The results show that the generation and reaction of excess free radicals and reactive oxygen species are closely related to the occurrence and development of many diseases and the aging process of organism in the condition of homeostasis imbalance of organism. Free radicals can destroy biological macromolecules (such as proteins, enzymes and DNA), causing DNA mutations or breaks, and damage to functional proteins and membrane structures. Free radicals damage organism is an important inducement to accelerate the aging of human body. Supplementation of antioxidant nutrients can help reduce oxidative damage and delay.
Therefore, it is of great significance to find antioxidant foods and Chinese herbal medicines which can effectively eliminate free radical activity in the protection of human health. The mechanism of scavenging free radicals by natural products is complex and is generally related to the antioxidant active substances that are rich in natural products, the antioxidant substances in the body are supplemented by the high active antioxidant components (such as flavonoids, tannins, unsaturated fatty acids, vitamins, etc.) in natural products to enhance the endogenous antioxidant enzyme activity. To prevent the formation and further damage of free radical chain reaction. It is reported that flavonoids and phenolic compounds have scavenging effects on free radicals, in addition, the structural factors related to antioxidant activity, such as the number and location of phenolic hydroxyl groups, the spatial steric resistance produced by the combination of monomer and the ability of scavenging free radicals have a certain relationship, such as catechin and its oxides contain a number of free phenolic hydroxyl groups, With a strong ability to provide hydrogen proton, so that there is a high degree of oxidation of free radical reduction, so as to terminate the free radical chain reaction, to achieve the goal of scavenging free radicals.