Table 2.

Classification of antioxidants based on their origin

Antioxidants: based on their origin
Natural				Synthetic
Enzymatic	Non-enzymatic			BHA (Butylated hydroxytoluene), BHT (Butylated hydroxyanisole), Trolox, TBHQ (Tertiary-butyl hydroquinone)
Primary enzymes  Super oxide dismutase, catalase, glutathione peroxidase Secondary enzymes  Glutathione reductase, glutathione 6-phosphate dehydrogenase	Other antioxidants  Protein   Albumin, ceruloplasmin, lactoferrin, transferrin  Non protein   Bilirubin, Ubiquinol, Uric acid  Cofactors   Coenzyme Q10	Vitamins  Vitamin A, Vitamin C, Vitamin E
		Minerals  Selenium, zinc, cooper, iron
		Carotenoids  β-carotene, lycopene, lutein, zeaxanthin
		Polyphenols
		Flavonoids	Phenolic acid
		Flavonols  Quersetin, kaempherol Flavanols  Catechin Flavones  Chrysin Flavanones  Hesperidin Isoflavanoids  Genistein Anthocyanidins  Cyanidin, pelagonidin	Hydroxy-cinnamic acids  Ferulic, p-coumaric Hydroxy-benzoic acids  Gallic acid, ellagic acid
Endogenous		Exogenous