@Article{Letchoumy2007,
journal="Archives of Medical Science",
issn="1734-1922",
volume="3",
number="4",
year="2007",
title="Basic researchAntioxidative potential of black tea polyphenols in vitro and protective effects in vivo on mitochondrialredox status during experimental oral carcinogenesis",
abstract="  Introduction:  To evaluate the  in vitro  and  in vivo  antioxidant properties of the black tea polyphenols Polyphenon-B and BTF-35.   Material and methods:  The  in vitro  antioxidant activity of black tea polyphenols was screened using a panel of assays including 1,1-diphenyl-2-picrylhydrazyl (DPPH), 2,2\’-azinobis-(3-ethyl-benzothiazoline-6-sulfonic acid) (ABTS), hydroxyl radical anion (OH \• ), superoxide anion (O 2  \•\– ), and nitric oxide (NO) radical scavenging assays as well as assay for reducing power. The  in vivo  antioxidant potential was evaluated in the 7,12-dimethylbenz[a]anthracene (DMBA)-induced hamster buccal pouch (HBP) carcinogenesis model. Hamsters were divided into 6 groups. Animals in groups 1 to 3 were painted with 0.5% DMBA three times a week for 14 weeks. While hamsters in group 1 received no further treatment, animals in groups 2 and 3 received a diet containing 0.05% Polyphenon-B and BTF-35 respectively, from four weeks before DMBA painting until the end of the experiment. Animals in groups 4 and 5 were given Polyphenon-B and BTF-35 alone respectively, and group 6 animals served as controls. All the animals were sacrificed after 18 weeks.   Results:  In  in vitro  studies, both Polyphenon-B and BTF-35 showed high radical scavenging activity and reductive potential. Dietary administration of Polyphenon-B and BTF-35 suppressed DMBA-induced HBP tumours by modulating mitochondrial lipid and protein oxidation and enhancing manganese superoxide dismutase (MnSOD), catalase (CAT), reduced glutathione (GSH) and GSH-dependent enzymes in the buccal pouch and liver. Conclusions: Our study suggests that the antioxidative properties of tea polyphenols may be responsible for chemoprevention of HBP carcinogenesis.  Of the two tea polyphenols analysed, BTF-35 was more effective than Polyphenon-B both  in vitro  and  in vivo .",
author="Letchoumy, P. Vidjaya
and Mohan, K.V.P. Chandra
and Hara, Yukihiko
and Nagini, Siddavaram",
pages="330--339",
url="https://www.termedia.pl/Basic-research-Antioxidative-potential-of-black-tea-polyphenols-in-vitro-and-protective-effects-in-vivo-on-mitochondrialredox-status-during-experimental-oral-carcinogenesis,19,9691,1,1.html"
}