Streptazones A, B(1), B(2), C, and D: new piperidine alkaloids from streptomycetes

Five new piperidine alkaloids (1-5), named streptazones A, B(1), B(2), C, and D, were isolated from Streptomyces strains FORM5 and A1. Their structures were established on the basis of detailed MS and NMR analysis. Streptazone A (1) exhibited significant cytotoxic activity against selected human tumor cell lines.