Role of Antioxidants in the Prevention of Cancer

This review study evaluated the literature on the role of oxidative stress in malignant disorders and to search sources of promising antioxidants: pharmaceutical, dietary supplements, or investigational compounds. Oxidative stress plays important role in the pathogenesis of many cancers. Although a chemoprevention approach, which is a relatively new and promising strategy to prevent cancer using natural dietary compounds and synthetic substances, showed promising results in in vitro and animal studies, many showed mixed results after clinical trials. In several clinical trials, selenium, vitamin E, and carotenoids were shown to have no protective role as chemopreventive agents. Although flavonoids and resveratrol supplementation, along with a well-balanced diet rich in fruits and vegetables containing antioxidants, were shown to lower the incidence of prostate, breast, renal, and other cancers in in vitro and small trials, further research through larger clinical trials is needed to determine the optimal dosage and formulation that elicit antioxidant and anticarcinogenic effects. A preliminary literature search of PubMed was performed using the terms antioxidants, oxidative stress, cancer, malignant disorders, and chemoprevention. Bibliographies of all articles retrieved were reviewed.