| 摘要 |
PROBLEM TO BE SOLVED: To obtain the subject preparation high in melanogenesis inhibitory effect, stability and safety, and free from unfavorable color and odor. SOLUTION: This skin whitening preparation is obtained by formulating a base preparation for external use with suitably 0.0001-5.0wt.% or so of a (-)-epicatechin-contg. fraction which is afforded by the following process: a polar solvent extract from at least one kind of plant selected from Polygonum cuspidatum Sieb. et Zucc., Polygonum cuspidatum Sieb. et Zucc. var. hachidyoense Ohwi and Polygonum sachalinense Fr. Schm. is concentrated under reduced pressures, the resultant concentrate is dissolved in 30vol.% ethanol again and then subjected to fractionation by resin column chromatography followed by elution with 40vol.% ethanol, and the resultant fraction is further fractionated by silica gel chromatography. |
