Cespitularia

Abstract: Four new cytotoxic diterpenes, cespitularins A-D (1-4), having the verticillane skeleton, a new cytotoxic norditerpene, cesputularin E (5), that possesses a novel norverticillane skeleton, and three new diterpenes, cespitularins F-H (6-8), possessing a novel carbon skeleton named cespitularane, were isolated from the methylene chloride solubles of the Formosan soft coral Cespitularia hypotentaculata. The structures of cespitularins A-H (1-8) were elucidated by 1D and 2D NMR spectral analysis, and their cytotoxicity against selected cancer cells was measured in vitro.

Abstract: Ten zooxanthellae-free Dendronephthya species , twelve zooxanthellate soft coral species of the genera Sarcophyton, Lobophytum, Cladiella, Lytophyton, Cespitularia, and Clavularia, and the hermatypic coral Caulastrea tumida were examined for the first time to elucidate the fatty acid (FA) composition of total lipids. In Dendronephthya species, the main FAs were 20:4n-6, 24:5n-6, 16:0, 18:0, 7-Me-16:1n-10, and 24:6n-3 which amounted on the average to 26.0, 12.7, 12.1, 6.0, 4.8, and 4.0% of the total FA contents, respectively. For zooxanthellate soft corals, the main FAs were 16:0 (25.7%), 20:4n-6 (18.2%), 24:5n-6 (6.2%), and 18:4n-3 (5.6%), as well as 16:2n-7, which amounted up to 11.8% in Sarcophyton aff. crassum. Corals with zooxanthellae had low contents of 24:6n-3. The significant difference (p<0.01) between azooxanthellate and zooxanthellate soft corals was indicated only for 12 of 46 FAs determined. The principal components analysis confirmed that 7-Me-16:1n-10, 17:0, 18:4n-3, 18:1n-7, 20:4n-6, 22:5n-6, 24:5n-6, and 24:6n-3 are useful for chemotaxonomy of Dendronephthya. The azooxanthellate soft corals studied were distinguished by the absence of significant depth-dependent and species-specific variations of FA composition, low content of 16:2n-7, an increased proportion of bacterial FAs, predominance of n-6 FAs connected with active preying, and a high ability for biosynthesis of tetracosapolyenoic FAs.

Abstract: A novel trisnorsesquiterpene (1,4-dimethyl-2,3,3a,4,5,6-hexahydroazulene) and an optical antipode of the known sesquiterpene cubebol have been isolated from the soft coral Cespitularia species. The pigment in a small blue Alcyonium species has been identified as guaiazulene.

Abstract: The structure elucidation of three new diterpenes , isolated from a soft coral Cespitularia species, is reported. Two of the metabolites (3), (7E,11E,1R*,3aS*,4S*,12aR*)-11-iso-propyl-1,4,8-trimethyl- 1,2,3,3a,4,5,6,9,10,12a-decahydrocyclopentacycloundecene-1,4-diol, and (4), (4E,7E,11E)-11-isopropyl-1,4,8-trimethyl-1,2,3,3a,6,9,10,12a-octahydrocyclopentacyclo-undecen-1-ol, are shown to possess a further cyclized cembrane skeleton, the structure of (3) being determined by a single-crystal X-ray determination while that of (4) was deduced from spectral comparison with (3). The structure of the remaining diterpene (5) (4,5-deoxyneodolabelline) was deduced from 1H and 13C n.m.r . spectroscopic studies and shown to be closely related to the recently reported clavularian metabolite neodolabelline (8). An authentic sample of neodolabelline (8) was chemically transformed into (5) by the action of a zinc-copper couple establishing the absolute structure of (5).