Antisecretory Activity Research Articles

Stronger inhibition of gastric acid secretion by lafutidine, a novel H2 receptor antagonist, than by the proton pump inhibitor lansoprazole

To compare the antisecretory activity and plasma drug concentrations of a single oral dose of 10 mg lafutidine, a novel H2 receptor antagonist, with those of the proton pump inhibitor lansoprazole (LPZ) 30 mg. Ten volunteers without H pylori infection participated in this crossover study comparing lafutidine 10 mg with LPZ 30 mg. Intragastric pH was monitored for 6 h in all participants, and blood samples were collected from four randomly selected individuals after single-dose administration of each drug. The median intragastric pH was significantly higher in individuals who received lafutidine 10 mg than in those who received LPZ 30 mg 2, 3, 4, 5, and 6 h after administration. Maximal plasma drug concentration was reached more promptly with lafutidine 10 mg than with LPZ 30 mg. In H pylori-negative individuals, gastric acid secretion is more markedly inhibited by lafutidine than by LPZ.

Early effects of Lansoprazole orally disintegrating tablets on intragastric pH in CYP2C19 extensive metabolizers

To compare rabeprazole (RPZ; 10 mg) with Lansoprazole orally disintegrating tablets (LPZ; 30 mg OD) in terms of antisecretory activity and blood drug concentration after a single dose. Eight H pylori -negative cytochrome P450 (CYP) 2C19 extensive metabolizers were assigned to receive a single oral dose of RPZ 10 mg or LPZ 30 mg OD. Twelve hour intragastric pH monitoring was performed on the day of treatment. Blood samples were also collected after the administration of each drug. LPZ 30 mg OD induced a significantly earlier rise in blood drug concentration than RPZ 10 mg; consequently, LPZ 30 mg OD induced a significantly earlier rise in median pH in the third and fourth hours of the study. In H pylori-negative CYP2C19 extensive metabolizers, LPZ 30 mg OD induced a significantly faster inhibition of gastric acid secretion than RPZ 10 mg.

Esomeprazole

Esomeprazole (Nexium); S-omeprazole) is a single optical isomer proton-pump inhibitor (PPI) approved for the management of reflux oesophagitis, the symptomatic treatment of gastro-oesophageal reflux disease (GORD), the prevention and healing of NSAID-associated gastric ulcer disease (and the prevention of NSAID-associated duodenal ulcers in the UK), the treatment of Helicobacter pylori infection and associated duodenal ulcer disease (and prevention of relapse of H. pylori-associated peptic ulcers in the UK), and the treatment of Zollinger-Ellison syndrome (and other hypersecretory syndromes in the US).Once-daily oral esomeprazole 40 mg demonstrates greater antisecretory activity than other PPIs. Overall, in well designed clinical studies of 4 weeks' to 6 months' duration in patients with GORD, esomeprazole had similar or better efficacy than other agents. In patients requiring ongoing treatment with NSAIDs, co-therapy with once-daily esomeprazole 20 or 40 mg achieved relief of gastrointestinal symptoms or prevented ulcer occurrence, more effectively than placebo. Esomeprazole was also better than ranitidine 150 mg twice daily in healing NSAID-associated gastric ulcers. In addition, the drug has demonstrated efficacy as part of a triple-therapy regimen for the eradication of H. pylori infection, the healing of H. pylori associated duodenal ulcers and the prevention of relapse of gastric ulcers. Esomeprazole also effectively treated patients with Zollinger-Ellison syndrome. Esomeprazole is generally well tolerated with an adverse-event profile similar to that of other PPIs. Thus, the efficacy and tolerability of esomeprazole for the management of GORD and H. pylori eradication remains undisputed, and the data support its use for the first-line treatment of NSAID-associated gastric ulcer disease and Zollinger-Ellison syndrome.

The anti-secretory and anti-ulcer activities of esomeprazole in comparison with omeprazole in the stomach of rats and rabbits

Proton pump inhibitors (PPIs) are widely used to treat hyperacid secretion and stomach ulcers. The study investigated the anti-secretory and anti-ulcer effects of esomeprazole, the S-isomer of omeprazole on dimaprit, histamine and dibutyryl adenosine 3, 5 cyclic monophosphate (dbcAMP)-evoked gastric acid secretion, acidified ethanol (AE) and indomethacin (INDO)-induced haemorrhagic lesions and on prostaglandin E2 (PGE2) level in the rat in vivo and rabbit in vitro preparations. The effect of omeprazole was also investigated for comparison. Dimaprit-induced acid secretion was significantly (P < 0.05) inhibited by both PPIs in a dose-dependent manner. In the isolated rabbit gastric glands, both PPIs elicited marked reductions in histamine- and dbcAMP-evoked acid secretion with similar potency. The lesions induced by either AE or INDO were significantly (P < 0.05) reduced in the presence of either esomeprazole or omeprazole compared to control values. Increasing doses of esomeprazole before AE treatment resulted in a marked degree of cytoprotection and an elevation in the concentration of bound PGE2 in the stomach tissue homogenate. The results show that esomeprazole and omeprazole were equally effective against gastric haemorrhagic lesions induced by either AE or INDO and in inhibiting dimaprit-, dbcAMP- and histamine-induced gastric acid secretion in the rat and rabbit stomach both in vivo and in vitro. The gastro-protective effect of esomeprazole was found to be proportional to the bound PGE2 levels in the glandular area of the stomach.

5-Substituted 1 H-pyrrolo[3,2- b]pyridines as inhibitors of gastric acid secretion

A series of novel 1 H-pyrrolo[3,2- b]pyridines was prepared relying on a copper iodide catalyzed cyclization of 2-prop-1-ynylpyridin-3-amines. A structure–activity relationship was established focusing on the influence of the substitution pattern in position 1, 3, and 5 of the heterocycle on anti-secretory activity, lipophilicity, and p K a value. Some of the compounds proved to be potent inhibitors of the gastric acid pump.

Physiopathologie de la diarrhée à rotavirus

The rotavirus is the major cause of infantile gastroenteritis. The virus infects the mature enterocytes of the villus tip of the small intestine and induces a watery diarrhea. Diarrhea can occur in the absence of histological changes in the intestine, and, conversely, the histological changes can be asymptomatic. Rotavirus decreases the activities of digestive enzymes at the apical brush border membrane and inhibits Na+ -solute cotransport systems. Accumulation of carbohydrates in the intestinal lumen as well as malabsorption of nutrients and a concomitant inhibition of water absorption can lead to a malabsorptive component of diarrhea. Since the discovery of the NSP4 enterotoxin, several hypotheses have been proposed in favour of an additional secretion component in the pathogenesis of diarrhea. Rotavirus induces a moderate net chloride secretion at the onset of the diarrhea. The mechanisms appear to different from those used by bacterial enterotoxin that cause pure secretory diarrhea. Rotavirus stimulated C1- reabsorption in villi, and failed to stimulate C1- secretion in crypt. Intestinal villi could secrete chloride as a result of rotavims infection. The chloride secretory response is regulated by a dependant calcium signalling pathway induced by NSP4. The overall response is weak, suggesting that NSP4 may exert both secretory and subsequent antisecretory actions, hence limiting C1- secretion.

An Experimental Study and a Randomized, Double-Blind, Placebo-Controlled Clinical Trial to Evaluate the Antisecretory Activity ofLactobacillus acidophilusStrain LB Against Nonrotavirus Diarrhea

Previous studies have shown that selected strains of Lactobacillus have the capacity to antagonize rotavirus-induced diarrhea. However, only a few reports have documented their efficacy against nonrotavirus diarrhea. This study involved an experimental investigation and a clinical trial of the antisecretory activity of Lactobacillus acidophilus strain LB in the context of nonrotavirus diarrhea. The activity of a culture of L. acidophilus LB or of the lyophilized, heat-killed L. acidophilus LB bacteria plus their spent culture medium was tested in inhibiting the formation of fluid-formed domes in cultured human intestinal Caco-2/TC7 cell monolayers infected with diarrheagenic, diffusely adhering Afa/Dr Escherichia coli C1845 bacteria. A randomized, double-blind, placebo-controlled clinical trial of male or female children who were 10 months of age and presented with nonrotavirus, well-established diarrhea was conducted to evaluate the therapeutic efficacy of a pharmaceutical preparation that contains 10 billion heat-killed L. acidophilus LB plus 160 mg of spent culture medium. Infection of the cells with C1845 bacteria that were treated with L. acidophilus LB culture or the lyophilized, heat-killed L. acidophilus LB bacteria plus their culture medium produced a dosage-dependent decrease in the number of fluid-formed domes as compared with cells that were infected with untreated C1845 bacteria. The clinical results show that in selected and controlled homogeneous groups of children with well-established, nonrotavirus diarrhea, adding lyophilized, heat-killed L. acidophilus LB bacteria plus their culture medium to a solution of oral rehydration solution shortened by 1 day the recovery time (ie, the time until the first normal stool was passed) as compared with children who received placebo oral rehydration solution. Heat-killed L. acidophilus LB plus its culture medium antagonizes the C1845-induced increase in paracellular permeability in intestinal Caco-2/TC7 cells and produces a clinically significant benefit in the management of children with nonrotavirus, well-established diarrhea.

Novel imidazo[1,2- a]pyrazine derivatives as potent reversible inhibitors of the gastric H +/K +-ATPase

A series of novel 6-substituted imidazo[1,2- a]pyrazines were synthesized via palladium catalyzed amino- or alkoxycarbonylation as key step. The anti-secretory activity of these compounds has been assessed in a binding assay against H +/K +-ATPase from hog gastric mucosa. Some of the compounds proved to be potent inhibitors of the gastric acid pump.

Preparation of tetrahydroimidazo[2,1- a]isoquinolines and their use as inhibitors of gastric acid secretion

A series of novel tetrahydroimidazo[2,1- a]isoquinolines was prepared based on a hetero Diels–Alder reaction between an enamine and 1,2,4-triazine as key step. A structure–activity relationship was established focussing on the influence of the substitution pattern in position 3 and 6 of the heterocycle on antisecretory activity, lipophilicity, and p K a value. Potent inhibitors of the gastric acid pump were identified.

Novel indanyl-substituted imidazo[1,2- a]pyridines as potent reversible inhibitors of the gastric H +/K +-ATPase

A series of novel 8-indanylamino- and 8-indanyloxy-substituted imidazo[1,2- a]pyridines with reduced lipophilicity was synthesized from easily accessible starting compounds. The anti-secretory activity of these compounds has been assessed in a competitive binding assay against H +/K +-ATPase from hog gastric mucosa. Some of the compounds proved to be potent inhibitors of the gastric acid pump.

Pharmacological Profile of Novel Acid Pump Antagonist 7-(4-Fluorobenzyloxy)-2,3-dimethyl-1-{[(1S,2S)-2-methyl cyclopropyl]methyl}-1H-pyrrolo[2,3-d]pyridazine (CS-526)

The pharmacological profiles of the novel acid pump antagonist 7-(4-fluorobenzyloxy)-2,3-dimethyl-1-{[(1S,2S)-2-methylcyclopropyl]methyl}-1H-pyrrolo[2,3-d]pyridazine (CS-526) were investigated in terms of hog gastric H+,K+-ATPase activity, gastric acid secretion, and acute gastroesophageal lesions in comparison with other proton pump inhibitors (PPIs). CS-526 inhibited H+,K+-ATPase activity in a concentration-dependent manner, with an IC50 value of 61 nM. The inhibitory effect of CS-526 on H+,K+-ATPase activity was more potent than that of any of the other PPIs examined. The inhibitory mechanism of CS-526 on H+,K+-ATPase was a competitive antagonism to the K+ binding site of H+,K+-ATPase, and it was also a reversible inhibition. In pylorus-ligated rats, intraduodenal or oral administration of CS-526 inhibited gastric acid secretion in a dose-dependent manner, and the ID50 values were 2.8 or 0.7 mg/kg, respectively. In Heidenhain pouch dogs, intrapouch administration of CS-526 inhibited histamine-stimulated gastric acid secretion in a dose- and retention time-dependent manner. In a reflux esophagitis model, intraduodenal and oral administration of CS-526 prevented esophageal lesions with ID50 values of 5.4 and 1.9 mg/kg, respectively. Lansoprazole prevented esophagitis only by intraduodenal administration (ID50 = 2.2 mg/kg). Furthermore, CS-526 inhibited acute gastric mucosal lesions. These data demonstrate that the novel acid pump antagonist CS-526 has potent antisecretory and antiulcer effects. These findings indicate that CS-526 would have a curative effect on gastroesophageal reflux disease via its potent antisecretory and antiulcer actions.

Antiulcerogenic potential of Strychnos potatorum Linn seeds on Aspirin plus pyloric ligation-induced ulcers in experimental rats

Strychnos potatorum (Fam: Loganiaceae) Linn seeds are useful in the treatment of gastropathy in Indian traditional system of medicine. The present study describes the antiulcerogenic potential of S. potatorum Linn seeds on aspirin plus pyloric ligation (Aspirin+PL)-induced gastric ulcer model to substantiate its folklore claim. The seed powder (SPP) and aqueous extract of the seeds (SPE) at two doses 100 and 200 mg/kg, p.o. prevented ulcer formation by decreasing acid secretory activity and increasing the mucin activity in rats. The antiulcerogenic potential was further confirmed by the histopathological studies of stomach mucosa. The results indicate that SPP and SPE exhibit antiulcerogenic activity by both antisecretory and mucoprotective actions. The mucoprotective action of SPP and SPE may be due to the presence of polysaccharides in seeds. The antiulcerogenic potential of SPP and SPE was compared with the standard antiulcer drug, ranitidine.

Effect of Crude Methanol Extract of Terminalia avicennioides in Normal Gastric/Histamine-Induced HCl Secretions in Rats

ABSTRACT Terminalia avicennioides is used commonly in Nigeria and other countries worldwide in traditional medicine for the treatment of various ailments including gastroduodenal ulcers. The dark-brown methanol extract obtained from the bark of the plant was tested to determine its antisecretory gastric acid activities using rats. The extract at the dose rates of 350,420, and 504 mg/kg, inhibited significantly (P < 0.05) gastric acid secretion in normal rats. The extract at the highest dose (504 mg/kg) used also significantly (P < 0.05) inhibited gastric acid secretion in rats pre-treated with histamine, which may indicate that the extract inhibits HCl secretion by interacting with H2-receptors. This finding undoubtedly validates the folkloric use of T. avicennioides in the control of gastroduodenal ulcers.

Gastroprotective Effect of Fenugreek Seeds (Trigonella foenum graecum) on Experimental Gastric Ulcer in Rats

ABSTRACT The effect of fenugreek seeds (Trigonella foenum graecum) compared with ranitidine was studied on aspirin-induced gastric ulcer. The gel fraction isolated from the seeds showed significant ulcer protective effect. The cytoprotective effect of the seeds seemed to be not only due to the anti-secretory action but also due to the effects on mucosal glycoproteins. The fenugreek seed gel also prevented the rise in lipid peroxidation induced by aspirin presumably by enhancing antioxidant potential of the gastric mucosa thereby lowering mucosal injury. Histological studies revealed that the soluble gel fraction prevents lesion formation and is effective as ranitidine. These observations show that fenugreek seeds possess antiulcer potential.

Antibacterial, antisecretory and antihemorrhagic activity of Azadirachta indica used to treat cholera and diarrhea in India

Indigenous uses of Azadirachta indica A. juss (Maliaceae) (locally known as neem) leaves in different parts of India for curing gastrointestinal disorder such as diarrhea and cholera is wide spread. The objective of the present study was to evaluate the antibacterial and antisecretory activity of neem extract against Vibrio cholerae, a causative agent of watery diarrhea such as cholera. The methanol extract of neem leaf was tested for its antibacterial, antisecretory and antihemorrhagic activity against Vibrio cholerae. Azadirachta indica extract had significant antibacterial activity against the multi-drug-resistant Vibrio cholerae of serotypes O1, O139 and non-O1, non-O139. The minimum inhibitory concentration reached by 50% (MIC 50) and 90% (MIC 90), and minimum bactericidal concentration for the extract were 2.5, >5, and 10 mg/ml, respectively. Neem extract showed antisecretory activity on Vibrio cholerae induced fluid secretion in mouse intestine with inhibition values of 27.7%, 41.1%, 43.3%, 57.0%, and 77.9% at doses of 100, 200, 300, 450 and 1800 mg/kg, respectively. Oral administration of the extract inhibited hemorrhage induced by Vibrio cholerae in mouse intestine at a dose ≥300 mg/kg. The results obtained in this study give some scientific support to the uses of neem employed by the indigenous people in India employed for the treatment of diarrhea and dreadful disease cholera.

Nonsteroidal, antiinflammatory drug-induced gastrointestinal injuries and related adverse reactions: Epidemiology, pathogenesis and management

A large proportion of the population all over the world consumes acetylsalicylic acid (ASA: aspirin) or other nonsteroidal, antiinflammatory drugs (NSAIDs). This is associated with a considerable morbidity and mortality. Elderly patients, patients with prior history of peptic ulcer disease (PUD) or its complications, those who require high doses of NSAIDs and those undergoing concomitant therapy with corticosteroids or anticoagulants, are at particularly high risk of developing gastroduodenal injuries and related adverse reactions. Gastroduodenal mucosal injuries induced by NSAIDs vary from subtle microscopic to gross macroscopic changes including ulcers. These injuries are induced by both topical and systemic actions of NSAIDs. Inhibition of gastroduodenal cyclooxygenase (COX) enzyme by NSAIDs is considered to be a major pathogenetic factor. Reactive oxygen species (ROS) appear also to play a significant role in the pathogenesis of mucosal injury. Withdrawal of NSAIDs is preferably the first therapeutic option; however, it is not feasible in the majority of patients. Therefore, several drugs including antisecretory drugs (ASDs-proton pump inhibitors and Histamine-2 receptor antagonists) and misoprostol, a prostaglandin analog are used for the prevention and treatment of NSAID-induced gastroduodenal injuries. Among ASDs, proton pump inhibitors (PPIs) are the most commonly used drugs. The antiulcerogenic effect of PPIs is similar to that of misoprostol and superior to standard doses of histamine-2 receptor antagonists (H2-RAs). The adverse effects of m, isoprostol such as diarrhea, abdominal pain, nausea, flatulence, headache, dyspepsia, vomiting, constipation, abortifacient and teratogenicity limit its general use. Aside from their antisecretory action, PPIs also possess an antioxidative effect. PPI maintenance is recommended in chronic NSAID treatment in those with an increased risk of complications and is more effective than Helicobacter pylori eradication. Low PPI dosage maintenance is as effective as a standard dosage regimen. The effect of H. pylori eradication remains controversial. It is advocated in naïve NSAID users, in chronic users with recent ulcer or ulcer complications and in those with an increased risk of ulcer and ulcer complications. In addition, some herbs have shown inhibition of gastric mucosal damage experimentally induced by necrotizing agents through their antisecretory and antioxidant properties.

Constituents and Antiulcer Effect of Alchornea glandulosa: Activation of Cell Proliferation in Gastric Mucosa during the Healing Process

Alchornea glandulosa (Euphorbiaceae) is a plant used in folk medicine as an antiulcer agent. Rats pretreated with methanolic extract obtained from the leaves of A. glandulosa (AG) showed a dose-dependent effect and significant reduction of gastric ulcers induced by absolute ethanol at the doses of 500 (57%) and 1000 mg/kg (85%) in relation to the control group. Pretreatment of mice with AG (500, 1000 mg/kg, p.o.) showed dose-dependent activity and significantly decreased the severity of lesions caused by HCl/ethanol and by non steroidal anti inflammatory drug-induced gastric lesions. Pretreatment with AG also induced antisecretory action via local and systemic routes and a significant decrease in the total gastric acid content. The gastroprotective effects of AG involved the participation of nitric oxide and increased levels of endogenous sulfhydryl compounds, which are defensive mechanisms of the gastrointestinal mucosa against aggressive factors. The ability of AG to heal gastric ulcers was evaluated after 14 consecutive days of treatment. The results showed that single oral administrations of AG (250 mg/kg/once daily) potently stimulates gastric epithelial cell proliferation that contributes to the accelerated healing of gastric ulcers induced by acetic acid. In addition, no subacute toxicity (body weight gain, vital organs, and serum biochemical parameters) was observed during treatment with AG. Phytochemical investigation of AG led to the isolation of myricetin-3-O-alpha-L-rhamnopyranoside, quercetin-3-O-alpha-L-arabinopyranoside, quercetin-3-O-beta-D-galactopyranoside, quercetin, amentoflavone, methyl gallate, gallic acid, and pterogynidine. We also established the phytochemical profile of AG with the quantification of total phenolic compounds. These compounds may contribute to the observed antiulcerogenic effects of AG.

How do the rotavirus NSP4 and bacterial enterotoxins lead differently to diarrhea?

Rotavirus is the major cause of infantile gastroenteritis and each year causes 611 000 deaths worldwide. The virus infects the mature enterocytes of the villus tip of the small intestine and induces a watery diarrhea. Diarrhea can occur with no visible tissue damage and, conversely, the histological lesions can be asymptomatic. Rotavirus impairs activities of intestinal disaccharidases and Na+-solute symports coupled with water transport. Maldigestion of carbohydrates and their accumulation in the intestinal lumen as well as malabsorption of nutrients and a concomitant inhibition of water reabsorption can lead to a malabsorption component of diarrhea. Since the discovery of the NSP4 enterotoxin, diverse hypotheses have been proposed in favor of an additional secretion component in the pathogenesis of diarrhea. Rotavirus induces a moderate net chloride secretion at the onset of diarrhea, but the mechanisms appear to be quite different from those used by bacterial enterotoxins that cause pure secretory diarrhea. Rotavirus failed to stimulate Cl- secretion in crypt, whereas it stimulated Cl- reabsorption in villi, questioning, therefore, the origin of net Cl- secretion. A solution to this riddle was that intestinal villi do in fact secrete chloride as a result of rotavirus infection. Also, the overall chloride secretory response is regulated by a phospholipase C-dependent calcium signaling pathway induced by NSP4. However, the overall response is weak, suggesting that NSP4 may exert both secretory and subsequent anti-secretory actions, as did carbachol, hence limiting Cl- secretion. All these characteristics provide the means to make the necessary functional distinction between viral NSP4 and bacterial enterotoxins.

Improvement in symptoms after H2-receptor antagonist-based therapy for eradication ofH pyloriinfection

To investigate the therapeutic effects of triple therapy combining lafutidine with clarithromycin and amoxicillin on H pylori infection and the resolution of gastroesophageal symptoms after eradication. We conducted a randomized, multicenter, open-label controlled trial to compare the effectiveness of a triple therapy of lafutidine, clarithromycin, and amoxicillin (lafutidine group) with that of a triple therapy of lansoprazole, clarithromycin, and amoxicillin (lansoprazole group) in patients with H pylori infection. The study group comprised 22 patients with gastric ulcers and 18 patients with duodenal ulcers who had H pylori infection. H pylori eradication rates were similar in the lafutidine group (14/20, 70%) and the lansoprazole group (14/20, 70%). Gastroesophageal reflux and abdominal symptoms improved after eradication therapy in both groups, whereas abdominal discomfort, diarrhea, and constipation were unchanged. H pylori status had no apparent effect on improvement of gastroesophageal reflux or abdominal symptoms after treatment. Adverse events were similar in both groups. The triple therapy including lafutidine is equivalent to triple therapy including lansoprazole in terms of H pylori eradication rates and improvement in gastroesophageal reflux and abdominal symptoms. These results are attributed to the fact that lafutidine has strong, continuous antisecretory activity, unaffected by CYP2C19 polymorphisms.

Gastric Antisecretory and Antiulcer Activities of Decalepis arayalpathra.

Decalepis arayalpathra. Joseph & Chandrasekharan (Periplocaceae) is locally called “amrithapala.” The Kani tribe of the Trivandrum district of Kerala uses the tuberous roots of this plant to treat peptic ulcers. In the current study, the ethanol extract of D. arayalpathra. roots significantly decreased the pepsin secretion at a dose of 250 mg/kg and the gastric juice volume and acid output at a dose of 500 mg/kg in pylorus ligated rats. Pretreatment with D. arayalpathra. extract (500 mg/kg, p.o.) provided significant protection against the peptic ulcerogenic effect of ethanol administered individually or in combination with indomethacin or hydrochloric acid. Our studies also revealed that preitreatment with D. arayalpathra. significantly decreased malondialdehyde levels and increased gastric wall mucus production and the protein concentration of the stomach wall of ethanol-treated rats at a dose of 500 mg/kg. The gastroprotective effect of D. arayalpathra. observed in the current study may be attributed to its effect on stimulating protein concentration and mucus production of the stomach wall. In addition to its gastric antisecretory activity, D. arayalpathra. exerts a cytoprotective effect, which could be partly due to the presence of antioxidant phytocompounds like flavonoids.