Abstract
Chemoprevention is currently regarded as one of the most promising avenues for cancer control. The inhibition of the tumor promotion stage in multistage carcinogenesis as a means of chemoprevention. The anti-tumor-promoting activity of numerous methanol extracts from edible Japanese, Thai, and Indonesian plants as well as marine algae was screened with the use of an in vitro assay, the tumor-promoter-induced Epstein-Barr virus activation test in Raji cells. More than 20 active constituents have so far been isolated and identified. Of these compounds, both auraptene, which occurs widely in citrus fruits, and l'-acetoxychavicol acetate (ACA), a major constituent of great galangal (a condiment in southeast Asia), are promising new chemopreventers because of their conspicuous anticarcinogenesis activities in mouse skin, rat tongue, and rat colon. The action mechanisms by which they inhibit carcinogenesis are suggested to be suppression of the generation of Superoxide anions through leukocyte inactivation in the postinitiation (promotion) phase and induction of xenobiotic phase II enzymes in the initiation phase. This review highlights our criteria for advantageous plant selection to discover new types of effective chemopreventers and presents the chemopreventive activities of two functionally novel compounds in rodent models as well as the action mechanisms so far considered.
Get full access to this article
View all access options for this article.