Topoisomerase i inhibitors from theStreptomyces sp. strain KM86-9B isolated from a marine sponge

The crude extract ofStreptomyces sp. strain KM86-9B, isolated from a marine sponge, displayed significant inhibition on topoisomerase I activity. Investigation of the causative components by bioactivity-directed fractionation resulted in the isolation of a series of iso- and anteiso-fatty acids.