Green tea: nature’s defense against malignancies
National Institute of Food Science and Technology, University of Agriculture, Faisalabad.
The review is intended to highlight the biochemistry of green tea, its antioxidant potential, its immunopotentiating properties and mode of action against various cancers.
Green tea and its constituents are important components of strategies to prevent and cure various illnesses. The anti-carcinogenic and anti-mutagenic activities of green tea have been shown suggesting that it could reduce the prevalence of cancer and even provide protection. The pharmacological actions of green tea are mainly attributed to polyphenols that includes epigallocatechin-3-gallate (EGCG), epicatechin, epicatechin-3-gallate, epigallocatechin.
Green tea and its components can reduce cellular damage arising from oxidative stress. Green tea is supposed to enhance humoral and cell-mediated immunity, decreasing the risk of certain cancers, and may have certain advantage in treating inflammatory disorders. Much of the cancer chemopreventive properties of green tea are mediated by EGCG that induces apoptosis and promotes cell growth arrest, by altering the expression of cell cycle regulatory proteins, activating killer caspases, and suppressing nuclear factor kappa-B activation. Besides, it regulates and promotes IL-23 dependent DNA repair and stimulates cytotoxic T cells activities in a tumor microenvironment. It also blocks carcinogenesis by modulating the signal transduction pathways involved in cell proliferation, transformation, inflammation and metastasis.