The oxidation of LDL has been recognized as an important step in the pathogenesis ol atherosclerosis and much research has focused on the potential role of natural anlioxidanls in prolecling LDL. Plant phcnolics present in fruits, vegetables, and particularly rich in tea and wine, have received considerable attention because of their potential antioxidanl activity. Two types of green tea and two active components, catechin and cpicatcchin, were assessed lor their relative abilities to inhibit the oxidation of LDL mediated by human aortic endolhelial cells. Cells were incubated in phenol red-free Ham's F-10 media containing 200 μg LDL protein/ml. Varying levels of antioxidants, dissolved in DMSO were added to the incubation media prior to addition to the cells. Alpha-tocopherol and Trolox were used as references. After incubation conjugated diene formation was measured by spcetrophotomclry at 234 nm (an index of hydroperovide formation) and hevanal production by static headspace gas chromatography (an index of hydiopcroxidc decomposition). A dose dependent inhibition of LDL oxidation was observed on the basis of conjugated dienes and hexanal for all compounds tested. Extracts of green tea inhibited LDL oxidation by approximately 9.W at concentrations ranging from 0.6 to 5 ppm. The extracts inhibited oxidation by greater than 50% at concentrations ranging from 0.16 to 0.3 ppm. Both catechin and epicatechin inhibited oxidation by greater than 50% at concentrations below 5 μM. The poly phenolic components of green tea may thus have nutritional benefit as physiologically active inhibitors of LDL oxidation induced by cndothclial cells.
|Original language||English (US)|
|State||Published - 1996|
ASJC Scopus subject areas
- Agricultural and Biological Sciences (miscellaneous)
- Biochemistry, Genetics and Molecular Biology(all)
- Cell Biology