PURPOSE: To obtain a suppressant, comprising an ecdysteroid analog, having both differentiation promoting and division suppressing actions on keratinocytes sufficient to ameliorate psoriasis and high safety and effective in preventing and treating psoriasis.
CONSTITUTION: This medicinal composition comprises an ecdysteroid analog, preferably the one selected from polyporusterone A of formula I, polyporusterone B of formula II, 20-hydroxyecdysone of formula III, ponasterone A of formula IV and ponasteroside A of formula V. Furthermore, the analog in the case of, e.g. the polyporusterone A or polyporusterone B is obtained by extracting a natural substance such as Polyporus umbellatus FRIES with a polar solvent, then treating the resultant extract solution by column chromatography, etc.
YAMAMOTO MAKOTO
TSUJI KUNIO
TSUJI KUNIO