Since 1900 Gomberg proposed the Theory of free radicals (tripheylemthylradical), the study of free radicals has been deepened. Although the antioxidant capacity of traditional synthetic antioxidants is stronger, but the long-term consumption has the latent toxicity, some may even produce teratogenic, the carcinogenic effect, therefore is more and more people's rejection; bee pollen is the pollen grains collected by bees from flowers, containing flavonoids, vitamins, hormones, nucleic acids, enzymes and trace elements, which have anti-aging effects. , is a good antioxidant food. The antioxidation of Radix puerariae, Eucommia ulmoides leaves, Medlar, Hovenia, Poria, Schisandra chinensis, ginkgo biloba, bamboo leaves, lemon, citrus and propolis have been proved experimentally. Therefore, it is very important for food and pharmaceutical industry to select substances with antioxidant and scavenging free radicals from natural products.
Mechanism of scavenging free radicals in plant extracts
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 organisms under the condition of homeostasis imbalance. Free radicals reactive oxygen can destroy biological macromolecules (such as protein, enzyme and DNA), causing DNA mutation or rupture, functional protein and membrane structure destruction. The damage organism of free radicals is an important inducement to accelerate the aging of human body. Supplementation of antioxidant nutrients can help to reduce oxidative damage and delay. Therefore, it is very important to find antioxidant food and Chinese herbal medicine which can effectively remove free radical activity.
The mechanism of natural product scavenging free radicals is complex, which is generally related to the antioxidant active substances in natural products, through the natural products contain high active antioxidant components (such as flavonoids, tannins, unsaturated fatty acids, vitamins, etc.) to supplement the body antioxidant substances, to improve the body's endogenous antioxidant enzyme activities, To prevent the formation and further damage of the free radical chain reaction. It is reported that flavonoids and phenolic compounds have the scavenging effect on free radicals, in addition, the structural factors related to antioxidant activity, such as the number and location of phenolic hydroxyl groups, the steric resistance produced by the combination of monomers and the ability of scavenging free radicals have a certain relationship, such as catechins and their oxides contain a number of free phenolic hydroxyl, It has a strong ability to provide proton protons, so that there is a high degree of oxidation of free radical reduction, thus achieving the termination of free radical chain reaction, to achieve the purpose of scavenging free radicals.