Anti-Inflammatory Butenolides from a Marine-Derived Streptomyces sp. 13G036

Butenolides are a family of lactones containing a double bond and have been frequently found in the extracts of Streptomyces bacterial species with various pharmacological activities. In this study, seven butenolides (1-7) were discovered and isolated from the culture broth of a marine-derived Streptomyces sp. 13G036 based on a molecular networking analysis. Among the seven isolates, compound 7 was first isolated as a natural product in this study. The structures of compounds 1-7 were determined by combined analysis of 1D/2D Nuclear Magnetic Resonance (NMR) spectra, Mass Spectrometry (MS) spectra and electronic circular dichroism (ECD) data. Compounds 1-6 showed potential anti-inflammatory activities by inhibiting the production of nitric oxide (NO), tumor necrosis factor-alpha (TNF-alpha) and interleukine-6 (IL-6) in lipopolysaccharide-stimulated macrophages.