Natural antioxidants in oxidative stress-induced diseases

Natural antioxidants exhibit a wide range of biological effects including antibacterial, antiviral, anti-inflammatory, antiallergenic, antithrombotic, and vasodilatory actions. Medicinal plants basically contain various antioxidants, e.g., vitamins, carotenoids, and phenolic compounds such as catechin, epicatechin, lignin and tannins, and anthocyanins. In the group of polyphenolic compounds and flavonoids have been extensively studied and include catechins, proanthocyanins, anthocyanidins, flavones, flavonols, and their glycosides, which represent some major groups of natural antioxidants having significant protective effects against various human diseases.