Synthesis and antitumor activity of 4-cyclohexyl/aryl-5-(pyridin-4-yl)-2,4-dihydro-3H-1,2,4-triazole-3-thiones

The reaction of 2-isonicotinoyl-N-cyclohexyl/arylhydrazinecarbothioamide (2a-r) with sodium hydroxide, in each case, a single product was obtained. The structures of the compounds were confirmed on the basis of their elemental analysis and spectral data. The single crystal X-ray analysis confirmed the structure of these products as N-4-cyclohexyl/aryl-5-(pyridine-4-yl)-2,4-dihydro-3H-1,2,4-triazole-3-thiones (3a-r). The in vitro antitumor activity of compounds was screened against three cell lines; BEL-7402, HUH-7 and HepG2 human hepatoma using MTT assay. Sorafenib (50 A mu M) was used as a positive control. The results of the MTT-dye reduction assay indicated that most of the compounds exert potent cytotoxic/antiproliferative effect in a time and dose-dependent manner via induced apoptosis of HepG2 cells. Results also showed that the tested compounds could significantly enhance the activity of caspase-3 which plays a very important role as the central effecter during apoptosis. The effect of different substitutions on the aromatic portion on the activity was found to be in the following order CH3 > OCH3 > I > SO2NH2 > OC2H5 > C2H5 > NO2 > Cl > CH3CONH.