Document Detail


Theaflavin-3-gallate and theaflavin-3'-gallate, polyphenols in black tea with prooxidant properties.
MedLine Citation:
PMID:  18346048     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
This study compared the in vitro responses of human gingival fibroblasts and of carcinoma cells derived from the tongue to theaflavin-3-gallate (TF-2A) and theaflavin-3'-gallate (TF-2B), polyphenols in black tea. The antiproliferative and cytotoxic effects of the theaflavin monomers were more pronounced to the carcinoma, than to the normal, cells. In phosphate buffer at pH 7.4, the theaflavins generated hydrogen peroxide and the superoxide anion, suggesting that their mode of toxicity may be due, in part, to the induction of oxidative stress. In a cell-free assay, TF-2A and TF-2B reacted directly with reduced glutathione (GSH), in a time- and concentration-dependent manner. Intracellular storages of GSH were depleted on treatment of the cells with the theaflavin monomers. Depletion of intracellular GSH was more extensive with TF-2A than with TF-2B and was more pronounced in the carcinoma, than in the normal, cells. The toxicities of the theaflavins were potentiated when the cells were cotreated with the GSH depleter, d,l-buthionine-[S,R]-sulfoximine. In the presence of catalase, pyruvate and divalent cobalt, all scavengers of reactive oxygen species, the cytotoxicities of the theaflavins were lessened. TF-2A and TF-2B induced lipid peroxidation in the carcinoma cells, whereas in the fibroblasts, peroxidation was evident upon exposure to TF-2A, but not to TF-2B. These studies demonstrated that the black tea theaflavin monomers, TF-2A and TF-2B, act as prooxidants and induce oxidative stress, with carcinoma cells more sensitive than normal fibroblasts.
Authors:
Harvey Babich; Reena T Gottesman; Emily J Liebling; Alyssa G Schuck
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Publication Detail:
Type:  Comparative Study; In Vitro; Journal Article; Research Support, Non-U.S. Gov't     Date:  2008-07-01
Journal Detail:
Title:  Basic & clinical pharmacology & toxicology     Volume:  103     ISSN:  1742-7843     ISO Abbreviation:  Basic Clin. Pharmacol. Toxicol.     Publication Date:  2008 Jul 
Date Detail:
Created Date:  2008-07-07     Completed Date:  2008-09-09     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  101208422     Medline TA:  Basic Clin Pharmacol Toxicol     Country:  Denmark    
Other Details:
Languages:  eng     Pagination:  66-74     Citation Subset:  IM    
Affiliation:
Department of Biology, Stern College for Women, Yeshiva University, New York, NY, USA. babich@yu.edu
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MeSH Terms
Descriptor/Qualifier:
Antineoplastic Agents / pharmacology*
Antioxidants / pharmacology
Biflavonoids / pharmacology*
Catechin / pharmacology*
Cell Line
Cell Line, Tumor
Cell Proliferation / drug effects
Fibroblasts / drug effects,  metabolism
Flavonoids / pharmacology*
Gallic Acid / analogs & derivatives*,  pharmacology
Glutathione / metabolism
Humans
Hydrogen Peroxide / metabolism
Lipid Peroxidation / drug effects
Mouth / cytology
Oxidation-Reduction
Oxidative Stress / drug effects
Phenols / pharmacology*
Tea / chemistry*
Chemical
Reg. No./Substance:
0/Antineoplastic Agents; 0/Antioxidants; 0/Biflavonoids; 0/Flavonoids; 0/Phenols; 0/Tea; 0/polyphenols; 149-91-7/Gallic Acid; 154-23-4/Catechin; 31629-79-5/theaflavine gallate; 70-18-8/Glutathione; 7722-84-1/Hydrogen Peroxide

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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