Medicinal Flowers. XXXV.?Nor-oleanane-type and acylated oleanane-type triterpene saponins from the flower buds of Chinese Camellia japonica and their inhibitory effects on melanogenesis1)

摘要

The methanolic extract and its 1-butanol-soluble fraction from the flower buds of Camellia japonica , cultivated in Yunnan Province, China, showed inhibitory effects on melanogenesis in theophylline-stimulated B16 melanoma 4A5 cells. From the 1-butanol-soluble fraction, a new 28-nor-oleanane-type and three new oleanane-type triterpene saponins, sanchakasaponins A–D, were isolated together with four known triterpene saponins. Their chemical structures were elucidated on the basis of chemical and physicochemical evidence. The inhibitory effects on melanogenesis in theophylline-stimulated B16 melanoma 4A5 cells and structure–activity relationships of the saponins were investigated.