title: New A-nor steroids and their antifouling activity from the Chinese marine sponge Acanthella cavernosa.
abstract: A chemical examination of the Chinese sponge Acanthella cavernosa resulted in the isolation of three new A-ring contracted steroids, the ethyl esters of 2beta-hydroxy-4,7-diketo-A-norcholest-5-en-2-oic acid (1), 24S-ethyl-2beta-hydroxy-4,7-diketo-A-norcholest-5-en-2-oic acid (2), and 2beta-hydroxy-4,7-diketo-24R-methyl-A-norcholest-5,22(E)-dien-2-oic acid (3), along with four other known steroids (4-7). The structures were determined on the basis of extensive spectroscopic analysis. Compounds 1-3 showed antifouling activity toward the settlement inhibition of Balanus albicostatus with the EC(50) values of 8.2, 23.5, 31.6 microg/mL, respectively.
authors.affiliation: State Key Laboratory of Natural and Biomimetic Drugs, Peking University, Beijing 100083, People's Republic of China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Qiu
authors.forename: Zhi Wei
authors.initials: ZW
authors.lastname: Deng
authors.forename: Minjuan
authors.initials: M
authors.lastname: Xu
authors.forename: Qingshan
authors.initials: Q
authors.lastname: Li
authors.forename: Wen Han
authors.initials: WH
authors.lastname: Lin
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000302:isolation & purification / Q000494:pharmacology*; D009682:Magnetic Resonance Spectroscopy; D008386:Marine Biology; D009654:Norsteroids / Q000302:isolation & purification / Q000494:pharmacology*; D011161:Porifera / Q000737:chemistry*; D001468:Thoracica / Q000187:drug effects* / Q000254:growth & development
chemical_list: D000900:Anti-Bacterial Agents; D009654:Norsteroids