In vitro and in vivo evaluation of silver needle white tea extract against colon cancer
Abstract Background Tea (Camellia sinensis) is one of the most consumed beverages in the world. White tea is an unfermented tea made from young tea leaves or unopened buds. Methods The in vitro antiproliferation assay and in vivo Chemopreventive effects of white tea extract (WTE) using azoxymethane (AOM) induced aberrant crypt foci (ACF) in rats was assessed. Twenty-four adult male rats were injected 15 mg/kg body weight AOM subcutaneously once a week for two weeks and then were divided randomly into four groups. Group I (Cancer control), Group II (treated whit 200 mg/kg white tea extract), Group III (treated whit 400 mg/kg white tea extract) and group IV (35 mg/kg body weight 5-fluorouracil as reference control). On the last day of the experiment, the animals were euthanized using an overdose of ketamine and xylazine and the colon tissue was collected. The colon tissues were evaluated grossly and histopathologically for aberrant crypt foci (ACF). Prior to the cancer studies, the acute toxicity test was performed to demonstrate the safety usage of the extract. Results The antiproliferative activity of the extract was observed in HT-29 and HCT 116 colon cancer cells. The ACF score was significantly reduced following the white tea extract treatment in a dose-dependent manner. Furthermore, the acute toxicity study indicated that there were no nephrotoxic and hepatotoxic effects or any serum biochemical changes in the rats that were orally administered with 2000 mg/kg body weight of the extract. Conclusions This study suggested the the potential of white tea as a chemopreventative agent through inhibition of Azoxymethane-induced Colonic Aberrant Crypt Foci Formation in the male Sprague-Dawley rats.