title: Comparative study of the growth-inhibitory and apoptosis-inducing activities of black tea theaflavins and green tea catechin on murine myeloid leukemia cells.
abstract: Among the black tea polyphenols, theaflavins are generally considered to be the more effective components for the inhibition of carcinogenesis. In this study, we attempted to compare the growth-inhibitory and apoptosis-inducing activities of the four black tea theaflavins (TF-1, TF-2A, TF-2B and TF-3) with the major green tea catechin epigallocatechin-3-gallate (EGCG) on the murine myeloid leukemia WEHI-3B JCS cells. All the four black tea theaflavins were shown to exert potent anti-proliferative and cytotoxic effects on the leukemia WEHI-3B JCS cells in a dose-dependent manner. The observed anti-proliferative and cytotoxic effects were in the following order of potency: EGCG > TF-2B > TF-3 > TF-2A > TF-1. In addition, all theaflavins were capable of inducing apoptosis in the leukemia WEHI-3B JCS cells. Among the four theaflavins tested, TF-2B and TF-3 were found to be slightly more potent in inducing apoptosis of the WEHI-3B JCS cells than that of TF-2A and TF-1 but were comparable to the major green tea epicatechin EGCG. More interestingly, both TF-2B and TF-3 were found to be much more effective than TF-1 and TF-2B in reducing both the in vitro clonogenicity and in vivo tumorigenicity of the WEHI-3B JCS cells, suggesting that these two black tea theaflavins might represent potential candidates for the treatment of some forms of leukemia.
authors.affiliation: Department of Biochemistry, The Chinese University of Hong Kong, Shatin, China.
authors.forename: Hong-Lok
authors.initials: HL
authors.lastname: Lung
authors.forename: Wai-Ki
authors.initials: WK
authors.lastname: Ip
authors.forename: Zhen-Yu
authors.initials: ZY
authors.lastname: Chen
authors.forename: Nai-Ki
authors.initials: NK
authors.lastname: Mak
authors.forename: Kwok-Nam
authors.initials: KN
authors.lastname: Leung
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D044946:Biflavonoids / Q000494:pharmacology*; D002392:Catechin / Q000031:analogs & derivatives* / Q000494:pharmacology*; D002455:Cell Division / Q000187:drug effects*; D045744:Cell Line, Tumor; D005260:Female; D007951:Leukemia, Myeloid / Q000188:drug therapy* / Q000473:pathology; D051379:Mice; D008807:Mice, Inbred BALB C; D013662:Tea; D014410:Tumor Stem Cell Assay
chemical_list: D044946:Biflavonoids; D013662:Tea; C056068:theaflavin; D002392:Catechin; C045651:epigallocatechin gallate