Anti-ulcer effect of tea catechin in rats

Therapeutic potentialities of green tea (Camellia sinensis) in ischemic stroke: biochemical and molecular evidence

Ischemic stroke is a leading cause of disability and death in patients. Despite considerable recent advances in the treatment of ischemic stroke, only a limited number of effective neuroprotective agents are available for stroke. Green tea (Camellia sinensis) is a popular herbal plant, and numerous studies have indicated its health benefits for several diseases. Green tea is of interest due to its high content of catechin derivatives, including epicatechin, gallocatechin, epicatechin gallate, epigallocatechin, and epigallocatechin-3-gallate. This review tried to develop a feasible background for the potential effects of green tea and its bioactive derivatives concerning protection against ischemic stroke. Green tea's antioxidants, anti-inflammatory, anti-apoptotic, and neuroprotective effects are believed to be efficacious in stroke treatment. Evidence supports the idea that green tea can be used to assist in treating ischemic stroke.

Genus Parkia: Phytochemical, Medicinal Uses, and Pharmacological Properties

The genus Parkia (Fabaceae, Subfamily, Mimosoideae) comprises about 34 species of mostly evergreen trees widely distributed across neotropics, Asia, and Africa. This review aims to provide an overview of the current status of the species from the genus Parkia in terms of its relationship between its phytochemistry and medical uses. Comprehensive information on Parkia species was retrieved from electronic databases, which were Web of Science, ScienceDirect, PubMed, and Google Scholar. This review identified nine species from genus Parkia with properties of medicinal use. They are used traditionally to treat several ailments, such as diabetes, diarrhea, wounds, hypertension, cough, chronic piles, conjunctivitis, and measles. The most common species studied are P. biglobosa, P. speciosa, P. javanica, P. bicolor, P. biglandulosa, P. filicoidea, and P. clappertoniana. A considerable number of secondary metabolites, such as terpenoids, phenolic acids, flavonoids (aglycone and glycosides), and numerous volatile compounds have been identified in this genus, which are responsible for their diverse pharmacological activities. Their extracts, pure compounds and seed lectins have been reported for their anticancer, antimicrobial, antihypertensive, antiulcer, antidiabetic, anti-inflammatory, antioxidant, antimalarial, hepatoprotective, and antidiarrheal activities. The information gathered in this review might be of help for future studies in terms of the current knowledge on the link between the phytochemical components and medicinal uses. This could facilitate more discoveries on its potentials particularly in the pharmacological characteristics and potential to be developed into modern medicines.

Gastroprotective effects of irsogladine maleate on ethanol/hydrochloric acid induced gastric ulcers in mice

BACKGROUND/AIMS

This study was conducted to investigate the inhibitory effect of irsogladine maleate (IM) on gastric ulcers induced by ethanol and hydrochloric acid (HCl).

METHODS

Mice were pretreated with IM for 1 hours before ulcer induction. Gastric ulcers were induced by oral administration of an ethanol/HCl mixture. To clarify the action mechanism of IM, the roles of 3'5'-cyclic adenosine monophosphate (cAMP), nitric oxide (NO), adenosine triphosphate-sensitive potassium (KATP) channels, prostaglandins and transient receptor potential cation channel subfamily V member 1 (TRPV1) were investigated, and lipid peroxidation in the stomach of IM-treated and -untreated animals was also measured.

RESULTS

IM significantly reduced the extent of ethanol/HCl mixture-induced gastric ulceration. It exhibited dose-related gastroprotection against the ethanol/ HCl-induced lesions, while pretreatment with glibenclamide but not N(ω)-nitro- L-arginine methyl ester, reversed this action. While pretreatment with the TRPV1 antagonist capsazepine failed to effectively block the gastroprotective effect of IM, the non-selective cyclooxygenase inhibitor indomethacin almost abolished it. IM also decreased the level of thiobarbituric acid reactive substances.

CONCLUSION

We concluded that IM exhibited significant gastroprotective effects in an ethanol/HCl-induced ulcer model, which appear to be mediated, at least in part, by NO, cAMP, endogenous prostaglandins, KATP channel opening, activation of TRPV1 channels, and antioxidant properties.

Preventative and Therapeutic Potential of Flavonoids in Peptic Ulcers

Peptic ulcer disease is a common gastrointestinal tract disorder that affects up to 20% of the population of the world. Treatment of peptic ulcer remains challenging due to the limited effectiveness and severe side effects of the currently available drugs. Hence, natural compounds, owing to their medicinal, ecological, and other safe properties, are becoming popular potential candidates in preventing and treating peptic ulcers. Flavonoids, the most abundant polyphenols in plants, exhibit gastroprotective effects against peptic ulcer both in vivo and in vitro. In this review, we summarized the anti-ulcer functions and mechanisms, and also the bioavailability, efficacy, and safety, of flavonoid monomers in the gastrointestinal tract. Flavonoids exerted cytoprotective and rehabilitative effects by not only strengthening defense factors, such as mucus and prostaglandins, but also protecting against potentially harmful factors via their antioxidative, anti-inflammatory, and antibacterial activities. Although controlled clinical studies are limited at present, flavonoids have shown a promising preventable and therapeutic potential in peptic ulcers.

Protective Role of Black Tea Flavonoids Against Ethanol-Induced Gastropathy via Matrix Metalloproteinase Pathway

Abstract

Tea polyphenols are known to prevent various ailments like cancer, atherosclerosis, hypertension and diabetes. Our study aimed at to decipher the gastroprotective effect of aqueous black tea extract (BTE) against ethanol-induced gastric damage and the role of BTE in modulating MMP-9 activity and expression, both in vivo and in vitro. The protective role of BTE was assessed in Sprague-Dawley rats after inducing damage with 70% ethanol. Human gastric adenocarcinoma cells (AGS) were treated with ethanol in ex vivo experiment. MMP-9 activity and expression were investigated through gelatin zymography and western blotting. Reactive oxygen species (ROS) generation was also studied by fluorescence spectroscopy and confocal microscopy, with or without treatment of BTE both in vivo and in vitro experiments. In addition, the effect of citric acid treated BTE (cBTE), which mimics lemon tea, was examined on ethanol-induced gastropathy. BTE exhibited antiulcer activity through reduction of glutathione depletion, lipid peroxidation, protein oxidation, ROS production and inflammatory cell infiltration in rat gastric tissues. In addition, BTE significantly inhibited synthesis and secretion of proMMP-9 both in vivo and in vitro. The mitochondrial enzymes succinate dehydrogenase and NADH oxidase in rat gastric tissues were downregulated by BTE while protecting gastric ulcer. Citric acid addition to BTE was observer to enrich the lead compound, catechin. Interestingly, cBTE showed higher anti-ulcer activity than the untreated one. BTE shows protective role against ethanol-induced gastric ulcer in rats through scavenging ROS and downregulating proMMP-9 activity. While cBTE shows better protection due to enrichment of catechin and removal of tannins in tea extract leading to enhanced inhibitory role on proMMP-9 activity and ROS production.

Graphical Abstract

Circulating Hypoxia Responsive microRNAs (HRMs) and Wound Healing Potentials of Green Tea in Diabetic and Nondiabetic Rat Models

Green tea (Camellia sinensis) has many biological activities and may promote diabetic wound healing by regulation of circulating hypoxia responsive microRNAs (HRMs) which triggers the wound repairing process in diabetic and nondiabetic wounds. Thus, in this study, the potential effects of green tea extract (GTE) on the expression of miRNAs; miR-424, miR-199a, miR-210, miR-21, and fibrogenitic markers; hydroxyproline (HPX), fibronectin (FN), and nitric oxide (NO) were evaluated in wounds of diabetic and nondiabetic rats. The animals were topically treated with vaseline, 0.6% GTE, and 5%w/w povidone iodine (standard control). HPX, FN, and NO levels and microRNAs, miR-424, miR-210, miR-199a, and miR-21, were estimated in wound tissues using colorimetric, immunoassay, and molecular PCR analysis. In vitro analysis was performed to estimate active constituents and their antioxidant activities in methanolic green teat extract (GTE). Wounds treated with green tea, a dose of 0.6, healed significantly earlier than those treated with standard vehicle and vaseline treated diabetic wounds. Higher expressions of HRMs, miR-199a, and miR-21, and lower expression of HRMs, miR-424 and miR-210, were significantly reported in tissues following treatment with green tea extract compared to standard control vehicle. The tissues also contained more collagen expressed as measures of HPX, FN, and NO and more angiogenesis, compared to wounds treated with standard control vehicle. Diabetic and nondiabetic wounds treated with green tea (0.6%) for three weeks had lesser scar width and greater re-epithelialization in shorter periods when compared to standard control vehicle. Expression of HRMs, miR-199a, miR-21, and HRMs and miR-424 and miR-210 correlated positively with HPX, fibronectin, NO, better scar formation, and tensile strength and negatively with diabetes. In addition to antidiabetic and antioxidant activities of green tea components, GTE showed angiogenesis promoting activity in diabetic wound healing. In conclusion, Camellia sinensis extracts in a dose of 0.6% significantly promote more collagen and fibronectin deposition with higher expression of NO, promoting angiogenesis process via molecular controlling of circulating hypoxia responsive microRNAs: miR-424, miR-210, miR-199a, and miR-21 in diabetic and nondiabetic wounds. Our results support a functional role of circulating hypoxia responsive microRNAs: miR-424, miR-210, miR-199a, and miR-21 as potential therapeutic targets in angiogenesis and vascular remodeling in diabetic wound healing.

Avocado seeds (Persea americana Mill.) prevents indomethacin-induced gastric ulcer in mice

The long-term use of anti-inflammatory drugs is the most common cause of gastric ulcer disease, one of the major gastrointestinal disorders affecting people worldwide. Persea americana Mill. (avocado) seed is a by-product generally discarded as waste, but can be used to treat gastric disorder due to its anti-inflammatory, antioxidant and antimicrobial activities. The aim of the present study was to evaluate the potential protective effects of the ethyl acetate fraction of avocado seeds (SEAP) extracts against indomethacin-induced gastric ulcer in mice. It was found that SEAP were effective in mitigating oxidative stress through a decrease on the oxidized products levels (reduction of 90% in lipid peroxidation in plasma) and increasing superoxide dismutase enzyme (SOD) activity (4.25-fold increase compared to the indomethacin group), also preventing the rise in ulcer and lesions areas (92% of protection) and histological changes induced by indomethacin. Chemical analysis using mass spectrometry by (-)-ESI-FT-ICR MS revealed the presence of (-)-epicatechin and (+)-catechin, confirmed by HPLC-DAD, and other important phenolic compounds in avocado seeds, such as caffeoylquinic acid, flavonoids, phenylpropanoids and tannins, substances that promote inhibition of pathways involved in gastric ulcer formation. Thus, avocado seeds extract may be a suitable natural source for the prevention and treatment of gastric ulcer.

Spondias purpurea L. (Anacardiaceae): Antioxidant and Antiulcer Activities of the Leaf Hexane Extract

Spondias purpurea is used in folk medicine to treat diarrhea and diuresis. The objective of this study was to evaluate the phytochemical profile and antioxidant and antiulcer activities of the hexane extract of the leaves of S. purpurea (SpHE). Phytochemical profile was evaluated via thin layer chromatography (TLC) and HPLC. SpHE was screened for antioxidant activities using DPPH, ABTS, FRAP, and phosphomolybdenum assays. To determine its antiulcer properties, animals were pretreated with injured control, lansoprazole, ranitidine, carbenoxolone, or SpHE (12.5, 25, and 50 mg/kg) and were screened; acute ulcers were induced by HCl/ethanol, absolute ethanol, and nonsteroidal anti-inflammatory drug (NSAID). TLC revealed the presence of flavonoids, whereas HPLC analysis showed the presence of caffeic acid and epigallocatechin. The phenolic compounds and in vitro assays showed antioxidant activity. After gastric ulcer induction by using HCl/ethanol, SpHE reduced the area of ulcerative lesions by 82, 91, and 88%, respectively. In ethanol, SpHE reduced the area of ulcerative lesions by 77, 93, and 92%, respectively. In the NSAID, the percentages of protection were 70, 76, and 78%, respectively. SpHE promoted the minimization of ulcers, increased the levels of reduced glutathione, and decreased tumor necrosis factor. S. purpurea has antioxidant and antiulcer properties.

V79 Fibroblasts Are Protected Against Reactive Oxygen Species by Flax Fabric

Chinese hamster pulmonary fibroblasts (V79 cells) pre-treated with flax fabrics derived from non-modified or genetically engineered flax fibres and treated with H₂O₂ revealed a markedly lower level of intracellular reactive oxygen species (ROS) than control, non-pre-treated cells. The fabrics were prepared from fibres derived from two kinds of transgenic plants: W92 plants, which overproduce flavonoids, and M type plants, which produce hydroxybutyrate polymer in their vascular bundles and thus in fibres. Incubating the V79 cells with the flax fabrics prior to H₂O₂ treatment also reduced the amount of DNA damage, as established using the comet assay (also known as alkaline single-cell gel electrophoresis) and pulsed-field electrophoresis of intact cellular DNA. Selected gene expression analysis revealed the activator impact of fabrics on the apoptotic (BCL2 family, caspases) gene expression. This promoting activity was also detected for histone acetyltransferase (HAT; MYST2) gene expression. The flax fabric derived from both GM flax plants exhibited a protective effect against oxidative stress and ROS-mediated genotoxic damage, but the W92 fabric was the strongest. It is thus suggested that these fabrics might be useful as a basis for new biomedical products (e.g. wound dressings) that actively protect cells against inflammation and degeneration.

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.

Protective Effect of Camellia Oil (Camellia oleifera Abel.) against Ethanol-Induced Acute Oxidative Injury of the Gastric Mucosa in Mice

Camellia oil, a common edible oil in Taiwan and China, has health effects for the gastrointestinal tract in folk medicine, and it contains abundant unsaturated fatty acids and phytochemicals. However, the preventive effect of camellia oil on ethanol-induced gastric ulcers remains unclear. This study was aimed to evaluate the preventive effect of camellia oil on ethanol-induced gastric injury in vitro and in vivo as well as its mechanisms of action. In an in vitro study, our results showed that pretreatment of RGM-1 cells with camellia oil enhanced the migration ability as well as increased heat shock protein expression and reduced apoptotic protein expression. In animal experiments, mice pretreated with camellia oil effectively showed improved ethanol-induced acute injury of the gastric muscosa and oxidative damage through the enhancement of antioxidant enzyme activities and heat shock protein and PGE₂ production, as well as the suppression of lipid peroxidation, apoptosis-related proteins, pro-inflammatory cytokines, and NO production. Histological injury score and hemorrhage score in ethanol-induced gastric mucosal damage dramatically elevated from the control group (0.00 ± 0.0) to 3.40 ± 0.7 and 2.60 ± 0.5, respectively. However, treatments with camellia oil or olive oil (2 mL/kg bw) and lansoprazole (30 mg/kg bw) showed significant decreases in elevation of injury score and hemorrhage score (p < 0.05). Therefore, camellia oil has the potential to ameliorate ethanol-induced acute gastric mucosal injury through the inhibition of inflammation and oxidative stress.

Semipurified Ethyl Acetate Partition of Methanolic Extract of Melastoma malabathricum Leaves Exerts Gastroprotective Activity Partly via Its Antioxidant-Antisecretory-Anti-Inflammatory Action and Synergistic Action of Several Flavonoid-Based Compounds

Recent study has demonstrated the gastroprotective activity of crude methanolic extract of M. malabathricum leaves. The present study evaluated the gastroprotective potential of semipurified extracts (partitions): petroleum ether, ethyl acetate (EAMM), and aqueous obtained from the methanolic extract followed by the elucidation of the gastroprotective mechanisms of the most effective partition. Using the ethanol-induced gastric ulcer assay, all partitions exerted significant gastroprotection, with EAMM being the most effective partition. EAMM significantly (i) reduced the volume and acidity (free and total) while increasing the pH of gastric juice and enhanced the gastric wall mucus secretion when assessed using the pylorus ligation assay, (ii) increased the enzymatic and nonenzymatic antioxidant activity of the stomach tissue, (iii) lost its gastroprotective activity following pretreatment with N-omega-nitro-L-arginine methyl ester (L-NAME; NO blocker) or carbenoxolone (CBXN; NP-SH blocker), (iv) exerted antioxidant activity against various in vitro oxidation assays, and (v) showed moderate in vitro anti-inflammatory activity via the LOX-modulated pathway. In conclusion, EAMM exerts a remarkable NO/NP-SH-dependent gastroprotective effect that is attributed to its antisecretory and antioxidant activities, ability to stimulate the gastric mucus production and endogenous antioxidant system, and synergistic action of several gastroprotective-induced flavonoids.

Efficacy and safety of herbal medicines in treating gastric ulcer: A review

Gastric ulcer is a common disorder of the digestive system. Current therapeutic regimens largely rely on Western medicine. However, numerous studies have demonstrated that herbal medicines can effectively treat gastric ulcer in humans and various animal models via divergent mechanisms. This review updates the efficacy and safety of herbal medicines in treating gastric ulcer, and the mechanisms of their action in humans and animal models. Studies have demonstrated that the efficacy of herbal medicines is comparable or superior to that of drugs such as omeprazole or cimetidine in humans and animal models, and herbal medicines display fewer adverse effects. The mechanisms by which herbal medicines benefit gastric ulcer include stimulation of mucous cell proliferation, anti-oxidation, and inhibition of gastric acid secretion and H(+)/K(+)-ATPase activity. Some herbal medicines also exhibit antimicrobial properties. Utilization of herbal medicines could be a valuable alternative to treat gastric ulcer in humans effectively, with few adverse effects.

Gastroprotective bio-guiding fractionation of hydro-alcoholic extracts from green- and black-teas (Camellia sinensis)

Hydro-alcoholic extracts from leaves of Camellia sinensis (green- and black-tea leaves) were submitted to a fractionation, promoting the compound separation according to their polarity, and analyzed by ultra-high performance liquid chromatography-mass spectrometry. A wide range of compounds could be identified, such as catechins and their gallate (esters) or oxidation derivatives (theaflavins), glycosylated flavonoids and other phenolics, as well as lipids, saponins and alkaloids. Also have been developed, via bio-guided examination, the gastroprotective property of the compounds identified. The samples were assayed using the model of acute gastric lesions induced in rats by ethanol. Hydro-alcoholic extracts of green-tea and black-tea protected the gastric mucosa with ED₅₀=3.6 and 10.2mg/kg, respectively, with participation of gastric mucus and reduced glutathione (GSH). The ethyl acetate fraction from green-tea and aqueous fraction from black-tea were, respectively, 6 and 10 times more effectiveness than the initial extracts. Moreover, the epigallocatechin gallate (EGCG, 0.204mg/kg), a main component of ethyl acetate fraction from green tea, reduced the gastric lesion by 56% and restored the mucus levels, however the rutin (0.0133mg/kg), a flavonoid found in the most active fraction of black-tea, was less significant at the natural concentrations. These results have confirmed that the different compounds present in green- and black-tea hydro-alcoholic extracts and partitioned fractions produce relevant gastroprotection mainly via maintenance of the protective factors, mucus and GSH.

Apple polyphenol extracts protect against aspirin-induced gastric mucosal damage in rats

The protective role of two apple polyphenol extracts, Douglas-FB (FB) and Douglas-EF (EF), on gastric mucosal damage following aspirin ingestion was investigated in healthy rats. Polyphenol content of the apple extracts varied, with the EF extract having 20% w/w polyphenols and a high proportion of flavanols as epicatechin and procyanidin, whereas the FB extract comprised 12% w/w polyphenols, which were mostly flavonols as quercetin glycosides. Male Sprague-Dawley rats were allocated to control, FB and EF groups and fed the experimental diet during the 10-day trial. Control treatment rats received 1 mL of deionised water, whereas apple polyphenol treatment group rats, FB and EF received a concentration of 10(-2)  m polyphenols in 1 mL deionised water daily via oral gavage. At the end of 10-day feeding period, rats were fasted overnight, and the following morning, aspirin (200 mg/kg) was given by oral gavage. Four hours after aspirin administration, the animals were euthanised, and samples taken for analysis. Both apple polyphenol extracts significantly reduced the ulcer area, ulcer lesion index and gastric injury score. The glutathione in gastric mucosa was increased significantly in rats given FB apple extract. Despite their different polyphenol compositions, FB and EF apple extracts assisted in protecting the gastric mucosa following acute aspirin administration in rats.

Protective effects of oral administration of yeast thioredoxin against gastric mucosal injury

Thioredoxin (TRX) is a redox regulating protein which has protective effects against oxidative stress-induced damage to cells and tissues. In this study, we investigated the effects of orally administered TRX derived from edible yeast, Saccharomyces cerevisiae, on gastric mucosa. First, we examined the digestibility of orally administered yeast TRX in mice, and detected yeast TRX in the stomach for 4 h after administration. Next, we investigated the mitigation of gastric mucosal injury after the oral administration of yeast TRX in water-immersion restraint stress and HCl/ethanol-induced gastric ulcer models. Furthermore, we conducted DNA microarray analysis, using the HCl/ethanol-induced model, which revealed that several groups of genes related to tissue repair were upregulated in ulcer regions in the stomachs of rats administered with yeast TRX. These results demonstrated the viability of the use of oral administrations of yeast TRX to protect the gastric mucosa.

Gastric antiulcerogenic and hypokinetic activities of Terminalia fagifolia Mart. & Zucc. (Combretaceae)

The acute toxicity, the antioxidant activity, and the pharmacological activity on the gastrointestinal tract of rodents of the ethanolic extract (TFEE) from the bark of Terminalia fagifolia Mart. & Zucc. (Combretaceae) and of its aqueous (TFAqF), hydroalcoholic (TFHAF), and hexanic (TFHEXF) partition fractions have been evaluated. TFEE presented low acute toxicity, antioxidant, and antiulcerogenic activity against ethanol-induced ulcers, which was partially blocked by pretreatment with L-NAME and indomethacin. It reduced the total acidity and raised the pH of gastric secretion. Additionally, TFEE delayed gastric emptying and slightly inhibited the small intestinal transit and also presented a weakly antidiarrheal activity. The antiulcerogenic and antioxidant activity were also detected in TFAqF and TFHAF but not in TFHEXF. The antisecretory and gastroprotective activity of TFEE partially involve the nitric oxide and prostaglandin participation. Nevertheless, TFEE, TFAqF, and TFHAF drastically reduced the mucus layer adhered to the gastric wall of rats treated with ethanol or indomethacin. Complementary studies are required in order to clarify the paradox of the presence of a gastroprotector activity in this plant that, at the same time, reduces the mucus layer adhered to the gastric wall.

Banhabaekchulchunma-tang, a traditional herbal formula attenuates absolute ethanol-induced gastric injury by enhancing the antioxidant status

Background

Banhabaekchulchunma-tang (hange-byakujutsu-tenma-to in Japanese and banxia-baizhu-tianma-tang in Chinese) is a mixture of fourteen herbs. It is used traditionally for the treatment of anemia, anorexia, general weakness, and female infertility in China, Japan, and Korea. In this study, we investigated the protective effects of a Banhabaekchulchunma-tang water extract (BCT) against ethanol-induced acute gastric injury in rats.

Methods

Gastric injury was induced by intragastric administration of 5 mL/kg body weight of absolute ethanol to each rat. The positive control group and the BCT group were given oral doses of omeprazole (50 mg/kg) or BCT (400 mg/kg), respectively, 2 h prior to the administration of absolute ethanol. The stomach of each animal was excised and examined for gastric mucosal lesions. To confirm the protective effects of BCT, we evaluated the degree of lipid peroxidation, the level of reduced glutathione (GSH), and the activities of the antioxidant enzymes catalase, glutathione-S-transferase, glutathione peroxidase, and glutathione reductase in the stomach. In addition, we conducted an acute toxicity study to evaluate the safety of BCT according to OECD guideline.

Results

BCT reduced ethanol-induced hemorrhage, hyperemia, and loss of epithelial cell in the gastric mucosa. BCT reduced the increased lipid peroxidation associated with ethanol-induced acute gastric lesions, and increased the mucosal GSH content and the activities of antioxidant enzymes. In addition, BCT did not cause any adverse effects at up to 5000 mg/kg.

Conclusions

These results indicate that BCT protects the gastric mucosa against ethanol-induced gastric injury by increasing the antioxidant status. We suggest that BCT could be developed as an effective drug for the treatment of gastric injury caused by alcohol intake.

Dietary nitrate and reductive polyphenols may potentiate the vascular benefit and alleviate the ulcerative risk of low-dose aspirin

The recent revelation that daily low-dose aspirin not only lowers risk for vascular events, but also can notably decrease risk for a range of adenocarcinomas, decreasing total cancer mortality by about 20%, makes it highly desirable to implement this protective strategy on a population-wide basis. Nonetheless, the fact that low-dose aspirin approximately doubles risk for serious gastrointestinal bleeding may impede health authorities from recommending its use by people judged to be at low cardiovascular risk. Nitric oxide (NO) exerts gastroprotective effects by boosting blood flow and mucus production in the gastric mucosa - effects which demonstrably oppose the pro-ulcerative impact of aspirin and other NSAIDs. A nitrate-rich diet, as well as ingestion of reductive catechol-bearing polyphenols, can collaborate in promoting NO generation in gastric juice, and they are protective in rodent models of gastric ulceration. Moreover, a high-nitrate diet, as well as certain reductive polyphenols such as epicatechin and quercetin, can exert platelet-stabilizing effects complementary to those of aspirin, and act in other ways to preserve vascular health. Hence, diets rich in nitrate and reductive polyphenols have the potential to amplify the vascular-protective benefits of low-dose aspirin, while diminishing its pro-ulcerative risk. Low-dose aspirin may be more unequivocally recommendable within the context of such a dietary strategy.

Antioxidant action of mangrove polyphenols against gastric damage induced by absolute ethanol and ischemia-reperfusion in the rat

Rhizophora mangle, the red mangrove, has long been known as a traditional medicine. Its bark has been used as astringent, antiseptic, hemostatic, with antifungic and antiulcerogenic properties. In this paper, we aimed to evaluate the antioxidant properties of a buthanolic fraction of the R. mangle bark extract (RM) against experimental gastric ulcer in rats. Unib-Wh rats received pretreatment of R. mangle after the induction of gastric injury with absolute ethanol and ischemia-reperfusion. Gastric tissues from both methods were prepared to the enzymatic assays, the levels of sulfhydril compounds (GSH), lipid peroxides (LPO), and the activities of glutathione reductase (GR), glutathione peroxidase (GPx), superoxide dismutase (SOD) and myeloperoxidase (MPO) were measured. The RM protected the gastric mucosa in both methods used, ethanol-induced gastric ulcer and ischemia-reperfusion, probably, by modulating the activities of the enzymes SOD, GPx, and GR and increasing or maintaining the levels of GSH; in adittion, LPO levels were reduced. The results suggest that the RM antioxidant activity leads to tissue protection; thus one of the antiulcer mechanisms present on the pharmacological effects of R. mangle is the antioxidant property.

Epigallocatechin gallate accelerates healing of indomethacin-induced stomach ulcers in mice

Management of the gastric toxicity of non-steroidal anti-inflammatory drugs (NSAIDs) remains a crucial problem because the commercially available drugs have side effects and are often expensive. Therefore, we examined the potential of the green tea-derived polyphenol epigallocatechin gallate (EGCG) to treat indomethacin-induced stomach ulcers in mice. Administration of indomethacin (18 mg/kg, po) to mice induced ulceration in the glandular portion of the gastric mucosa, accompanied by increased lipid peroxidation (LPO) and protein oxidation and reductions in thiol defense, mucin, cyclooxygenase (COX) expression and prostaglandin (PG) synthesis in the gastric tissues. Daily oral administration of EGCG (2 mg/kg) or omeprazole (3 mg/kg) for 3 days produced similar (≈ 72-75%, p < 0.001) beneficial effects on the acute gastric ulceration. Treatment with the test samples partially reversed all the adverse oxidative effects of indomethacin. In addition, EGCG, but not omeprazole, enhanced expression of the COX isoforms and PG synthesis. The results suggest that the non-toxic and inexpensive tea polyphenol EGCG may be an excellent candidate for further evaluation as a potent anti-ulcer drug.

Comparative gastroprotective effect of post-treatment with low doses of rutin and cimetidine in rats

The anti-ulcerogenic potentials of low doses of rutin and cimetidine in ethanol-, acetic acid-, and stress-induced ulcers in rats have been evaluated and compared in this study. In each model, male Wistar rats were randomly divided into six groups (I-VI). Groups II-VI were administered 1 mL/100 g ethanol orally, 0.05 mL of 20% acetic acid submucosally or kept in a cold chamber for 6 h to induce ulcer in the ethanol-, acetic acid-, and stress-induced ulceration model, respectively. Thereafter, group III was post-treated with 300 mg/kg cimetidine and groups IV-VI with 20, 40, and 80 mg/kg rutin, respectively, while the control (group I) received distilled water in Tween 20. One hour after post-treatment, all groups were killed and the gastric ulcer index was calculated. Malondialdehyde (MDA) level, vitamin C content, and glutathione peroxidase (GPx) activity were evaluated in the gastric mucosa of animals. Post-treatment with rutin significantly reduced ulcerogen-induced gastric damage in all models. This effect was significant at all dose levels compared with the ulcer-induced groups. Rutin significantly reduced the MDA levels but increased the vitamin C content and GPx activity. Ulcer index and MDA level were highest in the ethanol-induced ulcer model while vitamin C content and GPx activity were lowest in the stress-induced ulcer model. The study showed that all three models of ulceration appeared to be linked to oxidative stress and also ascribed significant anti-ulcerogenic potential to rutin especially at lower doses of 20-80 mg/kg.

Abarema cochliacarpos: gastroprotective and ulcer-healing activities

ETHNOPHARMACOLOGICAL RELEVANCE

Abarema cochliacarpos (Gomes) Barneby & Grimes (Mimosaceae) is a species--in folk medicine of Lagarto city, Sergipe state, northeastern Brazil--reputed to heal gastric ulcer and gastritis.

AIM OF THE STUDY

Chloroform (CE) and methanolic (ME) extracts as well as ethyl acetate fraction (AF), butanolic fraction (AC) and aqueous fraction (AQF) of the methanolic extract of Abarema cochliacarpos bark were evaluated against acute gastric ulcer. The AC fraction was selected to assess its activity in ulcer healing and its gastroprotective effects via mucus and gastric secretion.

MATERIAL AND METHODS

The gastroprotective action of CE and ME extracts and the fractions of the latter were evaluated in a rodent experimental model. The action mechanisms, involvements of the antisecretory action and mucus production, toxicological and healing activity of the AC (150 mg/kg, p.o.) were evaluated. We also used histological analysis (HE and PAS) and immunohistochemical (PCNA, COX-2, VEGF and HSP-70) assays to evaluate the effects of Abarema cochliacarpos.

RESULTS

CE (200 and 400 mg/kg, p.o.) and ME (100, 200 and 400 mg/kg, p.o.) extracts were able to protect gastric mucosa against absolute ethanol. Respective inhibitions produced were: 65.31% and 83.80% by the first; 91.69%, 96.75% and 99.80% by the second; and 74.24% by the AC fraction. Antisecretory and mucus production effects were exhibited by the AC fraction, which also accelerated the healing of ulcerated gastric mucosa by stimulating proliferation factors (PCNA) and induced healing factors including COX-2, VEGF and HSP-70.

CONCLUSION

All these results suggest that Abarema cochliacarpos (Gomes) Barneby & Grimes presents gastroprotective effects and wound-healing properties.

Black tea and theaflavins assist healing of indomethacin-induced gastric ulceration in mice by antioxidative action

The healing activities of black tea (BT) and the theaflavins (TF) against the indomethacin-induced stomach ulceration were studied in a mouse model. Indomethacin (18 mg/kg, p.o.) administration induced maximum ulceration in the glandular portion of the gastric mucosa on the 3rd day, accompanied by increased lipid peroxidation and protein oxidation, depletion of thiol-defense and mucin, as well as reduced expressions of cyclooxygenases (COX) and prostaglandin (PG) E synthesis in the gastric tissues, and plasma total antioxidant status of mice. Treatment with BT (40 mg/kg), TF (1 mg/kg), and omeprazole (3 mg/kg) produced similar (74%-76%) ulcer healing, as revealed from the histopathological studies. Treatment with all the above samples reversed the adverse oxidative effects of indomethacin significantly. BT and TF also enhanced the PGE synthesis by augmenting the expressions of COX 1 and 2, but did not modulate acid secretion.

Protective effect of (+)-catechin against gastric mucosal injury induced by ischaemia-reperfusion in rats

Ischaemia and reperfusion are known to induce gastric lesions, predominantly due to excessive formation of reactive oxygen metabolites, adhesion of neutrophils to endothelial cells, microvascular dysfunction, gastric acid secretion, endogenous histamine and gastrin release. We have studied the effect of (+)-catechin on a gastric ulcer model involving damage to gastric injury by ischaemia-reperfusion (I/R) in rats. (+)-Catechin 50 mg kg−1 administered orally, once daily for three days after the initiation of I/R injury showed a significant (P &lt; 0.001) anti-ulcer activity against mucosal damage. However, (+)-catechin significantly decreased the lipid peroxidation and increased the level of catalase in the I/R condition. Elevated levels of alkaline phosphatase in the I/R group was significantly lowered (P &lt; 0.01) by (+)-catechin. The amount of H+K+ATPase was significantly decreased (P &lt; 0.001) in (+)-catechin-treated as compared with I/R rats. (+)-Catechin significantly decreased elevated plasma histamine (P &lt; 0.05) and corticosterone (P &lt; 0.05). The results suggested that (+)-catechin protected gastric mucosa against ischaemia-reperfusion-induced gastric ulcers by its antioxidant activity and mucus protection.

Gastroprotective activity of the chloroform extract of the roots from Arctium lappa L

Arctium lappa L. is used in folk medicine as a diuretic, depurative and digestive stimulant and in dermatological conditions. The objective of this study was to evaluate the effect and the possible mechanisms involved in the gastroprotective effects of a chloroform extract (CE) of the roots from A. lappa and its fractions. Oral pretreatment with CE (10, 30 and 100 mgkg−1) significantly reduced gastric lesions induced by ethanol by 61%, 70% and 76%, respectively. Oral administration of CE (100 mgkg−1 per day for 7 days) reduced the chronic gastric ulceration induced by acetic acid by 52%. Intraduodenal CE (100, 300 and 600 mgkg−1) reduced the total acidity of gastric secretion by 22%, 22% and 33%, respectively, while i.p. administration (10, 30 and 100 mgkg−1) inhibited total acidity by 50%, 60% and 67%, respectively. In-vitro, CE inhibited H+, K+-ATPase activity with an EC50 of 53 μgmL−1 and fraction A (30 and 100 μgmL−1) reduced this by 48% and 89%, respectively. CE had no effect on gastrointestinal motility. CE (250 μgmL−1) and fraction B (100 and 250 μgmL−1) had free-radical scavenging ability, inhibiting 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical activity by 50%, 20% and 55%, respectively. Collectively, the results show that the CE protects animals from gastric lesions by reducing gastric acid secretion via inhibition of gastric H+, K+-ATPase.

Nicotinamide alleviates indomethacin-induced gastric ulcers: a novel antiulcer agent

Nicotinamide, a precursor of nicotinamide adenine dinucleotide (NAD(+)), is an essential nutrient for cell growth that participates in DNA repair and energy production. Nonsteroidal anti-inflammatory drugs (NSAIDs)-induced gastropathy is an intricate process involving gastric mucus depletion, increased microvascular permeability, nitric oxide imbalance, as well as free radical production. The present study was conducted to test for the possible gastroprotective effect of nicotinamide utilizing an acute indomethacin-induced gastric ulcer model. Sucralfate possesses antiulcer/antioxidant properties; hence it was used as the reference drug. Indomethacin resulted in hemorrhagic mucosal lesions, increased microvascular permeability, and reduced the gastric mucosal contents of nitric oxide and mucus. Moreover, it produced an imbalance in the mucosal redox state as indicated by a decline of glutathione and glutathione peroxidase, which were associated with increased lipid peroxides. Comparable to sucralfate, nicotinamide markedly decreased the severity of indomethacin-induced gastric lesions and restored the levels of altered biochemical parameters. Gastroprotection afforded by nicotinamide is possibly mediated by conservation of gastric mucus, as well as nitric oxide contents, enhanced gastric microvascular permeability, and its antioxidant properties.

Phenolics, sugars, antimicrobial and free-radical-scavenging activities of Melicoccus bijugatus Jacq. fruits from the Dominican Republic and Florida

Edible fruits of the native South American tree Melicoccus bijugatus Jacq. are consumed fresh or in traditional food, drink and medicinal preparations. Some therapeutic effects of these fruits may be due to phenolics and sugars. Aqueous acetone, methanol or ethanol tissue extracts of different cultivars or collections of M. bijugatus fruits from the Dominican Republic and Florida were analyzed for total phenolics and free radical scavenging activity by UV-vis spectroscopy, sugars by gas chromatography, and antimicrobial activity by the disc diffusion assay. Total phenolics and free radical scavenging activities ranked: seed coat > embryo > pulp extracts. Montgomery cultivar fruits had the highest total phenolics. For sugars: pulp > embryo and highest in Punta Cana fruit pulp. In all extracts: sucrose > glucose and fructose. Glucose:fructose ratios were 1:1 (pulp) and 0.2:1 (embryo). Pulp extracts had dose-response antibacterial activity and pulp and embryo extracts had antifungal activity against one yeast species. Phenolics and sugars were confirmed with thin-layer chromatography and nuclear magnetic resonance. Sugar-free pulp fractions containing phenolics had slightly more antimicrobial activity than H2O-soluble pulp fractions with sugars. Results indicate M. bijugatus fruits contain phenolics, sugars and other H2O-soluble compounds consistent with therapeutic uses.

Gastroprotective constituents of Salvia officinalis L

The gastrointestinal activity of hydroalcoholic extract (HE) of Salvia officinalis was evaluated in a model of ethanol-induced gastric lesion. HE showed excellent activity, with ID(50) 84.0 (54.8-128.9) mg/kg. The acetic acid-induced ulcer and the total acidity of the gastric secretion were also reduced by HE, and, in vitro experiments, the H(+),K(+)-ATPase activity was inhibited. Carnosol was identified as a possible active constituent for the gastroprotective effect of HE.

Antiulcerogenic action of ethanolic extract of the resin from Virola surinamensis Warb. (Myristicaceae)

ETHNOPHARMACOLOGICAL RELEVANCE

Virola surinamensis (Myristicaceae), popularly known as "mucuíba", "ucuuba" or "ucuúba do igapó" is a large tree that grows abundantly in "Várzea" forest and on river banks in the Brazilian states of Amazonas and Tocantins. The resin obtained by cuts on the stem bark is a reputed folk remedy in its natural form for the treatment of ulcer, gastritis, inflammation and cancer.

AIM OF THE STUDY

The present work evaluated the pharmacological activity of the resin obtained from bark of V. surinamensis as antiulcerogenic in experimental in vivo model in order to observe whether its traditional use is justified.

MATERIALS AND METHODS

The preventive action of ethanolic extract of V. surinamensis was evaluated in experimental in vivo models in rodents that simulated this disease in human gastric mucosa.

RESULTS

Oral administration of acidified ethanol solution produced severe hemorrhagic lesions in glandular mucosa with ulcerative lesion of 50+/-11.5mm. In animals pretreated with V. surinamensis (500 mg/kg, p.o.) a significant inhibition of mucosal injury of 2.40+/-0.56 mm (95% inhibition) was detected. The V. surinamensis, at the same dose, also reduced significantly (p<0.05) the formation of gastric lesions induced by indomethacin (39%), stress (45%) and by pylorus ligature in mice (31%) when compared to animals treated with vehicle. The extract from V. surinamensis exerts gastroprotective action only when this extract contacts gastric mucosa (oral route) with increased pH values and reduced H+ concentration of gastric contents. The ethanolic extract of V. surinamensis resin was analyzed by TLC and spectrometric methods (NMR and ES-MS) and the main constituent of this extract was epicatechin.

CONCLUSIONS

We suggest that the epicatechin present in V. surinamensis resin may be among active principles responsible for the antiulcer activity shown by the tested resin but their used suggest carefulness because toxicological symptoms mentioned by population.

Effects of tea catechins on the gastrointestinal mucosa in rats

Although tea catechins are known to exert a potent antiulcer effect on the alimentary tract, there is scant information concerning their effects on normal mucus cell functions. Using original anti-mucin monoclonal antibodies, we studied the influences of long-term administration of catechins on the quantity and quality of mucin in rat gastrointestinal mucosa. Administration of 0.5% tea catechins significantly increased the mucin content of the ileum, but not the stomach. An enzyme-linked immunosorbent assay (ELISA) showed no remarkable qualitative changes in gastric mucin, but a selective increase and decrease in sulfo- and sialomucins, respectively, in the ileum of rats administered catechins. The ELISA results were consistent with both the immunohistochemical findings and the high-iron diamine-alcian blue staining pattern. These findings indicate that tea catechins modulate ileal mucin metabolism in the ileal mucosa, suggesting that further studies focusing on the ileal epithelium will assist in further elucidation of the mechanism of catechin effects.

Anti-inflammatory and hypolipemic effects in vitro of simvastatin comparing to epicatechin in patients with type-2 hypercholesterolemia

OBJECTIVE

The study involved 25 patients with type-2 hypercholesterolemia (mean age 49.3+/-11.3). The control group consisted of 28 healthy individuals (mean age 50.7+/-7.2).

METHODS

The cholesterol concentrations in plasma membranes of erythrocytes were measured by means of Liebermann-Burchard reagent. The membrane lipid peroxidation in whole erythrocytes was determined. The membrane fluidity was estimated by spin labelled method.

RESULTS

The in vitro study shows that the cholesterol concentration in membranes incubated with simvastatin and epicatechin decreases; in healthy donors there are no changes. Simvastatin does not lead to changes in the lipid peroxidation in the in vitro data. Epicatechin decreases the level of membrane lipid peroxidation in patients with hypercholesterolemia and in healthy donors. Simvastatin and epicatechin cause an increase in the fluidity of plasma membranes of erythrocytes.

CONCLUSIONS

Simvastatin causes the decrease in cholesterol concentration in erythrocytes membranes not only in the in vivo but also the in vitro experiments. Flavonoids have antioxidant properties in vitro. Simvastatin influences the lipid peroxidation only in vivo, not in vitro systems. This observation is an additional contribution to the statins' pleiotropic effect.