COMPONENTS OF BLACK TEA CAN INHIBIT CHEMICALLY INDUCED COLON CARCINOGENESIS THROUGH MODULATION OF CYCLOOXYGENASE-2 ACTIVITY
Chemoprevention of colorectal cancer has become essential in the modern industrialized world. Widely used beverages, like tea, rich in antioxidant flavanols are now being tested for their anticarcinogenic properties. Azoxymethane induced carcinogenic rodent model was used to assess the chemopreventive efficacy of black tea infusion, in terms of aberrant crypt foci, the preneoplastic lesion in colon. To determine the amount of individual polyphenols consumption, HPLC analysis of the infusion was carried out. The levels of colon cell proliferation and apoptosis were analyzed as well as the expression of cyclooxygenase-2 on the level of protein. The treatment resulted in significant inhibition of cell proliferation and induction of apoptosis, suppression of cyclooxygenase-2 expression and significant reduction in the incidence of aberrant crypt foci. The study exemplifies the synergistic action of various black tea components, which interfere different stages of colon carcinogenesis.
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