Assessment of the antimicrobial and antiproliferative activities of chloropyrazine-tethered pyrimidine derivatives: In vitro, molecular docking, and in-silico drug-likeness studies

Molecular hybridization (MH) of heterocyclic rings has enabled scientists to design and develop novel drugs and drug-like candidates. In our previous work, considering the importance of MH, we synthesized different kinds of chloropyrazine-tethered pyrimidine derivatives (22–40) containing either substituted phenyl or heteroaryl rings at position-6 of the pyrimidine ring and evaluated their antitubercular activity. Herein, we report the antimicrobial and antiproliferative activities of 22–40. The antiproliferative activity of the target hybrids was superior to the antimicrobial activity. However, some compounds showed greater antimicrobial activity than the standard drugs. For instance, among the nineteen derivatives, compound 31 containing a 2^′′,4^′′-dichlorophenyl ring, showed the most potent antibacterial and antifungal activities (MIC 45.37 µM), followed by compounds 25 and 30 bearing 4^′′-nitrophenyl and 2^′′,4^′′-difluorophenyl scaffolds with minimum inhibitory concentrations (MIC) values of 48.67 µM and 50.04 µM, respectively. Compound 35, containing a bioisosteric 2^′′-pyridinyl ring, showed the most potent antiproliferative activity against the prostate cancer cell line (DU-145) with an IC₅₀ value of 5 ± 1 µg/mL. Additional testing of compounds 22–40 on human normal liver cells (LO2) indicated that the compounds were more selective to cancer cell lines over normal cells. Further, molecular docking of the most potent compound 35 against dihydrofolate reductase (DHFR) (PDB ID: 1U72) had a good binding affinity with a docking score of −6.834. The SwissADME program estimated the drug-likeness properties of compound 35. Hybrid 35 is a potential lead molecule for the development of new anticancer drugs, whereas 31 is a promising antimicrobial lead candidate.