Six compounds including three new polyketide ones named eleubosas A-C (1-3) were isolated from the active frations of Eleutherine bulbosa. Their structures were elucidated by extensive spectroscopic methods, including NMR, MS and IR spectroscopic analyses data. All the isolates were evaluated against three pathogenic bacteria, Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa, and the results showed that compounds 1 and 2 displayed moderate inhibitory activities against E. coli with MIC values both 12.5 μg/mL, which are consistent with the clinical applications and need further studies.
Keywords: Eleutherine bulbosa; Iridaceae family; antimicrobial activity; eleubosas A-C.