sterol ring system oxidation pattern in marine sponges固醇环系统氧化模式在海洋海绵.pdf

Mar. Drugs 2005, 3, 84-111 Marine Drugs ISSN 1660-3397 /marinedrugs/ Review Sterol Ring System Oxidation Pattern in Marine Sponges Nittala S. Sarma,* M. Sri Rama Krishna and S. Ramakrishna Rao School of Chemistry, Andhra University, Visakhapatnam-530 003, India *Author to whom correspondence should be addressed; Tel. 0091-891-2844671, E-mail: nittalas@ Received: 31 January 2005 / Accepted: 7 June 2005 / Published: 7 June 2005 Abstract: The marine sponges (Porifera) are a unique group of sedentary organisms from which several novel natural products are reported, many of which have useful biological activities. In producing unusual sterols, they occupy a preeminent position among the various groups of organisms. The polar sterols of sponges reported as at the end of the year 2002 number about 250; their ring structure changing a hundred times. The oxidation pattern in the sterol ring system, from the point of view of biogenesis seems to be mainly of four types. Each sponge species is able to produce 5 sterols fitting into one of the four main biogenetic pathways viz., (i) 3β-hydroxy-∆ - sterol pathway, (ii) 3β-hydroxy-∆7 5,7 -sterol pathway, (iii) 3β-hydroxy-∆ -sterol pathway, and (iv) 3α-hydroxy sterol pathway. Keywords: Marine sponges, Polar sterols, Unusual sterols, Ring system, Oxidation pattern Introduction