Advanced Research on the Antioxidant Activity and Mechanism of Polyphenols from Hippophae Species—A Review

Oxidation is a normal consequence of metabolism in biological organisms. The result is the formation of detrimental reactive oxygen species (ROS) and reactive nitrogen species (RNS). A large number of studies have shown that polyphenolic compounds have good antioxidant properties. <i>Hippophae</i> species plants have high polyphenolic content and are widely used in food, medicinal, or the cosmetic field. The main polyphenols in <i>Hippophae</i> species are flavonoids, phenolic acids and tannins, which have multiple effects. However, there is a limited number of studies on polyphenols in <i>Hippophae</i> species plants. This review systematically summarizes the polyphenols compounds and antioxidant activity of <i>Hippophae</i> species plants, and it is noteworthy that the main mechanisms of the polyphenols of <i>Hippophae</i> with antioxidant activity have been summarized as follows: regulating enzyme activity, affect the antioxidant reaction of cells, and others. This review provides useful information for the further study and application of <i>Hippophae</i> species polyphenols and their antioxidant activity.