Chalcone derivatives containing 1,2,4-triazole and pyridine moiety: design, synthesis, and antiviral activity

A series of chalcone derivatives containing 1,2,4-triazole and pyridine were designed and synthesized, and their antiviral activities against tobacco mosaic virus (TMV) were evaluated. Notably, S7 (EC₅₀ = 89.7 μg/mL) exhibited excellent curative activity against the TMV, which was superior to that of ningnanmycin (NNM: EC₅₀ = 201.7 μg/mL). Molecular docking showed that S7 exhibited satisfactory affinities for the TMV coat protein (TMV-CP), with four strong conventional hydrogen bonds with amino acid residues. Further, microscale thermophoresis (MST) showed that S7 (Kd = 0.5340 ± 0.2233 μmol/L) bound more strongly to TMV-CP than NNM (Kd = 5.1186 ± 1.9568 μmol/L). The results of chlorophyll content, malondialdehyde (MDA) content, and biological enzyme activity confirmed that S7 enhanced the disease resistance of tobacco plants by affecting the change of chlorophyll content, interfering with plant lipid peroxidation, and enhancing SOD activity in plants, respectively.