Abstract
Calotroposide S (1), a new oxypregnane oligoglycoside has been isolated from the n-butanol fraction of Calotropis procera (Ait) R. Br. root bark. The structure of 1 was assigned based on various spectroscopic analyses. Calotroposide S (1) possesses the 12-O-benzoylisolineolon aglycone moiety with eight sugar residues attached to C-3 of the aglycone. It showed potent anti-proliferative activity towards PC-3 prostate cancer, A549 non-small cell lung cancer (NSCLC), and U373 glioblastoma (GBM) cell lines with IC50 0.18, 0.2, and 0.06 mu M, respectively compared with cisplatin and carboplatin.