Striatisporolide A, a butenolide metabolite from Athyrium multidentatum (Doll.) Ching, as a potential antibacterial agent.

The present study aimed to investigate the antibacterial activity of striatisporolide A (SA) against Escherichia coli (E. coli) and the underlying mechanism. Antibacterial activity was evaluated according to the inhibitory rate and zone of inhibition. The antibacterial mechanism was investigated by analyzing alkaline phosphatase (AKP) activity and ATP leakage, protein expression, cell morphology and intracellular alterations in E. coli. The results demonstrated that SA exerted bacteriostatic effects on E. coli in vitro. AKP activity and ATP leakage analysis revealed that SA damaged the cell wall and cell membrane of E. coli. SDS­PAGE analysis indicated that SA notably altered the level of 10 and 35 kDa proteins. Scanning electron microscopy and transmission electron microscopy analyses revealed marked alterations in the morphology and ultrastructure of E. coli following treatment with SA. The mechanism underlying the antimicrobial effects of SA against E. coli may be attributed to its actions of disrupting the cell membrane and cell wall and regulation of protein level. The findings of the present study provide novel insight into the antimicrobial activity of SA as a potential natural antibacterial agent.