Herbal Combination 'HAGE-101912' Ameliorates Gastroesophageal Reflux Disease in Rats.

Background: Gastroesophageal reflux disease (GERD) is a chronic, relapsing disorder. In this era of modern and fast-track lifestyle and food habits, the incidence of GERD is rapidly increasing. Currently, proton pump inhibitors (PPIs) are the primary choice of treatment. However, the associated side effects and a high relapse rate give rise to the need to explore alternative therapies. Objective: The study aimed to evaluate HAGE-101912, an herbal combination, in different experimental models of GERD. Methods: Antacid activity was assessed based on H+/K+ATPase inhibitory activity of parietal cells using artificial gastric juice. Tonic contraction of the lower esophageal sphincter (LES) was evaluated using an AD Instrument. A GERD model of the pylorus and fundus ligation (preventive and curative models) in rats was selected to assess the efficacy of HAGE-101912 at a dose of 250 mg/kg body weight, and various parameters such as the gastric pH, gastric volume, total acidity, gross esophageal ulcer index, and histopathological changes were evaluated. The prokinetic activity was assessed using the phenol red method. Results: HAGE-101912 increased the acid-neutralizing capacity (P < 0.001), decreased H+/K+ATPase activity (P < 0.01), and increased the contraction of the LES. In the preventive model, HAGE-101912 significantly reduced the gastric acid volume (P < 0.01), total acidity (P < 0.001), and gross esophageal ulcer index (P < 0.01); increased the gastric acid pH (P < 0.01); and protected the esophageal epithelium. In addition, HAGE-101912 increased gastric emptying and gastrointestinal transit through its prokinetic activity (P < 0.05). Conclusion: HAGE-101912 has a beneficial effect in GERD as it effectively inhibits the H+/K+ATPase, increases the gastric pH, restores the LES function, protects the esophageal epithelium, and increases gastric emptying and transit.

Effect of Rumex dentatus on Gastrointestinal Protection and Toxicology in Rodents via Investigating H+/K+-ATPase, Calcium Channels, and PDE Mediated Signaling.

This present study aims to delineate Rumex dentatus crude extract (Rd.Cr), n-Hexane, ethyl acetate, aqueous fractions (Rd.n-Hex, Rd.ETAC, and Rd.Aq), and emodin for antidiarrheal, antisecretory effects, anti-spasmodic, gastrointestinal transient time, anti-H. pylori, antiulcer effects, and toxicology. Plant extracts attributed dose-dependent protection against castor oil-induced diarrhea and dose-dependently inhibited intestinal fluid secretions in mice. They decreased the distance transverse by charcoal in the gastrointestinal transit model in rats. In rabbit jejunum preparations, it causes a concentration-dependent relaxation of both spontaneous and K+ (80 mM)-induced contraction, Rd.n-Hex and verapamil were relatively potent against K+-induced contractions and shifted the Ca2+ concentration-response curves (CRCs) to the right, Rd.Cr and Rd.ETAC shifted the isoprenaline-induced inhibitory CRCs to the left, showing potentiating effect similar to papaverine. Rd.n-Hex showed anti-H. pylori effect. Extracts and emodin also show an inhibitory effect against H+/K+-ATPase. Rumex dentatus showed a gastroprotective and antioxidant effect. Histopathological evaluation showed improvement in cellular architecture and decrease in the expression of inflammatory markers such as cyclooxygenase (COX2), tumor necrosis factor (TNF-α), and phosphorylated nuclear factor kappa B (p-NFƙB), validated through immunohistochemistry, ELISA, and western blot techniques. In RT-PCR, it decreases H+/K+-ATPase mRNA levels. Rumex dentatus was analyzed for certain safety aspects and exhibited a relative safety profile as no impairment was observed in kidneys, heart, liver, and brain further assisted by biochemical and hematological analysis. Docking studies revealed that emodin against H+/K+-ATPase pump and voltage gated L-type calcium channel showed E-value of -7.9 and -7.4 kcal/mol, respectively. MD simulations and molecular mechanics Poisson Boltzmann surface area and molecular mechanics Generalized Born surface area MMPBSA/GBSA findings are consistent with the in-vitro, in-vivo, and docking results. In conclusion, Rumex dentatus extracts and its phytoconstituent could be considered a potent antioxidant and anti-inflammatory drug candidates that possess anti-diarrheal, anti-secretary, antispasmodic, anti-H. pylori, and anti-ulcer potential. Toxicity studies were done according to OECD standards 425. It belongs to group 5 (LD50 > 2000 mg/kg), which suggests that it is in the lower toxicity class.

Pharmacological Basis of Rumex hastatus D. Don in Gastrointestinal Diseases with Focusing Effects on H+/K+-ATPase, Calcium Channels Inhibition and PDE Mediated Signaling: Toxicological Evaluation on Vital Organs.

This present study aimed to delineate Rumex hastatus D. Don crude extract (Rh.Cr), n-Hexane, ethyl acetate, aqueous fractions (Rh.n-Hex, Rh.ETAC, Rh.Aq) and rutin for antidiarrheal, antisecretory effects, anti-spasmodic, gastrointestinal transient time, anti H. pylori, antiulcer effects, and toxicology. The preliminary phytochemical analysis of Rumex hastatus showed different phytoconstituents and shows different peaks in GC-MC chromatogram. Rumex hastatus crude extract (Rh.Cr), fractions, and rutin attributed dose-dependent (50-300 mg/kg) protection (0-100%) against castor oil-induced diarrhea and dose-dependently inhibited intestinal fluid secretions in mice. They decreased the distance traversed by charcoal in the gastrointestinal transit model in rats. In rabbit jejunum preparations, Rh.Cr and Rh.ETAC caused a concentration-dependent relaxation of both spontaneous and K+ (80 mM)-induced contractions at a similar concentration range, whereas Rh.n-Hex, rutin, and verapamil were relatively potent against K+-induced contractions and shifted the Ca2+ concentration-response curves (CRCs) to the right, Rh.Cr (0.3-1 mg/mL) and Rh.ETAC (0.1-0.3 mg/mL) shifted the isoprenaline-induced inhibitory CRCs to the left. Rh.n-Hex, Rh.ETAC and rutin showed anti-H. pylori effect, also shows an inhibitory effect against H+/K+-ATPase. Rumex hastatus showed gastroprotective and antioxidant effects. Histopathological evaluation showed improvement in cellular architecture and a decrease in the expression of inflammatory markers such as, cyclooxygenase (COX-2), tumor necrosis factor (TN,F-α) and phosphorylated nuclear factor kappa B (p-NFƙB), validated through immunohistochemistry and ELISA techniques. In RT-PCR it decreases H+/K+-ATPase mRNA levels. Rumex hastatus was found to be safe to consume up to a dose of 2000 mg/kg in a comprehensive toxicity profile. Docking studies revealed that rutin against H+/K+-ATPase pump and voltage-gated L-type calcium channel showed E-values of -8.7 and -9.4 Kcal/mol, respectively. MD simulations Molecular Mechanics Poisson Boltzmann surface area and molecular mechanics Generalized Born surface area (MMPBSA/GBSA) findings are consistent with the in-vitro, in-vivo and docking results.

Novel Isoxazole Derivative Attenuates Ethanol-Induced Gastric Mucosal Injury through Inhibition of H+/K+-ATPase Pump, Oxidative Stress and Inflammatory Pathways.

Isoxazole derivatives are significant enough due to their wide range of pharmacological and therapeutic activities. The purpose of the current study is to use computational, in vitro, in vivo, and extensive molecular approaches to examine the possible anti-ulcer activity of 4-benzylidene-3 methyl-1,2-isoxazol-5(4H)-one (MBO). Biovia Discovery Studio visualizer (DSV) was utilized for virtual screening. A tissue antioxidant investigation, H+/K+-ATPase test, and anti-H. pylori activities were carried out. ELISA, immunohistochemistry, and PCR methods were employed for the proteome analysis. An ethanol-induced stomach ulcer model was used to examine the anti-ulcer potential in rats. The binding affinities for MBO ranged from -5.4 to -8.2 Kcal/mol. In vitro findings revealed inhibitory activity against H. pylori and the H+/K+-ATPase pump. It also enhanced levels of glutathione, catalase, and glutathione-S-transferase and reduced lipid peroxidation levels in gastric tissues of rats. In vivo results showed the gastro-protective effect of MBO (30 mg/kg) in ulcerative rat stomachs. The proteomic study revealed decreased expression of inflammatory markers (cyclooxygenase-2, p-NFkB, and TNF-α). In RT-PCR analysis, the expression levels of H+/K+-ATPase were reduced. Furthermore, ADMET (absorption, distribution, metabolism, excretion and toxicity) studies revealed that MBO has high GIT solubility and has a safer profile for cardiac toxicity. This study suggests that MBO displayed anti-ulcer potential, which may have been mediated through the inhibition of the H+/K+-ATPase pump, as well as antioxidant and anti-inflammatory pathways. It has the potential to be a lead molecule in the treatment of peptic ulcers with fewer adverse effects.

Validation of diagnostic strategies of autoimmune atrophic gastritis: A case report.

BACKGROUND: Autoimmune atrophic gastritis (AAG) is a type of chronic gastritis that mainly affects the gastric corpus. Due to the lack of standard diagnostic criteria and overlaps with the courses of Helicobacter pylori-related atrophic gastritis, reports on the diagnostic strategy of AAG at an early stage are limited. CASE SUMMARY: A 71-year-old woman with severe anemia was diagnosed with AAG. Endoscopic views and pathological findings showed the coexistence of normal mucosa in the gastric antrum and atrophic mucosa in the gastric fundus. Serological tests showed that anti-parietal cell antibodies and anti-intrinsic factor antibodies were both positive. Immunohistochemical results, which showed negative H+-K+ ATPase antibody staining and positive chromogranin A (CgA) staining, confirmed the mechanism of this disease. After vitamin B12 and folic acid supplementation, the patient recovered well. CONCLUSION: Successful diagnosis of AAG includes serological tests, endoscopic characteristics, and immunohistochemistry for H+-K+ ATPase and CgA antibodies.

Protective Effect of Pyrus ussuriensis Maxim. Extract against Ethanol-Induced Gastritis in Rats.

Pyrus ussuriensis Maxim (Korean pear) has been used for hundreds of years as a traditional herbal medicine for asthma, cough, and atopic dermatitis in Korea and China. Although it was originally shown to possess anti-inflammatory, antioxidant, and antiatopic properties, its gastroprotective effects have not been investigated. In the present study, we evaluated the protective effects of Pyrus ussuriensis Maxim extract (PUE) against ethanol-induced gastritis in rats. The bioactive compound profile of PUE was determined by gas chromatography mass spectroscopy (GC-MS) and high-performance liquid chromatography (HPLC). The gastroprotection of PUE at different doses (250 and 500 mg/kg body weight) prior to ethanol ingestion was evaluated using an in vivo gastritis rat model. Several endpoints were evaluated, including gastric mucosal lesions, cellular degeneration, intracellular damage, and immunohistochemical localization of leucocyte common antigen. The gastric mucosal injury and ulcer score were determined by evaluating the inflamed gastric mucosa and by histological examination. To identify the mechanisms of gastroprotection by PUE, antisecretory action and plasma prostaglandin E2 (PGE2), gastric mucosal cyclic adenosine monophosphate (cAMP), and histamine levels were measured. PUE exhibited significant antioxidant effects with IC50 values of 56.18 and 22.49 µg/mL for 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2'- azino-di-(3-ethylbenzothiazoline)-6-sulfonic acid (ABTS) inhibition (%), respectively. In addition, GC/MS and HPLC analyses revealed several bioactive compounds of PUE. Pretreatment with PUE significantly (p < 0.05) decreased the ulcer index by preventing gastric mucosal lesions, erosion, and cellular degeneration. An immunohistochemical analysis revealed that PUE markedly attenuated leucocyte infiltration in a dose-dependent manner. The enhancement of PGE2 levels and attenuation of cAMP levels along with the inhibition of histamine release following PUE pretreatment was associated with the cytoprotective and healing effects of PUE. In contrast, the downregulation of the H+/K+ ATPase pathway as well as muscarinic receptor (M3R) and histamine receptor (H2R) inhibition was also involved in the gastroprotective effects of PUE; however, the expression of cholecystokinin-2 receptors (CCK2R) was unchanged. Finally, no signs of toxicity were observed following PUE treatment. Based on our results, we conclude that PUE represents an effective therapeutic option to reduce the risk of gastritis and warrants further study.

Pretreatment of Blumea lacera leaves ameliorate acute ulcer and oxidative stress in ethanol-induced Long-Evan rat: A combined experimental and chemico-biological interaction.

Blumea lacera (Burm.f.) DC. is described as a valuable medicinal plant in various popular systems of medicine. The aim of the experiment reports the in vivo antiulcer activity of methanol extract of Blumea lacera (MEBLL) and in silico studies of bioactive constituents of MEBLL. In this study, fasted Long-Evans rat treated with 80 % ethanol (0.5 mL) to induce gastric ulcer, were pretreated orally with MEBLL at different doses (250 and 500 mg/kg, p.o., b.w) and omeprazole (20 mg/kg, p.o.) and distilled water were used as a reference drug and normal control respectively. In silico activity against gastric H+-K+ATPase enzyme was also studied. The findings demonstrated that the treatment with MEBLL attenuated markedly ulcer and protected the integrity of the gastric mucosa by preventing the mucosal ulceration altered biochemical parameters of gastric juice such total carbohydrate, total protein and pepsin activity. Additionally, the experimental groups significantly (p < 0.001) inhibited gastric lesions and malondealdehyde (MDA) levels and upregulated antioxidant enzymes level. Furthermore, nine compounds were documented as bioactive, displayed good binding affinities to against gastric H+-K+ATPase enzyme while these compounds illustrated inhibitory effect. From these studies, it is established MEBLL has ulcer healing property as unveiled by in vivo and in silico studies.

Gastroprotective effect of the alkaloid boldine: Involvement of non-protein sulfhydryl groups, prostanoids and reduction on oxidative stress.

Boldine is the main alkaloid of Peumus boldus Molina, widely used in the traditional medicine for the treatment of digestive disorders. It is a compound with excellent antioxidant and anti-inflammatory properties already described. Despite the widespread use of P. boldus for digestive disorders treatment, the gastroprotective effect of Boldine remains unknown. Considering the need for new approaches to treat gastric ulcers with fewer side effects than current therapy, this study aimed to investigate the gastroprotective effect of Boldine in mice, as well as the mechanisms underlying this effect. The gastroprotective effect of Boldine was evaluated on gastric ulcer induced by 60% ethanol/0.3 M HCl or indomethacin (100 mg/kg) in mice. Histological analysis and the mucin-like glycoprotein content were evaluated in ethanol-ulcerated tissue, as well as, oxidative stress and inflammatory parameters. The mechanisms involved in the effect of Boldine were evaluated by pretreating mice with NEM (a sulfhydryl group chelator, 10 mg/kg, i.p.), l-NAME (a non-selective nitric oxide synthase inhibitor, 70 mg/kg, i.p.), yohimbine (an alpha-adrenergic receptor antagonist, 2 mg/kg, i.p.) and indomethacin (a cyclooxygenase inhibitor, 10 mg/kg, i.p.). In addition, the in vitro effect of Boldine on H+/K+-ATPase activity was determined. Boldine was able to protect gastric mucosa against the damage induced by ethanol/HCl and indomethacin, as evidenced by reduced lesion area and histological analysis. Moreover, the alkaloid reduced oxidative stress and inflammatory mediators in ethanol-ulcerated tissue, beyond has increased mucin-like glycoprotein amount. Finally, Boldine effect is dependent on non-protein sulfhydryl groups and prostanoids but does not involve the inhibition of H+/K + -ATPase activity, being a promising natural resource for gastric ulcer treatment.

The Benefit of Passion Fruit as an Anti-ulcerogenic Diet: Scientific Evidence by In vitro and In silico H+/K+ATPase Inhibitory Activity Assessment.

BACKGROUND: H+/K+ ATPase a protein present in the gastric parietal cells is a better target for the prevention and treatment of gastric ulcer. Plant flavonoids have been reported to elicit anti-ulcer activity by inhibiting the proton pump as well as by antioxidant defense mechanism. METHODS: Chloroform fraction of hydro-alcoholic extract of passion fruit was screened for proton pump inhibitory assay using goat parietal cell. In-silico computational docking studies were carried out using Glide program in order to validate the inhibitory action of selected constituents. RESULTS: The flavonoid rich fruit possess a promising radical scavenging activity against DPPH. 10.41µg/mL is sufficient to inhibit 50% of ATPase enzyme activity. A synergistic activity was also achieved by the fruit with sub-effective doses of lansoprazole. Fenton's oxidation induced by H2O2 was also blunted by the fruit extract. CONCLUSION: The in-vitro and in-silico findings indicated that, passion fruit can be a good dietary supplement for the prevention and management of ulcer.

Trachyspermum ammi (L.) Sprague, superb essential oil and its major components on peptic ulcers: in vivo combined in silico studies.

BACKGROUND: Trachyspermum ammi (L.) Sprague is used for treating gastrointestinal disorders. Several studies indicated gastric antiulcer activity of T. ammi extract, yet the effect of its essential oil has not been studied on. OBJECTIVES: The present study evaluates chemical composition of T. ammi essential oil and anti-peptic ulcer effect of the essential oil as well as its three major components in ethanol induced-gastric ulcers in rats. METHODS: Primarily chemical composition of the essential oil was analyzed by gas chromatography-mass spectrometry (GC/MS). Rats received the essential oil (500, 250, 125, 62.5, 31.25 mg/kg), thymol (30, 100 mg/kg), para-cymene (100, 150 mg/kg) and gamma-terpinene (100, 150 mg/kg) using gavage tube along with ethanol 80%. Finally, dissected stomachs were assessed both macroscopically and microscopically to evaluate anti-ulcerative effect of the essential oil and the pure compounds. Moreover, molecular docking was utilized to explore the interactive behavior of the main components with active site residues of H+/K+ ATPase. RESULTS: Analysis of the essential oil indicated that para-cymene (37.18%), gamma-terpinene (35.36%) and thymol (20.51%) are the main components. Administration of different doses of the essential oil noticeably diminished the number of peptic ulcers in a dose-dependent manner. Among the main components, thymol was more potent than para-cymene and gamma-terpinene. Administration of the essential oil (500 mg/kg) and thymol (100 mg/kg) observed maximum inhibition percentage (98.58% and 79.37%, respectively). Molecular docking study provides the evidence of thymol ability to inhibit H+/K+ ATPase. CONCLUSIONS: The findings revealed that T. ammi essential oil can be applied to treat gastric ulcer as a natural agent. Graphical abstract.

Hydroalcoholic extract from Baccharis dracunculifolia recovers the gastric ulcerated tissue, and p-coumaric acid is a pivotal bioactive compound to this action.

Baccharis dracunculifolia is a medicinal plant native to southeastern Brazil and is the main botanical source used by bees (Apis mellifera) in the manufacture of green propolis and display similar gastroprotective action and chemical profile. This article reports the healing gastric ulcer activity of the hydroethanolic extract of B. dracunculifolia (HEBD) in an acetic acid-induced ulcer model. In addition to the extract, the isolated compounds ferulic acid, p-coumaric acid, caffeic acid, baccharin, and aromadendrin-4'-O-methyl ether were also assayed. HEBD at a dose of 300 mg/kg reduced the ulcerated area by 49.4% after treatment for 7 days, twice a day. Histological analyses revealed that the margins and base of the ulcer obtained significant regeneration, and periodic acid Schiff base staining showed a 78.2% increase in the mucin levels. The action on the enzymatic antioxidant system demonstrated an increased activity of superoxide dismutase and glutathione-S-transferase, in addition to raising glutathione reduced levels and myeloperoxidase activity. HEBD did not show cytotoxicity in the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenylterazole bromine test. In vitro, HEBD inhibited the H+ /K+ -ATPase enzyme and showed antioxidant activity in the 2,2 diphenyl-1-picryllydrazyl test. Regarding the isolated compounds, oral administration of p-coumaric acid (15 mg/kg) reduced the ulcerated area by 66.2%. The results suggest that HEBD recovers the gastric ulcerated tissue, raising mucus and antioxidant enzyme levels, and reducing the H+ /K+ -ATPase activity. In addition, the findings confirm that p-coumaric acid is a pivotal bioactive compound on the gastric healing effects elicited by HEBD. © 2019 BioFactors, 45(3):479-489, 2019.

Gastroprotective effect of araloside A on ethanol- and aspirin-induced gastric ulcer in mice: involvement of H+/K+-ATPase and mitochondrial-mediated signaling pathway.

The aim of this study was to elucidate the gastroprotective activity and possible mechanism of involvement of araloside A (ARA) against ethanol- and aspirin-induced gastric ulcer in mice. The experimental mice were randomly divided into control, model, omeprazole (20 mg/kg, orally) and ARA (10, 20 and 40 mg/kg, orally). Gastric ulcer in mice was induced by intragastric administration of 80% ethanol (10 mL/kg) containing 15 mg/mL aspirin 4 h after drug administration on day 7. The results indicated that ARA could significantly raise gastric juice volume and acidity; ameliorate gastric mucosal blood flow, gastric binding mucus volume, ulcer index and ulcer inhibition rate; suppress H+/K+-ATPase activity, which was confirmed by computer-aided docking simulations; inhibit the release of mitochondrial cytochrome c into the cytoplasm; inhibit caspase-9 and caspase-3 activities and down-regulate mRNA expression levels; down-regulate the mRNA and protein expressions of apoptosis protease-activating factor-1 and protein expression of cleaved poly(ADP ribose) polymerase-1; and up-regulate Bcl-2 mRNA and protein expressions and down-regulate Bax mRNA and protein expressions, thus elevating the Bcl-2/Bax ratio in a dose-dependent manner. Histopathological observations further provided supportive evidence for the aforementioned results. The results demonstrated that ARA exerted beneficial gastroprotective effects on alcohol- and aspirin-induced gastric ulcer in mice, which was related to suppressing H+/K+-ATPase activity as well as pro-apoptotic protein expression, and promoting anti-apoptotic protein expression, thus alleviating gastric mucosal injury and cell death.

Acid-gastric antisecretory effect of the ethanolic extract from Arctium lappa L. root: role of H+, K+-ATPase, Ca2+ influx and the cholinergic pathway.

BACKGROUND: Arctium lappa L., popularly known as burdock, is a medicinal plant used worldwide. The antiulcer and gastric-acid antisecretory effects of ethanolic extract from roots of Arctium lappa (EET) were already demonstrated. However, the mechanism by which the extract reduces the gastric acid secretion remains unclear. Therefore, this study was designed to evaluate the antisecretory mode of action of EET. MATERIALS AND METHODS: The effects of EET on H+, K+-ATPase activity were verified in vitro, whereas the effects of the extract on cholinergic-, histaminergic- or gastrinergic-acid gastric stimulation were assessed in vivo on stimulated pylorus ligated rats. Moreover, ex vivo contractility studies on gastric muscle strips from rats were also employed. RESULTS: The incubation with EET (1000 µg/ml) partially inhibited H+, K+-ATPase activity, and the intraduodenal administration of EET (10 mg/kg) decreased the volume and acidity of gastric secretion stimulated by bethanechol, histamine, and pentagastrin. EET (100-1000 µg/ml) did not alter the gastric relaxation induced by histamine but decreased acetylcholine-induced contraction in gastric fundus strips. Interestingly, EET also reduced the increase in the gastric muscle tone induced by 40 mM KCl depolarizing solution, as well as the maximum contractile responses evoked by CaCl2 in Ca2+-free depolarizing solution, without impairing the effect of acetylcholine on fundus strips maintained in Ca2+ -free nutritive solution. CONCLUSION: Our results reinforce the gastric antisecretory properties of preparations obtained from Arctium lappa, and indicate that the mechanisms involved in EET antisecretory effects include a moderate reduction of the H+, K+-ATPase activity associated with inhibitory effects on calcium influx and of cholinergic pathways in the stomach muscle.

Gastroprotective activity of the methanol extract from peels of Plinia edulis (Vell.) Sobral fruits and its isolated triterpenes: maslinic and ursolic acids.

According to the Brazilian folk medicine, the leaves of Plinia edulis (Vell.) Sobral (Myrtaceae), known as cambuca, are indicated in the treatment of gastric disorders. Infusions of P. edulis leaves were previously demonstrated to contain both maslinic (MA) and ursolic acids (UA). Both triterpenes have also been identified in the methanolic extract of peels from P. edulis fruit (MEPPE); however, the antiulcer effects of MEPPE have not yet been studied. This study therefore evaluates the gastroprotective potential of MEPPE, MA, and UA using ethanol/HCl- and indomethacin-induced gastric ulcers in mice. In addition, the in vitro effects of these compounds on the H+, K+-ATPase activity and on the free radical DPPH were measured. When used at concentration of 100 µg/mL, both MEPPE and UA were found to reduce the DPPH radical levels by 78.66 and 60.14%, respectively. However, MA did not reduce DPPH radical levels. Our results illustrated the antiulcer effects of MEPPE, MA, and UA against experimental ulcer models when administered by either the oral or the intraperitoneal routes. In addition, MEPPE reduced the size of ethanol/HCl-induced ulcers in a dose-dependent manner (log half-maximal effective oral dose, LogED50 = 1.09). Interestingly, UA promoted gastroprotection at lower doses than MA by increasing the production of mucin levels at 692%; however, it does not alter the activity of H+, K+-ATPase. In contrast, both MEPPE and MA, when incubated at concentrations of 10 and 100 µg/mL, inhibited H+, K+-ATPase activity in 61.81, 68.37, 54.04, and 70.45%, respectively. These results confirm that MEPPE, MA, and UA display gastroprotective activity through different modes of action; MA inhibits H+, K+-ATPase activity, whereas UA favour the mucus barrier.

The natural flavonoid myricetin inhibits gastric H+, K+-ATPase.

Myricetin (3,3',4',5,5',7-hexahydroxyflavone), a major flavonoid in berries and red wine, has been recently used as a health food supplement based on its antioxidant and antitumor properties. We report here that myricetin preferentially exerts inhibitory effects on gastric H+, K+-ATPase. Myricetin inhibited H+, K+-ATPase with a sub-micromolar IC50 value in an enzyme assay using freeze-dried tubulovesicles prepared from hog stomach. Na+, K+-ATPase and Ca2+-ATPase were also inhibited by myricetin in a dose-dependent manner, but the IC50 values for these enzymes were approximately an order of magnitude higher compared to the H+, K+-ATPase. In structure-inhibitory functional analysis of sixteen myricetin derivatives, several phenolic hydroxy groups attached to the flavonoid backbone were highlighted as essential modifications for the inhibition of P2-type ATPases. Furthermore, oral administration of myricetin significantly attenuated histamine-induced gastric acid secretion in an in vivo mouse assessment. Therefore, myricetin derivatives seem to be useful seed compounds for developing new drugs and supplements to alleviate gastric acid secretion.

Essential oil of Cymbopogon citratus (lemongrass) and geraniol, but not citral, promote gastric healing activity in mice.

Cymbopogon citratus, popularly known as lemongrass, is used for the treatment of gastric, nervous and hypertensive disorders, in addition to its use in the food and pharmaceutical industries. This study evaluated the gastroprotective and gastric healing effect of essential oil of C. citratus (EOCC), citral and geraniol at doses of 1-100 mg/kg (p.o) on acute ethanol-induced ulcer and chronic acetic acid-induced ulcer. Histological and histochemical evaluation was also performed, as well as the in vitro evaluation of the effects of these phytochemicals on H+/K+-ATPase activity. In the ethanol-induced gastric ulcer, the minimum effective oral dose of EOCC, citral and geraniol were 10, 100 and 3 mg/kg, reducing the ulcer area by 51.67%, 96.57% and 55.74%, respectively, compared to vehicle group (25.82 ±â€¯3.59 mm2). Moreover, EOCC (10 mg/kg, p.o) and geraniol (3 mg/kg), but not citral (100 mg/kg), accelerated the gastric healing process by 34.52 and 80.57%, compared to acetic-acid ulcerated group treated with vehicle (36.04 ±â€¯1.03 mm2). These healing effects were confirmed histologically by the contraction of the ulcer base and by the enhancement on mucin staining in slices of ulcer site from mice treated with EOCC or geraniol. Interestingly, EOCC and citral at 100 µg/ml inhibited the H+/ K+-ATPase activity by 28.26% and 44.36%, whereas geraniol did not change this parameter. Together, these findings confirm the gastroprotective and healing gastric ulcer effects of essential oil from aerial parts of C. citratus and added the information that geraniol, but not citral, promotes healing effects on installed ulcers.

Discovery, synthesis, and structure-activity relations of 3,4-dihydro-1H-spiro(naphthalene-2,2'-piperidin)-1-ones as potassium-competitive acid blockers.

With the aim to discover a gastric antisecretory agent more potent than the existing proton pump inhibitors, novel 3,4-dihydro-1H-spiro(naphthalene-2,2'-piperidin)-1-one derivatives, which could occupy two important lipophilic pockets (described as LP-1 and LP-2) of H+,K+-ATPase and can strongly bind to the K+-binding site, were designed based on a docking model. Among the compounds synthesized, compound 4d showed a strong H+,K+-ATPase-inhibitory activity and a high stomach concentration in rats, resulting in potent inhibitory action on histamine-stimulated gastric acid secretion in rats. Furthermore, 4d exerted significant inhibitory action on histamine-stimulated gastric-acid secretion in rats with a rapid onset and moderate duration of action after the administration. These findings may lead to a new insight into the drug design of potassium-competitive acid blockers.

Protective Effects of Cinnamic Acid Derivatives on Gastric Lesion

P-methoxycinnamic acid and 3,4,5-trimethoxycinnamic acid are the compounds found in Polygalae Radix, the root of Polygala tenuifolia Willdenow, and have been reported to have hepatoprotective and anti-neurodegenerative effects. On the other hand, there are no reports of their effects on gastric lesions. This study examined the inhibitory effects of cinnamic acids, including p-methoxycinnamic acid, 3,4,5-trimethoxycinnamic acid, and 8 compounds (cinnamic acid, 2-(trifluoromethyl) cinnamic acid, 3-(trifluoromethyl) cinnamic acid, trans-4-(trifluoromethyl) cinnamic acid, 4-(dimethylamino) cinnamic acid, 3,4-(methylenedioxy) cinnamic acid and 3,4-dihydroxycinnamic acid), which were selected based on their presence in medicinal herbs and molecular weight, against gastric lesions. Animal models were used to confirm the protective effects on acute gastritis caused by the administration of HCl/EtOH. Gastric acid inhibition was examined by an acid-neutralizing test and the proton pump (H⁺/K⁺-ATPase) inhibiting activity. In addition, antioxidant tests were performed and the gastric emptying rate was determined. The results showed that cinnamic acid, p-methoxycinnamic acid, and 3,4,5-trimethoxycinnamic acid had an inhibitory effect on gastric lesions.

Design, synthesis and biological evaluation of bisabolangelone oxime derivatives as potassium-competitive acid blockers (P-CABs).

With the aim of searching novel P-CABs, seven bisabolangelone oxime derivatives were designed, synthesized, characterized and evaluated the H(+),K(+)-ATPase inhibitory activities guided by computer aided drug design methods. The binding free energy calculations were in good agreement with the experiment results with the correlation coefficient R of -0.9104 between ΔGbind and pIC50 of ligands. Compound 5 exhibited the best inhibitory activity (pIC50=6.36) and most favorable binding free energy (ΔGbind=-47.67 kcal/mol) than other derivatives. The binding sites of these compounds were found to be the hydrophobic substituted groups with the Cys813 residue by the decomposed binding free energy analysis.

Pharmacological reports about gastroprotective effects of methanolic extract from leaves of Solidago chilensis (Brazilian arnica) and its components quercitrin and afzelin in rodents.

Solidago chilensis Meyenmost (Asteraceae), popularly known as "Brazilian arnica" or "arnica-do-campo," is widely used in the folk medicine to treat gastric disorders. Based on this, the gastroprotective activity of S. chilensis methanolic extract was investigated. Besides, a phytochemical study allowed isolation of two flavonoids (quercitrin and afzelin). The gastroprotective effects were investigated in acute gastric ulcer models, and the antisecretory activity was assessed in vivo and in vitro. The adhered mucus levels, reduced glutathione (GSH) content and myeloperoxidase (MPO) activity were quantified in ulcerated tissues. The contribution of isolated compounds in extract effects was evaluated, and its doses were calculated according to its yield. To evaluate the in vivo healing properties of S. chilensis methanolic extract, a chronic gastric ulcer was induced in mice by 10 % acetic acid. Evaluation of tumor necrosis factor (TNF) levels was also performed at the site of the acetic acid-induced gastric ulcer. In parallel, effects on cell viability and cell proliferation of fibroblasts (L929 cells) were determined by in vitro trials. Firstly, the S. chilensis methanolic extract (100 or 300 mg/kg) reduced the ulcer area induced by ethanol/HCl in mice when compared to the vehicle group. Moreover, the S. chilensis extract (300 mg/kg) prevented the mucus depletion, the increase in MPO activity and the decrease in the GSH levels in the ulcerated gastric tissue. The S. chilensis extract also was able to decrease the indomethacin-induced gastric ulcer in rats at a dose of 100 mg/kg. The antisecretory effect of the extract (100 mg/kg, intraduodenal (i.d.)) was confirmed by the reduction in the volume and acidity in parallel to an increase in the pH of gastric content. In addition, quercitrin (1.38 mg/kg, but not 0.46 mg/kg) and afzelin (0.026 and 0.078 mg/kg) decreased the ethanol/HCl-induced gastric ulcer. In this model, quercitrin (1.38 mg/kg) prevented the depletion of gastric GSH content and both quercitrin (1.38 mg/kg) and afzelin (0.078 mg/kg) reduced the MPO activity. These compounds also inhibited the H(+),K(+)-ATPase activity at a concentration of 1-100 µg/ml. In addition, the participation of quercitrin and afzelin in these effects also was confirmed. Furthermore, after 4 days of the treatment, an oral administration of S. chilensis methanolic extract (100 mg/kg) reduced the area of the gastric ulcer induced by acetic acid and the regeneration of the gastric mucosa was accompanied by a reduction in gastric TNF levels. The healing properties of the extract also were confirmed by enhancement of proliferation and coverage of scratched wounds in a fibroblast monolayer. Together, our results confirmed the gastroprotective effect of S. chilensis methanolic extract as well as its gastric healing potential and provided some support to the traditional use of S. chilensis for prevention and treatment of gastric lesions in complementation to its known anti-inflammatory properties.