The influence of the Chuyou Yuyang granule on the Toll-like receptor/nuclear factor-κB signal pathway in Helicobacter pylori-positive peptic ulcer patients.

BACKGROUND: The cure rate of Helicobacter pylori (HP)-positive peptic ulcer has appeared to downward trend, and the resistance of the ulcer relapse has become a hot issue. METHODS: Hematoxylin and eosin staining was used to detect the repair of the damaged tissues in patients after treatment with the Chuyou Yuyang granule (CYYY). Elisa was used to analyze the expression of cytokine interleukin 18 (IL-18) and tumor necrosis factor α (TNF-α) in the patients' serum. Western blot analysis was used to explore the mechanism of the CYYY. Reverse-transcription polymerase chain reaction (RT-PCR) was used to detect the expression of microRNA-155a (miR-155a) and miR-146a in the blood of the patients and to confirm whether CYYY could cure peptic ulcer through regulation of miR-155a and miR-146a. RESULTS: The damaged gastric mucosal tissues of ulcer patients were significantly repaired by treating with CYYY. The pro-inflammatory cytokine IL18 and TNF-α were notably repressed after treating with CYYY. In addition, CYYY played a key role in regulation of the Toll-like receptor (TLR4)/nuclear factor-κB (NF-κB) signal pathway and the expression of miR-155a and miR-146a. CONCLUSION: CYYY was a highly effective therapeutic method for peptic ulcer patients by inhibiting the activation of the TLR4/NF-κB signal pathway and suppressing the expression of miR-155a and miR-146a.

A modified pectic polysaccharide from turmeric (Curcuma longa) with antiulcer effects via anti-secretary, mucoprotective and IL-10 mediated anti-inflammatory mechanisms.

Antiulcer potency and inhibitory effects on Helicobacter pylori of structurally defined low molecular weight modified pectin from turmeric (MTrPP) has been previously demonstrated by us. Given that ulcer is a disorder characterized by inflammatory responses leading to initiation, aggravation and perpetuation of disease conditions, the present study aims to understand the possible anti-inflammatory mechanisms through which MTrPP delivered antiulcer effects. Rats triggered with early phase gastric inflammation (LPS) followed by ulcer induction (swim-stress) were pretreated with MTrPP (150 mg/kg b.w.) for 14 days. Inflammation and ulcer-specific markers were screened to assess the protective effects. MTrPP offered up to 91% protection by limiting the production of pro-inflammatory factors (TNF-α, IL-8, NF-κB) and by the tight differential regulation of cyclooxygenase (COX-1, 2), mitogen-activated-protein-kinase (p-p38, p-ERK-1/2) and matrix metalloproteinase (pro-MMP-9). MTrPP showed modulatory effects through inhibition of galectin-3, oxidative stress, H+,K+-ATPase and elicitation of gastro-protective mediators such as, mucin, prostaglandin E2, NOx, zinc, IgA etc. Results revealed that MTrPP mediated the overall protection by creating an environment conducive to protection by switching from the inflammatory to anti-inflammatory phase via IL-10 over expression.

Evaluation of the antioxidant and gastroprotective activity and HPLC analysis of the hydroalcoholic extract of Tocoyena formosa leaves (Cham. & Schlecht) K. Schum.

The peptic ulcer is a gastric disorder that affects millions of people and yet they cause many side effects. In this sense, natural products represent an important alternative to the discovery of compounds with gastroprotective activity. The present work has as its objective to evaluate the antioxidant and gastroprotective activity of the Hydroalcoholic Extract of Leaves from Tocoyena formosa (Cham. & Schlecht.) K. Schum (HELTF), this being much emphasized in traditional medicine for inflammatory morbidities and gastric symptoms. For the evaluation of the antioxidant activity, FRAP and DPPH tests were carried out, and for the evaluation of the gastroprotective activity, gastric lesion induction by ethanol, acidified ethanol, indomethacin and physical barrier tests were used. Antioxidant assay of HELTF revealed an EC50 of 558.66 µM FeSO4/g and IC50 of 189.78 µg/ml for FRAP and DPPH respectively. In gastroprotective, in ethanol model, all the doses presented significant activity in comparison to controls, however, in the gastric lesion induction test by acidified ethanol and indomethacin, only the dose of 200 mg/kg presented with significance. In the physical barrier test presented evidence that protection by the formation of a protective layer associated with mucus. Concluded, therefore, that HELTF possesses antioxidant and significate gastroprotective activity.

Co-administration of Magnesium Ion Prevents Indomethacin-Induced Intestinal Ulcerogenic Lesions in Adjuvant-Induced Arthritis Rats.

In a study to find ways to prevent the side effects of indomethacin (IMC), we previously reported that magnesium ion (Mg2+) can prevent the onset of IMC-induced gastric mucosa in adjuvant-induced arthritis (AA) rats, a model for rheumatoid arthritis (RA). In this study we investigated whether the co-administration of IMC and Mg2+ prevents the formation and aggravation of intestinal ulcerogenic lesions in AA rats. The single oral administration of an excessive dose of IMC (40 mg/kg) induces hemorrhagic lesions and nitric oxide (NO) production via inducible nitric oxide synthase (iNOS) in the jejunal and ileal mucosa of AA rats, and the extent of the lesions, as well as iNOS and NO levels in AA rats are higher than in normal rats. On the other hand, the co-administration of 200 mg/kg Mg2+ attenuates intestinal ulceration and the elevation in the iNOS and NO levels in AA rats. Further, hemorrhagic lesioning and enhanced iNOS and NO levels in AA rats also result from the repetitive oral administration of 3 mg/kg IMC (therapeutic dose) for 42 d (once a day), and these changes are also prevented by the co-administration of 200 mg/kg Mg2+. In conclusion, the co-administration of Mg2+ suppresses the ulcerogenic response to IMC in the jejunal and ileal mucosa of AA rats, probably by preventing the elevation of iNOS and NO levels in the region.

Fatty acid composition and mechanisms of the protective effects of myrtle berry seed aqueous extract in alcohol-induced peptic ulcer in rat.

This study aimed to investigate the antiulcer and antioxidant activities of myrtle berry seed aqueous extract (MBSAE) in a peptic ulcer model induced by ethanol in male Wistar rats. MBSAE is rich in total polyphenols, total flavonoids, and unsaturated fatty acids, particularly linoleic (18:2) and oleic (18:1) acids. MBSAE also exhibited in vitro antioxidant activity using 2,2-diphenyl-1-picrylhydrazyl (DPPH) (IC50 = 172.1 µg/mL) and superoxide anion (IC50 = 200.24 µg/mL) scavenging activities. In vivo, MBSAE provided dose-dependent protection against ethanol-induced gastric and duodenal macroscopic and histological alterations. Also, it inhibited secretory profile disturbances and lipid peroxidation, and preserved normal antioxidant enzyme activities and nonenzymatic antioxidant levels. More importantly, we showed that acute alcohol intoxication increased gastric and duodenal calcium, hydrogen peroxide, and free iron levels, whereas MBSAE treatment protected against intracellular mediator deregulation. In conclusion, we suggest that MBSAE has potent protective effects against alcohol-induced peptic ulcer in rat. This protection might be related in part to its antioxidant properties as well as its opposite effects on some studied intracellular mediators.

Protective effect of essential oil of Pistacia atlantica Desf. on peptic ulcer: role of α-pinene.

OBJECTIVE: To evaluate the efficacy of Pistacia atlantica Desf. oleoresin essential oil on peptic ulcer (PU) and its antibacterial effect on metronidazole-resistant Helicobacter pylori, as well as chemical composition of the essential oil. METHODS: The essential oil was standardized using gas chromatography mass spectrometry (GC/MS) analysis. Acute toxicity of the essential oil was assessed in animal model. In vitro anti-Helicobacter pylori activity was performed through disc diffusion and minimum inhibitory concentration method. For gastroprotective assay, rats received Pistacia atlantica Desf. essential oil (25, 50 and 100 mg/kg orally) 1 h before induction of ulcer by ethanol. Macroscopic (ulcer index and protection rate) and microscopic examination were performed. RESULTS: The GC/MS analysis of the essential oil led to the identification of twenty constituents and α-pinene is predominant constituent. The essential oil was safe up to 2000 mg/kg. All Helicobacter pylori strains were susceptible to the essential oil and the MIC ranged from 275 to 1100 µg/mL. The ulcer index for treated groups was significantly reduced compared to control (P < 0.001) with EC(50) value of 12.32 mg/kg. In microscopic examination, Pistacia atlantica attenuated destruction and necrosis of gastric tissue. CONCLUSION: Current study exhibited protective effect of standardized Pistacia atlantica essential oil against ethanol-induced gastric ulcer and its antibacterial activity on Helicobacter pylori. α-pinene might be the responsible agent.

An overview of malaria transmission from the perspective of Amazon Anopheles vectors

In the Americas, areas with a high risk of malaria transmission are mainly located in the Amazon Forest, which extends across nine countries. One keystone step to understanding the Plasmodium life cycle in Anopheles species from the Amazon Region is to obtain experimentally infected mosquito vectors. Several attempts to colonise Ano- pheles species have been conducted, but with only short-lived success or no success at all. In this review, we review the literature on malaria transmission from the perspective of its Amazon vectors. Currently, it is possible to develop experimental Plasmodium vivax infection of the colonised and field-captured vectors in laboratories located close to Amazonian endemic areas. We are also reviewing studies related to the immune response to P. vivax infection of Anopheles aquasalis, a coastal mosquito species. Finally, we discuss the importance of the modulation of Plasmodium infection by the vector microbiota and also consider the anopheline genomes. The establishment of experimental mosquito infections with Plasmodium falciparum, Plasmodium yoelii and Plasmodium berghei parasites that could provide interesting models for studying malaria in the Amazonian scenario is important. Understanding the molecular mechanisms involved in the development of the parasites in New World vectors is crucial in order to better determine the interaction process and vectorial competence.

Effect of the oral intake of probiotic Pediococcus acidilactici BA28 on Helicobacter pylori causing peptic ulcer in C57BL/6 mice models.

Probiotic lactic acid bacteria are being proposed to cure peptic ulcers by reducing colonization of Helicobacter pylori within the stomach mucosa and by eradicating already established infection. In lieu of that, in vitro inhibitory activity of pediocin-producing probiotic Pediococcus acidilactici BA28 was evaluated against H. pylori by growth inhibition assays. Further, chronic gastritis was first induced in two groups of C57BL/6 mice by orogastric inoculation with H. pylori with polyethylene catheter, and probiotic P. acidilactici BA28 was orally administered to study the eradication and cure of peptic ulcer disease. H. pylori and P. acidilactici BA28 were detected in gastric biopsy and fecal samples of mice, respectively. A probiotic treatment with P. acidilactici BA28, which is able to eliminate H. pylori infection and could reverse peptic ulcer disease, is being suggested as a co-adjustment with conventional antibiotic treatment. The study provided an evidence of controlling peptic ulcer disease, by diet mod

HANS SELYE AND THE STRESS RESPONSE: FROM "THE FIRST MEDIATOR" TO THE IDENTIFICATION OF THE HYPOTHALAMIC CORTICOTROPIN-RELEASING FACTOR.

Selye pioneered the stress concept that is ingrained in the vocabulary of daily life. This was originally build on experimental observations that divers noxious agents can trigger a similar triad of endocrine (adrenal enlargement), immune (involution of thymus) and gut (gastric erosion formation) responses as reported in a letter to Nature in 1936. Subsequently, he articulated the underlying mechanisms and hypothesized the existence of a "first mediator" in the hypothalamus able to orchestrate this bodily changes. However he took two generations to identify this mediator. The Nobel Laureate, Roger Guillemin, a former Selye's PhD student, demonstrated in 1955 the existence of a hypothalamic factor that elicited adrenocorticotropic hormone release from the rat pituitary and named it corticotropin releasing factor (CRF). In 1981, Wylie Vale, a former Guillemin's Ph Student, characterized CRF as 41 amino acid and cloned the CRF1 and CRF2 receptors. This paves the way to experimental studies establishing that the activation of the CRF signaling pathways in the brain plays a key role in mediating the stress-related endocrine, behavioral, autonomic and visceral responses. The unraveling of the biochemical coding of stress is rooted in Selye legacy continues to have increasing impact on the scientific community.

In vivo sedative and gastroprotective activities of Salvia plebeia extract and its composition of polyphenols.

Animal experiments were performed to develop Salvia plebeia (Labiatae) as a medicinal herb with sedative and gastroprotective activities; the former activity was measured using a pentobarbital-induced assay and the latter activity was measured in two gastric lesion-induced assays (HCl/EtOH-induced and indomethacin/bethanechol-induced assays) in mice. The MeOH extract and its EtOAc fraction were effective, although the former was less active than the latter. Rosmarinic acid (RA) isolated from S. plebeia was active in the same method at 10 and 20 mg/kg (p.o.). HPLC quantification demonstrated that RA comprised the largest proportion (28.5% of the MeOH extract, 33.0% of EtOAc extract; 4.46% of dry weight) of S. plebeia. The contents of five other compounds were much less than that of RA, although the contents of the three glycosides, 6-hydroxyluteolin 7-O-glucoside (0.28% of dry weight), cynaroside (0.35%) and nepitrin (0.43%) were higher than those of the two aglycones, quercetin (0.024%) and eupatilin (0.058%). The HPLC method was validated in terms of linearity, precision, accuracy and reproducibility. These results suggest that the main polyphenol, RA, plays a major role in the sedative and gastroprotective effects of S. plebeia.

Factors modulating the outcome of treatment for the eradication of Helicobacter pylori infection.

A group of 180 H. pylori culture positive dyspeptic patients (64 patients with peptic ulcer, PU) completed a 2-week treatment with omeprazole, amoxicillin and metronidazole and underwent endoscopy again 6-8 weeks after the end of therapy. One hundred and twenty-four patients (68.8%) were successfully treated. Factors increasing the rates of eradication were the presence of PU (p=0.007) and anti-CagA serum antibodies (p=0.003). Factors negatively modulating eradication were the presence of coccoid forms (p=0.0008) and metronidazole-resistant strains (p=0.001); degrees of histological gastritis had no significant effect on eradication rates. Microscopic examination of smeared biopsies for the detection of the coccoid morphoytpe of H. pylori may help avoiding therapeutic failures.

Pharmacological mechanisms underlying gastroprotective activities of the fractions obtained from Polygonum minus in Sprague Dawley rats.

The leaves of Polygonum minus were fractionated using an eluting solvent to evaluate the pharmacological mechanisms underlying the anti-ulcerogenic activity of P. minus. Different P. minus fractions were obtained and evaluated for their ulcer preventing capabilities using the ethanol induction method. In this study, Sprague Dawley rats weighing 150-200 g were used. Different parameters were estimated to identify the active fraction underlying the mechanism of the gastroprotective action of P. minus: the gastric mucus barrier, as well as superoxide dismutase, total hexosamine, and prostaglandin synthesis. Amongst the five fractions from the ethanolic extract of P. minus, the ethyl acetate:methanol 1:1 v/v fraction (F2) significantly (p < 0.005) exhibited better inhibition of ulcer lesions in a dose-dependent manner. In addition, rats pre-treated with F2 showed a significant elevation in superoxide dismutase (SOD), hexosamine and PGE2 levels in the stomach wall mucosa in a dose-dependent matter. Based on these results, the ethyl acetate:methanol 1:1 v/v fraction was considered to be the best fraction for mucous protection in the ethanol induction model. The mechanisms underlying this protection were attributed to the synthesis of antioxidants and PGE2.

Endoscopic topical application of Ankaferd Blood Stopper® in gastrointestinal bleeding.

AIM: This was a prospective study investigating the efficacy of Ankaferd Blood Stopper(®) (ABS), an herbal preparation, in patients with upper gastrointestinal (UGI) bleeding. MATERIALS AND METHODS: A total of 30 patients (22 male, 8 female) who had UGI bleeding (with differing causes) were included in the study. ABS was used to stop the bleeding. RESULTS: Primary hemostasis was achieved in 26 of the 30 cases. CONCLUSIONS: ABS is an effective and safe agent to use in patients with UGI bleeding.

Evaluation of dextran-flufenamic acid ester as a polymeric colon-specific prodrug of flufenamic acid, an anti-inflammatory drug, for chronotherapy.

Dextran-flufenamic acid ester (Dex-FFA) with varied degree of substitution (DS) was prepared by imidazolide method. Dex-FFA was stable in pH 1.2 or pH 6.8 buffer. The depolymerization degree of Dex-FFA by dextranase decreased as DS increased. Dex-FFA with DS of 13 or 20 released FFA up to 70% or 21% of the dose, respectively, on 24 h-incubation with the 10% cecal contents. FFA was liberated up to 29% of the dose on 24 h-incubation of dextranase pre-treated Dex-FFA with the homogenates of the upper intestine, whereas no FFA was detected devoid of dextranse-pretreatment. Upon oral administration of Dex-FFA (DS 13, 20 mg equivalent of FFA/kg) or FFA (10 mg/kg) to rats, t(max) for FFA with Dex-FFA administration delayed approximately 6 h compared with that of free FFA administration, while C(max) for FFA was similar. The plasma level for FFA became greater around 6 h after administration of Dex-FFA than free FFA and it was maintained throughout the period of 24 h-experiment. Dex-FFA markedly attenuated gastric ulcerogenicity of FFA. Taken together, Dex-FFA could be useful as a colon-specific prodrug which possesses anti-inflammatory properties and offers opportunities as a chronotherapeutic approach for the treatment of arthritis.

[Therapeutic and preventive effects of sulfate-chloride-sodium mineral water in experimental peptic ulcer].

Healthy animals and individuals with experimental peptic ulcer were used to evaluate effect of weakly mineralized Tselitel'nitsa water on hormonal control of metabolic and trophic reactions. The mineral water was found to activate regulation of carbohydrate metabolism by insulin and cortisol due to the formation of adaptive reactions during a course of its therapeutic intake. The mineral water promoted realization of trophic effects of gastrin and insulin in animals with peptic ulcer the size of which significantly decreased. A preventive course of therapy with the mineral water was shown to enhance resistance of experimental animals to stressful factors.

[Effect of yiqi huoxue formula on healing quality and recurrence rate of peptic ulcer].

OBJECTIVE: To study the effect of yiqi huoxue formula (YHF) on healing and recurrence of peptic ulcer. METHODS: Adopting randomized and controlled principle, the 46 patients with active peptic ulcer were randomly allocated into the treated group and the control group, they received respectively the treatment of YHF + Omeprazole and Omeprazole alone for 5 weeks. If exhibiting positive Hp, the Trigeminy one-week eradicating treatment, using Omeprazole, Clarithromycin and Amoxicillin, was applied firstly, after then, followed with the prescriptive treatment. Gastroscopy was performed before and after treatment to assess the status of Hp eradicating and the endoscopic and histological maturity of regenerated mucosa. Meanwhile, the changes of vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF) levels were detected with ELISA. Patients with ulcer healed were followed up for 6 months to observe the condition of recurrence. RESULTS: The percentage of Sc phase maturity and excellent histological maturity of regenerated mucosa obtained in the treated group were more than those in the control group respectively (P < 0.05), and levels of VEGF and bFGF increased significantly in the treated group after treatment (P < 0.05). But the difference of ulcer recurrence rate between the two groups in the 6-month follow-up study showed no statistically significance. However, the recurrence rate in patients with excellent histological maturity of regenerated mucosa was lower than that with good histological maturity (P < 0.05); and it was decreasing along with the progressing of regenerated mucosa endoscopic maturity, i.e., Sc < Sb < Sa (P < 0.01). CONCLUSION: YHF can improve the quality of ulcer healing, and its mechanism is possibly related to the increase of VEGF and bFGF expressions. The higher the quality of ulcer healing, the lower the recurrence rate.

Cerebral venous thrombosis associated with iron deficiency anemia.

A 55-year-old man presented with generalized seizures and postictal left hemiparesis. Computed tomography scanning of his head showed a low density area in the right frontal lobe. Cerebral angiography demonstrated a partial defect in the superior sagittal sinus and cortical veins, indicating the presence of cerebral venous thrombosis. He had bleeding from a peptic ulcer and the laboratory data revealed iron deficiency anemia concomitant with an elevation of D-dimer and thrombin-antithrombin III complex (TAT). After the anemia resolved with the treatment of the peptic ulcer and iron supplementation, the TAT and D-dimer levels were normalized, and the occluded veins were recanalized. In a cerebral venous thrombosis associated with iron deficiency anemia, treatment for the anemia may improve hypercoagulable state without antithrombotic therapy, although the long-term monitoring of TAT and D-dimer levels is required.

Effect of aqueous extract of neem (Azadirachta indica) leaves on offensive and diffensive gastric mucosal factors in rats.

Standardized aqueous extract of Neem (Azadirachta indica) leaves (AIE) has been reported to show both ulcer protective and ulcer healing effects in normal as well as in diabetic rats. To study the mechanism of its ulcer protective/healing actions, effects of AIE (500 mg/ kg) was studied on various parameters of offensive acid-pepsin secretion in 4 hr pylorus ligation, pentagastrin (PENTA, 5 microg/kg/hr)-stimulated acid secretion and gastric mucosal proton pump activity and defensive mucin secretion including life span of gastric mucosal cells in rats. AIE was found to inhibit acid-pepsin secretion in 4 hr pylorus ligated rats. Continuous infusion of PENTA significantly increased the acid secretion after 30 to 180 min or in the total 3 hr acid secretion in rat stomach perfusate while, AIE pretreatment significantly decreased them. AIE inhibited the rat gastric mucosal proton pump activity and the effect was comparable with that of omeprazole (OMZ). Further, AIE did not show any effect on mucin secretion though it enhanced life span of mucosal cells as evidenced by a decrease in cell shedding in the gastric juice. Thus, our present data suggest that the ulcer protective activity of AIE may be due to its anti-secretary and proton pump inhibitory activity rather than on defensive mucin secretion. Further, acute as well as sub acute toxicity studies have indicated no mortality with 2.5 g/kg dose of AIE in mice and no significant alterations in body or tissues weight, food and water intake, haematological profile and various liver and kidney function tests in rats when treated for 28 days with 1 g/kg dose of AIE.

Protective effects of nedocromil sodium and sodium cromoglycate on gastroduodenal ulcers: a comparative study in rats.

Stabilization of mast cells plays a key mechanism to protect gastrointestinal tract from injury. This study presents a comparative evaluation of mast cell stabilizers nedocromil sodium (NDS) and sodium cromoglycate (SCG) in experimental gastric and duodenal ulcers in rats. Wistar rats of either sex were used in this study. Both NDS and SCG, in the doses of 10, 30 and 100 mg/kg were given intraperitoneally for gastric secretion studies and by gavage for antiulcer studies. Acid secretion studies were undertaken in pylorus-ligated rats. Gastric lesions were induced by water immersion restraint stress (WIRS), indomethacin and ethanol whereas duodenal ulcers were produced by cysteamine. The level of glutathione (GSH) and gastric wall mucus were measured in glandular stomach of rats following ethanol-induced gastric lesions. SCG was more effective than NDS in preventing WIRS- and indomethacin-induced gastric lesions whereas reverse was true in ethanol- and cysteamine-induced ulcers. All the 3 doses of SCG offered almost equal protection against WIRS-induced gastric lesions whereas only medium and high dose of NDS provided significant protection in this model of ulcer. NDS significantly inhibited cysteamine-induced duodenal ulcers whereas SCG failed to do so. Pretreatment with NDS or SCG significantly and dose-dependently protected gastric mucosa against ethanol-induced injury, while the former drug appeared to be more effective. The cytoprotective effects of these two drugs were accompanied by the attenuation of ethanol-induced depletion of gastric wall mucus and GSH. The differential effects of NDS and SCG against various gastric lesions rationalize the possible benefits of a combined therapy (NDS+SCG) for the treatment of complex gastroduodenal ulcers.

Antioxidant activity of hydroalcoholic leaf extract of ocimum sanctum in animal models of peptic ulcer.

In the present study, a hydroalcoholic extract of ocimum sanctum leaves has been investigated for its antioxidant activity in animal models of peptic ulcer with the aim of exploring a possible correlation between its antioxidant and antiulcer activities. Gastric ulcers were produced in rats by ethanol treatment and pyloric ligation whereas duodenal ulcers were produced in guinea pigs by histamine treatment. The animals were divided into six groups of six animals each in all these three models of peptic ulcer. Group I served as diseased control in which distilled water (10 ml/kg) orally was administered as placebo. Group II, III and IV received the test drug (ocimum sanctum leaf extract) in doses of 50 mg/kg, 100 mg/kg and 200 mg/ kg respectively orally once daily for 7 days. Group V was administered ranitidine (10 mg/kg orally) once daily for 7 days and served as standard for comparison. Group VI consisted of healthy control for baseline malondialdehyde (MDA) and superoxide dismutase (SOD) levels. The antioxidant activity was by evaluated estimating plasma MDA in ethanol treated rats and histamine treated guinea pigs and estimating SOD in pyloric ligated rats and histamine treated guinea pigs. In ethanol treated rats, ocimum sanctum leaf extract (100 mg/kg & 200 mg/kg) significantly decreased the levels of MDA to 2.45 +/- 0.29 nmole/ml and 2.40 +/- 0.14 nmole/ml respectively in comparison to 4.87 +/- 0.06 in the diseased control. Similarly, in the histamine treated guinea pig group, the same doses of the extract significantly lowered the levels of MDA to 2.45 +/- 0.12 nmole/ml and 2.37 +/- 0.16 nmole/ml respectively when compared to 4.66 +/- 0.11 in the diseased control. The extract (100 mg/kg & 200 mg/ kg) also increased the levels of SOD in pyloric ligated rats to 1.78 +/- 0.12 U/ml and 1.89 +/- 0.08 U/ml respectively when compared to 1.29 +/- 0.06 U/ml in the diseased control. In the histamine treated guinea pig group also, the same doses of the extract produced a rise in the SOD levels to 2.10 +/- 0.11 U/ml and 2.20 +/- 0.14 U/ml respectively when compared to 1.32 +/- 0.07 in the diseased control. Since lowered levels of MDA and increased levels of SOD signify antioxidant activity, the antiulcer activity of ocimum sanctum might be due to this mechanism.