Design, synthesis and inhibitory activity of 2-nitro-1-arylethylene derivatives against Magnaporthe grisea

In order to screen novel inhibitors against Magnaporthe grisea, substituted 2-nitro-1-arylethylene (2) and substituted 2-bromo-2-nitro-1-arylethylene derivatives (3) were rationally designed and synthesized based on the structural information of 1,3,8-trihydroxynaphthalene reductase (3HNR).In addition, Inhibition assay for 3HNR and antifungal activity to M. grisea are done, furthermore, the probable binding mode of 3HNR and target compound was analyzed by using Molecular Docking method. Results showed that most of target compounds possessed high inhibitory activity against 3HNR (IC503a and 3b showed the highest inhibitory activity (IC50=0.53 μmol/L). Most of the compounds exhibited certain antifungal activity to M. grisea at 50 μg/mL, the inhibition rate of 2e, 3a and 3b exceeded 96%. Compound 3a and 3b exhibited excellent antifungal activity against M. grisea (EC50=16.4 μg/mL for 3a, EC50=11.6 μg/mL for 3b, respectively). Analysis result of Molecular Docking method indicated that nitrostyrene compounds showed strong interactions with 3HNR from M. grisea. The hydrogen bonds between the Br atoms of the compound 3 and two hydroxyl groups, separately from Tyr223 and Tyr178 of 3HNR explain the excellent inhibitory activity of compound 3.