In vitro cytotoxicity of a theaflavin mixture from black tea to malignant, immortalized, and normal cells from the human oral cavity.
The growth inhibitory effects of a theaflavin mixture from black tea were more pronounced to malignant (CAL27; HSC-2; HSG1) and immortalized (S-G; GT1) cells than to normal (HGF-2) cells from the human oral cavity. Studies with malignant carcinoma CAL27 cells and immortalized GT1 fibroblasts showed that cytotoxicity of the theaflavin mixture was enhanced as the exposure time was increased, with the tumor CAL27 cells more sensitive than the GT1 cells. Hydrogen peroxide (H(2)O(2)) was detected in cell culture medium amended with the theaflavin mixture. The level of H(2)O(2) in cell culture medium amended with the theaflavin mixture was lessened in the presence of catalase and CoCl(2); the level of authentic H(2)O(2) was also lessened in the presence of CoCl(2), suggesting that Co(2+) led to the rapid catalytic decomposition of H(2)O(2). The cytotoxicity of the theaflavin mixture was due, in part, to the generation in the cell culture medium of H(2)O(2), which lessened the intracellular levels of glutathione in the CAL27 cells and, to a lesser extent, in the GT1 cells. For both cell types, coexposures of the theaflavin mixture with catalase or CoCl(2) afforded protection.
Babich
H
H
Department of Biology, Stern College for Women, Yeshiva University, 245 Lexington Avenue, New York, NY 10016, USA. babich@yu.edu
Pinsky
S M
SM
Muskin
E T
ET
Zuckerbraun
H L
HL
D044946:Biflavonoids / Q000494:pharmacology*; D002392:Catechin / Q000031:analogs & derivatives / Q000494:pharmacology*; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D005978:Glutathione / Q000032:analysis; D006801:Humans; D006861:Hydrogen Peroxide / Q000378:metabolism; D010936:Plant Extracts / Q000494:pharmacology; D013662:Tea
D044946:Biflavonoids; D010936:Plant Extracts; D013662:Tea; C056068:theaflavin; D002392:Catechin; D006861:Hydrogen Peroxide; C045651:epigallocatechin gallate; D005978:Glutathione