Abstract
When the CHCl3 extract obtained by partitioning the methanolic extract of Periploca sepium between H2O and CHCl3 was subjected to column chromatography on silica gel, the antitumor activity against Sarcoma 180 ascites in mice was concentrated in the fraction eluted with CHCl3-MeOH (10 : 1). From the antitumor fraction, eight products, S-1-S-8, were isolated. S-1 was identified as 12β-hydroxypregna-4, 6, 16-triene-3, 20-dione (neridienone-A), obtained for the first time from Asclepiadaceous plants, by direct comparison with an authentic sample and the others were found to be steroidal glycosides. A new compound S-2A (named periplocogenin), and two known aglycones S-3A and S-5A, obtained by hydrolyzing the above glycosides with diluted acid, were respectively identified as 3β-O- (4', 6'-dideoxy-3'-O-methyl-Δ3'-D-2'-hexosulosyl) -Δ5-pregnene-17α, 20 (S) -diol, periplogenin, and Δ5-pregnene-3β, 20 (S) -diol from the proton and carbon-13 nuclear magnetic resonance spectral data. The structure of S-6A was identical with that of S-5A, and S-7A and S-8A were identical with S-2A.
