Plant polyphenols and their role in cancer prevention and chemotherapy

Abstract

Chemoprevention has been proposed as the good tool to target these high-risk cancer patients. Among various identified chemopreventive agents, plant polyphenols (PPs) have been shown to be safe and highly effective in inhibiting of carcinogen-induced mutagenesis and tumorigenesis in bioassays and animal models for different target organ sites. The compounds derived from the plants are of considerable interest among oncologists. PPs have been studied for their chemopreventive and chemotherapeutic properties against human cancer, including green tea polyphenols, genistein (found in soy), apigenin (celery, parsley), luteolin (broccoli), quercetin (onions), kaempferol (broccoli, grapefruits), curcumin (turmeric), etc. Whilst such naturally occurring polyphenols have been the subject of numerous mechanistic studies in cells, information on their clinical properties, which might help assess their promise as human cancer chemopreventive agents, is scarce. The more we discuss their molecular mechanisms and cellular targets, the better we could utilize these natural gifts for the prevention and treatment of human cancers. The abundance of flavonoids and related phenolics in the plant kingdom makes it possible that several hitherto uncharacterised agents with cancer preventive potential are still to be identified,whichmay constitute attractive alternatives to currently used chemopreventive drugs. In this article, the effective PPs against human cancers will also be discussed, with more emphases on the basic conceptions of phenolics with strong antioxidant activity.