Cyclopeptides from marine actinomycete Streptomyces sp. G261

Abstract

According to the results from our screening program, the EtOAc extract of a Streptomyces sp. (strain G261) collected in Cu Lao Cham - Quang Nam showed antimicrobial activity against Enterococcus faecalis, Bacillus cereus, Pseudomonas aeruginosa and Candida albicans. Seven secondary metabolites Cyclo-(Leu-Pro) (1), Cyclo-(Pro-Gly) (2), Cyclo-(Pro-Ala) (3), Cyclo-(Leu-Tyr) (4), Cyclo-(Pro-Tyr) (5), and Cyclo-trans-4-OH-(Pro-Phe) (6) were isolated from the cultures broth of Streptomyces (strain G261). Their structures were determined by MS and 2D NMR spectroscopic analysis, as well as by comparison with reported data in literature.