Evaluation of antiulcer potential of Mimusops hexandra in experimental gastro duodenal ulcers.

The study was aimed to investigate antiulcer effects of acetone extract and its different fractions Mimusops hexandra against experimental gastro-duodenal ulcers. 80% acetone extract of stem bark of Mimusops hexandra (Extract A, p.o.) and its different fractions namely diethyl ether (Extract A1, p.o.), ethyl acetate (Extract A2, p.o.) and aqueous (Extract A3, p.o.) were tested for the presence of preliminary phytoconstituents and were screened for their antiulcer potential in experimental animals using ethanol-HCl and aspirin-induced gastric damage at the dose of 500 mg kg-1p.o. Extract A2 being the most active fraction amongst all the fractions tested was also studied at different doses to find its ED50. Further, to establish the mechanism of action, Extract A2 was also tested for its effects in acetic acid-induced gastric ulcer models and cysteamine-induced duodenal ulcer. The effect was compared with cimetidine. Flavonoids (quercetin), procyanidins, saponins and triterpenoids were found to be present in bark. Oral administration of Extract A2 inhibited formation of gastric lesions induced by aspirin in a dose dependent manner. Elevated level of lipid peroxidation due to ethanol-HCl and aspirin induced gastric damage was significantly (p<0.05) reduced by the treatment with Extract A2. Further, Extract A2 at the dose of 100 mg kg-1 (p.o.) reduced extent of acetic acid induced gastric ulcer in experimental animals. Moreover, protection afforded by Extract A2 against cysteamine-induced duodenal lesions was evident from dose dependent decrease in ulcer index (p<0.05), score for intensity (p<0.05) and total lesion area (p<0.05), when compared with the control group. The antiulcer activity shown by Extract A2 in experimental gastro-duodenal ulcer could be attributed to decrease in gastric acid secretory activity along with strengthening of mucosal defensive mechanisms.

Renal toxicity of lisinopril and rosuvastatin, alone and in combination, in Wistar rats.

The aim of study was to evaluate the effect of commonly used lisinopril, rosuvastatin and their combined action on site-specific nephrotoxicity in rats using clusterin and microalbumin nephrotoxic biomarkers and other related parameters using oral gavage. Rosuvastatin at 2 different doses showed increase in urinary microalbumin levels whereas lisinopril and its combination with rosuvastatin at 2 different doses did not show urinary microalbumin excretion indicating beneficial effects of lisinopril in terms of reducing microalbumin. Urinary clusterin levels significantly increased in high-dose treated animals of lisinopril and rosuvastatin. The use of lisinopril plus rosuvastatin at low dose also led to worsened renal function by raising urinary clusterin levels (217 ± 4.6 ng/ml) when compared with the control (143 ± 3.3 ng/ml). Renal histopathology showed multifocal regeneration of tubules indicating proximal tubule damaged. These results indicate that lisinopril (50 mg/kg), rosuvastatin (100 mg/kg), lisinopril+rosuvastatin (20+40 mg/kg) and lisinopril+rosuvastatin (50+100 mg/kg) showed toxicity only on proximal tubules.

A novel use of methylene blue as a pharmacological tool.

INTRODUCTION: A new use of methylene blue as an ulcerogenic agent and the mechanisms involved were identified with an objective to exploit methylene blue as a pharmacological tool to study investigational antiulcer agents. METHODS: Ulcerogenic potential was assessed using electron microscopy and measurement of an ulcer index after administering methylene blue (5-125 mg kg(-1), p.o.) or absolute ethanol (99%v/v, 2 ml, p.o.) to fasted rats. Estimation of thiobarbituric acid reactive substances, superoxide dismutase, reduced glutathione and catalase was used to assess oxidative stress. H(+)/K(+) ATPase activity, gastric mucosal blood flow and gastric acid secretion were measured to study the mechanism of methylene induced gastric ulcer. RESULTS: Methylene blue (100 mg kg(-1), p.o.) produced marked ulceration of the gastric mucosa due to increased levels of thiobarbituric acid reactive substances, activities of the H(+)/K(+) ATPase and superoxide dismutase, and decreased blood flow to the gastric mucosa, activity of catalase combined with reduced glutathione levels. DISCUSSION: It may be concluded that methylene blue activates the H(+)/K(+) ATPase to increase gastric acid secretion and reduces blood supply to gastric mucosa to produce oxidative stress that subsequently causes ulceration of gastric mucosa. Methylene blue can be used as an ulcerogenic agent to study mechanisms of investigational antiulcer agents.

Study of Mimusops elengi bark in experimental gastric ulcers.

The present study was designed to investigate the effect of Mimusops elengi (Sapotaceae) against experimental gastric ulcers. The 50% alcoholic extract of Mimusops elengi (Ext E) and its different fractions namely ethyl acetate (Ext E1), n-butanol (Ext E2), methanol (Ext E3) and aqueous (Ext E4) were studied (p.o.) against ethanol-induced gastric damage. Ext E1 was also studied in ethanol-induced, pylorus-ligated and water-immersion plus stress-induced gastric ulcer models. Ranitidine HCl (80 mg kg(-1)) was used as a reference standard. In ethanol-induced gastric ulcer model, pantoprazole (20 mg kg(-1)) was also used as a reference standard. Ext E1 tested in mice up to the dose of 5000 mg kg(-1) (p.o.) did not produce any sign of toxicity. Ext E at the doses of 50, 100, 300 and 500 mg kg(-1) and its different fractions (100 mg kg(-1)) showed reduction in gastric ulceration (P < 0.05). Ext E1 at the doses of 10, 50 and 100 mg kg(-1) showed dose-dependent inhibition of gastric lesions against ethanol-induced gastric damage. In 19 h pylorus-ligated animals, Ext E1 at 50 and 100 mg kg(-1) doses showed significant reduction in ulcer index (P < 0.05). Significant reduction was also observed in total acidity, volume of gastric acid secretion, total acid output and pepsin activity (P < 0.05) when compared with the control group. Besides, Ext E1 showed increase in the mucosal glycoproteins that was evident from significant rise in total carbohydrates to protein ratio (TC:PR ratio) (P < 0.05), which is an indication of mucin activity. Ext E1 also showed protection against water-immersion plus stress-induced gastric lesions that was evident from dose-dependent decrease in ulcer index (P < 0.05), score for intensity (P < 0.05) and total lesion area (P < 0.05) when compared with the control group. It can be concluded from our study that Ext E1 possesses anti-ulcer activity against experimental gastric ulcers. The mechanism of anti-ulcer activity can be attributed to decrease in gastric acid secretory activity along with strengthening of mucosal defensive mechanisms.

Effect of SR 58611A, a beta-3 receptor agonist, against experimental gastro-duodenal ulcers.

The present study was designed to study the effect of SR 58611A, a selective beta 3-adrenoceptor agonist against gastric ulcers: pylorus ligation, water immersion plus restraint stress (WIRS), ethanol, aspirin-induced and on cysteamine-induced duodenal ulcers, in rats. SR 58611A (10 mg/kg, p.o.) was found to be effective in attenuating gastric ulceration and the results were comparable with those from standard cimetidine-treated group. Apart from reducing ulcer index, SR 58611A significantly decreased total acidity and thereby exhibited antisecretory activity in pylorus ligation model. SR 58611A showed significant reduction in ulcer index alongwith significant rise in the gastric wall mucus content in WIRS model. Further it showed significant cytoprotective activity against ethanol insult, that was evident from significant reduction in ulcer index. It showed significant reduction in gastric ulceration in aspirin-treated rats. The drug was found to be ineffective in inhibiting the cysteamine-induced duodenal ulcers as evident from the ulcer index and total lesion area parameters. It is concluded that SR 586111A possesses significant gastroprotective activity. This activity could be attributed to the inhibition of gastric acidity, increase in gastric wall mucus content and the reversal of gastric microvascular injury resulting into protection of the vascular integrity.