Kaïs Rtibi

Antidiarrheal and antioxidant activities of chamomile (Matricaria recutita L.) decoction extract in rats

ETHNOPHARMACOLOGICAL RELEVANCE Matricaria recutita L. (Chamomile) has been widely used in the Tunisian traditional medicine for the treatment of digestive system disorders. The present work aims to investigate the protective effects of chamomile decoction extract (CDE) against castor oil-induced diarrhea and oxidative stress in rats. METHODS The antidiarrheal activity was evaluated using castor oil-induced diarrhea method. In this respect, rats were divided into six groups: Control, Castor oil, Castor oil+Loperamide (LOP) and Castor oil+various doses of CDE. Animals were per orally (p.o.) pre-treated with CDE during 1h and intoxicated for 2 or 4h by acute oral administration of castor oil. RESULTS Our results showed that CDE produced a significant dose-dependent protection against castor oil-induced diarrhea and intestinal fluid accumulation. On the other hand, we showed that diarrhea was accompagned by an oxidative stress status assessed by an increase of malondialdehyde (MDA) level and depletion of antioxidant enzyme activities as superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx). Castor oil also increased gastric and intestinal mucosa hydrogen peroxide (H2O2) and free iron levels. Importantly, we showed that chamomile pre-treatment abrogated all these biochemical alterations. CONCLUSION These findings suggested that chamomile extract had a potent antidiarrheal and antioxidant properties in rats confirming their use in traditional medicine.

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

We 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.

Carob pods (Ceratonia siliqua L.) inhibit human neutrophils myeloperoxidase and in vitro ROS-scavenging activity

Natural antioxidants such as phenolic compounds protect cells against the damaging effects of reactive oxygen species (ROS). In this study, we investigated the effect of carob pods aqueous extract (CPAE) on the reactive oxygen species (ROS) production by human neutrophils, myeloperoxidase (MPO) activity and expression as well as lactoferrin and NADPH oxidase phosphorylation. Neutrophils were isolated from whole human blood using the ficoll–dextran method and ROS generation was measured by luminol-amplified chemiluminescence. Superoxide anion generation was detected by chemiluminescence using the lucigenin method. H2O2 was detected by the chemiluminescence assay. MPO activity was measured by the tetramethylbenzidine oxidation method. Western blotting analysis was used to determine the MPO and lactoferrin as well as P47phox–Ser-328 phosphorylation. The use of HPLC technique revealed the identification of many phenolic compounds in carob pods with pyrogallol as the main compound in the pulp and tannic acid in the seeds. We also found that CPAE inhibits luminol-amplified chemiluminescence in human neutrophils stimulated by PMA and that it is able to scavenge superoxide anion and hydrogen peroxide. Carob extract significantly reduces MPO activity and expression. More importantly, CPAE inhibits PMA-induced p47phox phosphorylation on Ser328 as well as lactoferrin release by neutrophils in a concentration-dependent manner. The effects are generally more marked for the seeds compared to the pulp. In conclusion, we suggest in the present study that Carob pods (Ceratonia siliqua L.) inhibit human neutrophils myeloperoxidase and in vitro ROS production.

Effects of Dates Pulp Extract and Palm Sap (Phoenix dactylifera L.) on Gastrointestinal Transit Activity in Healthy Rats

The current study was performed to measure the chemical composition and the effects of dates pulp extract and palm sap on gastrointestinal transit (GIT) activity in healthy adult rats. In this respect, male Wistar rats fasted for 24 hours were used and received per orally (p.o.) sodium chloride (NaCl) (0,9%) (control group) or various doses of dates pulp extract (150 and 300 mg/kg, body weight [b.w.]) and palm sap (0.4 and 4 mL/kg, b.w.). Two other groups of rats (batch tests) received, respectively, clonidine (an alpha-2 adrenergic agonist, 1 mg/kg, b.w.) and yohimbine (an alpha-2 adrenergic antagonist, 2mg/kg, b.w.). Chemical analysis showed that the dates pulp extract is more rich in sugars and minerals, especially potassium and sucrose, as compared with palm sap composition. On the other hand, in vivo study showed that the aqueous dates pulp extract significantly, and dose dependently, increased the GIT activity while the palm sap slightly increased it. Moreover, a converse effect has been observed using clonidine (decreased 68%) and yohimbine (increased 33%) on the GIT activity. These findings suggest that dates pulp extract and palm sap have a stimulating effect on GIT activity in rats and confirm their use in traditional Tunisian medicine for the treatment of constipation.

Effects of aqueous extracts from Ceratonia siliqua L. pods on small intestinal motility in rats and jejunal permeability in mice

The current study was performed to assess the effects of carob pod aqueous extracts (CPAE, pulp, seeds or mixture) on gastrointestinal transit (GIT) and intestinal epithelium permeability. In this aspect, male rats fasted for 16 hours were used and given by oral administration NaCl (0.9%, control group) or various doses of CPAE (50, 100 and 200 mg kg−1, b.w.). Two other groups of rats (batch tests) received clonidine (an alpha-2 adrenergic agonist, 1 mg kg−1) or yohimbine (an alpha-2 adrenergic antagonist, 2 mg kg−1). Two hours later, all animals were given a test meal containing charcoal and gum arabic in water. 30 minutes later, rats were anesthetized, a laparotomy was performed and the distance traveled by the meal compared to the total length of the small intestine was measured. Regarding the effect of CPAE on diarrhoea, the extract was administered orally to three groups of rats (ten in each group). Two other groups received normal saline (10 mL kg−1) and loperamide (10 mg kg−1) as a negative and standard group. Compared with the control group, the animals treated with the CPAE of pulp, seeds or a mixture (50% pulp and 50% seeds) of mature carob, showed a significant increase (3–25%) of GIT in a dose-dependent manner. By contrast, the CPAE of immature carob pods significantly and dose dependently decreased (3–19%) the GIT and diarrhoea (66–87%). However, clonidine and yohimbine respectively decreased (58%) and increased (30%) the GIT. More importantly, using the Ussing chamber system, we found that aqueous extracts of mature and immature carob pods significantly and dose-dependently increased or decreased intestinal epithelium permeability. The results indicate that carob possesses significant laxative and anti-diarrheal activities due to its opposite effects both on gastrointestinal propulsion and permeability. These findings confirm that the degree of maturity of carob characterized by a different phytochemical composition may be responsible for these actions.

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

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.

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

Abstract Context 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 6 h. 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.

Irinotecan chemotherapy-induced intestinal oxidative stress: Underlying causes of disturbed mucosal water and electrolyte transport

Irinotecan, a chemotherapy drug, can cause acute diarrhea immediately after administration. Hence, the present study was designed to investigate the gastrointestinal (GI) disturbances after an intraperitoneal (IP) administration of irinotecan in rats.Twenty Wistar rats were separated into two groups of ten. Group A was considered as a control group (NaCl, 0.9%). Group B was treated with irinotecan at a single dose of 200mgkg-1. The rats were observed for defecation. For the enteropooling test, the animals were sacrificed by decapitation 1h post-treatment. The small intestine was excised and the fluid was milked into a graduated tube and the volume was measured. After centrifugation of intraluminal liquid, the electrolyte concentrations in the supernatants were measured by flame photometry. Oxidative stress parameters and intracellular mediators as well as the MPO activity were determined in intestinal mucosa by colorimetric methods Our result indicated that irinotecan produces an intestinal fluid accumulation and electrolyte transport disorders. These effects were associated with augmented intestinal MPO activity and oxidative damage such as an elevation of MDA production and a depletion of enzymatic and non-enzymatic antioxidants. More than that, drug administration provoked intracellular mediator disturbances such as a free iron, H2O2 and calcium levels. In conclusion, the data suggest that irinotecan caused a gastrointestinal stress via oxidative stress-induced disturbances in water and electrolyte transport in the intestinal mucosa in rats.

Postnatal development and behavior effects of in-utero exposure of rats to radiofrequency waves emitted from conventional WiFi devices

The present work investigated the effects of prenatal exposure to radiofrequency waves of conventional WiFi devices on postnatal development and behavior of rat offspring. Ten Wistar albino pregnant rats were randomly assigned to two groups (n=5). The experimental group was exposed to a 2.45GHz WiFi signal for 2h a day throughout gestation period. Control females were subjected to the same conditions as treated group without applying WiFi radiations. After delivery, the offspring was tested for physical and neurodevelopment during its 17 postnatal days (PND), then for anxiety (PND 28) and motricity (PND 40-43), as well as for cerebral oxidative stress response and cholinesterase activity in brain and serum (PND 28 and 43). Our main results showed that the in-utero WiFi exposure impaired offspring neurodevelopment during the first seventeen postnatal days without altering emotional and motor behavior at adult age. Besides, prenatal WiFi exposure induced cerebral oxidative stress imbalance (increase in malondialdehyde level (MDA) and hydrogen peroxide (H2O2) levels and decrease in catalase (CAT) and superoxide dismutase (SOD) activities) at 28 but not 43days old, also the exposure affected acethylcolinesterase activity at both cerebral and seric levels. Thus, the current study revealed that maternal exposure to WiFi radiofrequencies led to various adverse neurological effects in the offspring by affecting neurodevelopment, cerebral stress equilibrium and cholinesterase activity.

Chemical constituents and pharmacological actions of carob pods and leaves (Ceratonia siliqua L.) on the gastrointestinal tract: A review

Carob tree, Ceratonia siliqua L., is a medicinal plant used in Tunisian traditional medicine for the treatment of the gastro-intestinal (GI) disorders. In this respect, a relatively large number of scientific publications on the carob tree have been published in recent years. Therefore, the present review was aimed to analyze the traditional uses, phytochemical constituents and pharmacological activities of Ceratonia siliqua on the GI tract. Indeed, previous investigations on the carob pods and leaves have revealed the presence of a number of compounds including high amounts of carbohydrates, dietary fibers, minerals, polyphenols, flavonoids and low amounts of protein and lipids. This plant possesses anti-inflammatory, antimicrobial, anti-diarrheique, antioxidant, anti-ulcer, anti-constipation and anti-absorptive of glucose activities in the gastrointestinal tract. Based on the chemical and pharmacological characteristics of C. siliqua, we concluded that this species has beneficial preventive and therapeutic properties, especially, in digestive tract.