Tail-Approach-Based Design and Synthesis of Coumarin-Monoterpenes as Carbonic Anhydrase Inhibitors and Anticancer Agents.

In this study, sixty novel coumarin-monoterpene compounds were synthesized in two series [thirty-two compounds () bearing a triazole ring in the first series, and twenty-eight compounds () bearing an alkyl chain in the second one]. Their inhibitory effects on the human carbonic anhydrase (hCA) isoforms I, II, IX, and XII and anticancer potentials were determined. All synthesized molecules selectively inhibited CA IX and XII. and were found to be the strongest inhibitors, with values of 1.9 nM against hCA IX. Also, showed the highest inhibitory activity with a value of 4.9 nM against hCA XII. Moreover, their cytotoxic effects on colon adenocarcinoma (HT-29), prostate adenocarcinoma (PC-3), and breast adenocarcinoma (MCF-7) cell lines were evaluated. According to the cytotoxicity results, (IC = 2.48 μM) and (IC = 3.91 μM) exhibited the highest cytotoxicity on the MCF-7 cells, while showed the strongest cytotoxic effect on both PC-3 (IC = 9.40 μM) and HT-29 (IC = 12.10 μM) cell lines. , , and decreased CA IX and CA XII protein expression in HT-29 cells, while and showed the strongest reduction of both CA IX and CA XII in MCF-7 cells. All of the selected compounds increased total apoptosis in a concentration-dependent manner in HT-29 and MCF-7 cells. has the strongest apoptotic effect in MCF-7 cells. increased early apoptosis primarily, while and increased total apoptosis in HT-29. In addition, PI/Hoechst staining proves that apoptotic cells are increased in HT-29 with an effect of , , and . As a result of the modeling studies, it has been shown that only the open coumarin form of the compounds can interact directly with the active-site Zn ion. It has been shown that coumarin-monoterpene structures with different alkyl and monoterpene groups both specifically inhibit CA IX and XII and exhibit specific cytotoxicity in different cell lines.