The research interests of Dr. Andersen's group involve the isolation and structure elucidation of novel organic metabolites produced by marine organisms. Biosynthetic studies are carried out on the novel metabolites when it is feasible. The structures of the new metabolites are elucidated primarily by spectroscopic analysis. Multipulse 1D and 2D nmr experiments play a pivotal role in the structure elucidation. As a rule, the molecules investigated have to meet one or more of the following criteria: i) they should be of theoretical interest due to the novelty of their biogenesis - for example terpenes with new carbon skeletons, ii) they should display in vitro biological activity which makes them potential leads for the development of pharmaceutical agents and/or iii) they should display biological activities that allow them to play a central role in the biology of the producing organism (i.e. chemical ecology). Some current projects are described below.
Marine invertebrates and bacteria are cont inually collected from tropical and cold temperate ocean habitats and their extracts are screened for novel cytotoxic secondary metabolites that are potential leads for the development of new anticancer drugs. Marine bacteria are being examined as a source of novel antibiotics that are active against 'antibiotic resistant' human pathogens. Marine invertebrate and microbial extracts are being examined as a source of i) novel protein phosphatase and protein kinase inhibitors, ii) novel antimitotic agents, and iii) new cell cycle check point inhibitors.
Dorid nudibranchs are delicate, shell-less and often highly colored molluscs that are apparently ill equipped to ward off predators. The defensive metabolites found in the skin extracts of nudibranchs are being studied. Recent efforts have been focused on using stable isotope methodology to study the de novo biosynthesis of terpenoid and polyketide metabolites by dorid nudibranchs.
Madangamine A, a cytotoxic pentacyclcic alkaloid isolated from the sponge Xestospongia ingens