Natural products along with their analogs have been intensively explored for their antimicrobial potential against 'ESKAPE' pathogens. Herein, we report a new natural product with strong antibacterial activity, sulfoxanthocillin (1), along with its decomposed product peniformamide (2), and the known compound xanthocillin X (3) from the deep-sea derived Penicillium sp. SCSIO sof101. The structures of compounds 1 and 2 were determined by extensive spectroscopic analysis. Compound 1 showed significant activity against series pathogens with MIC values ranging 0.06-8.0 μg mL-1. As an artificial unnatural product during the isolation process, compound 2 had lower antimicrobial activity than that of compound 1, which could be attributed to a change in structural modification from an isonitrile group in compound 1 to a formamide group in compound 2. In terms of cytotoxicity, 1 showed relatively low cytotoxicity against human tumor cell lines compared with xanthocillin X (3), suggesting that the sulfate group present in 1 should be a determinant of cytotoxic activities. Overall, sulfoxanthocillin (1) merits further attention as a potential lead compound for anti-infective interventions against Gram-negative and Gram-positive bacterial pathogens.
© 2023. The Author(s), under exclusive licence to the Japan Antibiotics Research Association.