Violapyrones A-G, α-Pyrone Derivatives from Streptomyces violascens Isolated from Hylobates hoolock Feces

Seven new 3,4,6-trisubstituted alpha-pyrone derivatives, violapyrones A-G (1-7), were isolated from Streptomyces violascens obtained from Hylobates hoolock feces. Their structures were elucidated on the basis of detailed spectroscopic analysis. The antimicrobial activities of 1-7 were evaluated against Gram-positive and Gram-negative bacteria and against fungi. Compounds 1-3 showed moderate antibacterial activities against Bacillus subtilis and Staphylococcus aureus with MIC values of 4-32 mu g/mL.