Terpenoid metabolites from three dorid nudibranchs and a new bromotryptamine derivative from the Northeast Pacific sponge Plocamissa igzo

Investigation of the terpenoid metabolites present in the extracts of three dorid nudibranchs has led to the isolation of sixteen known and ten new compounds. Structures were determined through extensive spectroscopic analysis. In addition, a new bromotryptamine derived compound was isolated from the Northeast Pacific sponge Plocamissa igzo. Specimens of Chromodoris geminus collected off the coast of Sri Lanka were found to contain the known spongian diterpenoid 34 aswell as the new metabolites 61 and 62. A study investigating the geographical variation in the metabolites present in Cadlina luteomarginata along the British Columbian coast revealed the drimane sesquiterpenoid albicanylacetate (72) to be the most widely distributed metabolite. Specimensof the nudibranch collected at Rennell Sound contained thesesquiterpenoid metabolites 68, 69 and 78-80 which could be traced to a locally abundant prey sponge in the genus Acanthella. Interestingly, the algal metabolite violacene (81) was also present in both the sponge and nudibranch extracts. A single specimen of C. luteomarginata collected in the process of actively laying eggs contained the sesquiterpenoids 68, 69 and 78 as well as the diterpenoidmetabolite 82. The egg mass of this individual contained the drimane derivatives 83 and 84, acetylated analogs of 72. Specimens collected off Anthony Island contained the previously described compoundsmicrocionin-2 (70), marginatafuran (74) and 9,1 1-dihydrogracillin A (87)as well as the new metabolites acanthene K (8 5 ), 20-acetoxymarginatone (86) and the labdane diterpenoid lutenenolide 68 X=NC 69 X = NCS 78 X = NHCHO 70 R1^p A cScience, Faculty ofChemistry, Department ofGraduat