Antimicrobial and cytotoxic activities of novel pyrimidine-2,4-dione connected with 2H-thiopyran derivatives

The purpose of this study is to develop a new pyrimidine-2,4-dione hybrid with 2H-thiopyran molecules as a potential antibacterial and antifungal agents against clinical pathogens that cause infectious diseases, in addition to conducting the cytotoxic screening. The synthesis of 2H-thiopyran connecting pyrimidine-2,4-dionederivatives was carried out in a medium consisting of water with an Mg(II) acetate catalyst. The antimicrobial activity of all synthesized compounds was tested against Gram-positive (Staphylococcus aureus (ATCC-25923), Enterococcus faecalis (clinical isolate), and Gram-negative (Klebsiella pneumoniae (clinical isolate), Escherichia coli (ATCC-2522), and Pseudomonas aeruginosa) bacteria. Antifungal activity was examined in vitro using Aspergillus niger, Candida albicans, Microsporum audouinii, and Cryptococcus neoformans as test organisms (clinical isolates). Cytotoxic assay was also performed in vitro at various concentrations. The highly active compound in this study was 3-((2,6-di(furan-2-yl)dihydro-2H-thiopyran-4(3H)-ylidene)amino)dihydropyrimidine-2,4(1H,3H)-dione which exhibited the lowest MIC value (8 µg/mL) with broad activity against one Gram-positive and three Gram-negative. The compound, 3-((2,6-di(furan-2-yl)dihydro-2H-thiopyran-4(3H)-ylidene)amino)dihydropyrimidine-2,4(1H,3H)-dione showed least MIC value (MIC: 0.25 µg/mL) against C. albicans. The compound 3-((2,6-bis(4-hydroxyphenyl)dihydro-2H-thiopyran-4(3H)-ylidene)amino)dihydro pyrimidine-2,4(1H,3H)-dione was highly active (GI50 0.03 µm) against HeLa cancer cell lines. The overall results indicated that a successful preparation of a few of the promising molecules, which are antimicrobials well as cytotoxicity has been achieved.