Glucosinolates and phenolics as antioxidants from plant foods.

Dietary glucosinolates and flavonoids exhibit anticarcinogenicity by blocking formation of endogenous or exogenous carcinogens and so preventing initiation of carcinogenesis. Glucosinolates act by induction of antioxidant and detoxifying enzymes such as glutathione-S-transferases and UDP-glucuronosyl transferase, and by inhibition of carcinogen-activating enzymes such as cytochrome P450 1A1. Flavonoids and other phenolic antioxidants act by direct free-radical scavenging. The distribution in foods and structure-function relationships for these classes of compounds are reviewed.