New polyhydroxy sterols from the marine sponge Callyspongia fibrosa (Ridley & Dendly)

作者：Rao Thota S Prakasa; Sarma Nittala S^*; Murthy Y L N; Kantamreddi Venkata S S N; Wright Colin W; Parameswaran P S

来源：Tetrahedron Letters, 2010, 51(27): 3583-3586.

DOI：10.1016/j.tetlet.2010.05.009

• Callyspongia fibrosa
• Polyhydroxylated steroid
• Antimalarial activity

Four new polyhydroxylated sterols are isolated from Marine sponge Callyspongia fibrosa collected from the Gulf of Mannar, western Bay of Bengal (India). The structural assignment is based on (1)H and (13)C NMR spectra. All sterols are based on the known 24S-24-methyl cholesterol 1 which is also isolated, and contain 3 beta,6 beta-dihydroxy system and 25-O-acetate as common features (except in the case of sterol 6 that has a Delta(25) in the place of 25-OAc). Additional OH substitution is also present at 5 alpha in 4a and at 8 beta in 5. A further 12 beta-OH is present in 6 and 7. The hydroxylation pattern is so far known only in coral sterols but is without a precedent in sponge sterols. The major steroid 4a showed antimalarial activity against Plasmodium falciparum on the chloroquine-resistant stain better than on the chloroquine-sensitive strain.

• 出版日期2010-7-7