Cysteine derivatives

A method for preventing, retarding, alleviating or treating a skin change due to aging or an undesirable aesthetic skin change, both caused or promoted by an oxidative stress, which method comprises applying onto the skin a cosmetic composition or a dermatologic preparation for external use comprising, as an effective ingredient, at least one selected from the cystine derivatives represented by the below-described general formula (III) and the salts thereof.

• 10
• In the above-described general formula (III), R10 and R12 represent a hydrogen atom, an aminocarbonyl group, an acyl group having 2-22 carbon atoms, an alkyl group having 1-22 carbon atoms, a hydroxyalkyl group having 1-22 carbon atoms or a 3-alkoxy-2-hydroxypropyl group whose alkoxyl group has 1-22 carbon atoms;
• the two W's and the two X's represent, each independently, a hydrogen atom or an alkyl group having 1-6 carbon atoms, and k and l stand, each independently, for an integer of 0 to 5, while R11 and R13 represent a hydrogen atom, an alkyl group having 1-22 carbon atoms, a hydroxyalkyl group having 1-22 carbon atoms or a 3-alkoxy-2-hydroxypropyl group whose alkoxyl group has 1-22 carbon atoms, with the proviso that when R10 and R12 represent a hydrogen atom or an acyl group having 2 carbon atoms, and k and l are each 1, R11 and R13 represent an alkyl group having 1-22 carbon atoms, a hydroxyalkyl group having 1-22 carbon atoms or a 3-alkoxy-2-hydroxypropyl group whose alkoxyl group has 1-22 carbon atoms.

A cosmetic composition or a dermatologic preparation for external use which comprises Component (A) and Component (B), each described below.

• Component (A):
• At least one selected from the cysteine or cystine derivatives represented by the below-described general formula (IV) and the salts thereof.
• 11
• In the above-described general formula (IV), R14 represents a hydrogen atom, an aminocarbonyl group, an acyl group having 2-22 carbon atoms, an alkyl group having 1-22 carbon atoms, a hydroxyalkyl group having 1-22 carbon atoms or a 3-alkoxy-2-hydroxypropyl group whose alkoxyl group has 1-22 carbon atoms;
• the two Y's represent, each independently, a hydrogen atom or an alkyl group having 1-6 carbon atoms, and m stands for an integer of 0 to 5, while A represents —O— or —NH—, R15 represents a hydrogen atom, an alkyl group having 1-22 carbon atoms, a hydroxyalkyl group having 1-22 carbon atom or a 3-alkoxy-2-hydroxypropyl group whose alkoxyl group has 1-22 carbon atoms, and R16 represents a hydrogen atom, an aminocarbonyl group, an acyl group having 2-22 carbon atoms, an alkyl group having 1-22 carbon atoms, a hydroxyalkyl group having 1-22 carbon atoms, a 3-alkoxy-2-hydroxypropyl group whose alkoxyl group has 1-22 carbon atoms, or a group represented by the below-described general formula (2), with the proviso that when R14 represents a hydrogen atom or when R14 represents an aminocarbonyl group or an acyl group having 2 carbon atoms and A represents —O—, R15 represents an alkyl group having 1-22 carbon atoms, a hydroxyalkyl group having 1-22 carbon atoms or a 3-alkoxy-2-hydroxypropyl group whose alkoxyl group has 1-22 carbon atoms.
• 12
• In the above-described general formula (2), R17 represents a hydrogen atom, an aminocarbonyl group, an acyl group having 2-22 carbon atoms, an alkyl group having 1-22 carbon atoms, a hydroxyalkyl group having 1-22 carbon atoms or a 3-alkoxy-2-hydroxypropyl group whose alkoxyl group has 1-22 carbon atoms;
• the two Z's represent, each independently, a hydrogen atom or an alkyl group having 1-6 carbon atoms, and n stands for an integer of 0 to 5, while B represents —O— or —NH—, and R18 represents a hydogen atom, an alkyl group having 1-22 carbon atoms, a hydroxyalkyl group having 1-22 carbon atoms or a 3-alkoxy-2-hydroxypropyl group whose alkoxyl group has 1-22 carbon atoms, with the proviso that when R17 represents a hydrogen atom or when R17 represents an aminocarbonyl group or an acyl group having 2 carbon atoms and B represents —O—, R18 represents an alkyl group having 1-22 carbon atoms, a hydroxyalkyl group having 1-22 carbon atoms or a 3-alkoxy-2-hydroxypropyl group whose alkoxyl group has 1-22 carbon atoms.
• Component (B):
• At least one selected from an anti-oxidant, anti-inflammatory drug and ultraviolet absorbor.