Abstract: An endophytic actinobacterial Streptomyces sp.PRh5 isolated from Dongxiang wild rice (Oryza rufipogon) showed markedly antibacterial and antifungal bioactivities.Guided by antibacterial assay,the bioactive components in fermentation broth of the strain PRh5 were separated by various chromatographic methods including silica gel column and Sephadex LH-20.Four monomer compounds were purified and identified as dibutyl phthalate (1),nigericin (2),13-docosenamide (3),nocardamin (4) respectively on the basis of ¹H NMR、¹³C NMR and MS analyses.It was concluded that strain PRh5 could be potentially developed as a new antimicrobial agent.

Key words: endophtic actinomycetes, Streptomyces sp.PRh5, antimicrobial activity, secondary metabolites