Bioactive secondary metabolites from Okinawan sponges and tunicates

Abstract

During our studies on new bioactive substances from marine organisms, we have isolated a number of unique secondary metabolites having unprecedented chemical structures as well as unique bioactivities. In this review we describe our recent results of isolation and structural elucidation of novel bioactive secondary metabolites isolated from Okinawan marine sponges and tunicates. The review is subdivided into the following five sections, 1) pseudodistomins and penaresidins: aliphatic amino alcohols with piperidine and azetidine rings, respectively, isolated from a tunicate Pseudodistoma kanoko and a sponge Penares sp., respectively; 2) shimofuridins: seven new nucleoside derivatives from an Okinawan compound tunicate Aplidium multiplicatum ; 3) manzamenones and Plakortis metabolites: new dimeric oxygenated fatty acid-derived substances and a series of other oxygenated lipid metabolites, isolated from sponges of the genus Plakortis ; 4) taurospongin A and acetylene acids: a novel acetylene-containing natural product consisting of a taurine and two fatty acid residues isolated from the Okinawan marine sponge Hippospongia sp. and other acetylenic fatty acids isolated from sponges of the genera Petrosia and Xestspongia ; and 5) theonezolides: novel 37-membered macrolides consisting of two principal fatty acid chains, isolated from a sponge of the genus Theonella . During our continuing research projects on the search for new bioactive substances from marine organisms mostly collected at Okinawa islands, we have isolated a number of unique secondary metabolites having unprecedented chemical structures as well as unique bioactivities, some of which are contributable to the basic stuidies of varoius fields of life science and the development of clinically drugs. We have previously published several review articles describing our studies related to marine natural products chemistry including the subjects of "marine alkaloids" [1], "bioactive metabolites of symbiotic marine microorganisms"[2], "sphingosine-related marine alkaloids"[3] "unique macrolides from marine dinoflagellates" [4], and "marine natural products and marine chemical ecology" [5]. In thisn revioew we describe our recent results of isolation and structural elucidation of novel bioactive secondary matabolites isolated from Okinawan marine sponges and tunicates.