title: Black tea extract: a supplementary antioxidant in radiation-induced damage to DNA and normal lymphocytes.
abstract: Myriad research has contributed significantly toward the understanding and identification of health benefits stemming from tea polyphenols and many other naturally occurring flavonoids present in fruits and vegetables. These flavonoids are known to mitigate reactive oxygen species-induced damage by scavenging them. In this study, hot-water black tea extract rich in flavonoids is evaluated as a supplementary antioxidant. The antioxidant efficacy of black tea extract was investigated by evaluating radioprotection conferred to pBR322 DNA, calf thymus DNA, and normal lymphocytes during gamma irradiation. The protection was measured by gel electrophoresis, fluorimetric study, cell viability assay, cytokinesis-blocked micronuclei assay, and comet assay. The 2,2-diphenyl-1-picrylhydrazyl scavenging ability of the tea extract used increased in a dose-dependent manner (IC50: 182.45 µg/mL). Positive correlation of radioprotection with antioxidant activity of black tea extract was observed in all systems. Maximum protection against radiation-induced damage was observed in pBR322 DNA and calf thymus DNA at ≥200 µg/mL of black tea extract. At a dose of black tea extract as low as 5 µg/mL, efficient radioprotection was observed in normal lymphocytes, which is encouraging and can be tested in the future as a natural antioxidant supplement during radiotherapy.
authors.affiliation: School of Biotechnology and Biological Sciences, West Bengal University of Technology, Kolkata, India.
authors.forename: Debjani
authors.initials: D
authors.lastname: Ghosh
authors.forename: Sandip
authors.initials: S
authors.lastname: Pal
authors.forename: Chabita
authors.initials: C
authors.lastname: Saha
authors.forename: Amit Kumar
authors.initials: AK
authors.lastname: Chakrabarti
authors.forename: Salil C
authors.initials: SC
authors.lastname: Datta
authors.forename: Subrata Kumar
authors.initials: SK
authors.lastname: Dey
mesh_terms: D000328:Adult; D000818:Animals; D000975:Antioxidants / Q000494:pharmacology*; D002417:Cattle; D002470:Cell Survival / Q000187:drug effects / Q000528:radiation effects; D020552:Comet Assay; D048749:Cytokinesis / Q000187:drug effects / Q000528:radiation effects; D004247:DNA / Q000187:drug effects / Q000528:radiation effects; D004249:DNA Damage / Q000187:drug effects* / Q000528:radiation effects*; D005720:Gamma Rays / Q000009:adverse effects; D006801:Humans; D066298:In Vitro Techniques; D008214:Lymphocytes / Q000187:drug effects* / Q000528:radiation effects*; D010936:Plant Extracts / Q000494:pharmacology*; D010957:Plasmids; D011835:Radiation Protection; D013662:Tea; D013950:Thymus Gland
chemical_list: D000975:Antioxidants; D010936:Plant Extracts; D013662:Tea; D004247:DNA