Summary: | 碩士 === 國立屏東科技大學 === 生物科技系所 === 105 === In recent years, a considerable number of studies have indicated the important role of free radicals in the progress of many human diseases. To realize what kind damage of activated oxygens and free radicals invoke on biological molecules is important in the study of progress and prevention of diseases. Reactive oxygen species (ROS) are important mediactors in the inflammatory response. However, the flavonoid compounds are common in plants, they are the natural plant antioxidants, with antioxidant capacity, scavenging free radicals, inhibit cancer cell growth and reduce cardiovascular disease. In this study, we examined the effects of Flavonoids—Naringerin, Quercetin, Luteolin and Eriodictyol on ROS production in PMA (Phorbol-12-myristate-13-acetate) stimulated U937 cells. There were compared with four flavonoid compounds by chemical method in DPPH (1,1-Diphenyl-2-picrylhydrazyl) scavenging free radical capacity, chelating ferrous iron effects and reducing power. The result indicated that Eriodictyol inhibited ROS production stronger than Naringerin. Eriodictyol pretreatment decrease the expression levels of P-p47 Phox and P-PKC δ in PMA stimulated U937 cell. Eriodictyol, containing two hydroxyl groups on B-ring, exhibited significantly higher antioxidant activity than Naringerin. Because of their different structural types in Naringerin, Quercetin, Luteolin and Eriodictyol, their respective antioxidant capacity tests have different results. In DPPH scavenging free radical capacity, there are 40.28 (±1.58), 22.60 (±2.04), 42.41 (±1.79) and 38.47 (±2.17) % , respectively. In chelating effects, there are 75.63 (±0.78), 51.83 (±1.72), 41.67 (±1.07) and 62.40 (±0.75)% , respectively. In reducing power, there are 0.57 (±0.0040)、0.88 (±0.0050)、0.43 (±0.0047)、0.60 (±0.0061), respectively. From the results, it is relatively close to the physiological experiment using cell model as antioxidative activity evaluation, before the health foods are doing the animal experiments. An innovative U937 cell model for antioxidative activity evaluation was developed in this experiment.
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