Role of glutathione in the antiulcer effect of hot water extract of black tea (Camellia sinensis)

The role of a hot water extract of black tea (Camellia sinensis (L). O. Kun tze Theaceae) in the gastric cytoprotective mechanisms was studied using ga stric mucosal lesions produced by various ulcerogens in rats as an experime ntal model. Prior oral administration of black tea extract (BTE) at 20 ml/k g, i.g. once a day for 7 days significantly reduced the incidence of gastri c erosions and severity induced by ethanol, diethyldithiocarbamate (DDC) an d diethylmaleate (DEM). This treatment also favorably altered the changes i n acid and peptic activity of gastric juice in these ulcerogen-treated anim als. Singular administration of succimer (60 mg/kg, i.g.), the standard sul fhydryl containing antiulcer drug used as a reference drug, was also effect ive. The levels of glutathione and glutathione peroxidase were significantl y decreased after treatment with ethanol, DDC and DEM, and this decrease wa s prevented by BTE pretreatment in the aforesaid manner. Other major featur es of BTE-induced reversal of ulcerogenic agents include a significant decr ease in the protein content and a marked increase in hexosamine and sialic acid content. These results suggest a major role for glutathione, an endoge nous antioxidant, in the cytoprotection against ulceration afforded by BTE.