Melanin dissolution method using amphipathic proteins

Abstract

The present invention relates to a method for dissolving melanin, comprising the steps of: adding melanin to an alkaline solution containing an amphiphilic protein to prepare a mixed solution; and adding an acidic solution to the mixed solution to adjust the pH of the mixed solution to 7 or lower.

Description

Technology Field

[0001] The present invention relates to a method for dissolving melanin, and more specifically, to a method for improving the solubility of melanin even under pH conditions below neutral using an amphiphilic protein, and to an aqueous melanin solution prepared thereby. Background Technology

[0002] Melanin is a pigment widely present in nature, existing in various forms such as eumelanin, pyomelanin, allomelanin, and neuromelanin. While melanin holds potential for utilization in diverse industrial fields like cosmetics, pharmaceuticals, and food, its applications are limited due to its very low solubility in water.

[0003] In conventional technology, strong alkaline conditions with a pH of 10 or higher were used to dissolve melanin. However, this method has the problem that it cannot be used under the neutral pH conditions required in actual applications. In particular, if the pH of a melanin solution dissolved under alkaline conditions is lowered to 7 or lower, a phenomenon occurs in which the melanin precipitates and precipitates.

[0004] Meanwhile, it is known in nature that melanin contained in squid ink maintains its water solubility even under neutral pH conditions. This is because various proteins and additives present in squid ink enhance the solubility of melanin. However, specific technologies for industrially applying this phenomenon have not yet been developed.

[0005] Therefore, there is a need for the development of new technologies that can improve the solubility of melanin even under neutral or lower pH conditions.

[0006] The technology forming the background of this invention, Korean Public Patent No. 10-1998-0702510, relates to melanin for cosmetic use. The problem to be solved

[0007] The present invention aims to solve the problems of the aforementioned conventional technology by providing a method for dissolving melanin that can improve the solubility of melanin even under pH conditions of neutral or lower.

[0008] In addition, the purpose is to provide an aqueous melanin solution that can maintain a dissolved state without precipitating melanin even under neutral or lower pH conditions.

[0009] In addition, the purpose is to provide a cosmetic composition comprising the above-mentioned aqueous melanin solution.

[0010] However, the technical problems that the embodiments of the present invention aim to solve are not limited to the technical problems described above, and other technical problems may exist. means of solving the problem

[0011] As a technical means for achieving the above-mentioned technical problem, the first aspect of the present invention provides a method for dissolving melanin, comprising the steps of: adding melanin to an alkaline solution containing an amphiphilic protein to prepare a mixed solution; and adding an acidic solution to the mixed solution to adjust the pH of the mixed solution to 7 or lower.

[0012] According to one embodiment of the present invention, in the step of preparing the mixed solution, the amphiphilic protein and the melanin may form an adduct, but are not limited thereto.

[0013] According to one embodiment of the present invention, in the step of adjusting the pH of the mixed solution to 7 or lower, precipitation of the melanin may not occur, but is not limited thereto.

[0014] According to one embodiment of the present invention, the dissolution rate of the melanin may be enhanced by the amphiphilic protein, but is not limited thereto.

[0015] According to one embodiment of the present invention, the amphiphilic protein may comprise, but is not limited to, a protein selected from the group consisting of soy protein isolate, pea protein, oat protein, lentil protein, chickpea protein, casein, albumin, gelatin, lactoferrin, and combinations thereof.

[0016] According to one embodiment of the present invention, the melanin may comprise, but is not limited to, a melanin selected from the group consisting of gallic acid melanin, eumelanin, pyomelanin, allomelanin, neuromelanin, and combinations thereof.

[0017] According to one embodiment of the present invention, the alkaline solution may comprise, but is not limited to, a solution selected from the group consisting of sodium hydroxide (NaOH), potassium hydroxide (KOH), calcium hydroxide (Ca(OH)2), barium hydroxide (Ba(OH)2), lithium hydroxide (LiOH), and combinations thereof.

[0018] According to one embodiment of the present invention, the acidic solution may comprise, but is not limited to, a compound selected from the group consisting of hydrochloric acid (HCl), sulfuric acid (H2SO4), nitric acid (HNO3), phosphoric acid (H3PO4), hydrobromide (HBr), hydroiodide (HI), and combinations thereof.

[0019] In addition, a second aspect of the present invention provides an aqueous melanin solution comprising melanin and an amphiphilic protein, wherein the melanin remains in a dissolved state under conditions of pH 7 or lower.

[0020] According to one embodiment of the present invention, the amphiphilic protein may comprise, but is not limited to, a protein selected from the group consisting of soy protein isolate, pea protein, oat protein, lentil protein, chickpea protein, casein, albumin, gelatin, lactoferrin, and combinations thereof.

[0021] According to one embodiment of the present invention, the melanin may comprise, but is not limited to, a melanin selected from the group consisting of gallic acid melanin, eumelanin, pyomelanin, allomelanin, neuromelanin, and combinations thereof.

[0022] In addition, the third aspect of the present invention provides a cosmetic composition comprising an aqueous melanin solution according to the second aspect of the present invention.

[0023] The means for solving the problem described above are merely exemplary and should not be interpreted as intended to limit the present invention. In addition to the exemplary embodiments described above, additional embodiments may exist in the drawings and the detailed description of the invention. Effects of the invention

[0024] The method for dissolving melanin according to the present invention utilizes an amphiphilic protein, thereby enabling the melanin to remain in a stably dissolved state even under pH conditions below neutral. This overcomes the limitation of conventional technology, where dissolution was only possible under alkaline conditions of pH 10 or higher, and can significantly improve the potential for industrial utilization of melanin.

[0025] Furthermore, since the amphiphilic proteins used in this invention include edible substances such as soybean isolate protein and pea protein, safety for the human body is ensured. This allows for their use in products applied directly to the human body, such as cosmetics and pharmaceuticals.

[0026] Furthermore, the method according to the present invention can improve the dissolution rate of melanin. According to experimental results, it was confirmed that melanin dissolves rapidly within 5 minutes in a solution to which an amphiphilic protein is added. This can significantly improve the efficiency of the manufacturing process.

[0027] Furthermore, the aqueous melanin solution according to the present invention can maintain high solubility without precipitation even when the pH is lowered to 4. This is a significantly improved result compared to the solubility in the absence of amphiphilic proteins.

[0028] However, the effects obtainable from this invention are not limited to those described above, and other effects may exist. Brief explanation of the drawing

[0029] FIG. 1 is a flowchart of a method for dissolving melanin according to one embodiment of the present invention. FIG. 2 is a schematic diagram of a method for dissolving melanin using soybean isolated protein according to one embodiment of the present invention. Figure 3 is the result of comparing the melanin dissolution rate with and without soy protein isolate (SPI) under pH 12 conditions according to one experiment of the present invention. Figure 4 is the result of comparing melanin solubility with and without soy protein isolate (SPI) during the process of changing pH from 12 to 4 according to one experimental example of the present invention. Specific details for implementing the invention

[0030] Embodiments of the present invention are described below with reference to the attached drawings to enable those skilled in the art to easily implement the invention. However, the present invention may be embodied in various different forms and is not limited to the embodiments described herein. Furthermore, in order to clearly explain the present invention in the drawings, parts unrelated to the explanation have been omitted, and similar parts throughout the specification are denoted by similar reference numerals.

[0031] Throughout this specification, when a part is described as being "connected" to another part, this includes not only cases where they are "directly connected," but also cases where they are "electrically connected" with other elements interposed between them.

[0032] Throughout the entire specification, when a component is described as being located "on," "on top," "on top," "under," "on bottom," or "on bottom" of another component, this includes not only cases where the component is in contact with the other component but also cases where another component exists between the two components.

[0033] Throughout this specification, when a part is described as "comprising" a certain component, this means that, unless specifically stated otherwise, it does not exclude other components but may include additional components.

[0034] As used herein, terms of degree such as “about,” “substantially,” etc., are used to mean at or near the stated value when inherent manufacturing and material tolerances are presented in the stated meaning, and are used to prevent unscrupulous infringers from unfairly exploiting the disclosure in which precise or absolute values ​​are mentioned to aid in understanding the invention. Furthermore, throughout this specification, “a step of” or “a step of” does not mean “a step for”.

[0035] Throughout this specification, the term “combination thereof” included in the Markush-type expression means one or more mixtures or combinations selected from the group consisting of the components described in the Markush-type expression, and means including one or more selected from the group consisting of said components.

[0036] Throughout the entire specification, the description "A and / or B" means "A, B, or A and B".

[0037] Hereinafter, the method for dissolving melanin according to the present invention will be described in detail with reference to the embodiments, examples, and drawings. However, the present invention is not limited to these embodiments, examples, and drawings.

[0039] As a technical means for achieving the above-mentioned technical problem, the first aspect of the present invention provides a method for dissolving melanin, comprising the steps of: adding melanin to an alkaline solution containing an amphiphilic protein to prepare a mixed solution; and adding an acidic solution to the mixed solution to adjust the pH of the mixed solution to 7 or lower.

[0040] The method for dissolving melanin according to the present invention utilizes an amphiphilic protein, thereby enabling the melanin to remain in a stably dissolved state even under pH conditions below neutral. This overcomes the limitation of conventional technology, where dissolution was only possible under alkaline conditions of pH 10 or higher, and can significantly improve the potential for industrial utilization of melanin.

[0041] FIG. 1 is a flowchart of a method for dissolving melanin according to one embodiment of the present invention.

[0042] First, a mixed solution is prepared by adding melanin to an alkaline solution containing an amphiphilic protein. (S100)

[0043] According to one embodiment of the present invention, in the step of preparing the mixed solution, the amphiphilic protein and the melanin may form an adduct, but are not limited thereto.

[0044] The aforementioned adduct refers to a complex formed by the interaction of the hydrophilic and hydrophobic portions of an amphiphilic protein with melanin. The hydrophobic portion of the amphiphilic protein binds to the hydrophobic region of melanin, while the hydrophilic portion is exposed to the aqueous solution to increase overall solubility.

[0045] The formation of such adducts acts as a major mechanism that enables melanin to be stably dispersed in an aqueous solution. In particular, melanin-protein adducts are maintained even under conditions where the pH drops to 7 or lower, which can prevent the precipitation of melanin.

[0046] According to one embodiment of the present invention, the dissolution rate of the melanin may be enhanced by the amphiphilic protein, but is not limited thereto.

[0047] The method according to the present invention can improve the dissolution rate of melanin. According to experimental results, it was confirmed that melanin dissolves rapidly within 5 minutes in a solution to which an amphiphilic protein is added. This can significantly improve the efficiency of the manufacturing process.

[0048] According to one embodiment of the present invention, the amphiphilic protein may comprise, but is not limited to, a protein selected from the group consisting of soy protein isolate, pea protein, oat protein, lentil protein, chickpea protein, casein, albumin, gelatin, lactoferrin, and combinations thereof.

[0049] The amphiphilic proteins used in this invention include edible substances such as soybean isolate protein and pea protein, thereby ensuring safety for the human body. This allows for their use in products applied directly to the human body, such as cosmetics and pharmaceuticals.

[0050] According to one embodiment of the present invention, the melanin may comprise, but is not limited to, a melanin selected from the group consisting of gallic acid melanin, eumelanin, pyomelanin, allomelanin, neuromelanin, and combinations thereof.

[0051] According to one embodiment of the present invention, the alkaline solution may comprise, but is not limited to, a solution selected from the group consisting of sodium hydroxide (NaOH), potassium hydroxide (KOH), calcium hydroxide (Ca(OH)2), barium hydroxide (Ba(OH)2), lithium hydroxide (LiOH), and combinations thereof.

[0052] Next, an acidic solution is added to the mixed solution to adjust the pH of the mixed solution to 7 or lower. (S200)

[0053] According to one embodiment of the present invention, in the step of adjusting the pH of the mixed solution to 7 or lower, precipitation of the melanin may not occur, but is not limited thereto.

[0054] The aqueous melanin solution according to the present invention can maintain high solubility without precipitation even when the pH is lowered to 4. This is a significantly improved result compared to the solubility in the absence of amphiphilic proteins.

[0055] According to one embodiment of the present invention, the acidic solution may comprise, but is not limited to, a compound selected from the group consisting of hydrochloric acid (HCl), sulfuric acid (H2SO4), nitric acid (HNO3), phosphoric acid (H3PO4), hydrobromide (HBr), hydroiodide (HI), and combinations thereof.

[0056] In addition, a second aspect of the present invention provides an aqueous melanin solution comprising melanin and an amphiphilic protein, wherein the melanin remains in a dissolved state under conditions of pH 7 or lower.

[0057] Regarding the melanin aqueous solution according to the second aspect of the present invention, detailed descriptions of parts that overlap with the first aspect of the present invention have been omitted, but even if such descriptions are omitted, the contents described in the first aspect of the present invention may be applied equally to the second aspect of the present invention.

[0058] The melanin aqueous solution according to the present invention is characterized by the ability to maintain a stably dissolved state of melanin even under conditions of pH 7 or lower. This is because an amphiphilic protein forms an adduct with melanin, allowing it to be stably dispersed in an aqueous solution.

[0059] These characteristics can significantly enhance the potential for industrial applications of aqueous melanin solutions. In particular, it has the advantage of being applicable to products used under neutral or weakly acidic conditions, such as cosmetics and pharmaceuticals.

[0060] According to one embodiment of the present invention, the amphiphilic protein may comprise, but is not limited to, a protein selected from the group consisting of soy protein isolate, pea protein, oat protein, lentil protein, chickpea protein, casein, albumin, gelatin, lactoferrin, and combinations thereof.

[0061] According to one embodiment of the present invention, the melanin may comprise, but is not limited to, a melanin selected from the group consisting of gallic acid melanin, eumelanin, pyomelanin, allomelanin, neuromelanin, and combinations thereof.

[0062] In addition, the third aspect of the present invention provides a cosmetic composition comprising an aqueous melanin solution according to the second aspect of the present invention.

[0063] Regarding the cosmetic composition according to the third aspect of the present invention, detailed descriptions of parts that overlap with the second aspect of the present invention have been omitted, but even if such descriptions are omitted, the contents described in the second aspect of the present invention may be applied equally to the third aspect of the present invention.

[0064] The cosmetic composition according to the present invention is characterized by being able to include melanin that remains stably dissolved even under conditions of pH 7 or lower. This can overcome the limitations of the limited use of melanin in existing cosmetic compositions.

[0065] In addition, the cosmetic composition according to the present invention has the advantage of ensuring safety for the human body because it contains an edible amphiphilic protein.

[0066] The cosmetic composition according to the present invention can be prepared in various formulations such as lotion, cream, essence, pack, and mask.

[0067] The present invention is to be explained in more detail through the following examples, but the following examples are for illustrative purposes only and are not intended to limit the scope of the present invention.

[0069] [Example 1] Preparation of an aqueous melanin solution using soybean isolated protein

[0070] FIG. 2 is a schematic diagram of a method for dissolving melanin using soybean isolated protein according to one embodiment of the present invention.

[0071] First, a soy protein isolate dispersion was prepared at a concentration of 10 mg / ml and stirred for 30 minutes.

[0072] Next, the pH of the soybean protein isolate dispersion was adjusted to 12 using 5N NaOH (pH 12 soybean protein isolate dispersion).

[0073] Next, a pH 12 solution was prepared by adding 5N NaOH to distilled water, and a pH 12 solution containing dissolved melanin was prepared by dissolving gallic acid melanin in the pH 12 solution.

[0074] Next, a mixed solution was prepared by mixing a pH 12 soy protein isolate dispersion and a pH 12 solution containing dissolved melanin in a 1:1 ratio.

[0075] Finally, HCl was added to lower the pH of the mixed solution to 7 or lower.

[0076] [Experimental Example 1] Effect of increasing melanin solubility of soybean isolate protein

[0077] To determine the effect of soy protein isolate on the solubility of melanin, the dissolution rates were compared during the process of dissolving melanin under pH 12 conditions. The dissolution status after 5 minutes and 20 minutes of stirring was observed for the experimental group with added soy protein isolate and the control group without added soy protein isolate.

[0078] As a result, as shown in Figure 3, it was confirmed that the melanin solution with added soy protein isolate dissolved much faster than the control group after 5 minutes of stirring. After 20 minutes of stirring, both solutions were water-soluble under conditions of pH 12.

[0079] [Experimental Example 2] Effect of maintaining melanin solubility of soybean isolate protein under neutral or lower conditions

[0080] To confirm the effect of maintaining the solubility of melanin according to pH changes, the dissolution state was observed while gradually lowering the pH of the dissolved melanin solution at pH 12 by adding HCl.

[0081] As can be seen in Figure 4, when the pH was lowered to 4, it was observed that melanin precipitated in a solid state in the control group without soy protein isolate. On the other hand, in the experimental group with added SPI, the aqueous state was maintained with almost no precipitation even under the same pH conditions.

[0082] As a result of quantitatively measuring solubility, the melanin solubility of the control group under pH 4 conditions was 0.37 mg / mL, but the experimental group with added soy protein isolate showed a solubility of 11.8 mg / mL, confirming a significant increase in solubility.

[0083] These results show that SPI is effective in maintaining the water solubility of melanin even under neutral or lower pH conditions by forming an adduct with melanin.

[0084] The foregoing description of the present invention is for illustrative purposes only, and those skilled in the art will understand that other specific forms can be easily modified without altering the technical concept or essential features of the present invention. Therefore, the embodiments described above should be understood as illustrative in all respects and not restrictive. For example, each component described as a single unit may be implemented in a distributed manner, and components described as distributed may likewise be implemented in a combined form.

[0085] The scope of the present invention is defined by the claims set forth below rather than by the detailed description above, and all modifications or variations derived from the meaning and scope of the claims and the concept of equivalents thereof should be interpreted as being included within the scope of the present invention.

Claims

Claim 1 A method for dissolving melanin, comprising: a step of preparing a mixed solution by adding melanin to an alkaline solution containing an amphiphilic protein; and a step of adjusting the pH of the mixed solution to 7 or lower by adding an acidic solution to the mixed solution. Claim 2 A method for dissolving melanin according to claim 1, wherein, in the step of preparing the mixed solution, the amphiphilic protein and the melanin form an adduct. Claim 3 A method for dissolving melanin according to claim 1, wherein, in the step of adjusting the pH of the mixed solution to 7 or lower, precipitation of the melanin does not occur. Claim 4 A method for dissolving melanin according to claim 1, wherein the dissolution rate of the melanin is enhanced by the amphiphilic protein. Claim 5 A method for dissolving melanin according to claim 1, wherein the amphiphilic protein comprises a protein selected from the group consisting of soy protein isolate, pea protein, oat protein, lentil protein, chickpea protein, casein, albumin, gelatin, lactoferrin, and combinations thereof. Claim 6 A method for dissolving melanin according to claim 1, wherein the melanin comprises a substance selected from the group consisting of gallic acid melanin, eumelanin, pyomelanin, allomelanin, neuromelanin, and combinations thereof. Claim 7 A method for dissolving melanin according to claim 1, wherein the alkaline solution comprises a compound selected from the group consisting of sodium hydroxide (NaOH), potassium hydroxide (KOH), calcium hydroxide (Ca(OH)2), barium hydroxide (Ba(OH)2), lithium hydroxide (LiOH), and combinations thereof. Claim 8 A method for dissolving melanin according to claim 1, wherein the acidic solution comprises a compound selected from the group consisting of hydrochloric acid (HCl), sulfuric acid (H2SO4), nitric acid (HNO3), phosphoric acid (H3PO4), hydrobromide (HBr), hydroiodide (HI), and combinations thereof. Claim 9 An aqueous melanin solution comprising melanin and an amphiphilic protein, wherein the melanin is maintained in a dissolved state under conditions of pH 7 or lower. Claim 10 A melanin aqueous solution according to claim 9, wherein the amphiphilic protein comprises a protein selected from the group consisting of soy protein isolate, pea protein, oat protein, lentil protein, chickpea protein, casein, albumin, gelatin, lactoferrin, and combinations thereof. Claim 11 A melanin aqueous solution according to claim 9, wherein the melanin comprises a substance selected from the group consisting of gallic acid melanin, eumelanin, pyomelanin, allomelanin, neuromelanin, and combinations thereof. Claim 12 A cosmetic composition comprising an aqueous melanin solution according to claim 9.

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