Objective:To observe the effects of marein, a flavonoid compound in plains coreopsis, on high glucose induced damage in human umbilical vein endothelial cells (HUVEC). MethodsThe cells in logarithmic growth phase were taken and divided into the normal group, high glucose model group and marein groups with different concentrations (50,0, 200,0 μmol/L). The cell viability was detected by CCK-8. The content of malondialdehyde (MDA),the activities of superoxide dismutase (SOD), catalase (CAT) and glutathione-peroxidase (GSH-PX) were assessed by enzyme-linked immunosorbent assay (ELISA), the protein expressions of vascular endothelial factor (VEGF), intercellular adhesion molecule-1 (ICAM-1) and monocyte chemoattractant protein-1 (MCP-1) in HUVEC were detected by Western blot.  Results:Compared with the normal group, the cell viability was significantly decreased in high glucose model groups (P<0.05), while the MDA content was significantly increased (P<0.05) and the activities of SOD, CAT and GSH-PX were decreased (P<0.05). Compared with the high glucose model group (50 mmol/L), the cell viability was obviously increased in marein treatment groups (50,0, 200 and 400 μmol/L), with statistically significant differences (P<0.05), and the cell viability was significantly increased with the increasing concentration of marein. The results of Western blot showed that the protein expressions of VEGF, ICAM-1 and MCP-1 were increased significantly in the high glucose group compared with the normal control group, with statistically significant differences (P<0.05). Compared with the model group, the protein expressions of VEGF, ICAM-1 and MCP-1 were significantly decreased in the marein treatment groups, with statistically significant differences (P<0.05).  Conclusion:Marein exerts a certain protective effect on high glucose-induced HUVEC damage.