title: Antagonistic effects of black tea against gamma radiation-induced oxidative damage to normal lymphocytes in comparison with cancerous K562 cells.
abstract: The potential of naturally occurring antioxidants to reduce the cellular oxidative damage induced by ionizing radiation has been studied for more than a decade for their pharmacological application during cancer treatment. It is already known that radioprotective efficacy of phytochemicals might influence various end points of radiation damage. Flavonoids are well-known natural radioprotectors, and their biological effects depend upon their chemical structure. In the present study, radioprotective effect of black tea rich in flavonoids was evaluated against gamma radiation-induced oxidative damage on normal lymphocytes and compared with erythroleukemic K562 cells. Pre-treatment with black tea extract (BTE) significantly reduced radiation-induced loss of cell viability, generation of reactive oxygen species, mitochondrial dysfunction, activation of caspase-3 and apoptosis in normal lymphocytes compared to K562 cells. BTE also regulates the activity of endogenous antioxidant enzymes. The changes in the mRNA expression of bax, bcl2, p53 and Nrf2 were also followed to evaluate regulation of radiation-induced apoptosis by BTE. These findings suggest that black tea may have the potential of a natural radioprotective agent which can be used as adjunct with radiation during cancer treatment.
authors: School of Biotechnology and Biological Sciences, West Bengal University of Technology, BF-142, Sector I, Salt Lake, Kolkata, 700064, India.
authors: Debjani
authors: D
authors: Ghosh
authors: Subrata Kumar
authors: SK
authors: Dey
authors: Chabita
authors: C
authors: Saha
mesh_terms: D000975:Antioxidants / Q000378:metabolism; D017209:Apoptosis / Q000187:drug effects / Q000528:radiation effects; D028241:Camellia sinensis / Q000737:chemistry; D005720:Gamma Rays / Q000009:adverse effects*; D006801:Humans; D020014:K562 Cells; D015227:Lipid Peroxidation / Q000187:drug effects / Q000528:radiation effects; D008214:Lymphocytes / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism / Q000528:radiation effects*; D020782:Matrix Metalloproteinases / Q000378:metabolism; D018384:Oxidative Stress / Q000187:drug effects* / Q000528:radiation effects*; D010936:Plant Extracts / Q000494:pharmacology*; D011837:Radiation-Protective Agents / Q000494:pharmacology; D013662:Tea / Q000737:chemistry*
chemical_list: D000975:Antioxidants; D010936:Plant Extracts; D011837:Radiation-Protective Agents; D013662:Tea; D020782:Matrix Metalloproteinases