Quinoline-thiazole-1,2,3 triazole hybrids: Synthesis, antimalarial, antimicrobial activity and molecular docking studies

A series of quinoline-thiazole appended 1,4-disubstituted 1,2,3-triazole were synthesized by performing Cu(I) catalyzed 1,3-dipolar cycloaddition reaction (“Click” reaction) and fully characterized by various spectral techniques like FTIR, NMR and HRMS. These compounds were evaluated for in vitro antimalarial activity against plasmodium falciparum. All the compounds (7a–7y) exhibited moderate to good activity in comparison to standard drug Quinine. Compound 7r (IC₅₀ 0.19 µg/mL) displayed appreciable activity comparable to Quinine (IC₅₀ 0.268 µg/mL). Further antimicrobial screening of the synthesized substituted triazoles were also carried out against two gram (+) bacteria (Staphylococcus aureus, Bacillus subtilis), two gram (–) bacteria (Escherichia coli, Klebsiella pneumonia) and two fungi (Candida albicans, Aspergillus niger). Results revealed that compound 7r reflected promising antimicrobial activity among the synthesized library of molecules. Molecular docking studies of broadly active antimalarial disubstituted triazoles 7m and 7r were explored in the active site of enzyme dihydroorotate dehydrogenase (DHODH) to have the probable mode of action.