Therapeutic effect of rebamipide on ammonia-induced gastric mucosal hemorrhagic lesion in rats

Tochu (Eucommia ulmoides) leaf extract prevents ammonia and vitamin C deficiency induced gastric mucosal injury

The ingestion of dietary antioxidants, including vitamin C (VC), is suggested to play an important role in the prevention of gastric cancer associated with Helicobacter pylori (HP) infection. Recently, water extracts of Tochu (Du-zhong, Eucommia ulmoidea OLIVER) leaves (WETL) have been reported to have potent antioxidant and antimutagenic effects. The present study investigated the effect(s) of VC and WETL on gastric mucosal injury induced by ammonia and a VC deficient diet. Guinea pigs fed the water containing ammonia and/or a VC-deficient diet were simultaneously treated with WETL or VC. Intramucosal levels of thiobarubiturate reactive substances (TBARS), an index of lipid peroxidation, increased significantly in animals fed ammoniated water and VC-deficient diets. This was accompanied by accelerated cell proliferation and increases in immunohistochemical staining indices for oxidative stress-induced DNA adducts and strand breaks (e.g., BrdU-uptake, 8-OhdG, ssDNA and the TUNEL reaction). The administration of either WETL or VC to the ammoniated water and VC-deficient diets ameliorated the increases in intramucosal TBARS levels and labeling indices of BrdU, 8-OHdG, ssDNA and TUNEL, i.e., the levels were similar to those measured in the normal-fed control animals. These data suggest that insufficient VC ingestion may be an important risk factor for gastric cancer development in patients with HP infections. Furthermore, our results suggest that WETL or some constituent may contribute to the prevention of oxidative gastric injury that precedes carcinogenesis.

Inhibitory effects of DA-9601 on ethanol-induced gastrohemorrhagic lesions and gastric xanthine oxidase activity in rats

The exposure of gastric mucosa to ethanol produces pathological changes such as inflammatory process, hemorrhagic erosions, even acute ulcers. The gastric mucosal lesions accompanied by a significant decrease of gastric blood flow and increase of reactive oxygen species (ROS) implicate a role of xanthine oxidase in ethanol-induced gastric hemorrhagic erosions. DA-9601, a novel antipeptic formulation of extracts of Artemisia asiatica Nakai, was studied for its inhibitory effect on gastric xanthine oxidase activity and type conversion of the enzyme that has a profound role in free radical generation. Intubation of absolute ethanol (4 g/kg) significantly induced gastrohemorrhagic lesions and lipid peroxidation in the rat stomach. Oral administration of DA-9601 at 40 mg/kg body weight significantly reduced ethanol-induced gastric mucosal hemorrhagic lesions and lipid peroxidation, which was proportional to the inhibitory effect of DA-9601 on alcohol-induced xanthine oxidase-type conversion and enzyme activity. The results suggest that alcohol-induced gastric mucosal damage may be, in part, due to the increased activity of xanthine oxidase and type conversion rate of the enzyme and that the preventive effect of DA-9601 on gastrohemorrhagic lesions would result from its inhibitory action against xanthine oxidase and oxidative stress in alcohol-treated rats.

Review article: the role of rebamipide in the management of inflammatory disease of the gastrointestinal tract

Rebamipide stimulates the generation of endogenous prostaglandins in the gastric mucosa and is reported to accelerate ulcer healing. This review discusses whether rebamipide can prevent Helicobacter pylori infection, reduce inflammation, accelerate healing after eradication, promote ulcer healing, and prevent progression of preneoplastic lesions. Furthermore, we evaluate its usefulness in other inflammatory conditions of the gastrointestinal tract. We conclude that rebamipide is an important candidate for long-term suppression of gastro-intestinal inflammation, particularly if reducing the complications of H. pylori infection without eradicating the organism becomes accepted. If its ability to accelerate mucosal normalization is confirmed, rebamipide could be added to eradication regimens. Little information exists on whether such therapy could help limit the development of pre-neoplastic lesions. In light of the dearth of effective drugs to control inflammation in idiopathic inflammatory bowel disease, the potential of any promising new and safe compound deserves to be fully explored. The next step is to devise a targeted plan of translational research, so that results from the bench may be used to design rigorously controlled international clinical trials.