Comparative study of the growth-inhibitory and apoptosis-inducing activities of black tea theaflavins and green tea catechin on murine myeloid leukemia cells.
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.
Lung
Hong-Lok
HL
Department of Biochemistry, The Chinese University of Hong Kong, Shatin, China.
Ip
Wai-Ki
WK
Chen
Zhen-Yu
ZY
Mak
Nai-Ki
NK
Leung
Kwok-Nam
KN
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
D044946:Biflavonoids; D013662:Tea; C056068:theaflavin; D002392:Catechin; C045651:epigallocatechin gallate