INHIBITORY EFFECT OF 6 GREEN TEA CATECHINS AND CAFFEINE ON THE GROWTHOF 4 SELECTED HUMAN TUMOR-CELL LINES

Green tea is an aqueous infusion of dried unfermented leaves of Camell ia sinensis (family Theaceae) from which numerous biological activitie s have been reported including antimutagenic, antibacterial, hypochole sterolemic, antioxidant, antitumor and cancer preventive activities, F rom the aqueous-alcoholic extract of green tea leaves, six compounds ( +)-gallocatechin (GC), (-)-epicatechin (EC), (-)-epigallocatechin (EGG ), (-)-epicatechin gallate (EGG), (-)-epigallocatechin gallate (EGCG) and caffeine, were isolated and purified, Together with (+)-catechin, these compounds were tested against each of four human tumor cell line s (MCF-7 breast carcinoma, HT-29 colon carcinoma, A-427 lung carcinoma and UACC-375 melanoma). The three most potent green tea components ag ainst all four tumor cell lines were EGCG, GC and EGG. EGCG was the mo st potent of the seven green tea components against three out of the f our cell lines (i.e. MCF-7 breast cancer, HT-29 colon cancer and UACC- 375 melanoma), On the basis of these extensive in vitro studies, it wo uld be of considerable interest to evaluate all three of these compone nts in comparative preclinical in vivo animal tumor model systems befo re final decisions are made concerning which of these potential chemop reventive drugs should be taken into broad clinical trials.