Dietary Phenolics as Cancer Chemopreventive Nutraceuticals: A Promising Paradigm

Cancer development is a dynamic and long term process which involves many complex factors through critical steps of initiation, promotion and progression, leading to an uncontrolled growth of cancerous cells throughout the body. It is believed that dietary constituents derived from plant sources have the ability to modify the process of carcinogenesis thus relating the food stuffs, beyond their basic nutritional benefits, to disease prevention. The concept of nutritional approach to disease prevention and therapy has thus given way to the popularity of bioactive components of food known as nutraceuticals. Nutraceuticals may range from isolated nutrients, herbal products, dietary supplements and special diets to genetically engineered ‘designer’ foods and processed products such as cereals, soups and beverages. Phenolic nutraceuticals derived from fruits, wines, vegetables and spices have been the subject of considerable scientific research in the last few decades for their chemopreventive action against cancer. These include curcumin (from the spice turmeric), resveratrol (from red grapes and red wine), epigallocatechin-3-gallate (EGCG, from green tea), ellagic acid and delphinidin (from pomegranate juice) and genistein (from soybean). Several mechanisms of pleiotropic action have been identified for the anti-cancer properties of these dietary agents, including induction of cell-cycle arrest and apoptosis, targeting the inflammatory and oxidative pathways and modulating the activities of signaling molecules critical to cellular growth and proliferation. The regulation of cancer cell growth by dietary nutraceuticals involves multiple molecular targets and thus unlike drugs these may have the advantage of simultaneously influencing various pathways that go awry in a complex multifactorial disease like cancer. Accumulating evidence in literature, based on epidemiological and laboratory (both in vitro and in vivo) studies, reveals the properties of dietary phenolics that can form the basis of their consideration as lead molecules in the synthesis of novel anti-cancer drugs and to further explore their role as pharmacologically active natural adjuvants to standard chemotherapeutic approaches. The underlying sections of this chapter will specifically focus on how nutraceuticals modulate the essential cellular pathways and thus affect the survival, proliferation, invasion, angiogenesis, and metastasis of the tumor.

Keywords: Nutraceuticals, plant polyphenols, cancer chemoprevention, anticancer, apoptosis, cell signaling.