Multi-evaluation Of Antioxidant Activity Of Three Functional Factors From Natural Foods

Objective: ROS-induced oxidative stress has been shown closely associated with humanchronic diseases. Natural functional foods with antioxidant activity factors can reduceoxidative damage, their activity evaluation methods are critical to research and development.There are CAA and other methods for rapid assessment, but they cannot fully reflect therelationship of Time-Concentration-Effect. This study used H2O2, high concentration ofglucose and oleic acid as inducers, which is related to common chronic diseases, causingvarying degrees of cellular oxidative damage. Added functional factors--lipoic acid,quercetin, and resveratrol as intervention, through physiological and biochemical methods toevaluate their antioxidant activity and discuss the relationship of Time-Concentration-Effect.Under dynamical damages, comparing the role differences and exploring functioncharacteristics of three functional factors. Providing a theoretical basis for the developmentand utilization of functional evaluation in the future.Methods: The human hepatoma cells (HepG2) were used as experimental cells. H2O2,high-glucose and oleic acid as inducers, causing varying degrees of cell damage. Choseappropriate concentration as model index. Added lipoic acid, quercetin, and resveratrol underdifferent concentration and time of injury and protection. The cell viability was measured byMTT assay, DCFH-DA was used as fluorescence probe for observing ROS level in cells,redox states were determined by using commercially available kits. Using PCA analysesexperimental data and compare effects of three factors in the same model. Real-time PCR wasused to determine the relative mRNA expression of genes, explored the possible mechanismof the protective effects.Results: Three inducers via reducing cell viability, elevating ROS levels, stimulatingcompensatory redox system, resulting in varying degrees of cellular oxidative damage.100μM H2O2acting for4h caused acute cell injury,33mM high-glucose and0.5mM oleic acidcaused easing damage after48h. Functional factors can alleviate oxidative damage to someextent. In short term, antioxidants were not sufficiently improving the injury at lowconcentration. While high concentrations were significantly improved. In long term, variousconcentrations of lipoic acid maintained protective effects; suitable concentration ofresveratrol and quercetin had good antioxidant activity, but high concentration of resveratrolappeared activity transformation.100μM lipoic acid of H2O2model at24h had strongestantioxidant activity;10μM resveratrol was of best antioxidant effect in high-glucose injury at48h,50μM resveratrol in high-glucose and oleic acid model for72h caused pro-oxidant effect.10μM quercetin had the best activity in oleic acid model at48h. Under the best antioxidantactivity, antioxidants via increased the expression of Nrf2-related genes and decreased theexpression of pro-oxidant genes, improving the cellular redox state.Conclusion: Multi-evaluations of antioxidant factors in different levels of injured cellsmodel, can show the changes in types, required concentration and activity of antioxidants indifferent situations of damage, and can visually evaluate its relationship of Time-Concentration-Effect.