Thiobarbiturates as potential antifungal agents to control human infections caused by Candida and Cryptococcus species

Hospitalized patients can suffer from Candida and Crytptococcus infections, aggravating underlying health conditions. Due to the development of drug-resistant microorganisms, we report here on the potential of some arylidene-thiobarbiturate to control five Candida spp. and one Cryptococcus species of medical interest. Initially, a bismuth nitrate catalyzed Knoevenagel condensation with thiobarbituric acid and aromatic aldehydes was developed. This new procedure generated seven new and thirteen known arylidene-thiobarbiturate derivatives (1-20) with excellent yields (81-95%), with a reaction time within 20 min. The antimicrobial activities of all compounds were evaluated against Candida albicans, C. tropicalis, C. parapsilosis, C. lusitaniae, C. dubliniensis, and Cryptococcus neoformans. Several compounds were as active as the commercially available drugs (IC50 < 1.95 A mu g mL(-1)) towards at least one microbial strain. The results suggest that some of the new compounds can serve as leads for new antimicrobial agents for the treatment of human fungal infections.