Antisecretory Action of the Extract of the Aerial Parts of Eremomastax speciosa (Acanthaceae) Occurs through Antihistaminic and Anticholinergic Pathways.

Objective. The objective of this study was to find out the possible antiulcer mechanism of action of Eremomastax speciosa. Method. Carbachol- and histamine-induced hypersecretion, associated with the pylorus ligation technique, were used in rats. Gastric mucosal ulceration, mucus production, pH, gastric volume, and acidity were measured. Results. Histamine and carbachol raised gastric acidity to 86.50 and 84.80 mEq/L, respectively, in the control rats, and the extracts (200 mg/kg) reduced gastric acidity to 34.60 and 39.00 mEq/L, respectively. Intraduodenal aqueous extract (400 mg/kg) in histamine- and carbachol-treated rats produced significant (P < 0.001) decreases in acid secretion to 28.50 and 28.80 mEq/L, respectively, and 100 percent inhibition of gastric ulceration. Augmented histamine-induced gastric acid secretion (90.20 mEq/L) was significantly reduced to 52.60 and 27.50 mEq/L by the 200 and 400 mg/kg doses of the aqueous extract, respectively. The extract significantly reduced (P < 0.001) the volume of gastric secretion and significantly increased mucus production. The ulcer inhibition potential of the extract significantly dropped to 25-44% (oral extract) and to 29-37% (duodenal extract) in carbachol/indomethacin-treated rats. Conclusion. The aqueous extract of E. speciosa has both cytoprotective and antisecretory effects. The antisecretory effect may involve a mechanism common to both cholinergic and histaminergic pathways.

Cytoprotective and antioxidant effects of the methanol extract of Eremomastax speciosa in rats.

BACKGROUND: Ethno-botanical information shows that Eremomastax speciosa is used in the traditional management of various stomach complaints including gastro-duodenal ulcers. MATERIALS AND METHODS: In this study, we tested the cytoprotective potential of the whole plant methanol extract (100-200 mg/kg, p.o), against HCl/ethanol, absolute ethanol, cold/restraint stress rats, and pylorus legated rats pre-treated with indomethacin. The effects of the extract on gastric lesion inhibition, the volume of gastric juice, gastric pH, gastric acid output, mucus production and gastric peptic activity were recorded. Oxidative stress parameters were measured in blood and gastric tissue samples obtained from the animals in all the models tested. RESULTS: The extract significantly (p<0.05), reduced the formation of cold/restraint ulcers by (31-60%, inhibition), completely inhibited (100%) the formation of lesions induced by HCl/ethanol at the highest dose, but was less effective against absolute ethanol (22-46% inhibition). The extract (200 mg/kg), significantly reduced lesion formation (P<0.01), gastric acidity (P<0.01), and volume of gastric secretions (P<0.05), in the indomethacin/pylorus ligation model, and did not affect the activity of pepsin in gastric juice. Blood concentrations of antioxidant enzymes (catalase, SOD and GSH), increased significantly and MDA concentrations decreased in all models tested. CONCLUSION: Cytoprotection by E. speciosa methanol extract was attributed to its ability to reduce acid secretion, and to enhance mucosal defence and in vivo antioxidant status.

In vitro and in vivo anti-Helicobacter/Campylobacter activity of the aqueous extract of Enantia chlorantha.

The aqueous extract of Enantia chlorantha Oliver (Annonaceae) stem bark, a plant widely used in Cameroon for the traditional treatment of gastritis and stomach problems, was assessed for in vitro and in vivo anti-Helicobacter/Campylobacter properties using the well diffusion assay, agar dilution assay, and killing rate determination. The in vitro activity was dose-dependent, and the same antimicrobial parameters (MAQ = 0.63 mg; MIC = 0.39 mg/mL; MBC = 1.56 mg/mL; ET(100) = 8 h) were obtained for both H. pylori and C. jejuni/coli. When the plasma active principle concentration equivalence was determined in vitro using plasma from rats exposed to a single dose (3000 mg/kg) of the extract, the peak absorption of E. chlorantha active principle against H. pylori occurred at 2 h. Plasma activity was nil 8 h after extract administration. The in vivo H. pylori eradication potency of the extract was assessed using mice infected with H. pylori. Antral mucus sample cultures from mice treated with E. chlorantha extract (500 and 1000 mg/kg for 3 days) did not yield any growth. The results suggest that in addition to its in vitro activity, E. chlorantha water extract also possesses in vivo antibiotic effects against H. pylori.

Antihypertensive and antioxidant effects of Allanblackia floribunda Oliv. (Clusiaceae) aqueous extract in alcohol- and sucrose-induced hypertensive rats.

AIM OF THE STUDY: Allanblackia floribunda Oliv. (Clusiaceae), an evergreen tree of the rain-forest has long been used in traditional African medicine to treat hypertension. The aim of this study was to evaluate the protective effect of Allanblackia floribunda aqueous extract on alcohol- and sugar-induced hypertension in rats. MATERIAL AND METHODS: Alcohol-induced hypertensive rats (AHR) were obtained by oral administration of ethanol (3g/kg/day) while sucrose (5, 6 and 7% in drinking water) was used for sucrose-induced hypertensive rat (SuHR). Both models of animals concomitantly received either aqueous extract (200 or 400mg/kg; p.o.) or nifedipine (10mg/kg; p.o.) all along the 8 weeks of experiment. Blood pressure and heart rate were measured using the direct cannulation method. The effects of the plant extract on lipid profile, oxidative stress markers, as well as on kidney and liver functions were evaluated at the end of the treatment by the colorimetric method. RESULTS: At the doses of Allanblackia floribunda (200 and 400mg/kg/day) significantly prevented (21.74; 26.65% and 11.71; 24.58% of reduction) the increase in mean blood pressure on AHR and SuHR, respectively. Administration of the plant extract at the dose of 400mg/kg led to the prevention of total cholesterol (42.82%), HDL-cholesterol (36.59%) and triglycerides (9.67%) increase in serum lipid in AHR as compared to the untreated AHR. In SuHR, the extract significantly prevented the high concentrations of total cholesterol (44.08%) and triglycerides (33.05%) induced by sucrose treatment as compared to the untreated SuHR, without affecting that of HDL-cholesterol. Allanblackia floribunda (200 and 400mg/kg) also prevented the increase in atherogenic index by 54.45 and 42.94% in AHR and by 23.70 and 44.32% in SuHR, respectively. Allanblackia floribunda (400mg/kg) prevented the increase in bilirubine (19.59 and 16.56%), urea (33.36 and 28.2%), ALT (29.55 and 33.09%) and AST (36.28 and 37.12%) of AHR and SuHR, respectively. Treatment with plant extract significantly prevented the increase of superoxide dismutase (SOD), malondialdehyde (MDA) and catalase and the decrease of reduced glutathione (GSH) concentration in aorta, heart, kidney and liver of AHR and SuHR. CONCLUSION: These results demonstrate that the aqueous extract of Allanblackia floribunda can prevent alcohol- and sugar-induced hypertension and oxidative stress in rats. These findings could therefore justify its use in traditional medicine.

Teratogenic effects, acute and sub chronic toxicity of the leaf aqueous extract of Ocimum suave Wild (Lamiaceae) in rats.

The aqueous extract from the leaves of Ocimum suave was evaluated for acute and sub chronic toxicity and teratogenic effects. Swiss mice were administered single oral doses of 2000, 4000, 6000 and 8000 mg/kg and monitored for death and body weight gained for 7 days (acute toxicity). In sub-acute toxicity, experimental rats, received daily doses of 250, 500 and 1000 mg/kg for 42 consecutive days and the toxic effects were assessed using biochemical and haematological data and histology of vital organs. In a teratogenic study, 1-day pregnant rats were administered orally 500 and 1000 mg/kg of extract daily for 21 consecutive days and 14th day corpora lutea and foetal implants and litter size at birth were noted. Reproductive performance of F(1) generation rats was studied by crossing them at maturity and recording the number, birth weight and physical presentation of the young offspring. Acute intake of extract up to 8000 mg/kg did not produce mortality or significant changes in general behaviour. Sub chronic treatment did not show any change in body and organ weights, feeding habits or behaviour between the control and the treated groups of both sexes. Haematological analysis and blood biochemistry revealed no toxicity effects of the extract. No gross abnormalities or histological changes were observed. Teratogenic and fertility studies did not reveal any toxic manifestations or foetal abnormalities. The leaf aqueous extract of Ocimum suave is non toxic in acute and sub chronic intake.

Effect of Sclerocarya birrea (Anacardiaceae) stem bark methylene chloride/methanol extract on streptozotocin-diabetic rats.

Sclerocarya birrea (Anacardiaceae) is used as a traditional treatment of diabetes in Cameroon. In this study, we investigated the possible antidiabetic effect of the stem bark extract in diabetic rats. Diabetes was induced by intravenous injection of streptozotocin (STZ, 55 mg/kg) to male Wistar rats. Experimental animals (six per group), were treated by oral administration of plant extract (150 and 300 mg/kg body weight) and metformin (500 mg/kg; reference drug) for comparison, during 21 days. The stem bark methanol/methylene chloride extract of Sclerocarya birrea exhibited at termination, a significant reduction in blood glucose and increased plasma insulin levels in diabetic rats. The extract also prevented body weight loss in diabetic rats. The effective dose of the plant extract (300 mg/kg) tended to reduce plasma cholesterol, triglyceride and urea levels toward the normal levels. Four days after diabetes induction, an oral glucose tolerance test (OGTT) was also performed in experimental diabetic rats. The results showed a significant improvement in glucose tolerance in rats treated with Sclerocarya birrea extract. Metformin, a known antidiabetic drug (500 mg/kg), significantly decreased the integrated area under the glucose curve. These data indicate that Sclerocarya birrea treatment may improve glucose homeostasis in STZ-induced diabetes which could be associated with stimulation of insulin secretion.

Leaf methanol extract of Bidens pilosa prevents and attenuates the hypertension induced by high-fructose diet in Wistar rats.

Chronic fructose treatment in rats has repeatedly been shown to elevate blood pressure in association with insulin resistance and hyperinsulinemia. The purpose of the current study was to investigate the effect of the leaf methanol extract of Bidens pilosa on systolic blood pressure (SBP) and plasma glucose, insulin, cholesterol, triglycerides and creatinine levels in rats with fructose-induced hypertension. Wistar rats that drank a 10% fructose solution for 3-6 weeks showed significant increase not only in plasma insulin and cholesterol levels but also in SBP. B. pilosa extract was able to prevent the establishment of hypertension and lower elevated blood pressure levels. The extract also reduced the highly elevated plasma insulin levels provoked by the high fructose diet. These results suggest that the leaf methanol extract of B. pilosa exerts its antihypertensive effect in part by improving insulin sensitivity.

Gastric cytoprotective anti-ulcer effects of the leaf methanol extract of Ocimum suave (Lamiaceae) in rats.

The anti-ulcerogenic potential of the leaf methanol extract of Ocimum suave (Lamiaceae) was investigated using four methods of gastric lesion induction in experimental Wistar rats (150-200 g): (1) HCl/ethanol-induced gastric lesions, (2) Absolute ethanol-induced gastric lesions, (3) Indomethacin-HCl/ethanol-induced gastric lesions, (4) Pylorus ligation-induced gastric lesions. Administration of the extract of O. suave to the rats by oral route (75-500 mg/kg) dose-dependently prevented the formation of acute gastric lesions induced using the four experimental techniques. The dose-dependent reduction of lesion formation was in all cases accompanied by significant increases in gastric mucus production. At the dose of 250 mg/kg there was complete inhibition of gastric lesions induced using the HCl/ethanol solution. Pre-treatment, by intraperitoneal route, with indomethacin significantly reduced the ability of the extract to inhibit the formation of HCl/ethanol-induced lesions. When the rats were subjected to pylorus ligation, the dose of 500 mg/kg completely inhibited lesion formation but did not have any effect on gastric acid secretion compared with the controls. The mucus secretion promoting effect of the extract was most significant when the gastric environment was highly acidic. These results suggest that a new anti-ulcer therapy regimen may be formulated which does not require the use of antacids and anti-secretory agents.