Next-Generation Carbazole-Linked 1,2,4-Triazole-Thione Derivatives: Strategic Design, Synthesis, Molecular Docking, and Evaluation of Antidiabetic Potential

Currently, available therapies for diabetes cannot achieve normal sugar values in a high percentage of treated patients. This work synthesized a series of carbazole-triazole-thione derivatives, and their potential antidiabetic activity was investigated against the key diabetic enzymes α-amylase and glycosidase. Normal human hepatic stellate cells (LX-2) were employed to assess their cytotoxicity and safety, followed by in vivo testing to investigate the hypoglycemic effect of the most promising agent. As a result, a set of 18 carbazole-1,2,4-triazole-thione derivatives were synthesized. Seven structures demonstrated potential inhibitory activity against α-amylase enzyme, with IC₅₀ lower than 6.4 μM. Among them, compounds <b>C5f</b>, <b>C5o</b>, and <b>C5r</b> exhibited the highest potency, with IC₅₀ values of 0.56, 0.53, and 0.97 μM, respectively, compared to the well-known α-amylase inhibitor acarbose, which has an IC₅₀ value of 5.31 μM. Exploring the inhibition potency of these series against α-glucosidase enzyme revealed that <b>C5f</b> and <b>C5r</b> compounds act as moderate inhibitors, with IC₅₀ values of 11.03 and 13.76 μM, respectively. Moreover, at 100 μM concentration, most of the evaluated compounds showed negligible cytotoxic effect against LX-2 cell lines, particularly compounds <b>C5o</b> and <b>C5s</b>, that demonstrated lower cytotoxic activity by 3-fold compared to the positive control 5-Flururicle (cell viability 13.45%). Thus, the <b>C5f</b> compound was selected for in vivo evaluation, and after administering five doses of this compound (10 mg/kg) to group III of mice, a significant reduction in glucose concentration was observed, bringing it down from 290.54 to 216.15 mg/dL, in comparison with the control group which did not show a reduction in blood glucose level. These observed in vitro and in vivo results were upheld by performing a set of chemoinformatic studies that elucidated the binding interactions of the most active derivatives within the enzyme's active site and highlighted the critical roles of both the 1,2,4-triazole-3-thione and carbazole scaffolds in these interactions. Finally, the drug-likeness profiles of our carbazole-triazole-thione derivatives suggest their potential as candidates for further in vivo studies and clinical trials.