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

Seven new 3,4,6-trisubstituted α-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 μg/mL.