Skin Whitening Agent

A method for inhibiting a dopa oxidase activity comprising administration or ingestion of an effective amount of a compound represented by the following formula (I) or a salt thereof to or by a subject:

• wherein,
• R1 and R2, being the same or different, each represent a hydroxyl group, or a C1-4 linear or branched alkoxy group, or R1 and R2 together form a methylenedioxy group;
• R3 and R4, being the same or different, each represent a hydroxyl group, or a C1-4 linear or branched alkoxy group, or R3 and R4 together form a methylenedioxy group;
• R5 represents a hydrogen atom, a hydroxyl group, a C1-5 linear or branched alkoxy group, a C1-4 acyl group, or a sugar residue selected from the group consisting of (D-apio-β-D-furanosyl)oxy, (β-D-glucopyranosyl)oxy, (3-O,4-O-dimethyl-D-xylopyranosyl)oxy, (2-O,3-O,4-O-trimethyl-β-D-xylopyranosyl)oxy, and (3-O-methyl-β-D-glucopyranosyl)oxy,
• R6 and R7 are each a hydrogen atom and R8 and R9 together represent an oxygen atom, or R8 and R9 are each a hydrogen atom and R6 and R7 together represent an oxygen atom.

A method for inhibiting melanin production comprising administration or ingestion of an effective amount of a compound represented by the following formula (I) or a salt thereof to or by a subject:

• wherein,
• R1 and R2, being the same or different, each represent a hydroxyl group, or a C1-4 linear or branched alkoxy group, or R1 and R2 together form a methylenedioxy group;
• R3 and R4, being the same or different, each represent a hydroxyl group, or a C1-4 linear or branched alkoxy group, or R3 and R4 together form a methylenedioxy group;
• R5 represents a hydrogen atom, a hydroxyl group, a C1-5 linear or branched alkoxy group, a C1-4 acyl group, or a sugar residue selected from the group consisting of (D-apio-β-D-furanosyl)oxy, (β-D-glucopyranosyl)oxy, (3-O,4-O-dimethyl-D-xylopyranosyl)oxy, (2-O,3-O,4-O-trimethyl-β-D-xylopyranosyl)oxy, and (3-O-methyl-β-D-glucopyranosyl)oxy,
• R6 and R7 are each a hydrogen atom and R8 and R9 together represent an oxygen atom, or R8 and R9 are each a hydrogen atom and R6 and R7 together represent an oxygen atom.

A method for whitening the skin comprising administration or ingestion of an effective amount of a compound represented by the following formula (I) or a salt thereof to or by a subject:

• wherein,
• R1 and R2, being the same or different, each represent a hydroxyl group, or a C1-4 linear or branched alkoxy group, or R1 and R2 together form a methylenedioxy group;
• R3 and R4, being the same or different, each represent a hydroxyl group, or a C1-4 linear or branched alkoxy group, or R3 and R4 together form a methylenedioxy group;
• R5 represents a hydrogen atom, a hydroxyl group, a C1-5 linear or branched alkoxy group, a C1-4 acyl group, or a sugar residue selected from the group consisting of (D-apio-β-D-furanosyl)oxy, (β-D-glucopyranosyl)oxy, (3-O,4-O-dimethyl-D-xylopyranosyl)oxy, (2-O,3-O,4-O-trimethyl-β-D-xylopyranosyl)oxy, and (3-O-methyl-β-D-glucopyranosyl)oxy,
• R6 and R7 are each a hydrogen atom and R8 and R9 together represent an oxygen atom, or R8 and R9 are each a hydrogen atom and R6 and R7 together represent an oxygen atom.