The gastric antisecretory activity of 3-methoxy-5,7,3'4'-tetrahydroxyflavan (ME)--a specific histidine decarboxylase inhibitor in rats

Protective effect of standardised fruit extract of Garcinia cowa Roxb. ex Choisy against ethanol induced gastric mucosal lesions in Wistar rats

BACKGROUND AND AIM

The fruit of Garcinia is a rich and valuable source of bioactive compounds and is traditionally used for treating wounds and ulcers. The present study was carried out to investigate the protective effect of chromatographically standardized fruit extract of Garcinia cowa (GCE) on ethanol-induced gastric lesions in rats and its possible mechanisms.

METHODS

The effect of GCE (200 and 400 mg/kg body weight) was evaluated by determining various gastric ulcer parameters like gastric wall mucus, non-protein sulfhydryls (NP-SH) content, microvascular permeability, endogenous antioxidant enzyme, and gastric histopathological study.

RESULTS AND CONCLUSIONS

Oral administration of GCE at doses of 200 and 400 mg/kg exhibited significant (p < .01) dose-dependent inhibition of ulcer index by 18.94-44.02%, respectively. Pre-treatment of rats with GCE (400 mg/kg) significantly restored the depleted gastric wall mucus level by 34.09% and NP-SH content by 33.35% induced by ethanol administration. In addition, GCE (400 mg/kg) showed a significant decrease in microvascular permeability of Evans Blue by 47.43%, rationalizing its protective effect. Furthermore, a significant increase in oxidative enzyme levels with reduction in malondialdehyde level and elevation of superoxide dismutase (SOD) activity was observed in the GCE treated group as compared to the ulcer control group. The histopathological assessment also confirmed the protective nature of GCE. HPTLC analysis showed the presence of 0.27%, 0.11% w/w gallic acid, and amentoflavone, respectively in GCE. The content of α-mangostin and xanthochymol in the G. cowa extract sample quantified by HPLC-PDA method was 0.72 and 8.46%, respectively. The results obtained indicate that the protective effect of GCE against gastric ulcers in rats through multiple actions confirmed by the reduction of oxidative stress and restoration of adhered gastric mucus, NP-SH content, and histological architecture.KEY MESSAGESEthanol is the most typical ulcerogenic agent and has been shown to extend the risk of ulcer in humans.Natural products are promising alternative medication for the development of new drugs to regulate gastrointestinal diseases.Garcinia cowa protects the gastric mucosa through multiple actions that include restoration of adhered gastric mucus and inhibition of lipid peroxidation.

Ameliorative and Safety Characteristics of Argemone mexicana in Indomethacin-Induced Peptic Ulcer

Argemone mexicana (A. mexicana) is a plant traditionally used in Nigeria and some African countries to treat peptic ulcer disease. In this study, the ameliorative effect of ethanolic leaf extract of A. mexicana in indomethacin-induced peptic ulcer and its safety were investigated. Phytochemical screening was performed using standard procedures. Ulcer was induced in rats by single oral administration dose of 25 mg/kg body weight (b.w.) indomethacin followed by treatment with 100, 200, and 400 mg/kg b.w. ethanolic leaf extract of A. mexicana. Ulcer-related indices such as gastric pH, acidity, pepsin, and Na+/K+-ATPase activities, glycoprotein, and mucus contents were determined. The status of antioxidant enzymes (superoxide dismutase, catalase, glutathione peroxidase, reductase, and transferase) in the stomach and duodenum of the rats was also evaluated. Safety of the extract in the liver and kidney was investigated by chromosomal aberration. The results showed that alkaloids, flavonoids, phenolics, and saponins present in the extract as phytochemical constituents. The extract at 200 mg/kg b.w. significantly (p < 0.05) attenuated the gastric pH, volume, and acidity of the stomach. It also significantly (p < 0.05) enhanced the glycoprotein and mucus contents in the mucosal membrane of rats. The status of antioxidant enzymes (superoxide dismutase, catalase, glutathione peroxidase, reductase, and transferase) in both tissues was also significantly improved. Study on safety evaluation revealed that the extract is relatively safe at the most active dose investigated. The study concluded that A. mexicana could serve as an alternative therapy for the development of a safer antiulcer drug.

Protective effect of hydro-alcoholic extract of Ruta graveolens Linn. leaves on indomethacin and pylorus ligation-induced gastric ulcer in rats

BACKGROUND

The search for an ideal and new antiulcer drug has been extended to herbals for novel molecules that decrease the incidence of relapse and afford better protection.

OBJECTIVE

The present study was designed to investigate the protective effect of hydro-alcoholic extract of Ruta graveolens (RGE) Linn. leaves on indomethacin (IND) and pylorus ligation-induced gastric ulcer in Wistar rats.

MATERIALS AND METHODS

The rats of all the six groups were deprived of food for 24 h. Then, the first group received 1 ml/kg/day p.o. of 1% carboxymethylcellulose calcium (CMC), second group 1 ml/kg/day p.o. of 1% CMC and third group 20 mg/kg/day p.o. of IND. Fourth and fifth groups received RGE 200 and 400 mg/kg/day p.o., respectively; while the sixth group 10 mg/kg/day p.o. omeprazole. After 30 min, last three groups received 20 mg/kg/day p.o. of IND also. All these treatments after food deprivation were repeated each day for 5 consecutive days. Pylorus ligation was performed on 6th day in last five groups. After 4 h, stomach by sacrifice of the rats was examined for ulcer index (UI) and gastric mucus. Gastric juice was assessed for acidity, pH and pepsin; while gastric tissues were assessed for thiobarbituric acid reactive substance (TBARS) and glutathione (GSH).

RESULTS

Fifth group showed significant decrease in UI (10.33 ± 0.67), TBARS (0.33 ± 0.03 mmol/mg), free acidity (48.78 ± 5.12 meq/l/100 g), total acidity (99.33 ± 9.31 meq/l/100 g), and pepsin activity (8.47 ± 0.41 μg/ml) levels while it showed significant increase in mucus (412.4 ± 21.6 μg/g), GSH (57.9 ± 4.8 mmol/mg) and pH (3.32 ± 0.27) compared to third group. Percent protection in RGE 400 mg was found to be 63.32 compared to indomethacin.

CONCLUSION

RGE possesses antiulcerogenic activity as it exhibits protective effect on gastric ulcer in rats.

Combination treatment of lycopene and hesperidin protect experimentally induced ulcer in laboratory rats

AIM

Lycopene, a carotenoid and hesperidin, a flavonoid are naturally occurring in vegetables and fruits. Synergistic effect of a combination of carotenoid and flavonoid has been reported due to its antioxidant activity. Therefore, the present study was aimed to evaluate the protective effect of this combination on pylorus ligation induced ulcers in rats.

MATERIALS AND METHODS

Thirty Wistar albino rats were divided into five groups (n = 6). Rats were fasted for 24 h before pylorus ligation. After 24 h of fasting the rats were treated with hesperidin (100 mg/kg) and lycopene (2 mg/kg) and their combination 1h prior to surgery. After an hour under ether anesthesia pylorus ligation was performed, after 5 h the animals were sacrificed, stomach was dissected, and gastric contents were collected and measured. Total acidity and pH of gastric content was estimated. Ulcer index was calculated, and macroscopic examination of the stomach was carried out.

RESULTS

The sham operated rats showed a significant increase in pH, volume of gastric content and total acidity and ulcer index. The rats pretreated with lycopene and hesperidin showed significant improvement in the ulcer conditions. However, rats treated with a combination of lycopene and hesperidin showed more significant restoration of gastric function as compared to sham operated rats. Moreover, a significant difference was also noted in rats treated with a combination as compared to lycopene and hesperidin treatment alone.

CONCLUSION

Thus experimentally the combination was seen to treat ulcers by anti-secretory, neutralizing, cytoprotective and mainly due to its antioxidant property.

Antiulcer activity of water soaked Glycine max L. grains in aspirin induced model of gastric ulcer in Wistar rats

INTRODUCTION

Glycine max L. with Drakshasava, widely used by traditional healers as a formulation for the treatment of peptic ulcer in rural northern Karnataka in India, appears to be effective as assessed by patients and in our previously published research work of traditionally used formulation.

AIM

The present study was undertaken to evaluate the safety and efficacy of the overnight water soaked G. max grains. This is one of the components of traditional formulation. The study, approved by Institutional Animal Ethics Committee was carried out in male Wistar rats after assessing its toxicity in mice.

MATERIALS AND METHODS

Four groups of rats (n = 6 in each group) were treated with aspirin 200 mg/kg oral. In addition to aspirin control group received normal saline, standard group received 20 mg/kg omeprazole and 3(rd) and 4(th) group received G. max 250 and 500 mg/kg, respectively. All treatments were administered orally every 24 h for 7 days. After 24 hours fasting, on the 8(th) day stomach contents were aspirated under anesthesia to estimate free and total acidity. Stomachs were opened along the greater curvature to calculate ulcer index and subjected to histopathology studies.

STATISTICS

The results were analyzed by one-way analysis of variance followed-by Dunnett's post hoc test. P ≤0.05 was considered as significant.

RESULTS

The severity of aspirin induced ulceration was found significantly (P < 0.05) decreased in test groups compared with the control group. Free and total acidity was significantly reduced in 500 mg/kg treated group, compared with the control group and was inferior to omeprazole treated group.

CONCLUSION

The grain of G. max was found to be effective against aspirin induced ulcers.

Gastroprotective effect of the three glucuronopyranoside flavonoids in rats

In this study, we investigated the protective action of glucuronopyranoside flavonoids (QGC, AGC, LGC) on gastritis in rats. QGC, AGC and omeprazole decreased the gastric volume significantly, and each ID₅₀ was 0.75, 0.54 and 8.5 mg/kg, respectively, thus the order of potency was AGC, QGC and omeprazole. They also decreased acid output, and each ID₅₀ was 7.81, 0.58 and 6.71 mg/kg, respectively, thus the order of potency was AGC, omeprazole and QGC. They inhibited gastritis induced by indomethacin, and it recovered significantly by increasing the GSH levels in gastritis. The gastric MPO activity in the gastritis group increased more than in the normal group. QGC, LGC, or AGC administration reduced moderately the MPO activity in a dose-dependent manner. This study demonstrated that AGC, QGC, or LGC showed potent efficacy on the gastritis, by preventing oxidative stress. These results suggest that QGC, AGC, or LGC have gastroprotective effect in rats.

Evaluation of antiulcerogenic potential of antioxidant α-tocopherol in pylorus-ligated albino rats

BACKGROUND

Oxidative free radicals and lipid peroxidation mediate gastric injury. α-Tocopherol is a redox agent with biological and antioxidant property, hence, may provide ulcer protection.

METHODS

Pylorus-ligated Shay rats (n=6) were used as the experimental gastric ulcer animal model. The rats were divided into three groups. Group I received saline (5 mL/kg), Group II α-tocopherol (12.5 mg/kg), and Group III omeprazole (3.6 mg/kg), orally daily for 5 days prior to ulcerogenic challenge. Nineteen hours after the challenge, the rats were sacrificed and their stomachs isolated and studied for degree of gastric injury. Formed gastric juice was collected for measurement of volume, titrimetric estimation of free and total acidity, and total acid output by the conventional methods. The ulcer index and total acid outputs were calculated.

RESULTS

α-Tocopherol exerted significant (p<0.05) antiulcer activity (the ulcer index was reduced to 7.4 ± 1.0 from the control value of 19.8 ± 4.1). α-Tocopherol also significantly reduced free and total acidity, gastric juice volume, and total acid output (p<0.01). The results were analyzed by ANOVA and Scheffe's multiple comparison test.

CONCLUSIONS

The study demonstrates that α-tocopherol has significant antiulcer activity. It, perhaps, acts by decreasing hydrochloric acid output.

Protective effect of standardized extract of Cleome viscosa against experimentally induced gastric lesions in the rat

CONTEXT

Cleome viscosa Linn. (Capparidaceae) is used traditionally in the Indian system of medicine as a carminative, anthelmintic, and diuretic, and used for healing wounds, ulcers and diarrhea.

OBJECTIVE

A 70% ethanol (EtOH) extract of the aerial parts of Cleome viscosa extract (CVE) was investigated for gastroprotective activity in different gastric ulcer models in order to validate ethnobotanical claims regarding the plant use in ulcers.

MATERIALS AND METHODS

CVE (100, 200 and 400 mg/kg body weight) was administered orally, twice daily for 5 d, for prevention from EtOH, pylorus ligation (PL) and cold restraint stress (CRS)-induced ulcers in rats. Estimation of H(+)K(+)ATPase activity and gastric wall mucous were performed in EtOH-induced ulcer, antioxidant enzyme activities in supernatant mitochondrial fraction of CRS-induced ulcer, and gastric secretion parameters were estimated in PL-induced ulcer model.

RESULTS

CVE showed significant (p < 0.01) dose-dependent inhibition of lesion index in EtOH 15.93-42.30%, PL 26.34-59.28% and CRS 22.58-54.03%, respectively. CVE prevents the oxidative damage of gastric mucosa by blocking lipid peroxidation and by a significant (p < 0.001) decrease in superoxide dismutase, and an increase in catalase activity. A significant (p < 0.01) decrease occurred in the level of H(+)K(+)ATPase, volume of gastric juice and total acidity. Simultaneously, the level of gastric wall mucus and pH were increased significantly (p < 0.05). High performance thin layer chromatography analysis showed the presence of quercetin and gallic acid (0.3% and 0.25% w/w, respectively) in CVE.

CONCLUSIONS

Results of our study showed that C. viscosa possesses significant gastroprotective activity, probably due to free radical scavenging activity, and validates the folklore claim.

Acute Toxicity and General Pharmacological Action of QGC EXT

It has been shown that QGC isolated and purified from Rumecis folium found protective effects of gastritis and esophagitis which EXT is an ethanol extract of it. We examined acute toxicity and the general pharmacological action of QGC EXT to search for any side effects of it in rats, mice, guinea pigs, and cats. In a single dose toxicity study, QGC EXT didn't show toxicological effects in rats and mice, and the LD₅₀ was over 5 g/kg in both animals, and there were also no changes in weight, feed and water intake during these toxicological experimental periods. We examined the general pharmacological action on central controlled behavior responses, and peripheral organs including blood pressure, heart rate, respiration and gastrointestinal system, We found that there were no significant changes in body temperature, locomotors activity, stereotyped behaviors, sleeping time, and convulsion. In other studies, writhing reaction, normal body temperature, there did not appear to be any changes. The large intestine movement and electrical field stimulation-induced contraction was not changes by its EXT. In addition, the influences on blood pressure, heart rates, and respiration by QGC EXT were not found. These results indicate that QGC EXT may be very safe as a new drug, since its LD₅₀ was very high over 5 g/kg and any side effects were not found.

Silymarin, an antioxidant bioflavonoid, inhibits experimentally-induced peptic ulcers in rats by dual mechanisms

INTRODUCTION

Antioxidants are reported to have antiulcer activity. We investigated silymarin, a bioflavonoid antioxidant, for antiulcer potential.

MATERIALS AND METHODS

Pylorus-ligated Shay rats (n=5) were used as the experimental gastric ulcer animal model. The rats, separated into three groups, were administrated silymarin (50 mg/kg), omeprazole (3.6 mg/kg), or saline (5 ml/kg) per orally daily for 5 days prior to ulcerogenic challenge. Nineteen hours after the challenge, the rats were sacrificed and their stomachs isolated. Formed gastric juice was collected for measurement of volume, titrimetric estimation of free and total acidity, and total acid output by the conventional methods. The ulcer index was calculated. Total acid output and free and combined acid quantities were calculated using the acidity value and the volume of formed gastric juice.

RESULTS

Silymarin exerted significant (P<.05) antiulcer activity (the ulcer index was reduced to 7.4 ± 1.0 from the control value of 19.8 ± 4.1). Silymarin also significantly reduced free and total acidity, gastric juice volume, total acid output, and combined acid content. The results were analyzed by ANOVA and Newman-Keuls multiple comparison test.

CONCLUSION

This study demonstrates that silymarin has significant antiulcer activity. It perhaps acts by decreasing hydrochloric acid output and increasing buffering power (combined acid).

Protective Effect of Ginger oil on Aspirin and Pylorus Ligation-Induced Gastric Ulcer model in Rats

The present investigation was performed in aspirin and pylorus ligation-induced ulcer model in Wistar rats, in which ability of ginger oil to provide gastric protection was studied at two different doses, 0.5 and 1 g/kg po. Gastric protection was evaluated by measuring the ulcer index, serum γ-GTP levels, total acidity of gastric juice and gastric wall mucus thickness. The results obtained in the present study indicated that ginger oil has a protective action against gastric ulcers induced by aspirin plus pylorus ligation in Wistar rats.

Protective effects of Punica granatum in experimentally-induced gastric ulcers

In the present investigation standardized aqueous methanolic extract of Punica (AMP) was used for its possible ulcer protective activity in wistar rats against different experimental models. Preliminary phytochemical screening of AMP reveals the presence of saponin, tannins, and flavonoids, which may be responsible for its activity. HPTLC finger prints of AMP showed the presence of 12 spots at different (retention factor) rf values. Oral administration of AMP (490 and 980 mg/kg bw) significantly reduced the ulcer lesion index produced by alcohol, indomethacin, and aspirin, at both doses in rats. Further, in pylorus-ligated rats AMP significantly reduces the ulcer lesions, gastric volume, and total acidity. It prevents the ulceration by increasing the pH and mucus secretion in pylorus ligated rats. The present study shows the anti-ulcer activity of AMP in experimentally-induced gastric ulcers.

Comparative study of proton pump inhibitors on dexamethasone plus pylorus ligation induced ulcer model in rats

The present study was designed to compare ulcer protective effect of proton pump inhibitors viz. omeprazole, rabeprazole and lansoprazole against dexamethasone plus pylorus ligation induced ulcer model. Dexamethasone (5 mg/kg) was used as an ulcerogen. Dexamethasone suspended in 1% CMC in water was given orally to all the rats 15 min after the pylorus ligation. Omeprazole (20 mg/kg), rabeprazole (20 mg/kg), and lansoprazole (20 mg/kg) were administered by oral route 30 min prior to ligation was used for ulcer protective studies, gastric secretion and mucosal studies. Effects of proton pump inhibitors were determined by the evaluation of various biochemical parameters such as ulcer index, free and total acidity, gastric pH, mucin, pepsin and total proteins. Oral administration of proton pump inhibitors showed significant reduction in gastric acid secretion and ulcer protective activity against dexamethasone plus pylorus ligation induced ulcer model. The % protection of omeprazole, rabeprazole and lansoprazole was 84.04, 89.36 and 79.78, respectively. Rabeprazole significantly inhibited the acid-pepsin secretion and increased the gastric mucin secretion. The observations made in the present study suggest that rabeprazole is the most effective gastric antisecretory and ulcer healing agent as compared to omeprazole and lansoprazole.

Evaluation of Myrtus communis Linn. berries (common myrtle) in experimental ulcer models in rats

The present study was conducted to investigate the protective effect of the dried berries of Myrtus communis L. in gastric ulcer against ethanol, indomethacin and pyloric ligation induced models in Wistar rats. Two doses of aqueous extracts of M. communis (AE( 1) and AE(2)) at the dose 105 and 175 mg/kg, respectively, and methanolic extracts (ME(1) and ME(2)) at the dose of 93 and 154 mg/kg, respectively, were administered orally to animals prior to the exposure of ulcerogens. The parameters taken to assess anti-ulcer activity were ulcer index, gastric juice volume, gastric pH, total acidity, gastric wall mucus and histopathological studies. Oral administration of AE(1) and AE(2) significantly reduced the ulcer index in all models of ulcers. Low dose of aqueous extract and high dose of methanolic extract of M. communis exhibited more significant effect in comparison to omeprazole (standard drug) in ethanol-induced ulcer model. Both the doses of aqueous and methanolic extracts also reduced the gastric juice volume, total acidity and increased the gastric pH and gastric wall mucus content in all the models of ulcers used in the present study. Histopathological examinations of gastric tissues of rats treated with the aqueous and methanolic extracts in indomethacin-induced ulcer exhibited significant ulcer-protective effect at both the dose levels.

The Inhibitory Effect of Quercetin-3-O-beta-D-Glucuronopyranoside on Gastritis and Reflux Esophagitis in Rats

It was evaluated the inhibitory action of quercetin-3-O-beta-D-glucuronopyranoside (QGC) on reflux esophagitis and gastritis in rats. QGC was isolated from the herba of Rumex Aquaticus. Reflux esophagitis or gastritis was induced surgically or by administering indomethacin, respectively. Oral QGC decreased ulcer index, injury area, gastric volume, and acid output and increased gastric pH as compared with quercetin. Furthermore, QGC significantly decreased gastric lesion sizes induced by exposing the gastric mucosa to indomethacin. Malondialdehyde levels were found to increase significantly after inducing reflux esophagitis, and were reduced by QGC, but not by quercetin or omeprazole. These results show that QGC can inhibit reflux esophagitis and gastritis in rats.

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.

Antiulcer and in vitro antioxidant activities of Jasminum grandiflorum L

The study was aimed at evaluating the antiulcer and antioxidant activities of 70% ethanolic axtract of leaves of Jasminum grandiflorum L. (JGLE). The leaves of Jasminum grandiflorum L. (Family: Oleaceae) is used in folk medicine for treating ulcerative stomatitis, skin diseases, ulcers, wounds, corns - a hard or soft hyperkeratosis of the sole of the human foot secondary to friction and pressure (Stedman's Medical Dictionary, 28th ed. Lippincott Williams & Wilkins, Philadelphia. p. 443), etc., Antiulcerogenic activity of JGLE (100 and 200 mg/kg, b.w., orally) was evaluated employing aspirin + pylorus ligation (APL) and alcohol (AL) induced acute gastric ulcer models and ulcer-healing activity using acetic acid-induced (AC) chronic ulcer model in rats. Both the antisecretory and cytoprotection hypothesis were evaluated. The antioxidant activity of JGLE has been assayed by using in vitro methods like 2,2-diphenyl-1-picrylhydrazylhydrate (DPPH) assay, reductive ability, superoxide anion scavenging activity, nitric oxide scavenging activity and total phenolic content, in order to explain the role of antioxidant principles in the antiulcerogenic activity of the extract. There was a significant (P<0.01) dose-dependent decrease in the ulcerative lesion index produced by all the three models in rats as compared to the standard drug famotidine (20 mg/kg, b.w. orally). The reduction in gastric fluid volume, total acidity and an increase in the pH of the gastric fluid in APL rats proved the antisecretory activity of JGLE. Additionally, JGLE completely healed the ulcer within 20 days of treatment in AC model as evidenced by histopathological studies. Like antiulcer activity, the free radical scavenging activities of JGLE depends on concentration and increased with increasing amount of the extract. These results suggest that leaves of Jasminum grandiflorum possess potential antiulcer activity, which may be attributed to its antioxidant mechanism of action.

The effects of apigenin-7-O-beta-D-glucuronopyranoside on reflux oesophagitis and gastritis in rats

1. This study evaluated the inhibitory action of apigenin-7-O-beta-D-glucuronopyranoside (AGC), apigenin, and omeprazole on reflux oesophagitis and gastritis in rats. AGC was isolated from Clerodendron trichotomum leaves. 2. Oesophagitis and gastritis were induced by surgical procedure and the administration of indomethacin, respectively. The intraduodenal (i.d.) administration of AGC decreased the volume of gastric juice and increased the gastric pH compared with apigenin and omeprazole. The acid output was more inhibited by AGC in a dose-dependent manner than by apigenin and omeprazole. Compared with apigenin and omeprazole, AGC significantly decreased the size of gastric lesions, which were induced by exposure of the gastric mucosa to indomethacin. 3. Malondialdehyde (MDA) content, which is the end product of lipid peroxidation, was increased significantly after the induction of reflux oesophagitis. The MDA content was decreased by AGC (i.d. 3 mg kg(-1)), but not by either apigenin or omeprazole. This suggests that AGC has an antioxidative effect. In the oesophagitis group, the mucosal levels of glutathione (GSH) were significantly lower than that in the normal group. However, the GSH levels were preserved after administering the AGC, suggesting that AGC possesses scavenging activity. 4. In summary, AGC is more potent than apigenin and omeprazole at inhibiting reflux oesophagitis and gastritis and may therefore be a promising drug for their treatment.

The effect of luteolin-7-O-β-d-glucuronopyranoside on gastritis and esophagitis in rats

This study evaluated the inhibitory action of luteolin-7-O-beta-D-glucuronopyranoside, luteolin which was isolated from Salix gilgiana leaves, and omeprazole on reflux esophagitis and gastritis in rats. Reflux esophagitis and gastritis were induced surgically and by the administration of indomethacin, respectively. The intraduodenal administration of luteolin-7-O-beta-D-glucuronopyranoside decreased the ulcer index, injury area, gastric volume and acid output, and increased the gastric pH compared with luteolin. Luteolin-7-O-beta-D-glucuronopyranoside significantly decreased the size of the gastric lesions that had been induced by exposing the gastric mucosa to indomethacin. The malondialdehyde content, which is the end product of lipid peroxidation, was increased significantly after inducing of reflux esophagitis. The malondialdehyde content was decreased by Luteolin-7-O-beta-D-glucuronopyranoside but not luteolin or omeprazole. Luteolin-7-O-beta-D-glucuronopyranoside has a more potent antioxidative effect than luteolin. Luteolin-7-O-beta-D-glucuronopyranoside is a promising drug for the treatment of reflux esophagitis and gastritis.

Gastroprotective effect of cardamom, Elettaria cardamomum Maton. fruits in rats

Cardamom, the fruits of Elettaria cardamomum Maton. (Zingiberaceae) commonly known as "Heel khurd" is used in Unani system of medicine to treat gastrointestinal disorders. A crude methanolic extract (TM), essential oil (EO), petroleum ether soluble (PS) and insoluble (PI) fractions of methanolic extract, were studied in rats at doses of 100-500, 12.5-50, 12.5-150 and 450 mg/kg, respectively for their ability to inhibit the gastric lesions induced by aspirin, ethanol and pylorous ligature. In addition their effects on wall mucus and gastric acid output were recorded. All fractions (TM, EO, PS, PI) significantly inhibited gastric lesions induced by ethanol and aspirin but not those induced by pylorus ligation. TM proved to be active reducing lesions by about 70% in the EtOH-induced ulcer model at 500 mg/kg. The PS fraction reduced the lesions by 50% at 50 and 100mg/kg (no dose response was observed) with similar effect than the PI fraction at 450 mg/kg. In the aspirin-induced gastric ulcer, the best gastroprotective effect was found in the PS fraction, which inhibited lesions by nearly 100% at 12.5mg/kg. In our experimental conditions, the PS extract at doses >or=12.5mg/kg proved to be more active than ranitidine at 50mg/kg.

Antiulcer activity of methanol fraction of Barleria lupulina Lindl. in animal models

The objective of the present study was to evaluate the gastric cytoprotective activity of the methanol extract of aerial parts of the plant Barleria lupulina Lindl (Acanthaceae) in albino rats using various models of ulcers such as drug induced ulcers, restraint ulcers, duodenal ulcers and pylorus ligated ulcers. The effect of the extract on gastric secretion and lipid peroxidation (thiobarbituric acid reacting substances TBARS) was also studied in rats. The extract at the tested dose of 200 mg/kg significantly reduced the volume of gastric juice, total acidity and the ulcer index in pylorus ligated rats. It also afforded significant protection against alcohol and indomethacin induced ulcer as well as stress induced ulceration. TBARS in the stomach of indomethacin treated rats was also reduced. In addition, it gave protection against duodenal ulcers. The study suggests that the methanol extract of aerial parts of Barleria lupulina Lindl. has a protective effect against experimental gastric and duodenal ulcers.

Evaluation of the gastric antiulcerogenic effect of large cardamom (fruits of Amomum subulatum Roxb)

Large cardamom (fruit of Amomum subulatum Roxb, N.O. Zingiberaceae) commonly known as 'Heel kalan' or 'Bari Ilaichi' is used in Unani system of medicine in gastrointestinal disorders. A crude methanolic extract and its different fractions, viz. essential oil, petroleum ether (60-80 degrees ), ethyl acetate and methanolic fractions, were studied in rats for their ability to inhibit the gastric lesions induced by aspirin, ethanol and pylorus ligature. In addition their effects on wall mucus, output of gastric acid and pepsin concentration were recorded. The crude methanolic extract of A. subulatum and its fractions, viz. essential oil, petroleum ether and ethyl acetate, inhibited gastric lesions induced by ethanol significantly, but not those which were induced by pylorus ligation and aspirin. However, ethyl acetate fraction increased the wall mucus in pylorus ligated rats. The results suggest a direct protective effect of ethyl acetate fraction on gastric mucosal barrier. While the observation of decrease in gastric motility by essential oil and petroleum ether fractions suggests the gastroprotective action of the test drug. These investigations validate the use of 'Heel kalan' in gastrointestinal disorders by Unani physicians.

Evaluation of the gastric antiulcer activity of fixed oil of Ocimum sanctum (Holy Basil)

The fixed oil of Ocimum sanctum L. (Labiatae) was found to possess significant antiulcer activity against aspirin-, indomethacin-, alcohol-, histamine-, reserpine-, serotonin- and stress-induced ulceration in experimental animal models. Significant inhibition was also observed in gastric secretion and aspirin-induced gastric ulceration in pylorus ligated rats. The lipoxygenase inhibitory, histamine antagonistic and antisecretory effects of the oil could probably have contributed towards antiulcer activity. O. sanctum fixed oil may be considered to be a drug of natural origin which possesses both anti-inflammatory and antiulcer activity.

Protection by Rhinax in various models of ulceration in rats

The effect of Rhinax on gastric damage in different animal models including gastric ulceration induced by a necrotic agent such as 0.6 N HCl, indomethacin, and intragastric distension was studied. Treatment with Rhinax at a dose of 160 mg/kg protected gastric mucosa against the damage induced by oral administration of indomethacin and intragastric distension. The volume and acidity of gastric juice in pyloric ligated rats was reduced by Rhinax. It also significantly promoted gastric mucus secretion in normal animals. On the basis of these observations, we conclude that Rhinax possesses anti-ulcer activity and that the observed activity may be due to the modulation of defensive factors by improvement in gastric cytoprotection.

Evaluation of possible mechanism of anti-ulcerogenic activity of UL-409, a herbal preparation

UL-409, a herbal preparation was investigated for its anti-ulcerogenic activity and possible mechanism of action in different experimental models. Oral administration of UL-409 at a dose of 600 mg/kg significantly reduced the volume of gastric secretion, total acidity and free acidity in aspirin + pylorus-ligated rats. The drug appeared to strengthen the gastric mucosal defense mechanism by significantly increasing the total carbohydrate:protein ratio in aspirin + pylorus-ligated rats. The major mechanism involved appears to be due to promotion of mucosal protection by augmenting gastric mucin activity. Pre-treatment with UL-409 showed inhibition of alcohol-induced contraction of isolated rat fundus preparation which was reversed by indomethacin suggesting a possible involvement of the cyclo-oxygenase system.

Evaluation of Nigerian traditional medicines: II. Effects of some Nigerian folk remedies on peptic ulcer

Antiulcer activity of four medicinal plants, Diodia sarmentosa (whole plant), Cassia nigricans (leaves), Ficus exasperata (leaves) and Synclisia scabrida (leaves), which are commonly used by the Nigerian traditional healers for the treatment of peptic ulcer were investigated. Acute toxicity tests were also carried out. The results revealed that the four extracts possess significant anti-ulcerogenic properties in a dose-dependent way. They protected rats from aspirin-induced ulcerogenesis, delayed intestinal transit, increased the pH, and decreased both the volume and acidity of gastric secretion. These results correlate with local use of the plants.

Protective effect of UL-409, a herbal formulation against physical and chemical factor induced gastric and duodenal ulcers in experimental animals

UL-409, a herbal formulation, was investigated for its possible ulcero-protective activity in Wistar rats of either sex and male guinea pigs. Oral administration of UL-409 at a dose of 600 mg/kg significantly prevented the occurrence of cold-restraint stress induced ulcerations. It significantly inhibited gastric ulceration induced by alcohol and aspirin, as well as cysteamine and histamine induced duodenal ulcers in rats and guinea pigs, respectively. The volume and acidity of gastric juice in pyloric ligated rats was reduced by UL-409. It also significantly, and dose dependently, promoted gastric mucus secretion in normal as well as in stress, drug and alcohol induced ulceration in animals. On the basis of these observations, we conclude that UL-409 possesses antiulcer activity and that the observed activity may be due to the modulation of defensive factors by improvement in gastric cytoprotection.

Gastric H+, K(+)-ATPase inhibition by catechins

Five catechins, (+)-catechin, (-)-epicatechin, (-)-epicatechin gallate, (-)-epigallocatechin and (-)-epigallocatechin gallate, inhibited gastric H+, K(+)-ATPase activity with IC50 values ranging from 1.7 x 10(-4) to 6.9 x 10(-8) M, with (-)-epigallocatechin gallate as the most potent inhibitor. The intensity of inhibitor activity paralleled the number of phenolic hydroxy groups in the molecule. The inhibition of the enzyme by (-)-epicatechin was competitive with respect to ATP and noncompetitive with respect to K+. These findings suggest that the anti-secretory and anti-ulcerogenic effects of catechins previously reported, are due to their inhibitory activity on gastric H+, K(+)-ATPase.

The protective effect of Meciadanol (O-methyl-3(+)-catechin) on experimental ulceration

Meciadanol, (O-methyl-3(+)-catechin), a histidine decarboxylase inhibitor was shown to have a marked protective action against experimental peptic ulceration in three rat models. The three methods used to induce ulceration were the instillation of absolute alcohol, pyloric ligation following an ulcerogenic South Indian diet and the instillation of rice bran oil into the stomach after pyloric ligation. Meciadanol was shown to reduce incidence, numbers and areas of ulceration and protected mast cells against degranulation and to preserve a normal vascular patterns. Furthermore, Meciadanol reduced gastric acid output and concentration in the pylorus ligation model. These results indicate that Meciadanol may be useful for the treatment of peptic ulcers in humans.

Gastric protection by meciadanol. A new synthetic flavonoid inhibiting histidine decarboxylase

Flavonoids reportedly inhibit histidine decarboxylase and reduce gastric mucosal histamine content. We studied the effects of acute and chronic intragastric administration to rats of meciadanol, a new synthetic flavonoid (Zyma S.A., Nyon, Switzerland). The action of meciadanol was compared to that of 16,16-dimethyl PGE2. Meciadanol did not affect acid or pepsin output at any dose used. High doses of 16,16-dimethyl PGE2 reduced both acid and pepsin output. Meciadanol partially prevented aspirin-induced lesions but the prevention required chronic administration of meciadanol. In contrast, a single dose of meciadanol completely prevented ethanol-induced lesions. Chronic administration of meciadanol also completely prevented ethanol-induced lesions. 16,16-Dimethyl PGE2 prevented both aspirin-induced and ethanol-induced lesions in doses that did not affect acid or pepsin output. Meciadanol did not influence the effect that either aspirin or ethanol had on endogenous mucosal PGI2. Thus, the dose range of meciadanol that protected against ulcerogens did not affect either gastric acid secretion or pepsin output. Therefore, we conclude that meciadanol's action represents true cytoprotection, which was previously attributed only to prostaglandins.

Histidine decarboxylase inhibition: a novel approach towards the development of an effective and safe gastric anti-ulcer drug

The involvement of histamine in mediating gastric function under normal and pathological conditions has been largely established. The relationship between gastric acid production and peptic ulcer diathesis is also well known. Recently, endogenous histamine formation and its release from mast cells has been implicated in the pathogenesis of human and experimental gastric ulcers produced by restraint and pyloric ligation. It has also been implicated in the gastric mucosal damage produced by drugs like aspirin, phenylbutazone and reserpine. These observations suggest that histidine decarboxylase inhibitors may be useful in the prevention of such lesions. Our studies on the evaluation of some histidine decarboxylase inhibitors show that these compounds have a promising potential for developing an effective and safe anti-ulcer drug. This mini-review incorporates the results of our studies which have been adequately supported by other studies as well.

The gastric antisecretory activity of 3-methoxy-5,7,3'4'-tetrahydroxyflavan (ME)--a specific histidine decarboxylase inhibitor in rats

3-Methoxy-5,7,3'4'-tetrahydroxyflavan (ME), a specific histidine decarboxylase inhibitor, has been shown to significantly reduce the gastric acid secretion and gastric tissue histamine levels in 6 h pylorus ligated rats. It has been found to be as effective as cimetidine in reducing the gastric acid secretion. However, cimetidine does not affect the gastric tissues histamine levels in the normal or pylorus ligated rats. These observations clearly establish that the two drugs reduce the gastric acid secretion by different mechanisms and suggest that their combination may show a potentiated gastric anti-ulcer activity.