AIM:To explore the effect of polyphenolic compound 3,5-dihydroxy-4-methoxybenzyl alcohol(DHMBA)on hypoxia/reoxygenation(H/R)injury of human umbilical vein endothelial cells(EA.hy926 cells)and its po-tential mechanisms.METHODS:To construct an H/R model,the EA.hy926 cells were cultured in an acidic hypoxia buffer while in an anaerobic workstation.The cells were divided into control,H/R,H/R+different doses of DHMBA,H/R+edaravone(antioxidant)and H/R+reactive oxygen species(ROS)inducer oligomycin A+DHMBA groups.Cell viability was measured by CCK-8 assay,and tumor necrosis factor-α(TNF-α)and interleukin-6(IL-6)levels in cells were mea-sured by ELISA.Phosphorylation of endothelial nitric oxide synthase(eNOS)and nuclear factor-κB(NF-κB)p65 were measured by Western blot.Intracellular NO levels were determined by laser confocal microscopy.Glutathione(GSH)/glu-tathione disulfide(GSSG)oxidation balance was determined by the dinitrobenzoic acid chromogenic method.Intracellular ROS levels were measured by flow cytometry.Lactate dehydrogenase(LDH)leakage was determined using nitro blue tet-razolium staining.Scratch assays were performed to assess cell migration.RESULTS:DHMBA exhibited no significant cytotoxicity between 125 and 1 000 μmol/L.In H/R-injured human umbilical vein endothelial cells,DHMBA improved cell survival,inhibited phosphorylation of NF-κB p65,reduced the content of TNF-α and IL-6,and increased phosphory-lation of eNOS and NO levels.DHMBA also suppressed ROS overload and restored the ratio between GSH and oxidized GSH,decreased in LDH leakage and increased cell migration in H/R-injured human umbilical vein endothelial cells.CONCLUSION:DHMBA can alleviate H/R-induced oxidative stress,inflammation,cellular damage,and dysfunction,which are associated with the ability of DHMBA to inhibit ROS production in human umbilical vein endothelial cells.