Induction of apoptosis by polyphenolic compounds in cancer cells

Abstract

Apoptosis, one of the main types of programmed cell death, is a kind of defense mechanism that eliminates the cells that are abnormal or not needed and plays a critical role for the development and maintenance of tissue homeostasis. Apoptosis can be triggered by various physiological and pathological stimuli. Apoptotic pathways require activation of caspases, a group destructive cystein proteases responsible for the cleavage of the key cellular proteins. Recent studies indicate that are two main apoptotic pathways, including extrinsic or death receptor pathway and intrinsic or mitochondrial pathway. Many natural compounds induce apoptosis in various cancer cells by acting through these pathways. These compounds are either antioxidants or inducers of antioxidant defense mechanism. Polyphenols (alone or in combination) are major constituents of plant-derived antioxidants that induce apoptosis by variety of mechanisms in cancer cells and reduce the risk of cancer. This chapter is focused on the effects of polyphenols such as resveratrol, quercetin and tannic acid on apoptosis in various cancers such as breast, colon and prostate cancers.