| 摘要 |
PROBLEM TO BE SOLVED: To obtain a bleaching agent having melanin suppressing actions and tyrosinase activity suppressing actions and excellent in lightening and bleaching effects on pigmentation, dermal stains, ephelides and chloasmata after sunburn by using jurubidine. SOLUTION: This bleaching agent is obtained by using (25S)-3β- amino-5α,22αO-spirostan (jurubidine) represented by formula I or (25R)-3β- amino-5α,22αO-spirostan (isojurubidine) represented by formula II. The above compound in an amount of 0.001-20.0 wt.% is contained to thereby afford a skin preparation for external use excellent in bleaching effects. The dosage form of the above skin preparation for external use can optionally be selected if the bleaching effects can sufficiently be exhibited. Any dosage form such as a solution-system, a solubilized system, an emulsified system, a powder dispersed system, a water-oil two-layer system or a water-oil-powder three-layer system may be used.
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