Objective: To study the protection action and possible mechanism of total flavonoids from Lycium barbarum(FLB) on the injured human umbilical vein endothelial cells(HUVEC)induced by hydrogen peroxide(H2O2). Method: The HUVEC oxidative stress damage model was established by using H2O2.This study was divided into as follows:normal group

1 mmol·L-1 H2O2 injury group

FLB protective groups(100

200

400 mg·L-1)incubation for 24 hours and positive control (vitamin C 20 mg·L-1)group incubation for 24 h. MTT method was used to detect cell activity that was protected by FLB from damage caused by 1 mmol·L-1 H2O2.The levels of malondialdehyde (MDA)and superoxide dismutase (SOD)

the activity of lactate dehydrogenase (LDH)

the generation of nitric oxide(NO)in the supernatan were measured. Result: The levels of MDA and the activity of LDH were increased

the generation of No and the activity of SOD decreased obviously in H2O2 damage model group

the differences are significant (P<0.01).In FLB protection group

the activity of LDH and the levels of MDA were decreased

the generation of NO and the activity of SOD were increased obviously

the differences were significant(P<0.01). There was a dose dependent manner between the decreased degree of MDA

the activity of LDH

the degree of NO generation

the activity of SOD and FLB. Conclusion: FLB has the ability to protect vascular endothelial from damage caused by H2O2

its mechanism of the protecting of total FLB may be related to inhibiting lipid peroxidation damage cells

effectively improving the cell's antioxidant enzyme activity

eliminatimg free radicals

and promoting the production of NO.