Possible role of oxygen free radicals in ethanol-induced gastric mucosal damage in rats

Anti-Inflammatory, Antinociceptive, Antipyretic, and Gastroprotective Effects of Eurycoma longifolia Jack Ethanolic Extract

Tongkat ali (Eurycoma longifolia Jack) (ELJ) is a plant in the Simaroubaceae family. Its roots are used in traditional Thai medicine to treat inflammation, pain, and fever; however, the antiulcer abilities of its ethanolic extract have not been studied. This study examined the anti-inflammatory, antinociceptive, antipyretic, and gastroprotective effects of ethanolic ELJ extract in animal models and found that ELJ effectively reduced EPP-induced ear edema in a dose-dependent manner and that a high dose of ELJ inhibited carrageenan-induced hind paw edema formation. In cotton-pellet-induced granuloma formation, a high dose of ELJ suppressed the increases in wet granuloma weight but not dry or transudative weight. In the formalin-induced nociception study, ELJ had a significant dose-dependent inhibitory impact. Additionally, the study found that yeast-induced hyperthermia could be significantly reduced by antipyretic action at the highest dose of ELJ. In all the gastric ulcer models induced by chemical substances or physical activity, ELJ extracts at 150, 300, and 600 mg/kg also effectively prevented gastric ulcer formation. In the pyloric ligation model, however, the effects of ELJ extract on gastric volume, gastric pH, and total acidity were statistically insignificant. These findings support the current widespread use of Eurycoma longifolia Jack in traditional medicine, suggest the plant's medicinal potential for development of phytomedicines with anti-inflammatory, antinociceptive, and antipyretic properties, and support its use in the treatment of gastric ulcers due to its gastroprotective properties.

UPLC-QTOF-MS/MS-based metabolomic approach and gastroprotective effect of two chemotypes of Egletes viscosa (L.) less. against ethanol-induced gastric ulcer in mice

ETHNOPHARMACOLOGICAL RELEVANCE

Egletes viscosa (L.) (macela) is a native wild herb that can be found in different states of northeastern Brazil. The infusions of its flower buds are traditionally used for the treatment of gastrointestinal disorders. E. viscosa possesses two chemotypes (named A and B), distinguishable by the composition of the essential oil from the flower buds. Although there are previous studies of the gastroprotective effect of the isolated constituents of E. viscosa, its infusions have not been investigated yet.

AIM OF THE STUDY

The present study aimed to evaluate and compare the chemical composition and the gastroprotective effect of flower bud infusions of E. viscosa from chemotype A (EVCA) and chemotype B (EVCB).

MATERIALS AND METHODS

Sixteen infusions were brewed with flower buds according to the traditional preparation mode and were analyzed through a UPLC-QTOF-MS/MS based metabolomic approach for determination of their metabolic fingerprints and quantification of bioactive compounds. Afterward, these data were analyzed by chemometric methods (OPLS-DA) for discrimination of the two chemotypes. Additionally, infusions of EVCA and EVCB (50, 100 and 200 mg/kg, p.o.) were evaluated on gastric ulcers induced by absolute ethanol (96%, 0.2 mL, p.o.) in mice. To elucidate the gastroprotective mechanisms, the effect of EVCA and EVCB on gastric acid secretion and gastric wall mucus was determined and the role of TRPV1 channels, prostaglandins, nitric oxide and K_ATP channels were assessed. Moreover, the oxidative stress-related parameters and the histological aspects of the stomach tissue were analyzed.

RESULTS

The chemotypes can be discriminated from each other using UPLC-QTOF-MS/MS chemical fingerprints. Both chemotypes presented similar chemical compositions, consisting basically of caffeic acid derivatives, flavonoids and diterpenes. The quantification of bioactive compounds demonstrated that chemotype A possesses more ternatin, tanabalin and centipedic than chemotype B. EVCA and EVCB (50, 100 and 200 mg/kg, p.o.) significantly decreased the severity of ethanol-induced gastric lesions, as shown by a reduction in histological alterations and leucocyte infiltration in gastric tissue. The gastroprotective mechanism of both infusions involves an antioxidant effect, maintenance of gastric mucus and reduction gastric secretion. Stimulation of endogenous prostaglandins and nitric oxide release, activation of TRPV1 channels, and K_ATP channels are also involved in the gastroprotection of the infusions.

CONCLUSION

The gastroprotective effect of EVCA and EVCB was equivalent and mediated through antioxidant and antisecretory actions, including the activation of TRPV1 receptors, stimulation of endogenous prostaglandins and nitric oxide, and opening of K_ATP channels. The presence of caffeic acid derivatives, flavonoids and diterpenes in both infusions is involved in mediating this protective effect. Our findings support the traditional use of infusions of E. viscosa for gastric disorders regardless of the chemotype.

Protective Effect of Oyster Peptides Derived From Crassostrea gigas on Intestinal Oxidative Damage Induced by Cyclophosphamide in Mice Mediated Through Nrf2-Keap1 Signaling Pathway

Oyster peptide (OP) has exhibited useful biological activities and can be used in multi-functional foods. OP has been reported to play a significant role in intestinal protection, but its specific mechanism is still not completely understood. The aim of this study was to analyze the potential effect of OP on oxidative damage of mice intestine induced by cyclophosphamide (Cy). The experimental results revealed that intragastric administration of OP significantly increased average bodyweight, improved ileum tissue morphology and villus structure, as well as increased the activities of superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSH-Px) in oxidized mice serum and liver. The content of malondialdehyde (MDA) in the mice serum and liver homogenate was found to be markedly decreased. Moreover, OP significantly increased the relative mRNA expression levels of superoxide dismutase (SOD), glutathione peroxidase (GSH-P_X), quinone oxidoreductase (NQO1) and heme oxidase-1 (HO-1) in ileum. Western-blot results indicated that prior administration of OP significantly up-regulated the Nrf2 production in ileum, and substantially decreased then Keap1 gene expression. In conclusion, intake of OP was found to markedly improve intestinal oxidative stress in vivo, and this effect was primarily mediated through the simulation of antioxidant Nrf2-Keap1 signaling pathway. This study is beneficial to the application of peptide nutrients in the prevention or mitigation of intestinal oxidative damage.

Structural characterization of two Hericium erinaceus polysaccharides and their protective effects on the alcohol-induced gastric mucosal injury

Hericium erinaceus, a traditional edible mushroom, is known as a medicine food homology to ameliorate gastrointestinal diseases. However, the relationship between the structural characteristics of Hericium erinaceus and its stomach-protecting activity remains unclear. Here, the structural properties of two polysaccharides from Hericium erinaceus, mycelium polysaccharide (HMP) and fruiting body polysaccharide (HFP) were investigated by spectral approaches. The results showed that the distribution of HMP was more uniform compared to HFP. Both HMP and HFP have triple helix structures, but the HMP conformation showed greater stability. Subsequently, the preventive effect of HMP and HFP on ethanol-induced gastric mucosal injury was also evaluated in rats and GES-1 cells, and it showed that both HMP and HFP had significant protective activity against gastric mucosal injury, but HMP showed better activity than HFP. These results suggested that conformational stability polysaccharide in Hericium erinaceus is more related to its gastric-protecting activity.

Phytochemical properties, biological activities and medicinal use of Centaurium erythraea Rafn

ETHNOPHARMACOLOGICAL RELEVANCE

Centaurium erythraea is an important medicinal plant in many countries, e.g. Morocco, Algeria, Italy, Spain, Portugal, and countries of Balkan Peninsula. It is used in folk medicine to treat various illnesses. It is also used as an antiapoplectic, anticoagulant, anticholagogue, antipneumonic, hematocathartic, and as a hypotensive agent.

AIM OF THE REVIEW

In this review, previous reports on the taxonomy, botanical description, geographic distribution, ethnomedicinal applications, phytochemistry, pharmacological properties, and toxicity of Centaurium erythraea were critically summarized.

MATERIALS AND METHODS

Scientific search engines including PubMed, ScienceDirect, SpringerLink, Web of Science, Scopus, Wiley Online, SciFinder, and Google Scholar were consulted to collect data on C. erythraea. The data presented in this work summarized the main reports on C. erythraea phytochemical compounds, ethnomedicinal uses, and pharmacological activities.

RESULTS

C. erythraea is used in traditional medicine to treat various diseases such as diabetes, fever, rhinitis, stomach ailments, urinary tract infections, dyspeptic complaints, loss of appetite, and hemorrhoids, and as diuretic. The essential oils and extracts of C. erythraea exhibited numerous biological properties such as antibacterial, antioxidant, antifungal, antileishmanial, anticancer, antidiabetic, anti-inflammatory, insecticidal, diuretic, gastroprotective, hepatoprotective, dermatoprotective, neuroprotective, and inhibitory agent for larval development. Phytochemical characterization of C. erythraea revealed the presence of several classes of secondary metabolites such as xanthonoids, terpenoids, flavonoids, phenolic acids, and fatty acids.

CONCLUSIONS

Ethnomedicinal studies demonstrated the use of C. erythraea for the treatment of various disorders. Pharmacological reports showed that C. erythraea especially its aerial parts and roots exhibited potent, and beneficial activities. These findings confirmed the link between the traditional medicinal use and the results of the scientific biological experiments. Considering these results, further investigation using diverse in vivo pharmacological assays are strongly recommended to validate the results of its traditional use. Toxicological tests and pharmacokinetic studies are also required to validate the safety and efficacy of C. erythraea and its bioactive contents.

Gastroprotective Activities of Ethanol Extract of Black Rice Bran (Oryza sativa L.) in Rats

Black rice is a type of rice in the Oryza sativa L. species. There are numerous reports regarding the pharmacological actions of black rice bran, but scientific evidence on its gastroprotection is limited. This study aimed to evaluate the gastroprotective activities of black rice bran ethanol extract (BRB) from the Thai black rice variety Hom Nil (O. sativa L. indica) as well as its mechanisms of action, acute oral toxicity in rats, and phytochemical screening. Rat models of gastric ulcers induced by acidified ethanol, indomethacin, and restraint water immersion stress were used. After pretreatment with 200, 400, and 800 mg/kg of BRB in test groups, BRB at 800 mg/kg significantly inhibited the formation of gastric ulcers in all gastric ulcer models, and this inhibition seemed to be dose dependent in an indomethacin-induced gastric ulcer model. BRB could not normalize the amount of gastric wall mucus, reduce gastric volume and total acidity, or increase gastric pH. Although BRB could not increase NO levels in gastric tissue, the tissue MDA levels could be normalized with DPPH radical scavenging activity. These results confirm the gastroprotective activities of BRB with a possible mechanism of action via antioxidant activity. The major phytochemical components of BRB comprise carotenoid derivatives with the presence of phenolic compounds. These components may be responsible for the gastroprotective activities of BRB. The 2000 mg/kg dose of oral BRB showed no acute toxicity in rats and confirmed, in part, the safe uses of BRB.

Protective Effects of Dioscorea batatas Flesh and Peel Extracts against Ethanol-Induced Gastric Ulcer in Mice

Gastric ulcer is a major digestive disorder and provoked by multifactorial etiologies, including excessive alcohol consumption. In this study, we examined the gastroprotective effect of aqueous and ethanolic extracts of Dioscorea batatas Decne (DBD; commonly called Chinese yam) flesh or peel against acidified ethanol-induced acute gastric damage in mice. Our findings demonstrated that oral supplementation of aqueous or ethanolic extracts of DBD flesh or peel before ulcer induction was significantly effective in macroscopically and histologically alleviating ethanol-induced pathological lesions in gastric mucosa, decreasing the plasma levels of inflammatory mediators, such as nitric oxide and interleukin-6, attenuating the gastric expression of cyclooxygenase-2, and increasing the gastric content of prostaglandin E₂. In particular, pretreatment with the flesh extract prepared in 60% ethanol prominently decreased the expression of biomarkers of oxidative stress, including the plasma levels of 8-hydroxy-2-guanosine and malondialdehyde, and restored heme oxygenase-1 expression and superoxide dismutase activity in the stomach. Overall, these findings suggest that the oral supplementation with DBD extract, especially flesh ethanol extract, prior to excessive alcohol consumption, may exert a protective effect against ethanol-induced gastric mucosal damage in vivo, presumably through the activation of the antioxidant system and suppression of the inflammatory response.

Short Chain Fatty Acid Acetate Protects against Ethanol-Induced Acute Gastric Mucosal Lesion in Mice

Short chain fatty acids acetate and propionate have been demonstrated protective function in the intestinal mucosa. However, their impact on gastric mucosa has not yet been elucidated. The current study aimed to investigate the potential protective effects of acetate and propionate against ethanol-induced gastric mucosal lesion and the underlying mechanism in mice. ICR mice were orally treated with acetate and propionate, respectively, 30 min prior to the establishment of gastric mucosal injury model by challenge with absolute ethanol. The gastric samples were collected for the detection of oxidative, inflammatory and apoptotic related parameters. Acetate, but not propionate, attenuated the severity of gastric mucosal damage as evidenced by the gross changes of gastric mucosa, pathological aberrations. Acetate alleviated oxidative stress as shown by the increase in glutathione (GSH) content and superoxide dismutase (SOD) activities, and the decrease of malondialdehyde (MDA) level. The elevated concentrations of interleukin (IL)-1β, tumor necrosis factor (TNF)-α and IL-6, and the activation of nuclear factor-kappaB (NF-κB) p65 by ethanol stimulation was also reduced by acetate. Moreover, the anti-inflammatory factors, IL-4, LXA4 and IL-10, were up-regulated in acetate treated group. With respect to gastric mucosal apoptosis, acetate suppressed caspase-3 activity and BAX expression in favor of cell survival. These favorable actions were maybe associated with up-regulation of the gastric MUC5AC, the key defense factor of gastric mucosal system. These findings accentuate the gastroprotective actions of acetate in ethanol-induced gastric injury which were mediated via concerted multi-prolonged actions, including suppression of gastric oxidation, inflammation and apoptosis and promotion of MUC5AC expression.

Gastroprotective effects of the isopropanol extract of Artemisia princeps and its gastroretentive floating tablets on gastric mucosal injury

In this study, we investigated the gastroprotective effect of an isopropanol extract from the aerial parts of Artemisia princeps (IPAP) and developed a gastroretentive floating tablet of IPAP (IPAP-FR) for maximized local gastroprotective effects. Pre-treatment with IPAP ameliorated the gastric mucosal hemorrhagic lesions in ethanol/HCl- or indomethacin- treated rats. IPAP decreased mucosal hemorrhage of gastric ulcers induced by ethanol or indomethacin plus pyloric ligation in rats. The optimized floating tablet, IPAP-FR, floated on medium surface with more sustained eupatilin release compared to the non-floating control tablet. X-ray photographs in beagle dogs showed that IPAPFR was retained for > 2 h in the stomach. In the ethanol-induced gastric ulcer rat model, the gastric hemorrhagic lesion was improved more substantially with IPAP-FR compared to the non-floating control tablet. Based on these data, our data suggest that IPAP-FR has an improved therapeutic potential for the treatment of gastric ulcer.

Protective effects of hot spring water drinking and radon inhalation on ethanol-induced gastric mucosal injury in mice

Radon therapy using radon (222Rn) gas is classified into two types of treatment: inhalation of radon gas and drinking water containing radon. Although short- or long-term intake of spa water is effective in increasing gastric mucosal blood flow, and spa water therapy is useful for treating chronic gastritis and gastric ulcer, the underlying mechanisms for and precise effects of radon protection against mucosal injury are unclear. In the present study, we examined the protective effects of hot spring water drinking and radon inhalation on ethanol-induced gastric mucosal injury in mice. Mice inhaled radon at a concentration of 2000 Bq/m3 for 24 h or were provided with hot spring water for 2 weeks. The activity density of 222Rn ranged from 663 Bq/l (start point of supplying) to 100 Bq/l (end point of supplying). Mice were then orally administered ethanol at three concentrations. The ulcer index (UI), an indicator of mucosal injury, increased in response to the administration of ethanol; however, treatment with either radon inhalation or hot spring water inhibited the elevation in the UI due to ethanol. Although no significant differences in antioxidative enzymes were observed between the radon-treated groups and the non-treated control groups, lipid peroxide levels were significantly lower in the stomachs of mice pre-treated with radon or hot spring water. These results suggest that hot spring water drinking and radon inhalation inhibit ethanol-induced gastric mucosal injury.

The Pharmacological Potential of Rutin

The contemporary scientific community has presently recognized flavonoids to be a unique class of therapeutic molecules due to their diverse therapeutic properties. Of these, rutin, also known as vitamin P or rutoside, has been explored for a number of pharmacological effects. Tea leaves, apples, and many more possess rutin as one of the active constituents. Today, rutin has been observed for its nutraceutical effect. The present review highlights current information and health-promoting effects of rutin. Along with this, safety pharmacology issues and SAR of the same have also been discussed.

Curcuma aromatica Water Extract Attenuates Ethanol-Induced Gastritis via Enhancement of Antioxidant Status

Curcuma aromatica is an herbal medicine and traditionally used for the treatment of various diseases in Asia. We investigated the effects of C. aromatica water extract (CAW) in the stomach of rats with ethanol-induced gastritis. Gastritis was induced in rats by intragastric administration of 5 mL/kg body weight of absolute ethanol. The CAW groups were given 250 or 500 mg of extract/kg 2 h before administration of ethanol, respectively. To determine the antioxidant effects of CAW, we determined the level of lipid peroxidation, the level of reduced glutathione (GSH), the activities of catalase, degree of inflammation, and mucus production in the stomach. CAW reduced ethanol-induced inflammation and loss of epithelial cells and increased the mucus production in the stomach. CAW reduced the increase in lipid peroxidation associated with ethanol-induced gastritis (250 and 500 mg/kg, p < 0.01, resp.) and increased mucosal GSH content (500 mg/kg, p < 0.01) and the activity of catalase (250 and 500 mg/kg, p < 0.01, resp.). CAW increased the production of prostaglandin E₂. These findings suggest that CAW protects against ethanol-induced gastric mucosa injury by increasing antioxidant status. We suggest that CAW could be developed for the treatment of gastritis induced by alcohol.

Dietary intake assessment and biochemical characteristics of blood and urine in patients with chronic gastritis

Chronic gastritis is a prevalent gastroentestinal disease in Korea. The purpose of this study was to investigate status of foods and nutrients intake and health related biochemical indicators in the patients with chronic gastritis. Daily food and nutrient intake, blood lipids, and antioxidant indicators in the urine, were compared between a group of 19 patients diagnosed with chronic gastritis and a control group of 27 subjects having normal gastroscopy. No significant differences were found in age, height, weight, body mass index, and blood pressure between the two groups. Daily energy intakes were 1900.6 kcal for the chronic gastritis patient group, and 1931.8 kcal for the normal control group without significant difference. No significant difference was found between the two groups in all nutrient intakes except for cholesterol. The chronic gastritis patients consumed lower amount of sugars and sweeteners but greater amount of starchy food groups such as potatoes and legumes than subjects of control group consumed. Also the chronic gastritis patients showed higher serum triglyceride concentration than the normal subjects. These results indicate that the dietary pattern of chronic gastritis patients may have relation to a change in the serum lipid level; however, more systematic research with a larger samples size is required.

Gastroprotective Effects of Glutinous Rice Extract against Ethanol-, Indomethacin-, and Stress-induced Ulcers in Rats

This study was designed to evaluate the efficacy of an orally administered aqueous extract of glutinous rice (GRE) to protect against acute gastric mucosal lesions induced by ethanol, indomethacin, and water immersion restraint stress in rats and to characterize the active substances responsible for the protection. GRE was shown to dose-dependently prevent the gastric lesions induced by the above ulcerogenic treatments at doses of 30 to 300 mg/kg. GRE treatment increased the gastric mucin content and partially blocked the ethanol-induced depletion of the gastric mucus layer. Also, it increased the nonprotein sulfhydryl concentration in the gastric mucosa. The gastroprotective action of GRE was markedly enhanced by co-treatment with 4-8 mg/kg tea extracts. The activity of GRE was completely lost by heat treatment at 80℃ for 3 min or treatment with 0.01% pepsin at 37℃ for 1 h. Protein extraction studies indicated that prolamins are involved in the gastroprotective activity of GRE. Our results suggest that glutinous rice proteins are useful for the prevention and treatment of gastritis and peptic ulcer.

Cell proliferation in ventromedial hypothalamic lesioned rats inhibits acute gastric mucosal lesions

AIM

The role of mucosal layer thickness on prevention of acute gastric mucosal lesions (AGMLs) was examined in ventromedial hypothalamic (VMH)-lesioned rats.

MATERIALS AND METHODS

The incidence of AGMLs after 48-h fasting and 60% ethanol injection into the stomach after 24-h fasting, aggressive factors (gastric acid and serum gastrin) and defensive factors [hexosamine, gastric mucosal blood flow (GMBF), serum thiobarbituric acid reacting substances (TBARS), and thickness of the gastric mucosal layer] were evaluated in VMH-lesioned rats. The effects of cell proliferation on the gastric mucosal layer of these rats were evaluated by H-E staining and immunostaining with proliferating cell nuclear antigen (PCNA).

RESULTS

After 48-h fasting, no AGMLs were observed in VMH-lesioned and sham VMH-lesioned rats (controls). With 60% ethanol administration after 24-h fasting, the numbers of AGMLs were similar in the two groups, but the ulcer index, a marker of ulcer formation, was lower in VMH-lesioned rats compared to that in sham VMH-lesioned rats. VMH-lesioned rats showed increased gastric acid secretion and serum gastrin compared to sham VMH-lesioned rats, indicating an increase in aggressive factors in VMH-lesioned rats. The two groups had similar levels of gastric mucosal hexosamine, GMBF, and gastric mucosal TBARS, but VMH-lesioned rats had an increased thickness of the mucosal cell layer, indicating an increase in defensive factors in these rats. Histologically, VMH-lesioned rats had an increased total mucosal cell layer, especially for the surface epithelial cell layer, and an increased PCNA-labeling index, a marker of cell proliferation, especially in the proliferative zones of gastric mucosa, indicating increased cell proliferation in the proliferative zone of the gastric mucosa.

CONCLUSION

VMH-lesioned rats are resistant to AGML formation due to increased cell proliferation in gastric mucosa through elevating the levels of defensive factors over those of aggressive factors.

Protective effect of 3,4-methylenedioxyphenol (sesamol) on stress-related mucosal disease in rats

Stress-related mucosal disease (SRMD) causes considerable morbidity and mortality in critically ill patients. 3,4-Methylenedioxyphenol (sesamol) has been reported to have potent antioxidative and anti-inflammatory properties. The aim of this study was to investigate the effect of sesamol on water immersion restraint- (WIR-) induced SRMD in rats. Rat gastric ulcer and hemorrhage were induced by WIR. Rats were pretreated orally with various doses of sesamol (0.1, 0.3, and 1 mg/kg, resp.) 30 min before WIR. Gastric mucosal ulceration, hemoglobin, lipid peroxidation, mucus secretion, proinflammatory cytokines, and nuclear factor (NF)-κB levels were determined 4 h after WIR. In addition, the infiltration of neutrophil and macrophage into gastric mucosa was also determined after WIR. Water immersion restraint increased gastric mucosal ulcer and hemorrhage, tumor necrosis factor (TNF)-α, interleukin (IL)-1β, and IL-6 levels but failed to affect mucosal lipid peroxidation and mucus secretion compared with non-WIR. Sesamol significantly decreased gastric ulceration and hemorrhage and inhibited mucosal TNF-α, IL-1β, and IL-6 production and NF-κB activity in WIR-treated rats. In addition, increased myeloperoxidase and CD68 levels in gastric mucosa were found in WIR-treated rats compared to non-WIR rats. Sesamol did not affect myeloperoxidase but decreased CD68 levels in mucosa in WIR-treated rats. Sesamol may protect against SRMD by inhibiting gastric mucosal proinflammatory cytokines in rats.

A review of the gastroprotective effects of ginger (Zingiber officinale Roscoe)

The rhizomes of Zingiber officinale Roscoe (Zingiberaceae), commonly known as ginger is an important kitchen spice and also possess a myriad health benefits. The rhizomes have been used since antiquity in the various traditional systems of medicine to treat arthritis, rheumatism, sprains, muscular aches, pains, sore throats, cramps, hypertension, dementia, fever, infectious diseases, catarrh, nervous diseases, gingivitis, toothache, asthma, stroke and diabetes. Ginger is also used as home remedy and is of immense value in treating various gastric ailments like constipation, dyspepsia, belching, bloating, gastritis, epigastric discomfort, gastric ulcerations, indigestion, nausea and vomiting and scientific studies have validated the ethnomedicinal uses. Ginger is also shown to be effective in preventing gastric ulcers induced by nonsteroidal anti-inflammatory drugs [NSAIDs like indomethacin, aspirin], reserpine, ethanol, stress (hypothermic and swimming), acetic acid and Helicobacter pylori-induced gastric ulcerations in laboratory animals. Various preclinical and clinical studies have also shown ginger to possess anti-emetic effects against different emetogenic stimuli. However, conflicting reports especially in the prevention of chemotherapy-induced nausea and vomiting and motion sickness prevent us from drawing any firm conclusion on its effectiveness as a broad spectrum anti-emetic. Ginger has been shown to possess free radical scavenging, antioxidant; inhibition of lipid peroxidation and that these properties might have contributed to the observed gastroprotective effects. This review summarizes the various gastroprotective effects of ginger and also emphasizes on aspects that warranty future research to establish its activity and utility as a gastroprotective agent in humans.

Anti-inflammatory, gastroprotective and anti-ulcerogenic effects of red algae Gracilaria changii (Gracilariales, Rhodophyta) extract

Background

Gracilaria changii (Xia et Abbott) Abbott, Zhang et Xia, a red algae commonly found in the coastal areas of Malaysia is traditionally used for foods and for the treatment of various ailments including inflammation and gastric ailments. The aim of the study was to investigate anti-inflammatory, gastroprotective and anti-ulcerogenic activities of a mass spectrometry standardized methanolic extract of Gracilaria changii.

Methods

Methanolic extract of Gracilaria changii (MeOHGCM6 extract) was prepared and standardized using mass spectrometry (MS). Anti-inflammatory activities of MeOHGCM6 extract were examined by treating U937 cells during its differentiation with 10 μg/ml MeOHGCM6 extract. Tumour necrosis factors-α (TNF-α) response level and TNF-α and interleukin-6 (IL-6) gene expression were monitored and compared to that treated by 10 nM betamethasone, an anti-inflammatory drug. Gastroprotective and anti-ulcerogenic activities of MeOHGCM6 extract were examined by feeding rats with MeOHGCM6 extract ranging from 2.5 to 500 mg/kg body weight (b.w.) following induction of gastric lesions. Production of mucus and gastric juice, pH of the gastric juice and non-protein sulfhydryls (NP-SH) levels were determined and compared to that fed by 20 mg/kg b.w. omeprazole (OMP), a known anti-ulcer drug.

Results

MS/MS analysis of the MeOHGCM6 extracts revealed the presence of methyl 10-hydroxyphaeophorbide a and 10-hydroxypheophytin a, known chlorophyll proteins and several unidentified molecules. Treatment with 10 μg/ml MeOHGCM6 extract during differentiation of U937 cells significantly inhibited TNF-α response level and TNF-α and IL-6 gene expression. The inhibitory effect was comparable to that of betamethasone. No cytotoxic effects were recorded for cells treated with the 10 μg/ml MeOHGCM6 extract. Rats fed with MeOHGCM6 extract at 500 mg/kg b.w. showed reduced absolute ethanol-induced gastric lesion sizes by > 99% (p < 0.05). This protective effect was comparable to that conferred by OMP. The pH of the gastric mucus decreased in dose-dependent manner from 5.51 to 3.82 and there was a significant increase in NP-SH concentrations.

Conclusions

Results from the study, suggest that the mass spectrometry standardized methanolic extract of Gracillaria changii possesses anti-inflammatory, gastroprotective and anti-ulcerogenic properties. Further examination of the active constituent of the extract and its mechanism of action is warranted in the future.

Protective effect of extract from Rumex aquaticus herba on ethanol-induced gastric damage in rats

BACKGROUND/AIMS

In this study, we investigated the gastroprotective effect of extract including quercetin-3-O-β-D-glucuronopyranoside (EIQ) from Rumex aquaticus herba against the ethanol-induced gastric damage in rats.

METHODS

The rats were divided into eight groups composed of a non-ethanol group, only EIQ (10 mg/kg) group, groups with absolute ethanol after pretreatment with various doses of EIQ (1, 3 and 10 mg/kg), rebamipide (10 mg/kg), stillen (40 mg/kg) and a control receiving only absolute ethanol. Ethanol-induced gastric lesions, lipid peroxidation, neutrophil infiltration and glutathione level were measured. Superoxide dismutase (SOD) and catalase activity were assessed by an assay kit. Protein expression of SOD, catalase or hemoxygenase-1 (HO-1) was assessed by western blotting analysis.

RESULTS AND CONCLUSION

In the absolute ethanol treated group, gastric lesion and malondialdehyde levels were significantly increased with enhanced myeloperoxidase activity. Administration of EIQ 1 h prior to ethanol treatment significantly inhibited the formation of gastric lesions and the elevation of the malondialdehyde levels with myeloperoxidase activity. In addition, pretreatment with EIQ significantly increased the level of glutathione, and elevated the activity and protein expression of radical scavenging enzymes, such as SOD, catalase and HO-1. EIQ may exert anti-inflammatory and anti-oxidative effects against ethanol-induced gastric injury through the reduction of lipid peroxidation, myeloperoxidase activity and free radicals.

Gastroprotective effect of selenium on ethanol-induced gastric damage in rats

In the present study, we examined the gastroprotective effect of selenium against ethanol-induced gastric mucosal lesions in rats. The gastric mucosal lesions were produced by oral administration with various concentrations of ethanol for three days, and 80% ethanol treatment was determined to be the optimal condition for induction of gastric damage. To identify the protective effect of selenium on ethanol-induced gastric damage, various doses of selenium were given as pretreatment for three days, and then gastric damage was induced by 80% ethanol treatment. Selenium showed a protective effect against ethanol-induced gastric mucosal lesions in a dose dependent manner. Specifically, 100 μg/kg selenium showed the highest level of gastroprotection. In addition, selenium markedly attenuated ethanol-induced lipid peroxidation in gastric mucosa and increased activities of radical scavenging enzymes, such as superoxide dismutase (SOD), catalase, and glutathione peroxidase in a dose-dependent manner. Histological data showed that 100 μg/kg selenium distinctly reduced the depth and severity of the ethanol induced gastric lesion. These results clearly demonstrate that selenium inhibits the formation of ethanol-induced gastric mucosal lesions through prevention of lipid peroxidation and activation of enzymatic radical scavenging.

Protective Effect of Propolis Ethanol Extract on Ethanol-Induced Renal Toxicity: Anin VivoStudy

Acute p.o. administration of absolute ethanol (10 ml/kg) to fasted mice would produce extensive renal failure. Pretreatment with p.o. administration of propolis ethanol extract (PEE) could prevent such renal failure effectively and dose dependently. This renal protective effect of PEE may be contributed, at least in part, to its antioxidative activity. The maximal antioxidative effect against absolute ethanol (AE)-induced renal failure could be observed 1 hour after PEE administration. In order to further investigate the renal protective mechanism of PEE, lipid peroxidation and superoxide scavenging activity were conducted in vivo. PEE exhibited dose-dependent antioxidative effects on lipid peroxidation in mice renal homogenate. Results indicated that mice with acute renal failure have higher malonic dialdehyde (MDA) levels compared with those in PEE administered mice. It was concluded that the renal protective mechanism of PEE could be contributed, at least in part, to its prominent superoxide scavenging effect; hence, it could protect, indirectly, the kidney from superoxide-induced renal damages.

The Protective Effect of Quercetin-3-O-β-D-Glucuronopyranoside on Ethanol-induced Damage in Cultured Feline Esophageal Epithelial Cells

Quercetin-3-O-β-D-glucuronopyranoside (QGC) is a flavonoid glucoside extracted from Rumex Aquaticus Herba. We aimed to explore its protective effect against ethanol-induced cell damage and the mechanism involved in the effect in feline esophageal epithelial cells (EEC). Cell viability was tested and 2',7'-dichlorofluorescin diacetate assay was used to detect intracellular H₂O₂ production. Western blotting analysis was performed to investigate MAPK activation and interleukin 6 (IL-6) expression. Exposure of cells to 10% ethanol time-dependently decreased cell viability. Notably, exposure to ethanol for 30 min decreased cell viability to 43.4%. When cells were incubated with 50 µM QGC for 12 h prior to and during ethanol treatment, cell viability was increased to 65%. QGC also inhibited the H₂O₂ production and activation of ERK 1/2 induced by ethanol. Pretreatment of cells with the NADPH oxidase inhibitor, diphenylene iodonium, also inhibited the ethanol-induced ERK 1/2 activation. Treatment of cells with ethanol for 30 or 60 min in the absence or presence of QGC exhibited no changes in the IL-6 expression or release compared to control. Taken together, the data indicate that the cytoprotective effect of QGC against ethanol-induced cell damage may involve inhibition of ROS generation and downstream activation of the ERK 1/2 in feline EEC.

Preventive effect of probiotics and α-tocopherol on ethanol-induced gastric mucosal injury in rats

The protective effect of a probiotic mixture of 13 different bacteria and α-tocopherol on 98% ethanol-induced gastric mucosal injury was evaluated. Levels of gastric mucosal pro- and anti-inflammatory cytokines, malondialdehyde, and secretory immunglobulin A were measured. Rats were allocated into four groups: control, ethanol, probiotic, and α-tocopherol. The control and ethanol groups received skim milk for 14 days. Probiotic and α-tocopherol groups were administered probiotic mixture suspended in skim milk and 100 mg/kg α-tocopherol, respectively, by daily gavage for 14 days. On Day 15, gastric lesions were induced by administration of ethanol 98% (1 mL) to all rats except those in the control group. Probiotic, but not α-tocopherol, seemed to inhibit ethanol-induced gastric mucosal tumor necrosis factor-α, interferon-γ, and interleukin-2 production (P > .05). Ethanol caused the elevation of mucosal interleukin-4 level (compared to the control, P < .05). Probiotic pretreatment significantly suppressed the ethanol-induced increase of gastric mucosal interleukin-4 levels. Pretreatment with either probiotic or α-tocopherol inhibited the ethanol-induced increase of mucosal malondialdehyde concentration (P < .01 and P < .05, respectively). Probiotic pretreatment enhanced the gastric mucosal secretory immunoglobulin A concentration (P < .001). In conclusion, probiotic mixture and α-tocopherol reduced ethanol-induced gastric mucosal lipid peroxidation, suggesting that they may be beneficial for gastric lesions induced by lower ethanol concentration.

Gastroprotective effect of small centaury (Centaurium erythraea L) on aspirin-induced gastric damage in rats

The aim of this study was to determine the antiulcer and antioxidant activities of Centaurium erythraea L (small centaury) in aspirin (ASA) induced acute gastric ulcer model. The gastroprotective effect of the 50% aqueous-ethanolic small centaury (SC) extract was investigated in rats at a dose of ASA 200 mg/kg body weight. Twenty-one Sprague-Dawley albino rats were divided into three groups of seven rats each as follows: (1) control group; (2) acute ASA-treated group and (3) ASA plus SC group. At the end of the 4-h drug administration, ulcer index, oxidant and antioxidant levels were measured and compared between the groups. The percentage of lesion area to total gastric surface area (ulcer index) was significantly reduced (77%) in ASA plus SC group as compared with acute ASA-treated group. The oral administration of ASA decreased catalase (CAT), reduced glutathione (GSH), and increased lipid peroxidation (LPO) levels. Although myeloperoxidase (MPO) activity was increased by ASA, it was found to be lower in the ASA plus SC group. GSH and Vitamin A levels were determined higher in the ASA plus SC group compared with ASA group. These results suggest that SC extract protects against ASA-induced damage due to its antioxidizing activity.

Protective effect of Matricaria chamomilla on ethanol-induced acute gastric mucosal injury in rats

The antiulcerogenic and antioxidant properties of Matricaria chamomilla L. (Compositae) hydroalcoholic extract (MCE) on ethanol-induced gastric mucosal injury were investigated in rats. After the induction of gastric mucosal injury, all groups were sacrificed; the gastric ulcer index was calculated, and malondialdehyde (MDA) and reduced glutathione (GSH) in whole blood and gastric tissue, and serum ascorbic acid, retinol, and beta-carotene levels were measured in all groups. Pretreatment with MCE at some doses significantly reduced gastric lesions. Again, some doses of MCE significantly reduced the MDA, and significantly increased GSH levels in gastric tissue or whole blood. Serum beta-carotene and retinol levels were significantly higher in the 200 mg/kg MCE-administered group with respect to control. As a result, MCE clearly has a protective effect against ethanol-induced gastric mucosal lesions, and this effect, at least in part, depends upon the reduction in lipid peroxidation and augmentation in antioxidant activity.

Effects of Bidens pilosa L. var. radiata Scherff on experimental gastric lesion

Bidens pilosa L. var. radiata Scherff: (BP) is a plant used as a traditional folk medicine. BP, cultivated with only green manure on Miyako Island, Okinawa prefecture, was processed to powder and is referred to as MMBP. We have reported that MMBP has antioxidant, anti-inflammatory, and anti-allergy properties. In this study, we investigated the effects of MMBP on several experimental gastric lesions induced by HCl/EtOH, a non-steroidal anti-inflammatory drug, or cold-restraint stress, comparing these results with those of rutin or anti-ulcerogenic drugs (cimetidine or sucralfate) based on the lesion index and hemorrhage from the gastric lesions. Orally administered MMBP prevented the progression of the gastric lesions. Moreover, treatment with MMBP, rutin, or sucralfate, which had potent antioxidative activity, inhibited increases in the levels of thiobarbituric acid reactive substances (TBARS) in the gastric mucosal lesions. The inhibition of the gastric mucosal TBARS content by MMBP may have been due to the antioxidant effects of MMBP. These results indicate that MMBP prevents the progression of acute gastric mucosal lesions, possibly by suppressing oxidative stress in the gastric mucosa.

Antiulcer activity of aqueous extract of fruits of Momordica cymbalaria Hook f. in Wistar rats

Gastric ulcer is one of the most prevalent gastrointestinal disorders, which affects approximately 5%-10% of people during their life. The ulcer is an open sore that develops on the inside lining of the stomach (a gastric ulcer) or the small intestine (a duodenal ulcer). Both types of ulcers are also referred to as peptic ulcer disease. The present study was carried out to investigate antiulcer activity of aqueous extract of fruits of Momordica cymbalaria Hook f. Initially the aqueous extract of M. cymbalaria was subjected to acute oral toxicity study according to the Organisation for Economic Co-operation and Development (OECD) guidelines, based on which, 500 mg/kg dose of aqueous extract was selected for the study. The animals were pretreated before inducing ulcer. For inducing ulcer in the rats, 80% ethanol was used. Various parameters such as area of gastric lesion, nonprotein sulfhydryls (NP-SH) concentration, gastric wall mucus concentration, total acidity and volume of gastric content; and histopathological parameters like hemorrhage, edema, erosion, ulceration were studied in the control group and pretreated groups with aqueous extract of fruits of Momordica cymbalaria (500 mg/kg) and standard drug lanzoprazole (30 mg/kg). Pretreatment with aqueous extract of M. cymbalaria fruits showed significant (P < 0.05) decrease in the total acidity and ulcer index. Improvements in all histopathological parameters were noticed in the M. cymbalaria-treated group. It also showed significant decrease in gastric lesion and NP-SH and gastric wall mucus concentrations in the M. cymbalaria-treated group. Overall the aqueous extract of M. cymbalaria fruits was shown to possess significant (P < 0.05) antiulcer property in rats. The polyphenols like quercetin reported from the plant may attribute to the antiulcer property of the extract.

Effect of sesame oil on acidified ethanol-induced gastric mucosal injury in rats

BACKGROUND

Exposure of gastric mucosa to concentrated ethanol induces acute gastritis. Gastric mucosal lipid peroxidation plays a significant role in the pathogenesis of ethanol-induced gastric mucosal lesions. The aim of this study was to investigate the effect of sesame oil on acidified ethanol-induced gastric mucosal damage in rats.

METHODS

We performed gastric bilateral vagotomy in rats. A small incision on forestomach was made and stomach content was expelled. Normal artificial gastric acid (54 mM NaCl plus 100 mM HCl) or acidified ethanol (30% ethanol plus 150 mM HCl) was instilled into the stomach. Gastric lipid peroxidation, glutathione, and nitric oxide levels were measured 3 hours after acidified ethanol administration.

RESULTS

Acidified ethanol caused mucosal ulceration, luminal hemorrhage, lipid peroxidation, and a lower level of mucosal glutathione and nitric oxide production. Pretreatment of sesame oil, but not mineral oil, significantly decreased acidified ethanol-induced mucosal ulcer formation and luminal hemorrhage. Sesame oil reduced mucosal lipid peroxidation, as well as glutathione and nitric oxide production in acidified ethanol-treated stomachs. Furthermore, both sesame oil and mineral oil did not affect serum ethanol concentration in acidified ethanol-treated rats.

CONCLUSION

Sesame oil attenuates acidified ethanol-induced gastric mucosal injury by reducing oxidative stress in rats.

Effects of the oil and mucilage from flaxseed (linum usitatissimum) on gastric lesions induced by ethanol in rats

The anti-ulcer activity of the oil and mucilage obtained from flaxseed (Linum usitatissimum) was evaluated in a rat model of ethanol-induced gastric ulcer. Our results show that pretreatment of rats with flaxseed oil and flaxseed mucilage significantly reduced the number and length of gastric ulcers induced by ethanol. Flaxseed oil was more effective than flaxseed mucilage in reducing the number of ulcers. The reduction in ulcer severity (cumulative length in mm) provided by an oral dose of flaxseed oil (5 ml/kg) was more prominent than that obtained by ranitidine (50 mg/kg). This study indicates that both flaxseed oil and flaxseed mucilage can provide a cytoprotective effect against ethanol-induced gastric ulcers in rats.

Significance of ERK nitration in portal hypertensive gastropathy and its therapeutic implications

Portal hypertensive (PHT) gastric mucosa increases susceptibility to injury and delayed mucosal healing. It is possible that nitration of ERK by peroxynitrite might alter MAPK (ERK) signaling in PHT gastric mucosa, leading to delayed mucosal healing, since excessive nitric oxide production is implicated in PHT gastric mucosa and MAPK (ERK) signaling induces cell proliferation and leads to gastric mucosal healing in response to injury. Portal hypertension was produced by staged portal vein ligation, and sham-operation (SO) rats served as controls. Lipid peroxide (LPO) and nitrotyrosine increased significantly in PHT gastric mucosa compared with SO rats. ERK activation was impaired in PHT gastric mucosa in response to ethanol injury, whereas no significant difference in the phosphorylation of MEK, an upstream molecule of ERK, was seen between the two groups. The nitration of ERK by peroxynitrite, as detected by the coimmunoprecipitation of ERK and nitrotyrosine, was significantly enhanced in PHT gastric mucosa. Administration of rebamipide, a gastroprotective drug that acts as an oxygen-derived free radical scavenger, significantly decreased LPO and nitrotyrosine as well as the nitration of ERK by peroxynitrite in PHT gastric mucosa, therefore normalizing ERK activation and restoring the gastric mucosal healing response to ethanol injury. Enhanced nitration of ERK by peroxynitrite is involved in the impaired MAPK (ERK) signaling in PHT gastric mucosa. These findings demonstrate a new molecular mechanism in which PHT gastric mucosa is predisposed to injury and impaired healing.

Protective effects of cysteine, methionine and vitamin C on the stomach in chronically alcohol treated rats

A chronic intake of high dose alcohol may cause oxidative stress and inflammation in the stomach. It is hypothesized that cysteine-methionine and vitamin C may neutralize harmful compounds while potentiating the antioxidant capacity of the cell or tissue. The experimental animals were fed regular diets and were maintained for 90 days in the control group, the alcoholic group, which was given 2.5 g of 50% ethanol kg(-1) body wt. administered intragastrically every other day, or the alcoholic with antioxidant supplement group, to whom 2.5 g of 50% ethanol kg(-1) body wt. + a solution that contained 200 mg vitamin C, 100 mg cysteine and 100 mg methionine was administered intragastrically every other day. After the treatments, the stomach was taken for pathological and biochemical analysis. The stomach of the alcoholic group rats had higher scores of pathological findings compared with the control group, whereas the scores of the antioxidant-supplemented group were lower than the alcoholic group. In addition, the oxidized protein and lipid content in the stomachs of the alcoholic group were significantly higher than the control, but antioxidant supplementation lowered the amount of oxidation in the antioxidant supplemented group. The amount of stomach glutathione in the alcoholic group was higher than that of the control and antioxidant-supplemented groups. Interestingly, the level of total thiol in the stomach tissue of rats with antioxidant supplement was statistically higher than that of the control and alcoholic groups. In conclusion, the scores of the pathological findings in the stomach of rats with the antioxidant supplement were lower than the chronic alcohol-treated rats, albeit the amount of total thiol was increased in this group. Moreover, chronic alcohol treatment led to an increase in the level of lipid and protein oxidation in the stomach tissue of rats. A simultaneous intake of ascorbate/l-cys/l-met along with ethanol attenuated the amount of oxidation which suggested that cysteine-methionine and vitamin C could play a protective role in the stomach against oxidative damage resulting from chronic alcohol ingestion.

Leukotriene D4 receptor antagonist montelukast alleviates water avoidance stress-induced degeneration of the gastrointestinal mucosa

We investigated the role of montelukast (ML), a cysteinyl leukotriene-1 receptor antagonist, on the water avoidance stress (WAS)-induced degeneration of the rat gastric, ileal and colonic mucosa. One group of Wistar albino rats were exposed to chronic WAS (WAS group) 2h daily for 5 days. Another group was administered ML (10mg/kg; i.p.; WAS+ML group) following every WAS exposure for 5 days. Control rats were injected with the vehicle solution only. The stomach, ileum and colon were dissected and investigated for histopathological changes with a light microscope as well as for topographical changes with a scanning electron microscope. The levels of malondialdehyde (MDA, a biomarker of oxidative damage) and glutathione (GSH, a biomarker of protective oxidative injury) were also determined in all dissected tissues. In the WAS group, the stomach epithelium showed ulceration in some areas, dilatations of the gastric glands, degeneration of gastric glandular cells, and prominent congestion of the capillaries. In a similar fashion, degenerated epithelium and severe vascular congestions were observed in the ileum and colon. In all the tissues dense inflammatory cell infiltration and mast cell degranulation in mucosa were observed. The levels of MDA were significantly increased whereas those of GSH were significantly decreased in all test tissues in the WAS group compared to the control group. The morphology of gastric, ileal and colonic mucosa in WAS+ML group showed a significant amelioration showing a reduction in inflammatory cell infiltration and mast cell degranulation. Increased MDA and decreased GSH levels in the WAS group were also ameliorated with ML treatment. Based on the results, ML supplement seems attenuated inflammatory effects of WAS induction in gastrointestinal mucosa.

Protective effects of aqueous garlic extract in reducing water avoidance stress-induced degeneration of the stomach, ileum, and liver: morphological and biochemical study

We investigated the effect of aqueous garlic extract (AGE) on water avoidance stress (WAS)-induced degeneration of the gastric and ileal mucosa and liver parenchyma. Wistar albino rats were exposed to WAS (WAS group) for 5 days. After exposure of the animals to WAS, a 1 ml/kg aqueous garlic extract (AGE) was injected i.p. (WAS+AGE group). The stomach, ileum, and liver samples were investigated under light microscope for general morphology. Topography of gastric and ileal mucosa was investigated by scanning electron microscopy, and hepatocyte ultastructure by transmission electron micsroscopy. Malondialdehyde (MDA) and glutathione (GSH) levels of all tissues were also determined. In the WAS group, the epithelium of the stomach showed ulceration in some areas, dilatations of the gastric glands, and degeneration of gastric glandular cells. Severe vascular congestion and degeneration of ileal epithelium were observed. Prominent vascular congestion and dilated sinusoids, activated Kupffer cells with prominent morphology, dilated granular endoplasmic reticulum membranes, and focal picnotic nuclei were observed in liver parenchyma. AGE treatment reduced the degeneration of the gastric and ileal mucosa and liver parenchyma. Increased MDA levels and decreased GSH levels in the WAS group were reversed to control values after AGE treatment. Based on these results, AGE treatment significantly prevented WAS-induced degeneration in both morphology and biochemistry of gastrointestinal mucosa and liver parenchyma due to its potent free radical scavenging and antioxidant properties.

Effects of Onosma armeniacum root extract on ethanol-induced oxidative stress in stomach tissue of rats

This study investigated the effects of Onosma armeniacum K. (Boraginaceae) root extract (AR-1) on ethanol-induced stomach ulcers, and on some oxidant and antioxidant parameters, in stomach tissue in rats. The results obtained showed that AR-1 significantly inhibited ethanol-induced ulcers at 25, 50, 100 and 200 mg/kg doses. We found that 50, 100 and 200 mg/kg doses of AR-1 inhibited ulcers more effectively than did ranitidine. AR-1 at doses of 25, 50, 100 and 200 mg/kg significantly prevented the decrease in total glutathione (tGSH) level which occurs in damaged stomach tissues of rats given ethanol (control group). Only a 100 mg/kg dose of AR-1 significantly increased the glutathione S-transferase (GST) level in stomach tissue compared to the control. All doses of AR-1 except the 25 mg/kg dose eliminated the decrease in the superoxide dismutase (SOD) level in the stomach tissue of rats given ethanol. While all doses of AR-1 decreased malondialdehyde (MDA) levels significantly; all doses AR-1 except 25 mg/kg decreased myeloperoxidase (MPO) levels significantly compared to the control. The effect of AR-1 on catalase (CAT) activity was insignificant at all doses. AR-1 significantly increased nitric oxide (NO) levels at 50, 100 and 200 mg/kg doses compared to the control. Our results indicate that the protection of some antioxidant mechanisms and the inhibition of some oxidant mechanisms have a role in AR-1's antiulcer effect mechanism.

Gastroprotective effect of Terminalia arjuna bark on diclofenac sodium induced gastric ulcer

AIM

The present study was aimed to evaluate the effect of methanolic extract of Terminalia arjuna (TA) on diclofenac sodium induced gastric ulcer in experimental rats.

METHODS

Animals were induced for gastric ulcer with diclofenac sodium (DIC) (80mg/kg bodyweight in water, orally) and treated orally with TA in various doses ranging from 100mg/kg bodyweight to 500mg/kg bodyweight. The effective dose was 400mg/kg bodyweight, since this dose elicited a maximum reduction in lesion index. The gastroprotective effect of TA was assessed from volume of gastric juice, pH, free and total acidity, pepsin concentration, acid output in gastric juice, the levels of non-protein sulfhydryls (NP-SH), lipid peroxide (LPO), reduced glutathione (GSH), and activities of enzymic antioxidants--super oxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione-S-transferase (GST) and myeloperoxidase (MPO) in gastric mucosa. The levels of DNA, protein bound carbohydrate complexes--hexose, hexoseamine, sialic acid, fucose in gastric mucosa and gastric juice and the levels of RNA in gastric mucosa were assessed. The stomach tissues were used for adherent mucus content and also for the histological examination.

RESULTS

A significant reduction in lesion index was observed in ulcer induced animals treated with TA (DIC+TA) compared to ulcerated rats (DIC). A significant increase was observed in pH, NP-SH, GSH, enzymic antioxidants, protein bound carbohydrate complexes, adherent mucus content, nucleic acids with a significant decrease in volume of gastric juice, free and total acidity, pepsin concentration, acid output, LPO levels and MPO activities in DIC+TA rats compared to DIC rats. Histological studies confirmed the gastroprotective activity of TA.

CONCLUSION

From the data presented in this study it could be concluded that T. arjuna acts as an gastroprotective agent probably due to its free radical scavenging activity and cytoprotective nature.

Taurine ameliorates water avoidance stress-induced degenerations of gastrointestinal tract and liver

We investigated the role of taurine, is a potent free radical scavenger, on water avoidance stress (WAS)-induced degeneration of the gastric, ileal, and colonic mucosa and liver parenchyma. Wistar albino rats were exposed to chronic WAS (WAS group) 2 hr daily for 5 days. After exposing animals to chronic WAS (WAS + taurine group), 50 mg/kg taurine was injected IP for 3 days. Control animals received vehicle solution only. The stomach, ileum, colon, and liver samples were investigated under light microscope for histopathologic changes. To demonstrate the topography of the luminal mucosa of the stomach, ileum, and colon, scanning electron microscope was used and for hepatocyte ultastructure transmission electron microscope was used. Malondialdehyde (MDA, a biomarker of oxidative damage) and glutathione (GSH, a biomarker of protective oxidative injury) levels were also determined in all tissues. In the WAS group, the stomach epithelium showed ulceration in some areas, dilatations of the gastric glands, and degeneration of gastric glandular cells; prominent congestion of the capillaries was apparent. In the WAS group, severe vascular congestion was observed along with degeneration of ileal and colonic epithelium. Prominent vascular congestion and dilated sinusoids, activated Kupffer cells, dilated granular endoplasmic reticulum membranes, and focal pyknotic nuclei were observed in liver parenchyma. MDA levels (stomach, P < 0.01; ileum, colon, and liver P < 0.05) were increased and GSH levels (P < 0.01) were decreased in all tissues in the WAS group compared with the control group. The morphology of gastric, ileal, and colonic mucosa and liver parenchyma in the WAS + taurine group (stomach and ileum, P < 0.05; colon and liver, P < 0.01) showed a significant amelioration when compared to the WAS group. Increased MDA and decreased GSH levels in the WAS group were ameliorated with taurine treatment. Based on the results, taurine supplementation effectively attenuates the oxidative damage of gastrointestinal mucosa and liver because of WAS induction possibly by its antioxidant effects.

Protective effects of Ginkgo biloba extract on the ethanol-induced gastric ulcer in rats

AIM: To evaluate the preventive effect of Ginkgo biloba extract (GbE) on ethanol-induced gastric mucosal injuries in rats.

METHODS: Female Wistar albino rats were used for the studies. We randomly divided the rats for each study into five subgroups: normal control, experimental control, and three experimental groups. The gastric ulcers were induced by instilling 1 mL 50% ethanol into the stomach. We gave GbE 8.75, 17.5, 26.25 mg/kg intravenously to the experimental groups respectively 30 min prior to the ulcerative challenge. We removed the stomachs 45 min later. The gastric ulcers, gastric mucus and the content of non-protein sulfhydryl groups (NP-SH), malondialdehyde (MDA), c-Jun kinase (JNK) activity in gastric mucosa were evaluated. The amount of gastric juice and its acidity were also measured.

RESULTS: The findings of our study are as follows: (1) GbE pretreatment was found to provide a dose-dependent protection against the ethanol-induced gastric ulcers in rats; (2) the GbE pretreatment afforded a dose-dependent inhibition of ethanol-induced depletion of stomach wall mucus, NP-SH contents and increase in the lipid peroxidation (increase MDA) in gastric tissue; (3) gastric ulcer induced by ethanol produced an increase in JNK activity in gastric mucosa which also significantly inhibited by pretreatment with GbE; and (4) GbE alone had no inhibitory effect on gastric secretion in pylorus-ligated rats.

CONCLUSION: The finding of this study showed that GbE significantly inhibited the ethanol-induced gastric lesions in rats. We suggest that the preventive effect of GbE may be mediated through: (1) inhibition of lipid peroxidation; (2) preservation of gastric mucus and NP-SH; and (3) blockade of cell apoptosis.

Antiulcer activity of methanol fraction of Barleria lupulina Lindl. in animal models

The objective of the present study was to evaluate the gastric cytoprotective activity of the methanol extract of aerial parts of the plant Barleria lupulina Lindl (Acanthaceae) in albino rats using various models of ulcers such as drug induced ulcers, restraint ulcers, duodenal ulcers and pylorus ligated ulcers. The effect of the extract on gastric secretion and lipid peroxidation (thiobarbituric acid reacting substances TBARS) was also studied in rats. The extract at the tested dose of 200 mg/kg significantly reduced the volume of gastric juice, total acidity and the ulcer index in pylorus ligated rats. It also afforded significant protection against alcohol and indomethacin induced ulcer as well as stress induced ulceration. TBARS in the stomach of indomethacin treated rats was also reduced. In addition, it gave protection against duodenal ulcers. The study suggests that the methanol extract of aerial parts of Barleria lupulina Lindl. has a protective effect against experimental gastric and duodenal ulcers.

Estrogen neuroprotection against the neurotoxic effects of ethanol withdrawal: potential mechanisms

Ethanol withdrawal (EW) produces substantial neurotoxic effects, whereas estrogen is neuroprotective. Given observations that both human and nonhuman female subjects often show less impairment following EW, it is reasonable to hypothesize that estrogens may protect females from the neurotoxic effects of ethanol. This article is based on the assumption that the behavioral deficits seen following EW are produced in part by neuronal death triggered by oxidative insults produced by EW. The EW leads to activation of protein kinase C, especially PKCepsilon, which subsequently triggers apoptotic downstream events such as phosphorylation of nuclear factor-kappaB (NFkappaB) complex. On phosphorylation, active NFkappaB translocates to the nucleus, binds to DNA, and activates caspases, which trigger DNA fragmentation and apoptosis. In contrast, estrogens are antioxidant, inhibit overexpression of PKCepsilon, and suppress expression of NFkappaB and caspases. Estrogen treatment reduces the behavioral deficits seen during EW and attenuates molecular signals of apoptosis. The effects of ethanol and estrogen on each step in the signaling cascade from ethanol exposure to apoptosis are reviewed, and potential mechanisms by which estrogen could produce neuronal protection against the neurotoxicity produced by EW are identified. These studies serve as a guide for continuing research into the mechanisms of the neuroprotective effects of estrogen during EW and for the development of potential estrogen-based treatments for male and female alcoholics.

The protective effect of vitamin C, vitamin E and selenium combination therapy on ethanol-induced duodenal mucosal injury

In this study, the effect of a combination of vitamin C, vitamin E and selenium on ethanol-induced duodenal mucosal damage in rats was investigated morphologically and biochemically. The duodenal mucosal injury was produced by oral administration of 1 mL of absolute ethanol to each rat. Animals received vitamin C (250 mg/ kg), vitamin E (250 mg/kg) and selenium (0.5 mg/kg) for 3 days and absolute ethanol 1 hour after last antioxidant administration and were sacrificed 1 hour after absolute ethanol. Extreme degeneration in intestinal mucosa of rats given ethanol was observed morphologically. In addition, an increase in neuronal nitric oxide synthase immunoreactive areas was observed in the rats of the group given ethanol. On the other hand, a normal morphological appearance and a decrease in neuronal nitric oxide synthase immunoreactive areas were detected in the rats given ethanol+vitamin C+vitamin E+ selenium. In the group to which ethanol was administered, an increase in serum cholesterol and a decrease in serum albumin levels were determined. On the other hand, in the group to which ethanol+vitamin C+vitamin E+selenium were administered, serum cholesterol value decreased, and the serum albumin level increased. As a result, we can say that the combination of vitamin C, vitamin E and selenium has a protective effect on ethanol-induced duodenal mucosal injury.

The inhibition of gastric mucosal injury by Punicagranatum L. (pomegranate) methanolic extract

Administration of 70% methanolic extract of Punicagranatum fruit rind (250 mg/kg and 500 mg/kg) shows a percentage of inhibition in 22.37, 74.21 and 21.95, 63.41 in aspirin- and ethanol-induced gastric ulceration, respectively. In treated groups of animals, the in vivo antioxidant levels such as superoxide dismutase (SOD), catalase, glutathione (GSH) and glutathione peroxidase (GPx) levels were increased and found more or less equal to the normal values. The tissue lipid peroxidation level was found to be decreasing in treated groups of animals as compared to the control group. The histopathological examination of the stomach of the ulcerated animals shows severe erosion of gastric mucosa, sub-mucosal edema and neutrophil infiltration. All of these symptoms were found to be normal in treated groups. In general, the results of the present investigation revealed the gastroprotective activity of the extract through antioxidant mechanism.