Tablet of Spondias mombin L. Developed from Nebulized Extract Prevents Gastric Ulcers in Mice via Cytoprotective and Antisecretory Effects.

Spondias mombin L. (Anacardiaceae) has a worldwide distribution and is present in all regions of Brazil. Its leaves, flowers and bark are used as teas in folk medicine to treat diseases of the digestive system. This study aimed to evaluate the acute non-clinical toxicity, gastroprotective activity, and the related mechanisms of action of nebulized extract and tablets based on dried Spondias mombin (SmNE). SmNE screening showed the presence of flavonoids (0.65%), polyphenols (25.50%), where the major compound is gallic acid. In the acute oral toxicity assay, a dose of 2000 mg/kg of SmNE administered orally in Swiss mice did not induce any behavioral changes. SmNE (250 or 500 mg/kg p.o) significantly reduced the ulcerative lesion area when compared to the control group in ethanol and non-steroidal anti-inflammatory drug (NSAIDs) models. Results showed that treatment with SmNE (250 mg/kg) reduced acid secretion and gastric content, accompanied with an increase in pH. Previous administration of indomethacin and glibenclamide reversed the protection provided by SmNE, confirming the participation of prostaglandins (PGs) and ATP-sensitive potassium channels (KATP) in its gastroprotective effect. The SmNE tablets met the pharmacopeial quality requirements with gastroprotective activity and similar protection in comparison to the isolated extract administrated. In conclusion, SmNe has a gastroprotective activity related to cytoprotective mechanisms, such as the participation of endogenous prostaglandins and KATP channels, having an anti-secretory effect with systemic action. The formulation obtained presented gastroprotective effects similar to the administration of the extract, the tablets showed favorable compression characteristics by the direct route and met the pharmacopeial quality requirements.

The gastroprotective effect of red propolis extract from Northeastern Brazil and the role of its isolated compounds.

ETHNOPHARMACOLOGICAL RELEVANCE: Propolis has been used in folk medicine to treat gastric disorders for centuries. However, although studies have been conducted to validate the gastroprotective and anti-ulcer activity of some types of propolis, red propolis activity remains unknown. AIM OF THE STUDY: The present study aimed to evaluate the gastroprotective effect of the hydroalcoholic extract of red propolis (HERP), its mode of action, and the main compounds involved in its activity, therefore contributing to validate the chemical and pharmacological potential of this product. MATERIAL AND METHODS: The effect of HERP (30, 100 and 300 mg/kg p.o. and 30 mg/kg i.p.), and the isolated compounds vestitol (VS), neovestitol (NV), methylvestitol (MV), medicarpin (MD), and oblongifolin AB (OB) (10 mg/kg p.o.) were evaluated on gastric ulcers induced by 60% ethanol/0.3 M HCl (5 mL/kg, p.o.) in mice. Histological changes and mucin levels were assessed by HE and PAS, respectively. Moreover, oxidative stress parameters and myeloperoxidase activity were analyzed on ulcerated tissue. The effect of HERP on gastric acid secretion was evaluated by pyloric ligature model and the mechanisms involved in its gastroprotective effect were investigated by pretreating mice with L-NAME (a non-selective nitric oxide synthase inhibitor, 70 mg/kg, i.p.), NEM (a sulfhydryl group chelator, 10 mg/kg, i.p.), yohimbine (an alpha-adrenergic receptor antagonist, 2 mg/kg, i.p.) and indomethacin (a non-selective cyclooxygenase inhibitor, 10 mg/kg, i.p.). RESULTS: HERP (300 mg/kg p.o. or 30 mg/kg i.p.), MV, and MD (10 mg/kg p.o.) protected gastric mucosa against the damage induced by ethanol/HCl. Histological changes were attenuated by the HERP, MV, and MD. Moreover, HERP and MV increased mucin levels. Besides, oxidative stress and MPO activity were reduced by the three treatments. HERP did not display anti-secretory action, but its effect was abolished by indomethacin treatment. CONCLUSIONS: HERP displays gastroprotective property against ethanol/HCl-induced damage. Its effect is dependent on prostaglandins and mucin production. The compounds MV and MD may have an essential role in the activity of HERP. Our data contribute to validate the traditional use of propolis for gastric disorders.

An agent-based simulator for the gastrointestinal pathway of Listeria monocytogenes.

We developed an agent-based gastric simulator for a human host to illustrate the within host survival mechanisms of Listeria monocytogenes. The simulator incorporates the gastric physiology and digestion processes that are critical for pathogen survival in the stomach. Mathematical formulations for the pH dynamics, stomach emptying time, and survival probability in the presence of gastric acid are integrated in the simulator to evaluate the portion of ingested bacteria that survives in the stomach and reaches the small intestine. The parameters are estimated using in vitro data relevant to the human stomach and L. monocytogenes. The simulator predicts that 5%-29% of ingested bacteria can survive a human stomach and reach the small intestine. In the absence of extensive scientific experiments, which are not feasible on the grounds of ethical and safety concerns, this simulator may provide a supplementary tool to evaluate pathogen survival and subsequent infection, especially with regards to the ingestion of small doses.

Effects of Paeonol and Gastroretention Tablets of Paeonol on Experimental Gastric Ulcers and Intestinal Flora in Rats.

Paeonol, a major ingredient isolated from Moutan Cort, has various pharmacological effects. Our previous studies have shown that paeonol can exert antioxidant and anti-inflammatory therapeutic effects on ethanol-induced experimental gastric ulcer (GU). Therefore, in this study, we designed two GU models in rats induced by pyloric ligation (PL) and acetic acid and evaluated the protective effects of paeonol and gastroretention tablets of paeonol (GRT-Ps; 24, 48, and 96 mg/kg) on GU in rats and the effect of paeonol (48 mg/kg) on the intestinal flora. In vivo experiments showed that paeonol or GRT-Ps remarkably reduced gastric mucosal damage in a dose-dependent manner in the different types of models and improved the superoxide dismutase (SOD) activity and the malondialdehyde (MDA) content. And in fact, the sustained-release effect of GRT-Ps is more conducive to the improvement of GU compared with the rapid clearance of free drugs. In the PL-induced model, gastric secretion parameters, that is, pH and total acid, showed significant differences compared with the model group. In addition, paeonol treatment can improve the richness and diversity of the intestinal flora and increase the amount of beneficial bacteria, such as Lactobacillus. Paeonol and its stable sustained-release tablet GRT-Ps can promote ulcer healing by inhibiting oxidative stress and regulating the intestinal flora. This study can provide basis for the clinical treatment of GU with paeonol. Graphical Abstract.

Cytoprotective and antisecretory properties of methanolic extract of Distemonanthus benthamianus (Caesalpiniaceae) stem bark on acute gastric ulcer in rats.

OBJECTIVES: In African traditional medicine, Distemonanthus benthamianus (Caesalpiniaceae) is used to treat many diseases including gastric ulcers. We evaluated in this study, the cytoprotective and antisecretory properties of the methanolic extract of the stem bark of this plant using different technics of gastric lesion induction. METHODS: Cytoprotective and antisecretory activity of the methanolic extract of D. benthamianus stem bark was evolved through six methods of gastric lesion induction in experimental Wistar male rats (150-200 g): (1) gastric lesions induced by HCl/ethanol, (2) gastric lesions induced by Indomethacin- HCl/ethanol, (3) gastric lesion induced by Indomethacin, (4) gastric lesions induced by Pylorus ligation, (5) gastric lesions induced by histamine-Pylorus ligation, (6) gastric lesions induced by carbachol-Pylorus ligation. Mucus and gastric mucosal ulceration were evaluated. pH, gastric volume, and acidity were quantified in all pylorus ligation induction technics. Nitric oxide (NO) level was determined in indomethacin induced gastric ulcers. RESULTS: At different doses (125, 250 and 500 mg/kg), extract reduced significantly the ulcer index. In all models used, that is 100.00% with HCl/ethanol; 100.00% with HCl/ethanol/indomethacin; 95.70% with Indomethacin; 74.79% with pylorus ligation, 95.94% histamine-Pylorus ligation, 99.54% carbachol-Pylorus ligation at the highest dose of 500 mg/kg. The lesion formation reduces in all the methods used followed by a significant increase of mucus production. The pylorus ligation technic revealed that the extract has an antisecretory activity. CONCLUSIONS: The methanolic extract of D. benthamianus stem bark has both cytoprotective and antisecretory effects. This extract exerts its antisecretory effect trough cholinergic and histaminergic pathways.

Development and evaluation of a biorelevant medium simulating porcine gastrointestinal fluids.

Simulated human intestinal media, have proved to be a useful biopharmaceutics tool as a dissolution media for predicting in vivo dissolution and pharmacokinetic profile in humans. During drug product development preclinical animal models are also required to assess drug product performance, and there is a need to develop species specific intestinal media to similarly predict in vivo pharmacokinetic profiles in each preclinical model. Pigs, are increasingly being used in preclinical drug development, however to date there is a lack of quantitative information about the composition of porcine gastrointestinal (GI) fluids. As a result, a porcine biorelevant medium has not yet been developed, which is essential to improve interpretation and forecast of preclinical results using biorelevant in vitro dissolution studies. GI fluid samples, were collected from landrace pigs, and characterized. Fasted State Simulated Intestinal Fluid of pigs (FaSSIFp) was developed based on the physiological composition of the GI fluids in terms of pH, buffer capacity, osmolality, surface tension, as well as the bile salt, phospholipid and free fatty acid content. This study demonstrated that FaSSIFp was superior at predicting the solubility of the six model drugs in porcine intestinal fluids (PIF). A markedly high correlation (r2 0.98) was observed between the solubility obtained in PIF and FaSSIFp, whereas poor correlation (r2 0.12) was found for the solubility of the model drugs between human FaSSIF and PIF. This confirms that species specific biorelevant intestinal media are crucial to provide more accurate predictions of pharmacokinetic studies in preclinical models. Additionally, the availability of a species specific intestinal medium offers the potential to improve in vitro-in silico approaches to predict in vivo absorption and to reduce the overall number of animals needed in oral drug product development testing.

Consumption of medicines used for gastric acid-related disorders in Australia and South Korea: a cross-country comparison.

PURPOSE: The study's aim was to compare the use of proton pump inhibitors (PPIs), histamine 2-receptor antagonists (H2RAs) and mucoprotective medicines (MPs) used for gastric acid-related disorders (GARD) in Australia and South Korea (Korea) from 2004 to 2017. METHODS: Prescription data for PPIs, H2RAs and MPs for Australian outpatients were extracted from the Australian Statistics on Medicines annual reports, with dose-specific and expenditure data obtained from Medicare. Similar data were obtained from Korean National Health Insurance Service claims data. We analysed the volume and expenditure of medicines use annually using the defined daily dose per 1,000 population per day. We calculated which medicines accounted for 90% of use and estimated the proportions of use for low- and high-dose PPIs. RESULTS: While total utilisation for GARD medicines increased over time in both countries, patterns of use differed. Overall, use was somewhat higher in Australia but increased more rapidly in Korea. PPIs were used more extensively in Australia, while more MPs and H2RAs were used in Korea. Expenditure and use of low-dose PPIs is escalating in Korea. CONCLUSION: There were substantial differences in the use of GARD medicines in Australia and Korea over 14 years. Both countries face similar challenges to promote rational medicines use and contain medical care costs. The discrepant prescribing patterns can be attributed to differences in healthcare systems, pharmaceutical policies and demographics. This study provides a baseline to influence more rational use of these medicines. It provides insight into medicines policies for other countries that face similar challenges.

Bioavailability of Sulforaphane Following Ingestion of Glucoraphanin-Rich Broccoli Sprout and Seed Extracts with Active Myrosinase: A Pilot Study of the Effects of Proton Pump Inhibitor Administration.

We examined whether gastric acidity would affect the activity of myrosinase, co-delivered with glucoraphanin (GR), to convert GR to sulforaphane (SF). A broccoli seed and sprout extract (BSE) rich in GR and active myrosinase was delivered before and after participants began taking the anti-acid omeprazole, a potent proton pump inhibitor. Gastric acidity appears to attenuate GR bioavailability, as evidenced by more SF and its metabolites being excreted after participants started taking omeprazole. Enteric coating enhanced conversion of GR to SF, perhaps by sparing myrosinase from the acidity of the stomach. There were negligible effects of age, sex, ethnicity, BMI, vegetable consumption, and bowel movement frequency and quality. Greater body mass correlated with reduced conversion efficiency. Changes in the expression of 20 genes in peripheral blood mononuclear cells were evaluated as possible pharmacodynamic indicators. When grouped by their primary functions based on a priori knowledge, expression of genes associated with inflammation decreased non-significantly, and those genes associated with cytoprotection, detoxification and antioxidant functions increased significantly with bioavailability. Using principal components analysis, component loadings of the changes in gene expression confirmed these groupings in a sensitivity analysis.

Absorption Characteristics of Novel Compound Calcium Carbonate Granules: Effects of Gastric Acid Deficiency and Exogenous Weak Acids.

Calcium carbonates are commonly administered as supplements for conditions of calcium deficiency. We report here pharmacokinetic characteristics of a novel formulation, calcium carbonate compound granules (CCCGs), forming complexes of calcium carbonate and calcium citrate in water. CCCGs were compared to a kind of commonly-used calcium carbonate D3 preparation (CC) in the market in 5-week-old mice that had been treated with omeprazole, to suppress gastric acid secretion, and in untreated control mice. The results showed that: (1) CCCGs had better water solubility than CC in vitro; (2) In control mice, calcium absorption rates after CCCGs administration were comparable to those after CC administration; (3) Inhibition of gastric acid secretion did not affect calcium absorption after CCCGs, but moderately decreased it after CC; (4) The presence of phytic acid or tannin did not affect calcium absorption rates after CCCGs but did for CC; and (5) In normal mice, CCCGs did not inhibit gastric emptying and intestinal propulsion, and did not alter the gastrointestinal hormones. The results suggest that CCCGs may be therapeutically advantageous over more commonly used calcium supplement formulations, particularly for adolescents, because of their stable calcium absorption characteristics and their relatively favorable adverse effect profile.

Nuclear magnetic resonance-based metabolomics approach to evaluate preventive and therapeutic effects of Gastrodia elata Blume on chronic atrophic gastritis.

Chronic atrophic gastritis (CAG) is one of the most common digestive system diseases worldwide which defined by WHO as initial step of cancer. Gastrodia elata Blume (GEB) is a traditional herbal with multiple pharmacological activities which was widely used in Asian countries. This study aims to explore the preventive and therapeutical effects of Gastrodia elata Blume on auto-immune induced CAG in rats. Tissues of stomachs were collected and submitted to 1H NMR-based metabolomics analysis and histopathological inspection. The biochemical indexes of MDA, SOD, GSH, NO and XOD were measured. Gastrodia elata Blume could apparently ameliorate the damaged gastric glands and the biochemical parameters, enhance gastric acid secretion, and significantly relieve the inflammation of the stomach. Orthogonal signal correction-partial least squares-discriminant analysis (OSC-PLS-DA) of NMR profiles and correlation network analysis revealed that Gastrodia elata Blume could effectively treat CAG via regulating energy and purine metabolisms, and by anti-oxidation and anti-inflammation effects.

Refractory GERD, beyond proton pump inhibitors.

Pharmacologic therapy, surgery, minimally invasive therapies, and alternative therapies are different options available for the management of refractory GERD. The choice may depend on the cause of refractoriness. Increased gastric acid suppression therapy might be useful in the rare patients with persistent elevated esophageal acid exposure on proton pump inhibitors (PPI). Potassium-competitive acid blockers (P-CAB) might induce a more important acid inhibition than PPI. Baclofen might act as a reflux inhibitor and demonstrates a significant efficacy in rumination syndrome. The role of topical antacid-alginate in refractory GERD might be limited. Surgery might be a valid option in case of persistent pathological acid esophageal exposure despite PPI. Further evaluation of minimally invasive procedures is necessary. Finally diet, diaphragmatic breathing and transcutaneous electrical acustimulation might be of interest in patients with esophageal hypersensivity or functional symptoms.

Acid suppression medications reduce risk of oesophageal adenocarcinoma in Barrett's oesophagus: a nested case-control study in US male veterans.

BACKGROUND: Proton pump inhibitors (PPIs) and histamine-2 receptor antagonists (H2RAs) may reduce the risk of oesophageal adenocarcinoma (OAC) in Barrett's oesophagus; however, current epidemiologic studies are inconclusive. AIM: To evaluate the independent effects of PPIs and H2RAs on risk of OAC in patients with Barrett's oesophagus. METHODS: We conducted a nested case-control study of male veterans diagnosed with Barrett's oesophagus. Cases with incident OAC were matched by incidence density sampling on birth year and Barrett's diagnosis date to controls with Barrett's oesophagus who did not develop OAC. We identified prescription medication usage 1 year prior to Barrett's oesophagus diagnosis to 3 months prior to the OAC diagnosis. Odds ratios (OR) and 95% CI were estimated using conditional logistic regression. RESULTS: Compared with 798 controls, the 300 cases were less likely to use PPIs (90.0% vs 94.5%, P = 0.01) and H2RAs (19.7% vs 25.7%, P = 0.04). In the multivariable model including the use of statins, H2RAs, aspirin and nonsteroidal anti-inflammatory drugs, PPI use was associated with 41% lower risk of OAC (OR 0.59, 95% CI 0.35-0.99). While risk reduction of OAC was stronger for high-dose PPIs (omeprazole daily dose >40 mg, adjusted OR 0.11, 95% 0.04-0.36), we did not find a dose-response relationship with PPI duration (P trend = 0.45). Likewise, H2RA use was independently associated with 30% lower risk of OAC (OR 0.70, 95% CI 0.50-0.99). CONCLUSION: Use of PPIs and H2RAs among patients with Barrett's oesophagus are associated with lower risk of OAC. Further clinical trials are needed to confirm this possible chemopreventive effect.

Protective effect of oleane-12-en-3ß-ol-28-oic acid 3ß-D-glucopyranoside in ethanol induced gastric ulcer by enhancing the prostaglandin E2 level.

ETHNOPHARMACOLOGICAL RELEVANCE: Lantana camara is a popular invasive weed utilized in the management of ulcer in different part of world. Study of specific compound present in this plant responsible for their antulcer activity is main topic of concern. Current study designed for evaluation of the antiulcer activity of oleane-12-en-3ß-ol-28-oic acid 3ß-D-glucopyranoside (OAG) from Lantana camara L. MATERIALS AND METHODS: Antiulcer activity was carried out on NSAID's (Aspirin) and ethanol induced ulcer model. The efficacy of the OAG on ulcer index, percentage protection and gastric acid secretion were evaluated. RESULTS: Ulcer protection percentage (38.37%) was significant (P < 0.001) higher in the groups treated with the higher OAG dose (50mg/kg), it also recover the mucosa with no redness, no inflammation, mild dilation of blood vessels. OAG significantly (P < 0.01 and P < 0.001) reduce acidity, free acidity and gastric acid volume. It also significantly (P < 0.01) increases the pH of stomach. CONCLUSION: On the basis of results, it can be concluded that OAG shows significant gastroprotective activity by gastric acid secretion inhibition and afford protection against gastric mucosal damage. Further increase of prostaglandin E2 level establishes the mechanism of antiulcer activity of OAG.

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.

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.

Seeds of Buchholzia coriacea in Diet Mitigate Ischemic Reperfusion-Induced Gastric Ulceration in Experimental Rats.

Buchholzia coriacea (B. coriacea) seeds, in folk medicine, have been documented to prevent gastric ulceration though the mechanism is not fully elucidated. To clarify this, the gastro-healing activities were investigated using graded incorporation of B. coriacea seeds in the diet. Male Wistar rats (150-200 g) were divided into 7 groups (n = 15): unulcerated untreated control, ulcerated untreated control, unulcerated B. coriacea low (10%), ulcerated B. coriacea low (10%), nulcerated B. coriacea high (25%), ulcerated B. coriacea high (25%), and ulcerated omeprazole-treated groups. Rats were fed with B. coriacea diets for 7 weeks; thereafter, ulcer was induced by ischemic reperfusion method. Daily body weight, gastric acid secretion, hematological parameters, stomach ulcer score, and biochemical and histological analyses were evaluated on days 0, 3, and 7 post-ulcer induction. Results were subjected to one-way analysis of variance (ANOVA) and presented as mean ± standard error of the mean (SEM); p ≤.05 was considered significant. Significant decreases were observed in mean body weight of B. coriacea-fed compared with control and omeprazole-treated groups from week 7. Ulcerated B. coriacea-fed showed significant decrease in gastric acid secretion by days 3 and 7 compared with ulcerated control groups. Malondialdehyde content was significantly decreased in ulcerated B. coriacea-fed compared with control and omeprazole-treated groups. Significant increases in hematological variables (notably platelet count), superoxide dismutase, catalase, and nitric oxide levels of B. coriacea-fed compared with control and omeprazole-treated groups by days 0 and 3 were observed. Histological evaluations further confirmed these observations. B. coriacea diet enhanced gastric healing activities on ischemic reperfused gastric ulcer. Increased platelet count and nitric oxide levels may play significant roles in this process.

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.

Gastroprotective and anti-secretory mechanisms of 2-phenylquinoline, an alkaloid isolated from Galipea longiflora.

BACKGROUND: We previously described the gastroprotective effect of 2-phenylquinoline (2-PQ), the main alkaloid isolated from the bark of Galipea longiflora (Rutaceae). However, despite the significant and promising results, the pharmacological mechanisms of the gastroprotection induced by 2-PQ have not been investigated. PURPOSE: To evaluate the mechanisms underlying the gastroprotective effects of 2-PQ. STUDY DESIGN: We used an in vivo mouse ulcer model and in vitro methodologies involving H⁺/K⁺-ATPase and L929 murine fibroblasts. METHODS: The gastroprotective activity of 2-PQ (10-100 mg/kg, orally, p.o) was assessed against gastric ulcer induced by 60% ethanol/0.03 M hydrochloric acid (HCl) in mice or that induced by indomethacin (80 mg/kg, p.o) in rats. The cytotoxicity was assessed in L929 murine fibroblasts. Ulcerated tissues were analyzed histologically, histochemically, and biochemically. The antisecretory activity of 2-PQ was evaluated in vivo and in vitro. RESULTS: 2-PQ showed no cytotoxicity, reduced the lesion area induced by ethanol/HCl (log half-maximal effective dose, ED50 = 1.507), and the histological evaluation supported these results. Furthermore, 2-PQ reduced indomethacin-induced gastric ulceration. The gastroprotection was accompanied by normalization of superoxide dismutase (SOD) and glutathione-S-transferase (GST) activity, an intense increase in reduced glutathione (GSH) levels, and reduction in lipid peroxide (LPO) and tumor necrosis factor (TNF)-α levels in the gastric mucosa. The antisecretory properties of 2-PQ were confirmed by the decreased volume and total acidity of the gastric juice, and it reduced histamine- or pentagastrin-stimulated gastric acid secretion. However, 2-PQ did not change the in vitro H⁺/K⁺-ATPase activity or the content of gastric-adhered mucous in mice. In addition, pretreatment with N-ethylmaleimide, NG-nitro-l-arginine methyl esters, yohimbine, or indomethacin reversed the gastroprotective effect of 2-PQ, suggesting nitric oxide, nonprotein sulfhydryl compounds, α-2-receptors, and prostaglandin were involved. CONCLUSION: 2-PQ provides gastroprotection by reducing oxidative damage and inhibiting acid secretion mediated by histaminergic and gastrinergic regulatory pathways.

The Protective Potential of Phyllanthus niruri and Corilagin on Gastric Lesions Induced in Rodents by Different Harmful Agents.

The gastroprotective effect of the methanol extract of Phyllantus niruri and its main constituent, corilagin, were studied in vivo. The extract (50, 125, or 250 mg/kg, p. o.) inhibited ethanol-induced lesions in rats by 43 % (p < 0.001), 69 % (p < 0.001), and 99 % (p < 0.001), respectively. It also inhibited the formation of indomethacin-induced gastric ulcers in rats by 80 % (p < 0.01), 89 % (p < 0.01), and 97 % (p < 0.01). A decrease in lipid hydroperoxide levels (p < 0.01) and in myeloperoxidase activity (p < 0.05) evidenced a reduction of oxidative damage and neutrophil infiltration in gastric tissues from ulcerated mice using ethanol/HCl. Potent in vitro free radical scavenger activity (IC50 = 0.07) using the DPPH assay was observed. In contrast, the extract (250 mg/kg, i. d.) did not show antisecretory activity in pylorus-ligated rats, and also failed to inhibit the H+,K+-ATPase activity in vitro. However, in pylorus-ligated rats, the extract (50, 125, and 250 mg/kg, i. d.) increased adhered mucus content by 22 % (p < 0.05), 28 % (p < 0.01), and 38 % (p < 0.01), respectively. The involvement of prostaglandins, nonprotein endogenous sulfhydryl compounds, α2-receptors, and endogenous nitric oxide in the gastroprotection elicited by the extract was also evaluated. Finally, corilagin reduced the lesion area of ethanol-induced gastric ulcers in mice by 88 % (30 mg/kg, p. o.; p < 0.001). Based on these results, it has been concluded that P. niruri methanol extract possesses gastroprotective activity by different and complementary pathways, which together promote an improvement in gastric cytoprotection. The presence of corilagin may partially explain the effectiveness of the extract against gastric damage.

PMK-S005 Alleviates Age-Related Gastric Acid Secretion, Inflammation, and Oxidative Status in the Rat Stomach.

BACKGROUND/AIMS: The aim of this study was to evaluate the effect of the synthetic S-allyl-L-cysteine (SAC) PMK-S005 on gastric acid secretion, inflammation, and antioxidant enzymes in aging rats. METHODS: The rats were divided into four groups at 31 weeks of age and were continuously fed a diet containing a vehicle control, PMK-S005 (5 or 10 mg/kg), or lansoprazole (5 mg/kg). Gastric acid secretion and connective tissue thickness of the lamina propria were evaluated at 74 weeks and 2 years of age. Tumor necrosis factor (TNF)-α, interleukin (IL)-1ß, and COX-2 levels were measured by using enzyme-linked immunosorbent assays (ELISAs) or Western blot assays. Levels of antioxidant enzymes, including heme oxyganase 1 (HO-1) and NAD(P)H: quinone oxidoreductase 1 (NQO-1), were also measured. RESULTS: As the rats aged, gastric acid secretion significantly decreased, and the connective tissue of the lamina propria increased. However, 74-week-old rats in the PMK-S005 group exhibited greater levels of gastric acid secretion than those of the control and lansoprazole groups. The increase of TNF-α, IL-1ß, and COX- 2 expression in 74-week and 2-year-old control rats were inhibited by PMK-S005. In addition, the decrease in HO-1 and NQO-1 protein expression that occurred with aging was inhibited by PMK-S005 in the 74-week-old rats. CONCLUSIONS: These results suggest that PMK-S005 has therapeutic potential as an antiaging agent to ameliorate age-related gastric acid secretion, inflammation, and oxidative stress in the stomach.