Natural products and colon cancer: current status and future prospects

Abstract

Carcinogenesis is a multistage process consisting of initiation, promotion, and progression phases. Thus, the multistage sequence of events has many phases for prevention and intervention. Chemoprevention, a novel approach for controlling cancer, involves the use of specific natural products or synthetic chemical agents to reverse, suppress, or prevent premalignancy before the development of invasive cancer. Several natural products including grains, nuts, cereals, spices, fruits, vegetables, beverages, medicinal plants, and herbs, and their various phytochemical constituents including phenolics, flavonoids, carotenoids and alkaloids, as well as organosulfur compounds were suggested to confer protective effects against a wide range of cancers including colon cancer. Since diet has an important role in the etiology of colon cancer, dietary chemoprevention received attention for colon cancer prevention. However, identification of an agent with chemopreventive potential requires in vitro studies, and efficacy and toxicity studies in animal models before embarking on human clinical trials. Recent studies on natural products in colon cancer chemoprevention with respect to multiple molecular mechanisms in various in vitro, in vivo, and clinical studies are described in this overview. Drug Dev Res 69:460–471, 2008.