Whitening and freckle-removing essence and preparation method thereof

Abstract

The invention relates to the technical field of cosmetics, and discloses a whitening and freckle-removing essence and a preparation method thereof.The whitening and freckle-removing essence is formed by taking additives such as nicotinamide, EDTA, L-lactic acid, citric acid and a baicalein embedding material as main raw materials and mixing the main raw materials, the baicalein embedding material of the whitening and freckle-removing essence contains a coating type structure, and due to the fact that the skin surface carries negative charges, the skin surface is not prone to damage. A coating layer of the baicalein embedding material contains chitosan, so that the baicalein embedding material can be adsorbed on the surface of skin through electrostatic interaction to generate a slow-release effect and further perform targeted release, the whitening effect of the essence can be improved, in addition, after being embedded, baicalein can have good compatibility with other substances in the formula, and in addition, the baicalein embedding material can be used for whitening the skin. The flax aliphatic chain in the structure of the chitosan derivative has excellent anti-oxidation and anti-inflammatory effects, and can reduce the phenomenon of skin scars caused by inflammation.

Description

Technical Field

[0001] The invention relates to the technical field of cosmetics, and in particular to a whitening and freckle-removing essence and a preparation method thereof. Background Art

[0002] In the pursuit of beauty and self-confidence, pure and flawless skin has always been the yearning of many beauty lovers. In recent years, although the living standards have been continuously improved, the living environment of human beings has gradually deteriorated, which easily causes skin problems such as allergies and erythema. In addition, modern people have poor work and rest regularity and poor mental state, which can also cause endocrine disorders, causing redness and swelling of the skin, and directly causing dull skin color. These skin problems have a great impact on emotions, and bad emotions will further deteriorate the mental state, thus forming a vicious circle. Therefore, cosmetic products with whitening and freckle removal effects have gradually come out, and essence, as the leader of this type of product, has become a secret weapon for many people to improve skin color, fade spots, and enhance the overall brightness of the skin with its high efficiency and precision.

[0003] Melanin is the main factor that determines skin color, and tyrosinase is considered to be the decisive rate-limiting enzyme for melanocyte synthesis and pigmentation. Therefore, inhibiting tyrosinase activity plays an important role in skin whitening. Currently, the whitening products on the market are basically adjusted in this way.

[0004] At present, many substances that can inhibit the activity of tyrosinase have been discovered. Among them, flavonoids can inhibit the activity of tyrosinase by changing the conformation of tyrosinase. Therefore, they are widely used in cosmetics. Baicalensis is a very representative flavonoid substance with excellent melanin inhibition effect. It also has anti-inflammatory and antibacterial effects. It can be used as a whitening additive in cosmetics. However, it is easily oxidized and has poor water solubility. It is difficult to effectively match with the gas components in the essence, which makes it difficult to effectively exert its effects. Therefore, there are still deficiencies in practical application. Summary of the invention

[0005] In order to solve the problems mentioned in the background technology, the object of the present invention is to provide a whitening and freckle-removing essence and a preparation method thereof.

[0006] The purpose of the present invention can be achieved through the following technical solutions:

[0007] A method for preparing a whitening and freckle-removing essence, the essence comprising the following raw materials in parts by weight: 0.5-1 parts of niacinamide, 0.1-0.3 parts of EDTA, 0.2-0.4 parts of L-lactic acid, 0.2-0.4 parts of citric acid, 0.5-1.5 parts of ethyl ascorbic acid, 1-2 parts of baicalin embedding material, 4-8 parts of glycerol, 0.3-0.5 parts of xanthan gum, 0.1-0.4 parts of Pulsatilla striata extract, and 30-45 parts of water;

[0008] The preparation method comprises the following steps:

[0009] Step S1, weighing each raw material according to the mass fraction and setting aside;

[0010] Step S2, firstly, nicotinamide, EDTA, L-lactic acid, citric acid, ethyl ascorbic acid and glycerol are added into water, the temperature is controlled at 60-70° C., and the mixture is stirred and mixed evenly to obtain a precursor solution;

[0011] Step S3, lowering the temperature to 40-50°C, adding the Baicalin embedding material and Pulsatilla striata extract to the precursor liquid under continuous stirring, continuing to stir and mix evenly after the addition, then adding xanthan gum, mixing at a speed of 200-300 r / min for 20-30 min, cooling and discharging, and obtaining a whitening and anti-freckle essence.

[0012] As a further embodiment of the present invention, the method for preparing the Baicalin embedding material comprises the following steps:

[0013] The first step is to mix the liquid oil and Baicalin, stir evenly, control the temperature to 45-55°C, mechanically stir for 3-5 minutes, then cool to room temperature, continue stirring and mixing for 20-40 minutes, and then add an emulsifier to the formed mixed solution. After the addition, shear emulsification is carried out at a speed of 2000-3000r / min for 5-10 minutes to form an emulsified suspension;

[0014] The second step is to mix the chitosan derivative with an ethanol aqueous solution with a volume fraction of 60-70%, stir to form a uniform mixed liquid, and then pour it into pure water at a volume ratio of 1:4-5 to prepare a liquid phase material. Then, add the emulsified suspension to the liquid phase material, let it stand for 20-30 minutes after adding, and finally mechanically stir for 10-20 minutes, and then freeze-dry to obtain the Baicalin embedding material.

[0015] Specifically, in the above technical scheme, liquid oil is first used to dissolve Baicalin, and then an emulsifier is added for high-speed stirring and emulsification to form nano-scale Baicalin oil droplets, that is, an emulsified oil droplet suspension. In the second step, since the chitosan derivative contains long fat chains in its structure, it has poor solubility in aqueous solution. Therefore, an ethanol aqueous solution is used as a dispersant to disperse the chitosan derivative to form a mixed solution. Then, the mixed solution is quickly poured into a high volume of water. At this time, the water content in the system increases dramatically, and the solvent is converted from benign to poor, so that the hydrophobic fat chains in the molecular chains of the chitosan derivatives spontaneously shrink inward, and the hydrophilic segments such as hydroxyl groups expand outward, so that a cavity structure with hydrophilic outside and hydrophobic inside can be spontaneously formed to obtain a liquid phase material. At this time, the emulsified suspension is added to the liquid phase material, and the lipophilic emulsified droplets will spontaneously enter the cavity structure and be wrapped inside the cavity. Then, through freeze-drying treatment, a chitosan-coated Baicalin powder, that is, Baicalin embedded powder, can be formed.

[0016] As a further embodiment of the present invention, the liquid oil is octyl dodecanol or tricaprylin.

[0017] As a further embodiment of the present invention, the mass ratio of the liquid oil to Baicalin is 1:0.1-0.15.

[0018] As a further embodiment of the present invention, the emulsifier is glyceryl stearate or cetearyl alcohol.

[0019] As a further embodiment of the present invention, the preparation method of the chitosan derivative is as follows:

[0020] Chitosan is mixed with 1-3% acetic acid solution by volume, stirred until completely dissolved, sodium linolenate is added, and dicyclohexylcarbodiimide and 4-dimethylaminopyridine are added under stirring. After the addition is completed, the mixture is stirred for 2-3 hours under heat preservation, and the material is discharged and purified to obtain a chitosan derivative.

[0021] Specifically, sodium linolenate is used as a modifier, and dicyclohexylcarbodiimide and 4-dimethylaminopyridine are used as promoters to modify chitosan, thereby introducing a long hydrophobic fatty chain into the structure of chitosan to prepare a chitosan derivative.

[0022] As a further embodiment of the present invention, the mass ratio of chitosan to sodium linolenate is 1:0.1-0.2.

[0023] As a further solution of the present invention, the mass fraction of the mixed liquid is 5-15%.

[0024] As a further embodiment of the present invention, the volume ratio of the emulsified suspension to the liquid phase material is 1:8-12.

[0025] A whitening and freckle-removing essence is prepared by adopting the preparation method.

[0026] Beneficial effects of the present invention:

[0027] (1) The present invention adds L-lactic acid as an exfoliant in the formula, and by removing impurities from the skin, not only can the melanin particles on the skin surface be removed, scars are reduced, but also the skin's receptivity can be improved, so that active substances can be more easily introduced into the skin through the skin, resulting in a good nursing effect. The Baicalin embedding material in the formula contains a coating structure. Since the skin surface carries a negative charge, the coating layer of the Baicalin embedding material contains chitosan, so it can be adsorbed on the skin surface through electrostatic action. With the volatilization of the essence liquid water, the embedded Baicalin emulsified oil droplets will be gradually released under the action of pressure difference. Since the cell membrane is naturally hydrophobic and lipophilic, with the improvement of the skin's receptivity, the Baicalin emulsified oil droplets can penetrate the stratum corneum well, gradually enter the skin, and release Baicalin in the skin. Through this slow-release effect, not only can the oxidation of Baicalin be avoided, but also the utilization rate and absorption rate of Baicalin can be improved, achieving the effect of targeted release, thereby effectively inhibiting the activity of tyrosinase, reducing the generation of melanin, and then playing a role in fading spots and improving the whitening effect of the essence.

[0028] (2) The present invention uses a special preparation process to arrange the hydrophilic groups of the chitosan derivative in the coating layer of the baicalenzyme embedding material outward, thereby enabling the baicalenzyme embedding material to have good hydrophilicity and improve the compatibility of baicalenzyme with other substances in the formula. In addition, the flax fatty chain in the structure of the chitosan derivative has excellent antioxidant and anti-inflammatory effects, and can reduce the phenomenon of scarring caused by inflammation of the skin.

[0029] Of course, any product implementing the present invention does not necessarily need to achieve all of the advantages described above at the same time. DETAILED DESCRIPTION

[0030] The technical scheme of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0031] Example 1

[0032] A whitening and freckle removing essence, comprising the following raw materials in parts by weight: 0.5 parts of niacinamide, 0.1 parts of EDTA, 0.2 parts of L-lactic acid, 0.2 parts of citric acid, 0.5 parts of ethyl ascorbic acid, 1 part of baicalin embedding material, 4 parts of glycerol, 0.3 parts of xanthan gum, 0.1 parts of Pulsatilla striata extract, and 30 parts of water;

[0033] The preparation method of the whitening and freckle removing essence comprises the following steps:

[0034] Step S1, weighing each raw material according to the mass fraction and setting aside;

[0035] Step S2, firstly, nicotinamide, EDTA, L-lactic acid, citric acid, ethyl ascorbic acid and glycerol are added into water, the temperature is controlled to 65° C., and the mixture is stirred and mixed to obtain a precursor solution;

[0036] Step S3, lowering the temperature to 45°C, adding the Baicalin embedding material and Pulsatilla striata extract to the precursor liquid under continuous stirring, continuing to stir and mix evenly after the addition, then adding xanthan gum, mixing at a speed of 200 r / min for 30 minutes, cooling and discharging, and obtaining a whitening and anti-freckle essence.

[0037] Example 2

[0038] A whitening and freckle removing essence, comprising the following raw materials in parts by weight: 0.6 parts of niacinamide, 0.2 parts of EDTA, 0.3 parts of L-lactic acid, 0.3 parts of citric acid, 1 part of ethyl ascorbic acid, 1.8 parts of baicalin embedding material, 6 parts of glycerin, 0.4 parts of xanthan gum, 0.2 parts of Pulsatilla striata extract, and 35 parts of water;

[0039] The preparation method of the whitening and freckle removing essence comprises the following steps:

[0040] Step S1, weighing each raw material according to the mass fraction and setting aside;

[0041] Step S2, firstly, nicotinamide, EDTA, L-lactic acid, citric acid, ethyl ascorbic acid and glycerol are added into water, the temperature is controlled to 65° C., and the mixture is stirred and mixed to obtain a precursor solution;

[0042] Step S3, lowering the temperature to 45°C, adding the Baicalin embedding material and Pulsatilla striata extract to the precursor liquid under continuous stirring, continuing to stir and mix evenly after the addition, then adding xanthan gum, mixing at a speed of 300 r / min for 25 minutes, cooling and discharging, and obtaining a whitening and anti-freckle essence.

[0043] Example 3

[0044] A whitening and freckle removing essence, comprising the following raw materials in parts by weight: 1 part of niacinamide, 0.3 parts of EDTA, 0.4 parts of L-lactic acid, 0.4 parts of citric acid, 1.5 parts of ethyl ascorbic acid, 2 parts of baicalin embedding material, 8 parts of glycerin, 0.5 parts of xanthan gum, 0.4 parts of Pulsatilla striata extract, and 45 parts of water;

[0045] The preparation method of the whitening and freckle removing essence comprises the following steps:

[0046] Step S1, weighing each raw material according to the mass fraction and setting aside;

[0047] Step S2, firstly, nicotinamide, EDTA, L-lactic acid, citric acid, ethyl ascorbic acid and glycerol are added into water, the temperature is controlled to 65° C., and the mixture is stirred and mixed to obtain a precursor solution;

[0048] Step S3, lowering the temperature to 45°C, adding the Baicalin embedding material and Pulsatilla striata extract to the precursor liquid under continuous stirring, continuing to stir and mix evenly after the addition, then adding xanthan gum, mixing at a speed of 300 r / min for 20 minutes, cooling and discharging, and obtaining a whitening and anti-freckle essence.

[0049] The Baicalin embedding material in the above examples was prepared by the following method:

[0050] The preparation method of Baicalin embedding material comprises the following steps:

[0051] The first step is to mix 1.2g chitosan with 100mL acetic acid solution with a volume fraction of 2%, stir until completely dissolved, add 0.15g sodium linolenate, and add 0.03g dicyclohexylcarbodiimide and 0.01g 4-dimethylaminopyridine under stirring conditions. After the addition is complete, keep warm and stir for 3h, discharge, dialyze for 3 days, and then freeze and solidify in an environmental condition of -10°C, and finally dry completely in a freeze dryer at -50°C to obtain a chitosan derivative with a yield of 85.1%;

[0052] The amino content of chitosan and chitosan derivatives was tested by acid-base titration. The specific operation method is as follows, taking chitosan derivatives as an example:

[0053] Take 0.3g chitosan derivative sample, stir and mix it with 50mL of 0.1mol / L HCl standard solution to form a mixed solution, let it stand at 40℃ for 2h, then draw 10mL into another container, add 10mL deionized water and a drop of phenolphthalein indicator, shake well, titrate with 0.1mol / L sodium hydroxide standard solution until color change occurs, stop titration, record the amount of sodium hydroxide standard solution consumed T (mL), calculate the amino content of the sample using the formula (50×0.1-4×0.1×T) / 0.3, and the result is 3.819mmol / g. The same experiment was carried out with chitosan with the same parameters, and the result showed that the amino content was 12.531mmol / g. It can be reasonably inferred that the amino group of chitosan is condensed with sodium linolenate in this process and consumed;

[0054] Step 2: 1.5 g of octyldodecanol and 0.2 g of Baicalin were mixed and stirred evenly, and the temperature was controlled to 50°C, mechanically stirred for 5 minutes, and then cooled to room temperature, and stirred and mixed for 30 minutes, and then 0.02 g of glyceryl stearate was added to the formed mixed solution. After the addition, shear emulsification was performed at a speed of 2500 r / min for 10 minutes to form an emulsified suspension;

[0055] The third step is to mix the chitosan derivative with an ethanol aqueous solution with a volume fraction of 70%, stir to form a uniform mixed liquid with a mass fraction of 12%, then pour 240mL of 50mL of the mixed liquid into pure water to prepare a liquid phase material, then add 30mL of the emulsified suspension to the formed liquid phase material, let it stand for 30 minutes after adding, and finally mechanically stir for 15 minutes, and then freeze-dry to obtain the Baicalin embedding material.

[0056] Comparative Example 1

[0057] A whitening and freckle removing essence, comprising the following raw materials in parts by weight: 0.6 parts of niacinamide, 0.2 parts of EDTA, 0.3 parts of L-lactic acid, 0.3 parts of citric acid, 1 part of ethyl ascorbic acid, 1.8 parts of baicalin, 6 parts of glycerin, 0.4 parts of xanthan gum, 0.2 parts of Pulsatilla striata extract, and 35 parts of water;

[0058] The preparation method of the whitening and freckle removing essence comprises the following steps:

[0059] Step S1, weighing each raw material according to the mass fraction and setting aside;

[0060] Step S2, firstly, nicotinamide, EDTA, L-lactic acid, citric acid, ethyl ascorbic acid and glycerol are added into water, the temperature is controlled to 65° C., and the mixture is stirred and mixed to obtain a precursor solution;

[0061] Step S3, lowering the temperature to 45°C, adding Baicalin and Pulsatilla striata extract to the precursor liquid under continuous stirring, continuing to stir and mix evenly after addition, then adding xanthan gum, mixing at a speed of 300 r / min for 25 min, cooling and discharging, and obtaining a whitening and anti-freckle essence.

[0062] Comparative Example 2

[0063] A whitening and freckle removing essence, comprising the following raw materials in parts by weight: 0.6 parts of niacinamide, 0.2 parts of EDTA, 0.3 parts of L-lactic acid, 0.3 parts of citric acid, 1 part of ethyl ascorbic acid, 6 parts of glycerol, 0.4 parts of xanthan gum, 0.2 parts of Pulsatilla striata extract, and 35 parts of water;

[0064] The preparation method of the whitening and freckle removing essence comprises the following steps:

[0065] Step S1, weighing each raw material according to the mass fraction and setting aside;

[0066] Step S2, firstly, nicotinamide, EDTA, L-lactic acid, citric acid, ethyl ascorbic acid and glycerol are added into water, the temperature is controlled to 65° C., and the mixture is stirred and mixed to obtain a precursor solution;

[0067] Step S3, lowering the temperature to 45°C, adding the Pulsatilla striata extract to the precursor liquid under continuous stirring, continuing to stir and mix evenly after the addition, then adding xanthan gum, mixing at a speed of 300 r / min for 25 minutes, cooling and discharging, and obtaining a whitening and anti-freckle essence.

[0068] Test Case

[0069] a. The essences in Examples 1 to 3 and Comparative Examples 1 to 2 were subjected to a skin irritation test. The specific operation of the experiment was as follows: 50 healthy female New Zealand rabbits weighing about 2±0.2 kg were taken and divided into 5 groups on average, with an average of 10 rabbits in each group, respectively named as Example 1 Group, Example 2 Group, Example 3 Group, Comparative Example 1 Group and Comparative Example 2 Group. The dorsal hair on both sides of the spine of the New Zealand rabbits was scraped to form an area of ​​4 cm×4 cm without damaging the epidermis. The essence of the corresponding group was applied to the scraped dorsal hair area of ​​each group of New Zealand rabbits, and the application amount was 0.5 mL. After the coating was completed, gauze was used to cover and fix it. After 1 hour, the gauze was removed and washed. The same experimental steps were used for 3 consecutive days, 3 times each in the morning, noon and evening every day. After the last experiment, the New Zealand rabbits in each group were observed to see whether they had symptoms such as redness, swelling, erythema, erosion, eschar, etc. If the corresponding symptoms appeared, the number was recorded. The test results are shown in Table 1:

[0070] Table 1 - Results of irritation test

[0071] Group Number of rabbits showing symptoms Example 1 Group 0 Example 2 Group 0 Example 3 Group 0 Comparative Example 1 0 Example 2 Group 0

[0072] b. Select B16F10 mouse melanoma cells, which have the same function as the normal melanin synthesis of the human body, to test the whitening effect of the essence. Inoculate the cells in a 10% fetal bovine serum culture medium and culture them at 37°C. Digest and passage them every other day using 0.25% trypsin. Take the second generation of melanoma cells and place them in a 12-well plate at a seeding density of 100 cells / mL. Replace the liquid overnight. Then, add 2 mL of the essence in each embodiment and comparative example to the well plate. Set up a control group at the same time. The control group is not treated. After the addition, continue to culture at 37°C for 3 days. Skim the supernatant and use 1 mL PBS buffer was used for washing, and then 100 μL of trypsin was added. After digestion for 10 minutes, PBS buffer was added to stop digestion, the supernatant was removed, and then 0.1% polyethylene glycol octylphenyl ether by mass was added to each well, shaken, stored in an environment of minus 20°C for 20 minutes, and then placed at a temperature of 5°C for 30 minutes, the supernatant was removed again, and finally 1% sodium hydroxide dimethyl sulfoxide solution by mass was added, and kept warm at 80°C for 3 hours. The supernatant was placed in a 96-well plate, and the absorbance value at a wavelength of 490nm was read using an enzyme reader. By comparing with the control group, the melanin reduction rate was calculated, and the results are recorded in Table 2:

[0073] Group Melanin reduction rate / % Example 1 Group 86.91 Example 2 Group 87.10 Example 3 Group 87.03 Comparative Example 1 67.15 Example 2 Group 38.86

[0074] From the test results shown in Table 1, the essences in the embodiments of the present invention and the comparative examples have no obvious irritation and can effectively avoid irritation to the skin and cause verification problems.

[0075] In addition, from the test data in Table 2, it can be analyzed that the essence prepared with Baicalin embedding as raw material has obviously better whitening effect, and the melanin reduction rate is above 85%. The essence prepared directly with Baicalin as raw material may have poor compatibility and low transdermal permeability, resulting in significantly worse effect, but compared with the essence without Baicalin added, it still has an objective whitening effect.

[0076] Specific examples are used herein to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core ideas, including the best mode, and also enable any technician in the field to practice the present invention, including making and using any device or system, and implementing any combined method. It should be pointed out that for ordinary technicians in this technical field, without departing from the principle of the present invention, the present invention can also be improved and modified, and these improvements and modifications also fall within the scope of protection of the claims of the present invention. The scope of patent protection of the present invention is defined by the claims and may include other embodiments that can be thought of by those skilled in the art. If these other embodiments have structural elements similar to the literal expression of the claims, or if they include equivalent structural elements that are not substantially different from the literal expression of the claims, then these other embodiments should also be included in the scope of the claims.

Claims

1. A method for preparing a whitening and freckle removing essence, characterized in that: The essence comprises the following raw materials in parts by weight: 0.5-1 parts of niacinamide, 0.1-0.3 parts of EDTA, 0.2-0.4 parts of L-lactic acid, 0.2-0.4 parts of citric acid, 0.5-1.5 parts of ethyl ascorbic acid, 1-2 parts of baicalin embedding material, 4-8 parts of glycerol, 0.3-0.5 parts of xanthan gum, 0.1-0.4 parts of Pulsatilla striata extract, and 30-45 parts of water; The preparation method comprises the following steps: Step S1, weighing each raw material according to the mass fraction and setting aside; Step S2, firstly, nicotinamide, EDTA, L-lactic acid, citric acid, ethyl ascorbic acid and glycerol are added into water, the temperature is controlled at 60-70° C., and the mixture is stirred and mixed evenly to obtain a precursor solution; Step S3, lowering the temperature to 40-50°C, adding the Baicalin embedding material and Pulsatilla striata extract to the precursor liquid under continuous stirring, continuing to stir and mix evenly after the addition, then adding xanthan gum, mixing at a speed of 200-300 r / min for 20-30 min, cooling and discharging, and obtaining a whitening and anti-freckle essence.

2. The method for preparing a whitening and anti-freckle essence according to claim 1, characterized in that: The preparation method of the Baicalin embedding material comprises the following steps: The first step is to mix the liquid oil and Baicalin, stir evenly, control the temperature to 45-55°C, mechanically stir for 3-5 minutes, then cool to room temperature, continue stirring and mixing for 20-40 minutes, and then add an emulsifier to the formed mixed solution. After the addition, shear emulsification is carried out at a speed of 2000-3000r / min for 5-10 minutes to form an emulsified suspension; The second step is to mix the chitosan derivative with an ethanol aqueous solution with a volume fraction of 60-70%, stir to form a uniform mixed liquid, and then pour it into pure water at a volume ratio of 1:4-5 to prepare a liquid phase material. Then, add the emulsified suspension to the liquid phase material, let it stand for 20-30 minutes after adding, and finally mechanically stir for 10-20 minutes, and then freeze-dry to obtain the Baicalin embedding material.

3. The method for preparing a whitening and freckle removing essence according to claim 2, characterized in that: In the first step, the liquid oil is octyldodecanol or tricaprylin.

4. The method for preparing a whitening and anti-freckle essence according to claim 2, characterized in that: In the first step, the mass ratio of the liquid oil to Baicalin is 1:0.1-0.

15.

5. The method for preparing a whitening and anti-freckle essence according to claim 2, characterized in that: In the first step, the emulsifier is glyceryl stearate or cetearyl alcohol.

6. The method for preparing a whitening and freckle removing essence according to claim 2, characterized in that: In the second step, the preparation method of the chitosan derivative is as follows: Chitosan is mixed with 1-3% acetic acid solution by volume, stirred until completely dissolved, sodium linolenate is added, and dicyclohexylcarbodiimide and 4-dimethylaminopyridine are added under stirring. After the addition is completed, the mixture is stirred for 2-3 hours under heat preservation, and the material is discharged and purified to obtain a chitosan derivative.

7. The method for preparing a whitening and anti-freckle essence according to claim 6, characterized in that: The mass ratio of chitosan to sodium linolenate is 1:0.1-0.

2.

8. The method for preparing a whitening and freckle removing essence according to claim 2, characterized in that: In the second step, the mass fraction of the mixed liquid is 5-15%.

9. The method for preparing a whitening and freckle removing essence according to claim 2, characterized in that: In the second step, the volume ratio of the emulsified suspension to the liquid phase material is 1:8-12.

10. A whitening and freckle removing essence, characterized in that: The method is prepared according to claim 1.