Abstract
Prosapogenins, B and A, which are provided together with prosapogenin-C (diosgenin β-D-glucopyranoside) (II) on partial hydrolysis of dioscin (diosgenin 2-O- and 4-O-bis-α-L-rhamnopyranosyl-β-D-glucopyranoside=diosgenin β-chacotrioside) (I) were characterized as 4-O-(III) and 2-O-α-L-rhamnopyranosyl-β-D-glucopyranoside (IV), respectively. A glycoside found along with dioscin, gracillin and other spirostanol glycosides in the rhizoma of Dioscorea Tokoro MAKINO was isolated and identified with prosapogenin-B of dioscin on the basis of paper, thin-layer and, for the first time, gas liquid chromatographic comparisons and chemical evidence. The difference of the site of the probable enzymatic cleavage in the sugar portion (chacotriose) of dioscin from that of the splitting by acid hydrolysis was noted.
