26,27-cyclosterols and other polyoxygenated sterols from a marine sponge Topsentia sp.
Thirty sterols (1-30) were isolated from bioactive fractions of a marine sponge Topsentia sp., of which 16 were new (1, 2, 8, 10-14, 16, 17, 19, 21, 24, 25, 27, and 30). They were characterized as sterols with 10 different side chains and as having various functionalities including 5alpha,8alpha-epidioxy (1-9), 5alpha,6alpha-epoxy-7-ol (10-15), 5,8-dien-7-one (24-28), 5-en-3beta-ol (29), and 1(10-->6)abeo-5,7,9-triene-3alpha,11alpha-diol (30) units and included polyoxygenated sterols (16-23). One of the key features of these new sterols is the presence of the (24R,25R,27R)-26,27-cyclo-24,27-dimethylcholestane side chain, whose absolute stereochemistry was defined by an acid-catalyzed ring-opening method and by comparison with the four synthetic isomers of known absolute stereochemistry. The occurrence of several known fungal sterols and relevant new sterols in this sponge suggested their possible origin from symbiotic fungi. Selected compounds were tested against a panel of five human solid tumor cell lines and displayed moderate to marginal cytotoxicity.
Luo
Xuan
X
College of Pharmacy, Pusan National University, Busan 609-735, Korea.
Li
Famei
F
Shinde
Pramod B
PB
Hong
Jongki
J
Lee
Chong-O
CO
Im
Kwang Sik
KS
Jung
Jee H
JH
D000818:Animals; D000970:Antineoplastic Agents / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology; D004354:Drug Screening Assays, Antitumor; D006801:Humans; D007723:Korea; D008386:Marine Biology; D015394:Molecular Structure; D011161:Porifera / Q000737:chemistry*; D013237:Stereoisomerism; D013261:Sterols / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology
D000970:Antineoplastic Agents; D013261:Sterols