Construction and screening of 2-aryl benzimidazole library identifies a new antifouling and antifungal agent

Biofouling is the undesirable growth of organisms on artificial and natural structures immersed in either seawater or freshwater. It causes huge economic loss and also the global prohibition on known antifouling agents has led to increase hunt for safe and effective antifouling agents. In the past, marine natural products have shown tremendous potential by providing new skeletons which could be used as eco-friendly antifouling agents. Library of 2-aryl benzimidazole core inspired from marine natural products (oroidin and bromoageliferin), is identified and synthesized to explore antifouling/ antifungal properties for the first time. Twelve 2-aryl benzimidazole derivatives were synthesized and evaluated for their antifouling performance against 10 strains of marine biofilm forming bacteria developed on copper panels exposed for 14 days at Dona Paula, Arabian Sea, India. These compounds were also evaluated for antibacterial and antifungal activities. Two compounds i.e. 4j and 4l showed broad spectrum of antifouling activity against nine marine fouling species whereas, 2-(Furan-2-yl)1H-benzo[d]imidazole 4g showed strong antifungal activity against clinical pathogen Aspergillus niger. Our results reveal that the 2-aryl substituent on the benzimidazole core had strong impact on their biological profile. Additionally, here we report the first study of benzimidazole library as target in 10 representative fouling strains.