New anti-inflammatory metabolites produced by Streptomyces violaceoruber isolated from Equus burchelli feces.

Three new metabolites (2-4), together with one known compound, GTRI-02, (1) were isolated from a fermentation broth of Streptomyces violaceoruber derived from Equus burchelli feces. The structures of the new compounds 2-4 were established using comprehensive NMR spectroscopic data analysis as well as UV, IR and MS data. The anti-inflammatory activity of compounds 1-4 was tested by examining their ability to inhibit nitric oxide (NO) production in lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophage cells. Compound 2 showed a moderate inhibition of NO production with IC50 value of 51.2 μm.