Study of the Cytotoxic and Bactericidal Effects of Sila-substituted Thioalkyne and Mercapto-thione Compounds based on 1,2,3-Triazole Scaffold.

A series of sila-organosulphur compounds containing 1,2,3-triazole cores were screened for their cytotoxic activity on human breast cancer cell line MCF-7. Most of the tested compounds exhibited moderate-to-good activity against the cancer cells. Especially, the compound 4-((2-(trimethylsilyl)ethynylthio)methyl)-1-benzyl-1H-1,2,3-triazole (3a) from series of sila-substituted thioalkyne 1,2,3-triazoles (STATs) and the compounds 3-(1-benzyl-1H-1,2,3-triazol-4-yl)-1-mercapto-1,1-bis(trimethylsilyl)propane-2-thione (4a) and 1-mercapto-1,1-bis(trimethylsilyl)-3-(1-phenethyl-1H-1,2,3-triazol-4-yl)propane-2-thione (4e) from series of sila-substituted mercapto-thione 1,2,3-triazoles (SMTTs) exhibited promising cytotoxicity against MCF-7 with IC50 values of 35.17, 32.63 and 30.3 μg/mL, respectively. In addition, the possible mechanisms for inhibition of cell growth and induction of apoptotic cell death were explored by DAPI staining, cell cycle analysis and qRT-PCR. The synthetic compounds were evaluated for their in vitro antibacterial activities, and as a result, the most prominent effects were observed for 3e and 4e. Especially, 3e was found to be quite active against all the tested strains with the MIC values ranging from 15 to 62 μg/mL, except P. aeruginosa. The results of the time-kill assay suggested that the compound of 3e completely inhibited the growth of both gram-negative bacteria, A. baumannii, and gram-positive bacteria, S. aureus. In addition, SEM analysis confirmed morphostructural damage of the bacteria. Our findings could be applicable for developing dual-targeting anticancer/antibacterial therapeutics.