The Role of Increased Gastric Acid Secretion and Reactive Oxygen Species in the Pathophysiology of Reflux Esophagitis

Gastroesophageal reflux (GER) disease is a chronic disease characterized by the recurrent ascension of some of the gastric contents in the esophagus. Indeed, gastric acid secreted by parietal cells and the gastric pepsin activity, but not the intestinal alkaline content, are the most important pathogenic factors of GER. Several pathophysiological mechanisms are involved, the most important of which is the imbalance of the redox state of the esophageal tissue. Indeed, several studies have shown that reflux esophagitis is mediated by oxygen-derived free radicals. In this chapter, we describe the pathophysiology and important pathways, especially acid gastric contents and reactive oxygen species involved in pathology of GER

Protective effects of Artemisia campestris extract against gastric acid reflux-induced esophageal mucosa injuries.

International audienceArtemisia campestris L. has been widely used in alternative medicine to treat digestive system diseases, particularly gastroesophageal disorders. In the present investigation, we studied the putative protective effect of Artemisia campestris aqueous extract (ACAE) against gastro-esophageal reflux (GER)-induced esophagitis in rats. The experimental ophagitis was induced by the ligation of the pylorus as well as the junction between the forestomach and the corpus. We firstly found that ACAE administration at 100, 200 and 400 mg/kg, b.w., p.o. significantly protected GER-induced macroscopic and histological injuries in the esophagus tissue. Our extract also counteracted GER-induced esophagus lipoperoxidation, restored the depletion of antioxidant enzyme activities such as superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx) as well as thiol groups levels. Furthermore, we showed that acute GER provoked an increase in esophagus mucosa hydrogen peroxide (H2O2), free iron and calcium levels, whereas ACAE treatment reversed all GER-induced intracellular mediators' disturbances. In conclusion, we suggested that ACAE had potent protective effects against esophagitis due, in part, to its antioxidant properties as well as its opposite effect on some intracellular mediators

Ameliorative and antioxidant effects of myrtle berry seed (Myrtus communis) extract during reflux-induced esophagitis in rats

International audienceContext Myrtle, Myrtus communis L. (Myrtaceae), is a medicinal plant well known for its richness in phenolic compounds and its beneficial effects for the treatment of gastrointestinal disorders.Objective In the present work, the protective effect of the myrtle berry seed aqueous extract (MBSAE) against esophageal reflux (ER)-induced damage in esophagus mucosa as well as the mechanisms implicated was determined.Materials and methods In this respect, adult male Wistar rats were used and divided into seven groups: Control, ER, ER+various doses of MBSAE, ER+famotidine or ER+gallic acid. The ER was induced and animals were per orally (p.o.) treated with MBSAE or reference molecules during 6h. The phytochemical screening was determined using colourimetric analysis.Results MBSAE is rich in total polyphenols and anthocyanins and exhibited an important in vitro antioxidant activity. In vivo, we firstly found that ER led to marked macroscopic and histopathological changes in esophagus. The results showed, also, that the ER was accompanied by a state of oxidative stress as assessed by an increase of lipid peroxidation, a decrease of the sulphhydryl groups and glutathione levels, as well as antioxidant enzyme activities depletion. MBSAE abrogated all morphological, histopathological and biochemical alterations. We showed also that ER increased esophageal calcium, hydrogen peroxide (H2O2) and free iron levels while MBSAE treatment protected against intracellular mediators deregulation.Conclusion Our data suggest that MBSAE exerted a potential protective effect against ER-induced damage in rat esophagus, at least in part, due to its antioxidant properties

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

International audienceThis 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 mu g/mL) and superoxide anion (IC50 = 200.24 mu g/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

Antidiarrhoeal, antimicrobial and antioxidant effects of myrtle berries ( Myrtus communis L.) seeds extract

International audienceOBJECTIVES: The present study was carried out to determine the antidiarrheal effects of myrtle (Myrtus communis L.) berries seeds aqueous extract (MBSAE) from Tunisia as well as the involvement of its antimicrobial and antioxidant properties in such protection.METHODS: Adult male wistar rats were used and divided into six groups of ten each: control, Castor oil, Castor oil + Loperamide and Castor oil + various doses of MBSAE. Animals were per orally (p.o.) pre-treated with MBSAE for one hour and intoxicated by castor oil acute oral administration.KEY FINDINGS: Our results demonstrated that the MBSAE is rich in total and condensed tannins and exhibited a broad spectrum of antibacterial activity. In vivo, we found that MBSAE administration induced a significant dose-dependent protection against diarrhoea and intestinal fluid accumulation. Castor oil-induced intestinal hypersecretion was accompanied by an oxidative stress status in the intestine. More importantly, we showed that acute diarrhoea was accompanied by an increase in intestinal mucosa hydrogen peroxide (H2 O2 ), calcium and free iron levels while MBSAE pre-treatment reversed all castor oil-induced intracellular mediators disturbances.CONCLUSIONS: We suggest that MBSAE had a potent protective effects against castor oil-induced acute diarrhoea due in part to its antioxidant and antimicrobial properties

Myrtle berry seed aqueous extract inhibits human neutrophil myeloperoxidase in vitro and attenuates acetic acid-induced ulcerative colitis in rats

International audienceWe aimed in the present study to investigate the protective effect of a myrtle (Myrtus communis L.) berry seed aqueous extract (MBSAE) on acetic acid (AA)-induced colitis in rats as well as the mechanism implicated in this coli-protection. The use of the LC/MS technique allowed us to identify 18 phenolic compounds in the MBSAE. Secondly, we found that the MBSAE inhibited the luminol-amplified chemiluminescence of resting neutrophils and N-formyl-methionylleucyl-phenylalanine (fMLF) or phorbolmyristate acetate (PMA) stimulated neutrophils in a dose-dependent manner. The MBSAE had no effect on superoxide anions, but it inhibited H2O2 production in the cell free system stimulated with horseradish peroxidase (HRPO) and MPO release from the neutrophils. In vivo, the pre-treatment of rats with sulfasalazine (100 mg kg(-1)) and the MBSAE (25, 50, and 100 mg kg(-1)) significantly reduced AA-induced colonic mucosa lesions as well as histopathological changes. The MBSAE counteracted AA-induced lipid peroxidation and the depletion of the activity of antioxidant enzymes such as superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx). We also found that the myrtle extract inhibited the increase of the plasma scavenging activity (PSA) and preserved the content of non-enzymatic antioxidants such as sulfhydryl groups (-SH) and reduced glutathione (GSH). More importantly, acetic acid administration increased colonic hydrogen peroxide (H2O2), free iron and calcium levels, while the MBSAE pre-treatment reversed all intracellular mediator perturbations. In conclusion, our data suggests that the MBSAE exerted a potential protective effect against AA-induced injury and oxidative stress in the rat colon. This coli-protection might be related in part to its antioxidant and ROS scavenging activities or by negatively regulating Fenton reaction components such as H2O2 and free iron, which are known to lead to cytotoxicity mediated by intracellular calcium deregulation

Protective effect of Artemisia campestris extract against aspirin-induced gastric lesions and oxidative stress in rat

International audienceThe present study aims at evaluating the antiulcer and antioxidant effect of Artemisia campestris aqueous extract (ACAE) as well as the mechanism of action involved in such gastroprotection. The use of LC/MS allowed the identification of 11 phenolic compounds and the colorimetric analysis demonstrated that the ACAE exhibited an important in vitro antioxidant activity. We first showed that in vivo ACAE protected against macroscopic and histological changes induced by aspirin in stomach mucosa. Aspirin administration was accompanied by an oxidative stress status assessed by an increase in malondialdehyde (MDA) level, a decrease in the content of sulfhydryl -(SH) groups and a depletion of antioxidant enzyme activities such as superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx). Pre-treatment with ACAE protected against aspirin-induced gastric oxidative stress. More importantly, aspirin administration increased plasma and tissue hydrogen peroxide (H2O2), free iron and calcium levels, while the ACAE pre-treatment reversed all the effects of aspirin-induced intracellular mediators. In conclusion, we suggest that Artemisia campestris aqueous extract has potent antiulcer and antioxidant properties. This gastroprotection offered by ACAE might be related partly to the safety of sulfhydryl group as well as its opposite effect on some intracellular mediators such as hydrogen peroxide, free iron and calcium