Sérgio Faloni de Andrade

Evidence of gastric ulcer healing activity of Maytenus robusta Reissek: In vitro and in vivo studies.

ETHNOPHARMACOLOGICAL RELEVANCEnMaytenus robusta Reissek (Celastraceae) is traditionally used in Brazilian folk medicine to treat gastric ulcer, as a substitute for M. ilicifolia, which is almost extinct. The gastroprotective properties of M. robusta were demonstrated previously using only preventive approaches, such as acute gastric ulcer models. However, the healing effect of M. robusta in gastric ulcers remains unclear.nnnAIM OF THE STUDYnThe current study was carried out to investigate the healing effectiveness of M. robusta hydroalcoholic extract (HEMR) from aerial parts in the acetic acid-induced chronic ulcer model and to determine its effect on cell proliferation, scavenging free radicals, and inflammatory and oxidative damage.nnnMATERIAL AND METHODSnTo evaluate the healing properties of HEMR in vivo, chronic gastric ulcer was induced in rats by 80% acid acetic. Next, different groups of animals (n=6) were treated orally with vehicle (water plus 1% tween, 1 ml/kg), omeprazole (20mg/kg), or HEMR (1-10mg/kg), twice daily for 7 days. At the end of the treatment, the total ulcer area (mm(2)) was measured and a sample of gastric tissue was taken for histological and histochemical analysis. Evaluation of GSH and LOOH levels, GST, SOD, CAT and MPO activity was also performed at the site of the lesion. In parallel, radical scavenging activity, cytoprotective effect, and cell proliferation activity in fibroblasts (L929 cells) were determined by in vitro trials. The antisecretory properties were evaluated using the pylorus ligature model in rats, and the anti-Helicobacter pylori activity was determined in vitro. Acute toxicity was evaluated by relative organ weight and biochemical parameters in serum. The prokinetic properties were also evaluated in mice.nnnRESULTSnOral administration of HEMR (10mg/kg) reduced the gastric ulcer area by 53%, compared to the vehicle group (120.0 ± 8.3mm(2)), the regeneration of gastric mucosa was evidenced in histological analysis. Moreover, HEMR treatment increased gastric mucin content and reduced oxidative stress and inflammatory parameters at the site of the ulcer. In vitro, HEMR (1-1000 µg/ml) was able to scavenge free radical DPPH and promote cytoprotection against H2O2 in fibroblasts at 0.1-100 µg/ml. Moreover, HEMR healing properties also were confirmed by enhancement of proliferation and coverage of scratched wounds in fibroblast monolayer. However, HEMR (10mg/kg) by the intraduodenal route did not promote changes in volume, pH, total acidity or pepsin activity in the pylorus ligature model, and HEMR up to 2000 µg/ml also did not present considerable activity against H. pylori. In relation to gastrointestinal motility, HEMR (10mg/kg, p.o) did not provoke alterations. It is also important to mention that oral administration of HEMR did not produce any sign of acute toxicity in animals.nnnCONCLUSIONSnThe data here obtained show that M. robusta has evident ulcer healing potential, mainly through the strengthening of protective factors of gastric mucosa, such as mucus layer, antioxidant defenses and cell proliferation. Taking into account the advantages of cultivation and harvesting of M. robusta compared to M. ilicifolia, and the evidence presented here, it is plausible to conclude that hydroalcoholic extract obtained from aerial parts of M. robusta is an interesting source for the development of a phytotherapeutic formulation to treat gastric ulcer.

Genotoxic assessment of Rubus imperialis (Rosaceae) extract in vivo and its potential chemoprevention against cyclophosphamide-induced DNA damage.

ETHNOPHARMACOLOGICAL RELEVANCEnRubus imperialis Cham. Schl. (Rosaceae) is frequently used in traditional medicine as hypoglycemic, antinociceptive and antiviral remedy.nnnMATERIALS AND METHODSnSwiss albino mice were distributed in eight groups for acute treatment with Rubus imperialis extract (24 h). The extract doses selected were 50, 250 and 500 mg/kg b.w. administered by gavage alone or plus to CPA (50 mg/kg b.w.) administered by intraperitoneal injection. Control groups were treated in a similar way. Analyses were performed using the comet assay, on leukocytes (collected 4 and 24h after treatment) and liver (collected 24 h after treatment), and using the micronucleus test (MN) in bone marrow cells. Cytotoxicity was assessed by scoring 200 consecutive polychromatic (PCE) and normochromatic (NCE) erythrocytes (PCE/NCE ratio).nnnRESULTS AND CONCLUSIONnThe main compounds identified in the Rubus imperialis extract were saponins and steroidal compounds, with niga-ichigoside and tormentic acid being the major compounds. Tested doses of Rubus imperialis extract showed no genotoxic effects on leukocytes from peripheral blood or liver cells by the comet assay. However, the MN test showed an increase in the frequency of micronucleated cells at the two higher doses tested, indicating that this extract has clastogenic/aneugenic effects on bone marrow cells at higher doses. On the other hand, for all cells evaluated, the three tested doses of the Rubus imperialis extract promoted inhibition of DNA damage induced by CPA. Despite the chemoprevention observed, the clastogenicity/aneugenicity observed suggested caution about either continuous or high-dose usage of Rubus imperialis aerial parts extract by humans.

Antiulcer mechanisms of Vernonia condensata Baker: A medicinal plant used in the treatment of gastritis and gastric ulcer.

ETHNOPHARMACOLOGICAL RELEVANCEnThe leaves from Vernonia condensata Baker are broadly used in folk medicine for the treatment of gastric ulcers and dyspepsia. The Brazilian Public Health System (SUS) describes this species as having the potential to serve as a new herbal product with therapeutic benefits.nnnAIM OF THE STUDYnThe purpose of the study was to evaluate the gastroprotective activity and gastric healing properties of a crude ethanolic extract from leaves of V. condensata (CEEV) in different animal models.nnnMATERIALS AND METHODSnIn order to assess the gastroprotective potential of CEEV, ulcer models were established using ethanol and indomethacin. The gastric healing effect was then evaluated in the acetic acid-induced ulcer model, where the tissue was used to assess oxidative levels (reduced glutathione and lipid hydroperoxide levels, as well as superoxide dismutase and catalase activity), inflammatory [myeloperoxidase (MPO)] parameters, and mucin content. Furthermore, the ligature pylorus model, with and without secretagogue stimuli, was employed to investigate the mechanism of action of CEEV. In addition, H(+)K(+)-ATPase activity, MPO activity, and antioxidant activity through the DPPH assay were examined through in vitro trials. Phytochemical analyses were also performed. The ethanol/HCl-induced gastric ulcer method was employed to verify the gastroprotective effect of the main compound in CEEV.nnnRESULTSnCEEV (30 and 300mg/kg, p.o) exhibited gastroprotective activity and prevented both gastric lesions induced by ethanol or indomethacin in rats. The gastric healing effect of CEEV (300mg/kg, p.o. taken twice a day for a duration of seven days) was confirmed by examining the macroscopic and microscopic appearance of chronic gastric ulcers induced by acetic acid in rats. The restorative effect of CEEV was accompanied by a significant increase in mucin content (PAS staining) and by a reduction in oxidative stress and inflammatory parameters at the site of the ulcer. Moreover, CEEV (300mg/kg), administered via an intraduodenal route, significantly reduced the volume, pH, total acidity and pepsin activity of gastric content in the pylorus ligature model in rats. The gastric acid antisecretory effect of CEEV was maintained even in the presence of cholinergic and gastrinergic, but not histaminergic, stimuli. In vitro, CEEV (1-10µg/ml) was able to scavenge free radical DPPH, but did not promote inhibitory effects on MPO or H(+),K(+)-ATPAse activity. Phytochemical analysis of CEEV indicated that luteolin is the main compound present in the extract. However, luteolin (1, 3 and 10mg/kg, p.o or 1mg/kg, i.p.) did not promote gastroprotection against ethanol/HCl in mice. It is also important to mention that oral administration of CEEV did not produce any sign of acute toxicity in animals.nnnCONCLUSIONSnV. condensata extract demonstrates gastroprotective effects through the inhibition of gastric secretion via cholinergic and gastrinergic pathways. Furthermore, it exhibits cytoprotective effects, involving antioxidant activity, an increase in mucin content and inhibition of neutrophil migration. Thus, this medicinal plant may be a suitable natural source for the prevention and treatment of gastric lesions.

Hydroalcoholic Extract from Inflorescences of Achyrocline satureioides (Compositae) Ameliorates Dextran Sulphate Sodium-Induced Colitis in Mice by Attenuation in the Production of Inflammatory Cytokines and Oxidative Mediators

Achyrocline satureioides is a South American herb used to treat inflammatory and gastrointestinal diseases. This study evaluated intestinal anti-inflammatory effects of the hydroalcoholic extract of inflorescences of satureioides (HEAS) in dextran sulfate sodium (DSS) induced colitis in mice. Mice were orally treated with vehicle, 5-aminosalicylic acid (100u2009mg/kg), or HEAS (1–100u2009mg/kg). Clinical signs of colitis and colonic histopathological parameters were evaluated, along with the determination of levels of reduced glutathione and lipid hydroperoxide (LOOH), the superoxide dismutase (SOD), and myeloperoxidase (MPO) activity in colon. The colonic content of cytokines (TNF, IL-4, IL-6, and IL-10) was measured. Additionally, the effects of the extract on nitric oxide (NO) release by lipopolysaccharide (LPS) stimulated macrophages and diphenylpicrylhydrazyl levels were determined. Mucin levels and SOD activity, as well as the LOOH, MPO, TNF, and IL-6 accumulation in colon tissues, were normalized by the HEAS administration. In addition, the extract elicited an increase in IL-4 and IL-10 levels in colon. NO release by macrophages was inhibited by HEAS and its scavenger activity was confirmed. Together these results suggest that preparations obtained from inflorescences from A. satureioides could be used in treatment for IBD. Besides, this work corroborates the popular use of A. satureioides in inflammatory disorders.

The effects of baicalein on gastric mucosal ulcerations in mice: Protective pathways and anti-secretory mechanisms

Many flavonoids have been shown to present good results for the treatment of gastric ulcers. Baicalein, a bioactive flavonoid derived from the Scutellaria baicalensis Georgi root, possesses several biological effects, such as anti-inflammatory and antioxidant. This study was conducted to assess the gastroprotective properties of baicalein. Anti-ulcerogenic assay was performed using the protocol of ulcer induced by ethanol/HCl in mice; then, the role of presynaptic α2-receptors, sulfhydryl (SH) compounds, nitric oxide (NO), prostaglandin (PG) and ATP-sensitive K+ (KATP) channels in gastroprotection of baicalein was investigated. The levels of reduced glutathione (GSH) and the myeloperoxidase (MPO) activity were measured in the gastric mucosa. Parameters of gastric secretion (volume, [H+] and pH) were determined with or without the presence of the secretagogue agent histamine, as well as mucus in gastric contents, by the pylorus ligation model. Inxa0vitro H+,K+-ATPase activity was also determined. Baicalein (10, 30 and 100xa0mg/kg) exhibited a dose related gastroprotective effect (Pxa0<xa00.001) against acidified ethanol-induced lesions. The intraperitoneal treatment of mice with a α2-adrenoreceptor antagonist (yohimbine; 2xa0mg/kg), a SH compounds blocker (N-ethylmaleimide, NEM; 10xa0mg/kg), a non-selective inhibitor of NO synthase (Nw-nitro-L-arginine methyl ester hydrochloride, L-NAME; 10xa0mg/kg), a non-selective inhibitor of cyclo-oxygenase (indomethacin; 10xa0mg/kg) or a KATP channel blocker (glibenclamide; 10xa0mg/kg) was able to reverse (Pxa0<xa00.001) the gastroprotective response caused by baicalein (30xa0mg/kg). Baicalein (30xa0mg/kg; Pxa0<xa00.05) was able to increase GSH levels and decreasing MPO activity. The intraduodenal treatment with baicalein (30 and 100xa0mg/kg) significantly increased (Pxa0<xa00.05) the gastric mucus secretion. Additionally, the treatment with baicalein reduced (30 and 100xa0mg/kg; Pxa0<xa00.05) the secretion volume and total acid secretion, and also increased (10, 30 and 100xa0mg/kg; Pxa0<xa00.001) the pH value, after pylorus ligature. Baicalein (30xa0mg/kg) was also effective in inhibiting the effects of histamine on gastric secretion (volume, [H+] and pH; Pxa0<xa00.001). Baicalein at 10 and 30xa0μg/mL showed anti-H+,K+-ATPase activity. In conclusion, the present results provide convincing evidence that baicalein could be used as a cytoprotective (preventive effect) and anti-ulcerogenic (anti-secretory effect) agent in the gastric ulcers.

Constituents of leaves from Bauhinia curvula Benth. exert gastroprotective activity in rodents: role of quercitrin and kaempferol

The Bauhinia genus is known as “Pata-de-Vaca” and a wide variety of these species are used in Brazilian folk medicine due to their gastroprotective properties. This study aimed to investigate the antiulcer efficacy of the hydroalcoholic extract from B. curvula (HEBC) leaves, as well as its semi-purified fraction (SPFr) and the contribution of their phytochemicals constituents for this effect. For that, ethanol 60%/HCl 0.3xa0M- and indomethacin-induced gastric ulcer were performed in rodents. Gastric ulcerated tissues were processed for histological, histochemical and biochemical analysis. The oral treatment with HEBC and SPFr decreased the gastric ulcer induced by ethanol/HCl in mice and by indomethacin (only HEBC) in rats. The gastroprotective effect of HEBC was abolished in mice pretreated with Nω-Nitro-l-arginine methyl ester, N-Ethylmaleimide, glibenclamide or indomethacin. Both HEBC and SPFr reduced myeloperoxidase activity in parallel with a decrease of lipoperoxides content at the site of the lesion. On the other hand, HEBC did not alter volume, pH, total acidity or pepsin activity of acid gastric secretion in rats, and neither inhibited the in vitro H(+),K(+)-ATPase activity. Additionally, the compounds identified and isolated from the SPFr, the flavonoids quercitrin (65%) and kaempferol (35%), were able to diminish the extent of ulcerated area induced by both ethanol/HCl and indomethacin. Taking together, these findings show that B. curvula extracts present gastroprotective effect, mainly explained by the presence of flavonoids quercitrin and kaempferol, which may possibly improve the defensive factors of gastric mucosa.

Gastroprotective and anti-secretory mechanisms of 2-phenylquinoline, an alkaloid isolated from Galipea longiflora

BACKGROUNDnWe previously described the gastroprotective effect of 2-phenylquinoline (2-PQ), the main alkaloid isolated from the bark of Galipea longiflora (Rutaceae). However, despite the significant and promising results, the pharmacological mechanisms of the gastroprotection induced by 2-PQ have not been investigated.nnnPURPOSEnTo evaluate the mechanisms underlying the gastroprotective effects of 2-PQ.nnnSTUDY DESIGNnWe used an in vivo mouse ulcer model and in vitro methodologies involving H⁺/K⁺-ATPase and L929 murine fibroblasts.nnnMETHODSnThe gastroprotective activity of 2-PQ (10-100 mg/kg, orally, p.o) was assessed against gastric ulcer induced by 60% ethanol/0.03 M hydrochloric acid (HCl) in mice or that induced by indomethacin (80 mg/kg, p.o) in rats. The cytotoxicity was assessed in L929 murine fibroblasts. Ulcerated tissues were analyzed histologically, histochemically, and biochemically. The antisecretory activity of 2-PQ was evaluated in vivo and in vitro.nnnRESULTSn2-PQ showed no cytotoxicity, reduced the lesion area induced by ethanol/HCl (log half-maximal effective dose, ED50 =u20091.507), and the histological evaluation supported these results. Furthermore, 2-PQ reduced indomethacin-induced gastric ulceration. The gastroprotection was accompanied by normalization of superoxide dismutase (SOD) and glutathione-S-transferase (GST) activity, an intense increase in reduced glutathione (GSH) levels, and reduction in lipid peroxide (LPO) and tumor necrosis factor (TNF)-α levels in the gastric mucosa. The antisecretory properties of 2-PQ were confirmed by the decreased volume and total acidity of the gastric juice, and it reduced histamine- or pentagastrin-stimulated gastric acid secretion. However, 2-PQ did not change the in vitro H⁺/K⁺-ATPase activity or the content of gastric-adhered mucous in mice. In addition, pretreatment with N-ethylmaleimide, NG-nitro-l-arginine methyl esters, yohimbine, or indomethacin reversed the gastroprotective effect of 2-PQ, suggesting nitric oxide, nonprotein sulfhydryl compounds, α-2-receptors, and prostaglandin were involved.nnnCONCLUSIONn2-PQ provides gastroprotection by reducing oxidative damage and inhibiting acid secretion mediated by histaminergic and gastrinergic regulatory pathways.

Diuretic effect of extracts, fractions and two compounds 2α,3β,19α-trihydroxy-urs-12-en-28-oic acid and 5-hydroxy-3,6,7,8,4′-pentamethoxyflavone from Rubus rosaefolius Sm. (Rosaceae) leaves in rats

Although diuretics have been widely used to treat hypertension along with others cardiovascular and renal disorders, no scientific data have been recorded to support the diuretic properties of Rubus rosaefolius Sm. (Rosaceae), a plant popularly used in Brazil to treat hypertension. Male Wistar rats were orally treated with: vehicle; hydrochlorothiazide; aqueous (AERR) and methanolic (MERR) extracts; dichloromethane (DCM), hexane (HEX) and ethyl acetate (EA) fractions; and the isolated compounds 2α,3β,19α-trihydroxy-urs-12-en-28-oic acid (TUA) and 5-hydroxy-3,6,7,8,4′-pentamethoxyflavone (PMF). At the end of the experiment (after 8 or 24xa0h), urine volume and other urine or plasma parameters were measured. AERR and MERR, at 100 and 30xa0mg/kg, respectively, induced diuretic, natriuretic and kaliuretic effect. Additionally, the DCM and HEX, but not EA, at 10xa0mg/kg, also increased urine volume and Na+ and K+ excretion. Both active constituents, TUA and PMF, at doses of 1 and 3xa0mg/kg, showed an augmented diuretic and natriuretic index. While TUA revealed a kaliuretic action, PMF did not interfere with potassium excretion. The compounds increased urinary creatinine, but not urea, levels. TUA was able to decrease calcium excretion, as well as HCTZ, while PMF effect was associated with increased urinary prostaglandin E2 levels. The non-selective muscarinic receptor antagonist (atropine) prevented TUA-induced diuresis. In addition, indomethacin (a cyclooxygenase inhibitor) and atropine, exhibited the ability to block the diuretic effects prompted by PMF. Our study demonstrates the diuretic effect of extracts, fractions and two natural compounds obtained from R. rosaefolius leaves in rats.

Diuretic, natriuretic and potassium-sparing effect of nothofagin isolated from Leandra dasytricha (A. Gray) Cogn. leaves in normotensive and hypertensive rats

Active constituents from natural origin have long been used for the treatment of patients suffering from cardiovascular and renal diseases. This study therefore aimed to investigate the diuretic and natriuretic properties of nothofagin, a dihydrochalcone isolated from Leandra dasytricha (A. Gray) Cogn. leaves in normotensive and hypertensive rats. Male Wistar normotensive rats were orally treated with vehicle (1xa0ml/kg); hydrochlorothiazide (HCTZ; 25xa0mg/kg); ethyl acetate fraction from L.xa0dasytricha (EALD; 3-30xa0mg/kg) and nothofagin (NOT; 0.3-3xa0mg/kg). Spontaneously hypertensive rats (SHR) received NOT (1xa0mg/kg), HCTZ (25xa0mg/kg) or vehicle. The cumulative diuretic index, urinary electrolytes excretion (Na+ and K+), pH, density and conductivity were measured at the end of the experiment (after 8xa0h). A7r5 and L929xa0cell lines were used to measure cell viability after exposure to NOT. Nitric oxide generation was quantified in A7r5 cell supernatant, and DPPH assay was used for evaluating the antioxidant properties of NOT. The urinary volume of normotensive rats were increased after the treatment with EALD, without any changes in Na+ or K+ excretion. NOT was able to induce diuresis and natriuresis, but not kaliuresis, in both normotensive and hypertensive rats. The reduction in prostanoids generation through cyclooxygenase inhibition, as well as the muscarinic receptor antagonism, fully avoided NOT-induced increases in diuretic index. NOT, which did not interfere with L929 or A7r5 cell viability, was able to stimulate nitric oxide generation in A7r5 cell, besides showing an antioxidant effect in scavenging the free-radical DPPH. Taken together, our study shows, for the first time, the diuretic, natriuretic and potassium-sparing effect of nothofagin in rats, which was associated with prostanoids generation, muscarinic receptor activation and antioxidant properties.

Gastroprotective xanthones isolated from Garcinia achachairu: Study on mucosal defensive factors and H+, K+-ATPase activity

The present study was designed to investigate the gastroprotective effect of xanthones 7-preniljacareubin (PJB), 1,3,5,6-tetrahydroxy xanthone (THX), 3-demethyl-2-geranyl-4-prenylbellidypholine (DGP) and 1,5,8-trihydroxy-4, 5-dimethyl-2H-pyrane (2,3:3,2)-4-(3-methylbut-2-enyl) xanthone (TDP) isolated of branches from G.xa0achachairu. Their structures were identified through the spectroscopic analysis in comparison with previously reported data. The xanthones were tested at dose of 10xa0mg/kg against ethanol 60%/HCl 0.3xa0N-induced gastric ulcer in female swiss mice. The xanthones PJB, THX, DGP and TDP exhibit gastroprotective effect after intraperitoneal treatment, but only the first two displayed anti-ulcer activity after oral administration. Both PJB and THX augmented the antioxidative capacity of tissue by an increase in glutathione levels, as well as were able to prevent an increase in myeloperoxidase activity and tumor necrosis factor level. On the other hand, only THX showed an inxa0vitro free radical scavenger activity, and only PJB avoided mucus depletion on gastric mucosa, which was not associated with an increase in mucin production at glandular level. In addition, PJB and THX inhibited the inxa0vitro H(+)K(+)-ATPase activity at similar range as omeprazole. Together, these results demonstrate the anti-ulcer efficacy of xanthones isolated from G.xa0achachairu, which can contribute for future directions in the development of effective strategies to improve gastric diseases.