Spoxazomicins A-C, novel antitrypanosomal alkaloids produced by an endophytic actinomycete, Streptosporangium oxazolinicum K07-0460(T)

Abstract

Three novel antitrypanosomal alkaloids, named spoxazomicins A-C, were isolated by silica gel column chromatography and HPLC from the culture broth of a new endophytic actinomycete species, Streptosporangium oxazolinicum K07-0460(T). The structures of the spoxazomicins were elucidated by NMR and X-ray crystal analyses and shown to be new types of pyochelin family antibiotic. Spoxazomicin A showed potent and selective antitrypanosomal activity with an IC₅₀ value of 0.11 μg ml⁻¹ in vitro without cytotoxicity against MRC-5 cells (IC₅₀=27.8 μg ml⁻¹).