New series of chrysin derivatives(4a-4t)were designed and synthesized by introducing different substituted piperazines at C-7 position.Their inhibitory effects on FabH were evaluated using two Gram-negative bacterial strains,Escherichia coli and Pseudomonas aeruginosa,and two Gram-positive bacterial strains,Bacillus subtilis and Staphylococcus aureus.To our delight,most of these compounds exhibited a dramatic increase in inhibitory potency,compared with the control positive drugs.Among them,compound 4s exhibited the most potent inhibitory activity with IC50 values of 5.78 ± 0.24 μm inhibiting E.coli FabH and potent antibacterial activity against S.aureus and E.coli with MIC of 1.25 ± 0.01,1.15 ± 0.12 μg/mL,respectively,comparing to the control positive drugs penicillin G(7.56 ± 0.30 μm).Docking simulation was performed to position compound 4s into the FabH active site,and the result showed that compound 4s could bind well with the FabH as potent FabH inhibitor.