Role of Reduced Glutathione and Nitric Oxide in the Black Tea Extract-Mediated Protection Against Ulcerogen-Induced Changes in Motility and Gastric Emptying in Rats

Abstract

ABSTRACT-The aim of the present study was to investigate the underlying mechanism of the role of hot water extract of black tea [Camellia sinensis (L). O. Kuntze Theaceae] in normalizing the changes in intestinal transit and gastric emptying induced by various ulcerogenic agents in experimental rats. Intestinal transit as well as gastric emptying were significantly reduced in rats treated with glutathione (GSH) depleting agents, diethyl maleate (DEM), indoacetamide (IDA) and N-ethyl maleimide (NEM). Prior oral administration of black tea extract (BTE) at 20 ml / kg of a 10% solution, i.g. once a day for 7 days significantly increased the intestinal transit and gastric emptying with restoration of serum GSH level. Singular administration of succimer (60 mg/ kg, i.g.), the standard sulfhydryl containing antiulcer agent used as a reference drug, was also effective. Increase in intestinal transit caused by BTE was reversed both by N-omega-nitro-L-arginine methyl ester (L-NAME) (25 mg/ kg, i.p.) and N-omega-monomethyl-L-arginine (L-NMMA) (25 mg/ kg, i.p.), but not with N-omega-nitro-D-arginine methyl ester (D-NAME) (25 mg/ kg, i.p.). Furthermore, restoration of intestinal nitric oxide synthase (NOS) activity was found to be associated with BTE treatment. These results provide evidence that nitric oxide may play a role in BTE-mediated improvement of intestinal motility changes and gastric emptying induced by DEM, IDA and NEM.

Herbal Remedy: An Alternate Therapy of Nonsteroidal Anti-Inflammatory Drug Induced Gastric Ulcer Healing

“…Extensive work has been carried out regarding various medicinal attributes of green tea. The prophylactic action of the tea seed-derived triterpene saponins against ethanol-induced gastric mucosal lesions [49,50] and black tea extract against various ulcerogens [51,52] has been reported in rat models. Theaflavin (TF) is a major active component of black tea.…”

Effect on gastric function and symptoms of drinking wine, black tea, or schnapps with a Swiss cheese fondue: randomised controlled crossover trial

“…Animal experiments have shown that a hot water extract of black tea (Camellia sinensis) promotes gastric emptying in rats, possibly as a result of inhibition of nitric oxide mediated relaxation of the stomach by thearubignins and theaflavins. 26 …”

Antidiarrhoeal activity of hot water extract of black tea (Camellia sinensis)

“…More recently, it has been reported that the increase in intestinal transit caused by BTE was reversed by l -NAME and l -NMMA and that restoration of intestinal nitric oxide synthase (NOS) activity was found to be associated with BTE treatment (Maity et al , 2001). It has also been reported that the l -arginine induced reduction of UGT was partially reversed by both BTE and l -NMMA and that both these agents (BTE and l -NMMA) caused a marked enhancement of the tonic 'hump' responses to transmural stimulation in guineapig ileum longitudinal muscle preparation (Chaudhuri et al , 2000).…”

“…Recent reports from this laboratory indicate that while single administration of a 3% solution of BTE increased gastric transit (Chaudhuri et al ., 2000), chronic administration of a higher concentration of BTE, i.e. 10% solution failed to increase gastric transit (Maity et al , 2001). Apart from these studies and the antiulcer studies (Maity et al , 1995;1998) no other work has been carried out to investigate the effect of BTE on gastrointestinal function.…”