NOVEL CHOLESTANE GLYCOSIDES FROM THE BULBS OF ORNITHOGALUM-SAUNDERSIAE AND THEIR CYTOSTATIC ACTIVITY ON LEUKEMIA HL-60 AND MOLT-4 CELLS

Two novel 24(23-->22)abeo-cholestane glycosides with a six-membered he miacetal ring system and a five-membered acetal ring system (2, 3), de signated as saundersioside A and B, respectively, together with a new 16,23-epoxy-5 beta-cholestane glycoside (1) were isolated from the bul bs of Ornithogalum saundersiae. Their structures were determined by de tailed analysis of the H-1 and C-13 NMR spectra, including various two -dimensional spectroscopy, and acid-catalyzed hydrolysis. The conforma tions of the 16,23-epoxy moiety of 1 and the six-membered hemiacetal m oiety of 2 and 3 were studied through molecular mechanics and molecula r dynamics calculation methods. Compound 3 bearing a p-methoxybenzoyl group at the saccharide part showed potent cytostatic activity on leuk emia HL-60 and MOLT-4 cells, and the effect to HL-60 cells was reveale d to be mediated partially through induction of apoptosis by cell morp hology and DNA fragmentation. (C) 1997 Elsevier Science Ltd.