Anticancer Mechanistic Insights of Epigallocatechin-3-Gallate, an Active Ingredient of Green Tea (Camellia sinensis)

Abstract

Ineffectiveness of conventional anticancer drugs opens new challenges for researchers to search for effective, safe, and economical anticancer agents. Currently cancer is a global health concern, and heavy efforts are being done by researchers to evolve the effective anticancer drugs having minimum toxicity and broad safety profile. Green tea is one of the natural plant product consumed by people in every corner of the world. Its phytochemical constituents are polyphenol flavonoid catechins like epigallocatechin-3-gallate (EGCG), (−) epigallocatechin, and (−) epicatechin. EGCG is the major catechin and has been found to be highly effective against carcinogenesis in animal models and human clinical trials. It has been reported that EGCG inhibit tumorigenesis and malignancies by different molecular mechanisms like restraining the mitogen-activated protein kinase pathways, inhibition of growth factor cell signaling, induction of apoptosis, NFκB pathways inhibition, and inhibition of other molecular mechanisms discussed in this review. Besides acting directly as potent anticancer agent, it also enhances the activity of other allopathic currently available anticancer drugs by its additive or synergistic action and minimizes their toxicity. Therefore EGCG is one of the most potent anticancer compound having maximum efficacy and minimum cytotoxicity. It not only makes green tea as anticancer remedy but also provides new clues to evolve safe and potent anticancerous agents for researchers.