Design and Biological Evaluation of Novel Biphenyl-Dihydropyrimidinone Derivatives with Selective Anticancer and Non-Genotoxic Profiles

This study reports the p-toluenesulfonic acid-catalyzed synthesis of three novel 3,4-dihydropyrimidin-2(1H)-one derivatives (4a = PMe, 4b = PPh, 4c = PNO₂) based on a 1,1′-biphenyl, and the evaluation of their cytotoxic, genotoxic, antioxidant, and apoptosis-related effects in vitro and in vivo. Structural characterization was performed using FT-IR, ¹H NMR, APT-¹³C NMR, and LC/MS-MS. Cytotoxicity was assessed on A549 human lung cancer and MRC-5 normal lung fibroblast cells using the WST-8 assay, while genotoxicity was evaluated using the Drosophila wing SMART test. qRT-PCR was conducted to analyze gene expression related to cellular stress responses, antioxidant defense, and apoptosis in both cell lines and Drosophila melanogaster. All compounds exhibited dose-dependent cytotoxicity toward A549 cells with low toxicity in MRC-5 cells, indicating selective anticancer activity. Compound 4b showed the strongest cytotoxic effect (highest potency), whereas compound 4c exhibited the highest selectivity index (SI = 1.22), indicating a more favorable therapeutic window. Compound 4a induced a pro-apoptotic shift in the BAX/BCL-2 ratio, and all compounds enhanced antioxidant gene expression, particularly 4a. No significant genotoxic effects were detected. These findings suggest that the synthesized dihydropyrimidinone derivatives possess selective anti-cancer potential and favorable genotoxic safety profile, with mechanistic diversity supporting their relevance for targeted cancer therapy.