example 2 only mixed the lignin extract and the basil fiber extract at a ratio of 5:1, which was not homogeneous;

[0064] The phenolic groups contained in lignin give it excellent antioxidant properties and a relatively significant free radical scavenging ability. Each embodiment and comparative example is used as a sample, dissolved and diluted with anhydrous ethanol to prepare a 0.1g / L dilution, an equal volume (500μL) of the sample dilution is mixed with the DPPH solution, and recorded as Ai tube; an equal volume (500μL) of anhydrous ethanol is mixed with the sample dilution, and recorded as Aj tube; an equal volume of anhydrous ethanol is mixed with the DPPH solution, and recorded as Ac tube. After mixing evenly, the mixture is protected from light for 30 minutes, and the OD value is measured at 517nm. The free radical scavenging rate is calculated. Figure 2 .

[0065] In summary, the plant raw material with sunscreen effect obtained by the process of the above embodiment is a plant sunscreen raw material with high stability, good sunscreen effect, certain antioxidant effect, and can effectively remove free radicals generated by photo-oxidation.

[0066] When this plant raw material is combined with other sunscreens, they can enhance synergy and greatly improve the sun protection effect.

[0067] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be equivalent replacement methods and are included in the protection scope of the present invention.

Claims

1. A method for preparing a plant material having sunscreen effect, comprising the steps of: S1) extracting lignin from ginkgo leaves by alkali dissolution and acid precipitation, filtering impurities by coarse filtration, centrifuging the filtrate to obtain a precipitate, washing with deionized water for multiple times and centrifuging again to obtain a precipitate, and mixing the lignin precipitate with deionized water in a proportion to obtain a lignin extract; S2) soaking basil seeds in water to allow basil fibers to fully absorb water and swell, extracting by high-speed stirring, and filtering to obtain a basil fiber extract; S3) mixing and heating the lignin extract and the basil fiber extract, and maintaining the temperature to homogenize until the solution is stable and uniform; S4) homogenizing the crude homogenate in a microfluidizer; S5) sterilizing the homogenized liquid under high temperature and high pressure to obtain the plant sunscreen raw material.

2. The method for preparing a plant material with sunscreen effect according to claim 1, characterized in that In step S1, the ginkgo leaves are crushed into powder, the alkaline solution used is a 5% sodium hydroxide aqueous solution, and the acid solution is a 1% hydrochloric acid solution; The alkaline dissolution and acid precipitation method comprises the following steps: mixing the solid-liquid mixture in a solid-liquid ratio of 1:4, extracting the mixture in a water bath at 80° C. with stirring for 1-2 hours, dripping a 1% hydrochloric acid solution into the alkaline solution until the pH value is 2.0±0.5, filtering the mixture through a 100-mesh sieve to remove large particle impurities, centrifuging the filtrate at 4000 rpm for 5 minutes, discarding the supernatant and taking the precipitate, washing the precipitate twice with deionized water, and then centrifuging the mixture at 4000 rpm for 5 minutes, and uniformly mixing the precipitate and deionized water at a ratio of 1:

5.

3. The method for preparing a plant raw material with sunscreen effect according to claim 1, wherein in step S3 of the invention, the lignin solution and the basil fiber extract are mixed in a ratio of 1-5:1, heated in a water bath to 60-80°C, and homogenized at 3krpm for 30min-60min until the solution is stable and uniform.

4. a kind of preparation method of plant raw material with sunscreen effect described in claim 1, in described step S2, basil seeds are soaked in water for 1h at a solid-liquid ratio of 1:5, after basil fiber fully absorbs water and expands, first 500rpm is stirred and extracted for 30min, then 1000rpm is stirred and extracted for 30min, finally reduced to 500rpm and stirred for 30min, filtered and removed by 100 mesh screen to obtain basil fiber extract.

5. The method for preparing a plant material with sunscreen efficacy according to claim 1, wherein in step S4, the microfluidizer is set to a pressure of 1000 bar and the number of cycles is 1-3 times.

6. The method for preparing a plant raw material with sunscreen efficacy according to claim 1, wherein in step S5, the sterilization condition is: high pressure sterilization at 121°C for 15 minutes.

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