Cytotoxic and antibacterial beilschmiedic acids from a gabonese species of Beilschmiedia

Abstract

High-throughput natural products chemistry methods have facilitated the isolation of eight new and two known beilschmiedic acid derivatives from the leaves of a Gabonese species of Beilschmiedia. This class of compounds appears to be unique to two genera of the Lauraceae, and exhibits remarkable structural complexity for a fatty acid. Eight of the compounds were isolated in microgram quantities necessitating the use of a 1.7mm MicroCryoProbe to obtain NMR data, including a complete HMBC, for structure elucidation and dereplication. All of the compounds were screened for cytotoxic activity against NCI-H460 human lung cancer cells and antibacterial activity against a clinical isolate of methicillin-resistant Staphylococcus aureus. Results from enzymatic assays provided evidence that the observed activity was not the result of membrane disruption as one might expect from lipophilic compounds such as these.