Gilvocarcin HE: a new polyketide glycoside from Streptomyces sp.

A new antimicrobial polyketide glycoside (1) and three known compounds, gilvocarcins H (2), V (3) and M (4) were isolated from the ethyl acetate extract of Streptomyces sp. QD01-2. The structure of (1) was established by spectroscopic analysis, X-ray single crystal diffraction and CD spectra. The new compound (1) showed potent antimicrobial activities against Staphylococcus aureus, Bacillus subtilis, Escherichia coli and Candida albicans, with MIC values of 0.5-5.0 μM. Compound (1) also showed weak cytotoxicity against the MCF-7, K562 and P388 cell lines, with IC(50) values of 36, 39 and 45 μM, respectively. The results showed that the vinyl side chain helps to increase the cytotoxicity and antimicrobial activities of gilvocarcin-type glycosides. In addition, the NMR data of gilvocarcin H (2) were also reported for the first time.