The Role of Flavonoids and Garlic in Cancer Prevention

Abstract

The biological functions of garlic and of bioflavonoids relating to carcinogenesis are reviewed in this brief overview. The organosulfur compounds that constitute the active principle of garlic have a variety of actions inhibiting carcinogen formation, scavenging carcinogens, and suppress- ing tumor development. These effects are weil documented by numerous experimental studies. Clinical studies investigating the effect of garlic consumption on cancer incidence are fewer in number. Although as yet no conclusion can be reached, there are a number of studies that suggest that high garlic intake is associated with reduced incidence of certain cancers. Similarly, bioflavonoids have been extensively studied in vitro and in vivo and animal experiments give strong support to an anticarcinogenic activity of these compounds. Experimental tumor development is inhibited at various stages by bio- flavonoids but so far only one prospective clinical study, which shows no correlation between flavonoid intake and cancer inci- den ce, has been performed. It is concluded that both garlic and bioflavonoids are important biofactors that have great potential to inhibit cancer growth but will require more inves- tigations, especially clinical studies, to establish their effect in humans.