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Novel secondary metabolites from selected British Columbian marine invertebrates

University of British Columbia

Marine organisms show potential as sources for novel, biologically and pharmacologically active, secondary metabolites. Examination of three nudibranch and one bryozoan species for biologically active metabolites has led to the isolation and structural elucidation of nine new and two known secondary metabolites. The structures of all the compounds were determined by using a combination of spectral analysis, chemical interconversion, synthesis, and single-crystal X-ray diffraction analysis. The British Columbian dorid nudibranch Acanthodoris nanaimoensis yielded three new sesquiterpenoids. The structures of nanaimoal (61) , acanthodoral (64) , and isoacanthodoral (65) represent novel sesquiterpenoid carbon skeletons. The natural mixture of aldehydes 61, 64, and 65 exhibited antibacterial and antifungal activity. From Aldisa cooperi, two ∆⁴-3-ketosteroidal acids 23 and 24, and glycerol ether 25 were isolated. Acid 23 showed feeding deterrent activity against fish. The dendronotid nudibranch Meli be leonina gave 2,6-dimethy1-5-heptenal 53 and 2,6-dimethyl-5-heptenoic acid 54. The aldehyde 53 was responsible for the "grapefruit like" odour of the nudibranch. The bryozoan Phidolopora pacifica was examined in an attempt to correlate the absence of surface fouling, in the field, with the presence of biologically active secondary metabolites. The purine alkaloids 179 and 180, which contain the rare naturally occurring nitro functionality, were responsible for much of the antifungal and antialgal activity of the crude extracts. Three nitrophenols 181, 189, and 209 were also isolated from P. pacifica. Nitrophenol 181 had been previously shown to inhibit chloroplast development both in green plants and in the unicellular algae Euglena sp.

Text

2010-06-11

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http://hdl.handle.net/2429/25557

Chemistry

University of British Columbia

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