Synthesis and Bioactivity Evaluation of New 6-Aryl-5-cyano Thiouracils as Potential Antimicrobial and Anticancer Agents

Several novel 6-aryl-5-cyano thiouracil derivatives were synthesized and explored for their activities as antibacterial, antifungal and anticancer agents. The antimicrobial evaluation revealed that compounds 7b and 7c possessed superior antibacterial activity against the Gram positive bacteria S. aureus and B. subtilis compared to the reference drug amoxicillin. Moreover, compound 4i was found to be a broad spectrum antimicrobial agent and it also exhibited the highest antifungal activity against C. albicans, even higher than the reference drug amphotericin B (MIC = 2.34, 3.00 μg/mL respectively). Selected compounds were tested for in vitro cytotoxicity at a single 10^-5 M concentration in accordance to the NCI (USA) protocol. The preliminary screening results showed that most of the compounds had limited cytotoxic activity against renal cancer UO-31 and/or A498 cell lines. Nevertheless, compounds 6d and 6i displayed potent growth inhibitory effect toward non-small cell lung cancer HOP-92 and leukemia MOLT-4 cell lines, respectively.