A new di-O-prenylated flavone from an actinomycete Streptomyces sp MA-12

A new di-O-prenylated flavone, named 7,3-di-(,-dimethylallyloxy)-5-hydroxy-4-methoxyflavone (1), was isolated from the culture broth of the endophytic actinomycete Streptomyces sp. MA-12 isolated from the root of the semi-mangrove plant Myoporum bontioides A. Gray. The structure of 1 was determined by comprehensive spectroscopic methods, including 1D and 2D NMR experiments (COSY, HMQC, and HMBC). Primary bioassays showed that 1 at concentration of 0.25mM had moderate inhibitory activity against three plant pathogenic fungi including Colletotrichum musae, Gibberella zeae (Schweinitz) Petch, and Penicillium citrinum Thom.