| 内容提要: |
QLE, QLB30, and some polyphenols had good antioxidant activity, which were close to or even less than the IC50 of the vitamin C (IC50 = 0.147 mg/mL), and are expected to be used as the natural antioxidants. It has been proved that many polyphenols have typical o-dihydroxybenzene structures. The phenolic hydroxyl groups on them can give protons to dehydrogenation reaction, and then generate hydrogen bonds with another phenolic hydroxyl group to form a structure with lower activity and more stability, that is, O-benzoquinone structure. The activity of free radicals changed from strong to weak, which terminated the chain reaction and finally achieved the effect of eliminating free radicals. Tannins usually have more o-dihydroxybenzene structures such as galloyl groups and hexahydroxy dibenzoyl groups (HHDP), so they have better effect of eliminating free radicals. |