Black tea polyphenols suppress cell proliferation and induce apoptosis during benzo(a)pyrene-induced lung carcinogenesis

One of the most promising strategies for cancer prevention is chemoprevention by daily used food and beverages. Black tea, the most widely consumed beverage, is a source of compounds with antioxidative, antimicrobial, antimutagenic and anticarcinogenic properties. Lung cancer is the most common cause of cancer deaths in both men and women worldwide. Over one million people around the world are likely to be killed by lung cancer due to increased tobacco smoking and environmental pollutants, especially car exhausts. Therefore chemopreventive intervention using black tea and its active components may be a viable means to reduce lung cancer death. In the present investigation, we used benzo(a)pyrene (BP) to induce lung carcinogenesis in mice for the assessment of potential apoptosis-inducing and proliferation-suppressing effects of theaflavins and epigallocatechin gallate, active components of black tea. Hyperplasia, dysplasia and carcinoma in situ evident in the carcinogen control group on the 8th, 17th and 26th weeks respectively, were effectively reduced after treatment with theaflavins and epigallocatechin gallate. Significant reduction in number of proliferating cells and increased number of apoptotic cells was also found on the 8th, 17th and 26th week of treatment with theaflavins and epigallocatechin gallate in BP-exposed mice. Our observation suggests a promising role for black tea polyphenols in the prevention of lung cancer. (c) 2005 Lippincott Williams & Wilkins.