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 (12-43) bearing a triazole ring in the first series, and twenty-eight compounds (44-71) 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. 23 and 42 were found to be the strongest inhibitors, with K-i values of 1.9 nM against hCA IX. Also, 70 showed the highest inhibitory activity with a K-i value of 4.9 nM against hCA XII. Moreover, their cytotoxic effects on colon adenocarcinoma (MCF-7) cell lines were evaluated. According to the cytotoxicity results, 14 (IC50 = 2.48 mu M) and 63 (IC50 = 3.91 mu M) exhibited the highest cytotoxicity on the MCF-7 cells, while 23 showed the strongest cytotoxic effect on both PC-3 (IC50 = 9.40 mu M) and HT-29 (IC50 = 12.10 mu M) cell lines. 14, 23, and 66 decreased CA IX and CA XII protein expression in HT-29 cells, while 23 and 66 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. 14 has the strongest apoptotic effect in MCF-7 cells. 23 increased early apoptosis primarily, while 14 and 66 increased total apoptosis in HT-29. In addition, PI/Hoechst staining proves that apoptotic cells are increased in HT-29 with an effect of 14, 23, and 66. 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 Zn2+ ion. It has been shown that coumarinmonoterpene structures with different alkyl and monoterpene groups both specifically inhibit CA IX and XII and exhibit specific cytotoxicity in different cell lines.

Automated summary

In this study, sixty novel coumarin-monoterpene compounds were synthesized and evaluated for their inhibitory effects on hCA isoforms and anticancer potentials. All synthesized molecules selectively inhibited CA IX and XII, with compounds 23 and 42 showing the strongest inhibitory activity against hCA IX. Cytotoxicity evaluation revealed that compounds 14 and 63 exhibited the highest cytotoxicity on MCF-7 cells, while compound 23 showed the strongest cytotoxic effect on both PC-3 and HT-29 cell lines. Furthermore, compounds 14, 23, and 66 showed a reduction in CA IX and CA XII protein expression and increased apoptosis in different cell lines. The modeling studies demonstrated that only the open coumarin form of the compounds could interact directly with the active-site Zn2+ ion.