Breast cancer has become the second leading cause of
cancer-related deaths worldwide. The control of this disease can be achieved through
chemoprevention, which refers to the consumption of synthetic or naturally occurring agents to block, reverse, or delay the process of
tumor development.
Tea (Camellia sinensis), the most widely consumed beverage, has shown promises in the field of
cancer chemoprevention. Inhibition of
tumorigenesis by
green or black tea polyphenols has been demonstrated in various in vitro and in vivo models. Here, we examined the inhibitory effect of
green tea polyphenol (
GTP) and
black tea polyphenol (BTP) on the development of mammary
tumors- induced by 7, 12-dimethylbenz (a)
anthracene (DMBA) in female, Wistar rats. 13% and 33% of animals developed
tumors in
GTP and BTP supplemented groups, respectively. Both
GTP and BTP are effective in significantly inhibiting the cumulative number of mammary
tumors (by ~92% and 77%, respectively) and in reducing their growth. Mechanistically, we investigated the effects of
GTP and BTP on the components of cell signaling pathways, connecting biomolecules involved in
cancer development.
GTP and BTP supplementation as a sole source of drinking
solution leads to scavenging of
reactive oxygen species (ROS) (by ~72% and 69%, respectively) by inhibiting
cyclooxygenase-2 (Cox-2) and inactivation of phosphorylated forms of
nuclear factor-kappa B (NF-κB) and Akt. Altogether, the study suggests that both cultivars of
tea, i.e. green and black, have anti-tumorigenic potential against DMBA-induced mammary
tumorigenesis in Wistar rats. Further studies such as large and long term cohort studies and clinical trials are warranted.