Studies on the oxidative modification of low density lipoprotein induced by ultraviolet light and the protective effect of green tea polyphenols

Uitraviolet(UV)light irradiation acting on human low density lipoprotein(LDL)couldgive rise to oxidative modification of LDL.Thiobarbituric acid reactive substances(TBARS),rela-five electrophorefic mobility(REM),relative fluorescence intensity at 420 nm(the excitation wavelength was 360nm)and lipid conjugated dienes of UV-irradiated LDL were all elevated withthe increase of irradiation time.Addition of 0.01％ EDTA into the irradiation system could inhi-bit this reaction,but the effect was not so potent as that induced in the Cu-PBS-LDLoxidative modification system China green tea polyphenols(CGTP),on the other hand,had aneffective inhibitory effect with obvious dose-effect relationship.It was proposed that lipidperoxidation of LDL induced by free radicals which were generated from UV-irradiation andthe inhibitory effect of CGTP was attributed to its strong antioxidative action.