Since time immemorial, the folk medicine tries to cure diseases including tumors using various parts of plants. Numerous epidemiological studies have shown that there is a statistically significant association between the frequency of consumption of foods of plant origin and incidence of cancer.
In an effort to determine the cause of their favourable effect, many natural substances have been isolated from plants and their potential effects on different stages of carcinogenesis has been tested. Indeed, many from these substances hinder or stop, in vitro, tumor development.