Tea catechin synergies in inhibition of cancer cell proliferation and of a cancer specific cell surface oxidase (ECTO-NOX).
The anticancer properties of tea catechins are most frequently attributed to the principal catechin (-)-epigallocatechin-3-gallate (EGCg). Efficacy was evaluated using growth of cultured HeLa cells and inhibition of the enzymatic activity of a putative cell surface tea target enzyme, a cancer-associated cell surface-located NADH oxidase (ECTO-NOX) designated tNOX. The amounts of EGCg required to inhibit by both criteria was reduced 10 times by combination with inactive catechins such as (-)-epicatechin (EC), (-)-epigallocatechin (EGC) or (-)-epicatechin-3-gallate (ECG). Various synthetic mixtures based on purified catechins and decaffeinated tea extracts treated enzymatically to reduce the ester bond-containing catechins varying in EGCg content from 0.065 to 40% were of comparable efficacy to decaffeinated green tea extracts as long as EGCg was present and the ratio of total catechins to EGCg + EGC was about 1.5. Such mixtures appear to offer potential cancer protection and therapeutic advantages over those of EGCg alone through lowered toxicity of the mixture to normal cells and for more efficient blood delivery of orally-administered catechins to a tumour site.
Morré
D James
DJ
Departments of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, IN 47907, USA. morre@pharmacy.purdue.edu
Morré
Dorothy M
DM
Sun
Howard
H
Cooper
Raymond
R
Chang
Joseph
J
Janle
Elsa M
EM
D000970:Antineoplastic Agents / Q000494:pharmacology*; D000975:Antioxidants / Q000494:pharmacology; D001628:Beverages; D002392:Catechin / Q000031:analogs & derivatives* / Q000494:pharmacology*; D002455:Cell Division / Q000187:drug effects; D004357:Drug Synergism; D006367:HeLa Cells; D006801:Humans; D008856:Microscopy, Fluorescence; D009247:NADH, NADPH Oxidoreductases / Q000037:antagonists & inhibitors*; D010936:Plant Extracts / Q000494:pharmacology; D013329:Structure-Activity Relationship; D013662:Tea / Q000737:chemistry*; D013997:Time Factors
D000970:Antineoplastic Agents; D000975:Antioxidants; D010936:Plant Extracts; D013662:Tea; C417940:gallocatechin gallate; D002392:Catechin; C062669:epicatechin gallate; C045651:epigallocatechin gallate; D009247:NADH, NADPH Oxidoreductases; C431909:tumor-associated NADH oxidase