Purification of gastroprotective triterpenoids from the stem bark of Amphipterygium adstringens; role of prostaglandins, sulfhydryls, nitric oxide and capsaicin-sensitive neurons

Gastroprotective effect of a flavone from Lonchocarpus araripensis Benth. (Leguminosae) and the possible mechanism

The gastroprotective effect of DDF (3,6-dimethoxy-6“, 6”-dimethyl-[2“, 3”: 7,8]-chromeneflavone) from Lonchocarpus araripensis Benth. (Leguminosae) on gastric damage induced by absolute ethanol (96%, 0.2 mL/mouse) and indometacin (30 mg kg−1, p.o.) in mice was investigated. Intraperitoneally administered DDF at dose levels of 50, 100 and 200 mg kg−1 markedly reduced the gastric lesions in the ethanol model by 62, 72 and 96%, and in the indometacin model by 34, 70 and 75%, respectively, as compared with misoprostol (50 μg kg−1, p.o.), the reference compound that caused lesion suppression by 67% in ethanol model and by 72% against indometacin-induced ulceration. The ED50 of DDF in reducing gastric lesions induced by ethanol and indometacin (dose of the DDF that reduced the gastric lesion area by 50% in relation to the control value) was 50.87 and 61.56 mg kg−1, respectively. Mechanistic studies were carried out at 100 mg kg−1 DDF using the ethanol model. Compared with N-acetylcysteine (750 mg kg−1, p.o.), a donor of sulfhydryls, DDF only partially replenished the ethanol-induced depletion of gastric mucosal NP-SH. Pretreatment with TRPV1 antagonist capsazepine (5 mg kg−1, i.p.) or the non-selective cyclooxygenase inhibitor indometacin (10 mg kg−1, p.o.) effectively blocked the gastroprotective effect of DDF (100 mg kg−1) against ethanol damage. Furthermore, the effect of DDF was significantly reduced in mice pretreated with L-NAME, or glibenclamide, the respective inhibitors of nitric oxide synthase and K+ATP channel activation. These data provide evidence to show that DDF affords gastroprotection against gastric damage induced by ethanol and indometacin by different and complementary mechanisms, which include involvement of endogenous prostaglandins, nitric oxide release, the activation of TRPV1 receptor or K+ATP channels, besides a sparing effect on NP-SH reserve.

Gastroprotection and effect of the simultaneous administration of Cuachalalate (Amphipterygium adstringens) on the pharmacokinetics and anti-inflammatory activity of diclofenac in rats

This work aimed to study the effect of Cuachalalate methanol extract (CME) on the anti-inflammatory activity and pharmacokinetics of diclofenac sodium, a frequently prescribed non-steroidal antiinflammatory drug (NSAID). The gastroprotective effect of CME on the gastric injury induced by diclofenac was studied in rats. CME showed a gastroprotective effect of 15.7% at 1 mg kg−1 and 72.5% at dose of 300 mg kg−1. Omeprazole, used as anti-ulcer reference drug, showed gastroprotective effects of 50–89.7% at doses tested (1–30 mg kg−1). The value of the 50% effective dose for the anti-inflammatory effect of diclofenac sodium (ED50 = 1.14 ± 0.23 mg kg−1) using carrageenaninduced rat paw oedema model, was not modified by the concomitant administration of 30 or 100 mg kg−1 of CME. The effect of CME (30, 100 and 300 mg kg−1, p.o.) on the pharmacokinetics of diclofenac sodium was studied. It was observed that the simultaneous administration of diclofenac sodium and 300 mg kg−1 of CME decreased significantly the values of Cmax (7.08 ± 1.42 μg mL−1) and AUC (12.67 ± 2.97 μg h mL−1), but not the value of tmax (0.13 (0.1–0.25) h) obtained with the administration of diclofenac alone. The simultaneous administration of 30 or 100 mg kg−1 of CME did not modify the pharmacokinetic parameters of diclofenac. The experimental findings in rats suggest that CME at doses lower than 100 mg kg−1 protects the gastric mucosa from the damage induced by diclofenac sodium without altering either the anti-inflammatory activity or the pharmacokinetics of this NSAID.

Gastroprotective and cytotoxic effect of semisynthetic ferruginol derivatives

The gastroprotective abietane diterpene ferruginol has been shown to present high cytotoxicity. In order to obtain active compounds with less cytotoxicity, 18 semisynthetic ferruginol derivatives and totarol were assessed for their gastroprotective effects in the HCl/ethanol-induced gastric lesion model in mice, as well as for cytotoxicity in human gastric epithelial cells (AGS) and human lung fibroblasts (MRC-5). At 20 mg kg−1, the greatest gastroprotective effects were provided by abieta-8,11,13-triene (1), abieta-8,11,13-trien-12-yl-2-chloropropanoate (8), abieta-8,11,13-trien-12-yl propenoate (9), 12-(2,3,4,6-tetra-O-acetyl-β-D-glucopyranosyloxy)-abieta-8,11,13-triene (17) and 12-(β-D-galactopyranosyloxy)-abieta-8,11,13-triene (18), all of which were as active as the reference drug lansoprazole at 20 mg kg−1, reducing gastric lesions by 69, 76, 67, 72 and 61%, respectively. No relation was observed between lipophilicity and the gastroprotective effect. Compounds that showed the greatest cytotoxicity towards AGS cells were ferruginol (2), the corresponding formate (5), acetate (6), propionate (7), 8, 9, 12-(β-D-glucopyranosyloxy)-abieta-8,11,13-triene (16), 18 and totarol (20) (IC50 18–44 μM). Ferruginol and compounds 5–9, 16, 18 and 20 were the most toxic compounds against fibroblasts (IC50 19–56 μM), with a correlation to AGS cells. The derivative 19 was much more active against AGS cells than towards fibroblasts. The best activity/cytotoxicity ratio was found for compound 17, with a lesion index comparable with lansoprazole at 20 mg kg−1 and cytotoxicity >1000 μM towards MRC-5 and AGS cells, respectively. In conclusion, some derivatives showed a better gastroprotective effect/cytotoxicity ratio than the parent compound ferruginol. A total of 13 new compounds are reported here for the first time.

Antimycobacterial agents from selected Mexican medicinal plants

As part of the ICBG program Bioactive Agents from Dryland Biodiversity of Latin America, the present investigation was undertaken to explore the possible antimycobacterial potential of compounds derived from selected Mexican medicinal plants. Bioassay-guided fractionation of the crude extracts of Rumex hymenosepalus (Polygonaceae), Larrea divaricata (Zygophyllaceae), Phoradendron robinsonii (Loranthaceae) and Amphipteryngium adstringens (Julianiaceae) led to the isolation of several antimycobacterial compounds. Four stilbenoids, two flavan-3-ols and three anthraquinones were isolated from R. hymenosepalus. Two flavonols and nordihydroguaiaretic acid were obtained from L. divaricata. Sakuranetin was the antimycobacterial agent isolated from P. robinsonii. Two known triterpenoids and the novel natural product 3-dodecyl-1,8-dihydroxy-2-naphthoic acid were obtained from A. adstringens. In general, the isolates were identified by spectral means. The antimycobacterial activity of the secondary compounds isolated from the analysed species, as well as that of nine pure compounds previously isolated in our laboratories, was investigated; the MIC values ranged from 16 to 128μ mL−1. Among the tested compounds, the glycolipids, sesquiterpenoids and triterpenoids showed the best antimycobacterial activity. The antimycobacterial property of the glycolipids is reported for the first time. Although the tested compounds showed moderate antimycobacterial activity, their presence in the analysed species provides the rationale for their traditional use in the treatment of tuberculosis.

Gastroprotective effect of barbatusin and 3-beta-hydroxy-3-deoxibarbatusin, quinonoid diterpenes isolated from Plectranthus grandis, in ethanol-induced gastric lesions in mice

ETHNOPHARMACOLOGICAL RELEVANCE

Validate the popular use of Plectranthus grandis in gastric disorders through the active components.

AIMS

Isolation of barbatusin (BB) and 3beta-hydroxy-3-deoxibarbatusin (BBOH), diterpenes from Plectranthus grandis, and evaluation of their gastroprotective effect and possible mechanisms of action.

MATERIALS AND METHODS

Isolation and chemical characterization of diterpenes from Plectranthus grandis by chromatographic and spectroscopic methods and evaluation of gastroprotective action of the diterpenes through ethanol-induced gastric injury in mice model. It was evaluated the effect of capsazepine, indomethacin and the role of nitric oxide and K(ATP-) channels on the gastroprotective effect of BBOH and BB. Additionally it was measured the concentrations of gastric mucus, non-proteic-sulfhydryl groups and total thiobarbituric acid-reactive substances.

RESULTS

Orally administered BBOH and BB at doses of 5 and 10mg/kg, markedly reduced the gastric lesions by 59 and 96%, and 32 and 76%, respectively, with superior results as compared to N-acetylcysteine (150 mg/kg, i.p.), reference compound that caused 85% lesion suppression. Although BBOH presented a higher gastroprotection than BB they act by similar mechanisms in relation to N-acetylcysteine, and prevent the depletion of gastric mucus, gastric mucosal non-proteic-sulfhydryl groups as well as the increase in thiobarbituric acid-reactive species. Moreover, the gastroprotective effect of BB was effectively blocked in mice pretreated with TRPV1 antagonist capsazepine, by the non-selective cyclooxygenase inhibitor indomethacin, or by the nitric oxide synthase inhibitor L-NAME but not by K(+)(ATP) channel inhibitor glibenclamide. In contrast, the gastroprotective effect of BBOH was blocked only by indomethacin and glibenclamide pretreatments.

CONCLUSION

The protective role for BBOH and BB affording gastroprotection against gastric damage induced by ethanol indicates that these compounds contribute for the activity of Plectranthus species. The different modes of action are probably related to differences in their chemical structure.

Protective effect of anacardic acids from cashew (Anacardium occidentale) on ethanol-induced gastric damage in mice

Cashew nut-shell liquid and the contained anacardic acids (AAs) have been shown to possess antioxidant, lipoxygenase inhibitory, anti-Helicobacter pylori and antitumor properties. Despite these known effects, hitherto there were no published reports on their likely gastroprotective effects. The present study was designed to verify whether AAs afford gastroprotection against the ethanol-induced gastric damage and to examine the underlying mechanism(s). Gastric damage was induced by intragastric administration of 0.2mL of ethanol (96%). Mice in groups were pretreated orally with AAs (10, 30 and 100mg/kg), misoprostol (50 microg/kg), or vehicle (2% Tween 80 in saline, 10mL/kg), 45min before ethanol administration. They were sacrificed 30min later, the stomachs excised, and the mucosal lesion area (mm(2)) measured by planimetry. Gastroprotection was assessed in relation to inhibition of gastric lesion area. To study the gastroprotective mechanism(s), its relations to capsaicin-sensitive fibers, endogenous prostaglandins, nitric oxide and ATP-sensitive potassium channels were analysed. Treatments effects on ethanol-associated oxidative stress markers GSH, MDA, catalase, SOD, and total nitrate/nitrite levels as an index of NO were measured in gastric tissue. Besides, the effects of AAs on gastric secretory volume and total acidity were analysed in 4-h pylorus-ligated rat. AAs afforded a dose-related gastroprotection against the ethanol damage and further prevented the ethanol-induced changes in the levels of GSH, MDA, catalase, SOD and nitrate/nitrite. However, they failed to modify the gastric secretion or the total acidity. It was observed that the gastroprotection by AAs was greatly reduced in animals pretreated with capsazepine, indomethacin, l-NAME or glibenclamide. These results suggest that AAs afford gastroprotection principally through an antioxidant mechanism. Other complementary mechanisms include the activation of capsaicin-sensitive gastric afferents, stimulation of endogenous prostaglandins and nitric oxide, and opening of K(+)(ATP) channels. These combined effects are likely to be accompanied by an increase in gastric microcirculation.

Gastroprotective effect and cytotoxicity of abietane diterpenes from the Chilean Lamiaceae Sphacele chamaedryoides (Balbis) Briq

Objectives

The aim of this report was to isolate, identify and assess the gastroprotective effect and cytotoxicity of abietane diterpenes from the Chilean medicinal plant Sphacele chamaedryoides (Balbis) Briq. (Lamiaceae).

Methods

The isolated compounds were identified by spectroscopic means. The gastroprotective effect of the compounds was studied on the HCl/EtOH-induced gastric lesions model in mice. The cytotoxicity of the compounds was assessed on human normal lung fibroblasts (MRC-5) and gastric adenocarcinoma cells (AGS).

Key findings

From the aerial parts of the plant, five phenolic and five p-quinone abietanes, the sesquiterpene spathulenol and two flavonoids were obtained. The main diterpene from the plant was carnosol (7). Lansoprazole at 20 mg/kg reduced gastric lesions by 64.7% (P < 0.01), being statistically similar to carnosol at doses of 10 and 20 mg/kg; the percent lesion reduction with 7 at 5 mg/kg was 49.3%. At a single oral dose of 5 mg/kg, the diterpenes bearing a p-quinone moiety −6,7-dehydroroyleanone (1), royleanone (2), 7,20-epoxyroyleanone (3), taxoquinone (5) and horminone (6) - presented a gastroprotective effect of 54.4, 70.8, 65.0, 35.8 and 52.7%, respectively. Of the C-7 hydroxy derivatives, the activity was much lower for the 7β-OH isomer. The phenolic diterpenes 7 and 7-oxo-11,12,14-trihydroxy-8,11,13-abietatrien-20-al (8) inhibited gastric lesions by 49.3 and 53.0%, respectively. Royleanone (2), 7,20-epoxyroyleanone (3), horminone (6), 8 and spathulenol proved to be cytotoxic with IC50 values in the range of 11–67 μM. The selective cytotoxicity of compounds 1 (IC50: 61 and 366 μM) and 5 (IC50: 310 and 27 μM) against AGS cells and fibroblasts, respectively, merit additional studies.

Conclusions

All the abietanes obtained from S. chamaedryoides present either one or two phenolic OH groups, a quinone system, or both. Several compounds present in the plant showed higher gastroprotective effect than lansoprazole. The cytotoxic effect of most compounds was found at fairly high concentrations and lacked cell specificity. Further studies are required using different tumour cell lines and viability/proliferation assays to assess the specificity of the isolated compounds. The selective cytotoxicity of compounds 1 and 5 against AGS cells and fibroblasts, respectively, merit additional studies.

Bioassay-guided isolation of an anti-ulcer chromene from Eupatorium aschenbornianum: role of nitric oxide, prostaglandins and sulfydryls

Eupatorium aschenbornianum is considered useful in the treatment of gastric ulcer. In the current study the validity of this practice was tested by using the experimental model of an ethanol induced gastric ulcer in rats. The results show that E. aschenbornianum had gastroprotective activity, that the hexane extract had the highest protective activity (85.65+/-4.76%), and that encecanescin isolated from this extract was the main active gastroprotective agent. The effect elicited by encecanescin was attenuated by N(G)-nitro-L-arginine methyl ester, N-ethylmaleimide and indomethacin, which suggests that NO, prostaglandins and sulfydryl groups are involved in the mechanisms of gastroprotective action.

Chemosensory perception and medicinal plants for digestive ailments in a Mapuche community in NW Patagonia, Argentina

AIM OF THE STUDY

To document the richness of plant species used in gastrointestinal disorders and to investigate about the criteria of aroma and flavor associated with its recognition, classification, selection and use.

MATERIALS AND METHODS

Ethnobotanical fieldwork consisted of interviews to 30 inhabitants living in a Mapuche community of Northwestern Patagonia; data collected was analyzed by means of non-parametric statistics.

RESULTS

This work records 75 ethnospecies, pertaining to 40 botanic families. Lamiaceae, Asteraceae and Chenopodiaceae were the most frequently mentioned and described in terms of smell and taste. Most of species (69%) have notable aroma and/or flavor characteristics. The species presenting highest consensus in the population are positively associated with a higher frequency of organoleptic descriptions. In addition, local people consider these perceptions to be potentially useful in the search for substitutes when species are scarce or disappear from a locality.

CONCLUSIONS

It is possible to establish a preliminary system of classification of medicinal plants based on their organoleptic characteristics and relate this to their effects on health. Moreover the cultural interpretation of smell and taste is of great heuristic importance to ethnopharmacology, in that it indicates which plants are most likely to contain the main active ingredients sought.

Mouririelliptica: validation of gastroprotective, healing and anti-Helicobacter pylori effects

ETHNOPHARMACOLOGICAL RELEVANCE

Mouriri elliptica Martius (Melastomataceae) is species reputed in folk medicine to heal gastric ulcer and gastritis.

AIM OF THE STUDY

Methanolic extract (ME) and ethyl acetate fraction (EAF) from leaves of Mouriri elliptica were evaluated for their gastroprotective, healing, immunological, toxicological and anti-Helicobacter pylori activities.

MATERIAL AND METHODS

The gastroprotective action of ME and EAF was evaluated in rodent experimental models and to elucidate mechanisms of action, the antisecretory action, involvements of NO, SH, PGE(2), anti-Helicobacter pylori action of ME was evaluated. We also used immunohistochemical (PCNA and COX-2) and immunomodulatory (murine peritoneal macrophages) assays to evaluate Mouriri elliptica effects.

RESULTS

ME present gastroprotective action without antisecretory effect. Otherwise, ME showed anti-Helicobacter pylori action (MIC=0.025mug/mL) and was able to inhibit NO production by macrophages. This species also accelerate the healing of ulcerated gastric mucosa by stimulating proliferation factors (PCNA), COX-2 and maintained basal PGE(2) level independent action of NSAID in gastric mucosa. The phytochemical investigation showed that this species possesses phenolic acid derivatives, acylglycoflavonoids and condensed tannins which probably influenced their pharmacological action.

CONCLUSION

All these results suggest the efficacy and safety of Mouriri elliptica in combating and healing gastric ulcer.

Brazilian medicinal plant acts on prostaglandin level and Helicobacter pylori

Among the current treatment strategies for the peptic ulcer patient with Helicobacter pylori infection, the method of choice is triple therapy based on the concurrent use of proton inhibitors and two antibiotics. Alchornea triplinervia is a medicinal plant commonly used by people living in the Cerrado region of Brazil to treat gastrointestinal ulcers. In the present work we proposed therapy based on this medicinal plant that presents effective gastroprotective action with antibiotic effects. Oral pretreatment with methanolic extract (ME) of A. triplinervia in rats and mice decreased the gastric injuries induced by ethanol and HCl/ethanol. Increasing the dose reduced the gastroprotective effects of ME on the gastric lesions induced by nonsteroidal anti-inflammatory drug. After pylorus ligature of mice, oral administration of ME induced a decrease not only in total acid but also in the ulcer index. We also observed that ME displayed antibacterial activity against H. pylori. Liquid-liquid separation of ME indicated that active constituents responsible for the gastroprotective action are concentrated in the ethyl acetate fraction (EAF) (50% protection) rather than in the aqueous fraction, which did not induce significant gastroprotection at the same dose (100 mg/kg). EAF induced an increase of gastric mucosa prostaglandin (PG) E(2) levels, which remained high even after previous administration of indomethacin. The phytochemical profile of ME revealed that EAF contains mainly flavonoids. In conclusion, all these results suggest that ME did not show acute toxicity, but exhibited an antisecretory property, anti-H. pylori effect, and gastroprotective action. The observed effect did not involve the participation of nitric oxide or endogenous sulfhydryl groups. However, EAF showed a more efficient gastroprotective effect than ME at a lower dose and protected the gastric mucosa by increasing PGE(2).

The anti-ulcerogenic effects of Curatella americana L

ETHNOPHARMACOLOGICAL RELEVANCE

Curatella americana L. (Dilleneaceae) is a medicinal plant very frequently cited as acting against gastrointestinal disorders in ethnopharmacological inventories of the Cerrado region of Brazil.

AIM OF THE STUDY

The ethanolic extract (CEB) and infusion (BI) of Curatella americana bark were investigated for their ability to prevent and heal ulceration of the gastric mucosa.

MATERIALS AND METHODS

The preventive and healing actions of Curatella americana were evaluated in experimental in vivo models in rodents that simulated this disease in human gastric mucosa.

RESULTS

CEB significantly decreased the severity of gastric damage formation induced by the combination of several gastroprotective models (HCl/ethanol, indomethacin/bethanecol, absolute ethanol, stress and pylorus ligature). But, unlike CEB, the BI did not exert gastroprotective effect. The gastroprotective action of CEB involved antisecretory action, augmentation of gastric mucus (48%) and participation of endogenous sulfhydryl compounds that increase efficacy of barrier mucosa against injurious agents. CEB also presents effective healing action in chronic gastric disease (1.90+/-0.55 vs. 6.86+/-0.46 mm2)in the control) and its action mechanisms consisted of increasing the PGE2 (40%) and somatostatin levels (269%) while decreasing the gastrin level in rat plasma (79%).

CONCLUSIONS

The gastroprotective effect and healing action of Curatella americana involved modulation of PGE2, somatostatin and gastrin levels, probably due to the presence of oligomeric and polymeric proanthocyanidins in the bark.

Antioxidative action of methanolic extract and buthanolic fraction of Vochysia tucanorum Mart. in the gastroprotection

AIM OF THE STUDY

Vochysia tucanorum is an important medicinal plant used in the Cerrado of Brazil against gastric disorders and this study reveals the pharmacological action of this traditional medicine use.

MATERIALS AND METHODS

The methanolic extract (E-MeOH) and buthanolic fraction (Fr-Bu) obtained from V. tucanorum were challenged by different necrotizing agents in rodents. NO-synthase inhibitor (L-NAME) and SH blocker (NEM) were used to evaluate the participation of cytoprotective factors in E-MeOH and Fr-Bu gastroprotection. Antiulcerogenic action of V. tucanorum was evaluated in rats and mice at doses 250, 500 or 1000 mg/kg (E-MeOH) and 37.5, 75 or 150 mg/kg (Fr-Bu).

RESULTS

Both E-MeOH and Fr-Bu present elevated gastroprotective action in all in vivo experimental models, without signs of acute toxicity. The mechanisms involved in the gastroprotective action of E-MeOH and Fr-Bu are related to the antioxidant activity and protection to gastric mucosa NO levels. Phytochemical investigations of Fr-Bu identified different pentacyclic triterpenoids such as betulinic acid, erythrodiol, epi-betulinic acid and mixtures of ursolic acid and oleanolic acid derivatives as the major constituents. The presence of such triterpenoids in Fr-Bu is probably related to the potent gastroprotective action of this medicinal plant species.

CONCLUSION

Effectiveness in gastroprotection and the absence of acute toxicity indicate this species as a promising herbal drug that is in accordance with ethnopharmacological use against gastric disorders.

Byrsonima fagifolia: an integrative study to validate the gastroprotective, healing, antidiarrheal, antimicrobial and mutagenic action

ETHNOPHARMACOLOGICAL RELEVANCE

Ethnopharmacological survey indicated leaves of Byrsonima fagifolia Nied. (Malpighiaceae) against gastrointestinal disorders.

AIM OF THE STUDY

The methanolic extract from the leaves of Byrsonima fagifolia (denominated BF) was evaluated for toxic, mutagenic, gastroprotective, antidiarrheal, antibacterial and immunomodulatory activities.

MATERIALS AND METHODS

The preventive and healing action of BF against gastric ulcer was evaluated in experimental models in rodents. We evaluated immunomodulatory (by murine peritoneal macrophages), antidiarrheal (by induced diarrhea with castor oil and intestinal motility) and antibacterial action of BF against standard strain of Escherichia coli, Staphylococcus aureus and Helicobacter pylori. The safety of use of BF was also evaluated by mutagenic (Ames assay) and by analyses of toxicity parameters.

RESULTS

Phytochemical BF profile indicated the presence of phenolic compounds with antioxidant and radical-scavenging properties. BF significantly inhibited gastric lesions induced by ethanol and HCl/ethanol and endogenous mucosal sulphydryl groups (SHs) participated efficaciously in BF gastroprotection. BF blocked development of inflammation process and also has antidiarrheal actions. This extract accelerated the healing of the gastric ulcerated mucosa by stimulating proliferative factors and by increasing production of gastric mucus with no toxic action. The substances responsible for the protective action are concentrated in the ethyl acetate fraction that demonstrated no mutagenic action in vitro.

CONCLUSIONS

Byrsonima fagifolia presents gastroprotective, healing and antidiarrheal activities supporting previous claims that its traditional use by Brazilians can treat these gastrointestinal ailments.

Hancornia speciosa: indications of gastroprotective, healing and anti-Helicobacter pylori actions

ETHNOPHARMACOLOGICAL RELEVANCE

Mangaba (Hancornia speciosa Gomez) is a medicinal plant frequently cited in ethnopharmacological inventories of the central region of Brazil against gastrointestinal disorders such as diarrhoea, ulcer, gastritis and stomach ache.

AIM OF THE STUDY

The hydroalcoholic extract (HE) and infusion (BI) of Hancornia speciosa bark were investigated for their ability to prevent and heal rodent gastric ulcer.

MATERIALS AND METHODS

The preventive and healing action of both preparations of Hancornia speciosa were evaluated in experimental models in rodents that simulated this disease in human gastric mucosa.

RESULTS

BI did not exert gastroprotective effect, in contrast to HE (500mg/kg, p.o.) that decreased (p<0.05) the severity of gastric damage induced by HCl/ethanol (52%), indomethacin/bethanechol (51%), stress (52%) or pylorus ligature experiments (54%). HE increased (p<0.05) the pH and decreased acid output of gastric juice. This extract promoted increase of mucus amount (3.62mg/wt. tissue vs. 5.81mg/wt. tissue), healing action (67%) and displayed anti-Helicobacter pylori effect.

CONCLUSIONS

The antiulcer action of Hancornia speciosa resulted in increase of gastric mucus formation and antioxidant properties of polymeric proanthocyanidins present in the bark composition of this medicinal plant.

Bioassay-guided isolation of an anti-ulcer diterpenoid from Croton reflexifolius: role of nitric oxide, prostaglandins and sulfhydryls

Croton reflexifolius H. B. K (Euphorbiaceae) is a very common medicinal plant in the Huastecan region of Mexico that, according to local folk medicine, is considered useful in the treatment of gastritis and gastric ulcer. We have aimed to test the validity of this practice by using the experimental model of an ethanol-induced gastric ulcer in male Wistar rats. The results showed that C. reflexifolius had gastroprotector activity, that the hexane extract had the highest protective activity (64.38+/-7.72%), and that polyalthic acid isolated from this extract was the main active gastroprotector agent. Rats treated orally with polyalthic acid showed a gastroprotective effect similar to that elicited by carbenoxolone. As with carbenoxolone, the effect elicited by polyalthic acid was attenuated by pretreatment with either N(G)-nitro-L-arginine methyl ester (70 mgkg(-1), i.p.), a nitric oxide (NO) synthase inhibitor, or N-ethylmaleimide (10 mgkg(-1), s.c.), a blocker of sulfhydryl groups. This suggested that the gastroprotective mechanism of this diterpenoid involved the participation of both NO and endogenous sulfhydryl groups. Contrary to carbenoxolone, the gastroprotective effect of polyalthic acid was not affected by the inhibition of prostaglandin synthesis with indometacin (10 mgkg(-1), s. c.). In conclusion, Croton reflexifolius contains compounds with gastroprotector activity. Polyalthic acid, which was isolated from this plant, was the main compound with gastroprotector activity, having effectiveness similar to that found with the use of carbenoxolone. Whereas NO and sulfhydryl groups were involved in the mechanisms of gastroprotective action of polyalthic acid, prostaglandins were not.

Evaluation of the antiulcerogenic and analgesic activities of Cordia verbenacea DC. (Boraginaceae)

ETHNOPHARMACOLOGICAL RELEVANCE

Cordia verbenacea is a medicinal plant popularly used in Brazil as anti-inflammatory, antiulcer and anti-rheumatic agent without detailed pharmacological and toxicological studies.

AIM OF THE STUDY

The study was aimed to investigate the effects of Cordia verbenacea in antiulcer, analgesic and antioxidant assays, as well as to evaluate its toxic effects and phytochemical profile.

MATERIAL AND METHODS

Antiulcer activity of plant extract was evaluated using ethanol/HCl, ethanol and piroxican-induced gastric lesions methods. The pH, volume and total acid of gastric juice were determined by pylorus-ligated assay. Analgesic activity was evaluated by writhing, tail-flick and hot-plate tests. Antioxidant activity was determined by in vitro lipoperoxidation assay. Acute toxicity and number of deaths were evaluated by Hippocratic screening.

RESULTS

The ethanol leaf extract shows a potent antiulcer activity in the ethanol/HCl and absolute ethanol-induced gastric lesions. The IC(50) value of plant extract on the lipid peroxidation was 76.11mug/ml. Preliminary phytochemical tests were positive for flavonoids, steroids, saponins, fixed acids, alkaloids and phenols. In the analgesic models the extract did not present any activity.

CONCLUSIONS

Cordial verbenaceae showed a potent antiulcer activity at the dose of 125mg/kg and this effect may be associated with an improvement in stomach antioxidant mechanisms.

Gastroprotective effect of Cissus sicyoides (Vitaceae): involvement of microcirculation, endogenous sulfhydryls and nitric oxide

AIM OF THE STUDY

Cissus sicyoides L. is a medicinal plant popularly known in Brazil against various diseases and the research interest in this plant is justifiable because of its potential medicinal value in stomachache and gastric ulcer.

MATERIALS AND METHODS

The methanolic extract obtained from the leaves of Cissus sicyoides (Cc) was evaluated for the ability to protect the gastric mucosa against injuries caused by necrotizing agents (0.3 M HCl/60% EtOH, absolute ethanol, piroxicam and pylorus ligature) in rodents. We also evaluated microcirculation, antioxidant action and participation of NO (nitric oxide) and sulfhydryls (SH) groups in the Cc gastroprotective action.

RESULTS

Administration of Cc significantly reduced gastric lesions induced by different ulcerogenic agents in rodents. This extract administered by oral route significantly increased gastric volume without exerting antisecretory effect. The Cc effect involved an increase of the defense mechanism of the gastrointestinal mucosa such as NO and SH groups that prevent and attenuate the ulcer process. The Cc also has antioxidant property against oxidative stress but does not modify microcirculation response in gastric mucosa.

CONCLUSIONS

These results confirmed the traditional use of Cissus sicyoides for the treatment of gastric ulcer.

Role of Prostaglandins, Nitric oxide, Sulfhydryls and Capsaicin-sensitive Neurons in Gastroprotection of Stigmasterol and β-Sitosterol

In this investigation the gastroprotective activity of stigmasterol and β-sitosterol was evaluated. Gastric mucosal damage was induced in rats by intragastric ethanol (1 mL/rat). Rats treated orally with stigmasterol suspended in Tween 80 at 10, 30, 100 and 300 mg kg−1 showed 26.2, 39.6, 58.3 and 70.7% gastroprotection, respectively. β-Sitosterol at 10, 30,100 and 300 mg kg−1 showed 21.6, 42.5, 48.5 and 71.2% gastroprotection, correspondingly. The gastroprotection observed at 30 mg kg−1 for stigmasterol and β-sitosterol was attenuated in rats pretreated with indomethacin, (10 mg kg−1, s. c.), NG-nitro-L-arginine methyl ester (L-NAME, 70 mg kg−1, i. p.) and capsaicin (125 mg kg−1, s. c), suggesting that the gastroprotective mechanism of these sterols involves, at least in part, the participation of prostaglandins, nitric oxide (NO) and capsaicin-sensitive sensory neurons (CPSN). The gastroprotection of β-sitosterol was also attenuated by the pretreatment with N-ethylmaleimide (NEM, 10 mg kg−1, s. c.) indicating that endogenous sulfrydryls may be involved in the gastrorpotection of this compound. Carbenoxolone was used as a gastroprotective model drug and showed a dose-dependent gastroprotective effect (25.7, 33.6 and 88.3% of gastroprotection, at 3, 10 and 30 mg kg−1, respectively). The partial participation of PGs, sulfhydryls and NO was observed in the gastroprotective mechanism of carbenoxolone.

Vernonia polyanthes as a new source of antiulcer drugs

Methanolic (VPME) and chloroformic (VPCL) extracts, obtained from the aerial parts of Vernonia polyanthes, were investigated for its antiulcerogenic properties. Administration of VPME (250 mg/kg) and VPCL (50 mg/kg) significantly inhibited the gastric mucosa damage (64% and 90%, respectively) caused by absolute ethanol (p.o.). Otherwise, in NSAID-induced gastric damage, their gastroprotective effects have decreased. Since the VPCL extract resulted to be more effective than the VPME we focused our efforts over VPCL action mechanism of action.

Anti-Helicobacter pylori activity of anacardic acids from Amphipterygium adstringens

Amphipterygium adstringens (Schltdl.) Standl. (Anacardiaceae) is widely used in traditional Mexican medicine for the treatment of gastritis and ulcers. In this work, we studied the anti-Helicobacter pylori activity of its bark, this Gram-negative bacterium is considered the major etiological agent of chronic active gastritis and peptic ulcer disease, and it is linked to gastric carcinoma. From a bio-guided assay of the fractions obtained form a continuous Soxhlet extraction of the bark, we identified that petroleum ether fraction had significant antimicrobial activity against Helicobacter pylori. From this fraction, we isolated an anacardic acids mixture and three known triterpenes: masticadienonic acid; 3alpha-hydroxymasticadienonic acid; 3-epi-oleanolic; as well as the sterol beta-sitosterol. Only the anacardic acids mixture exhibits a potent dose-dependent antibacterial activity (MIC=10 microg/ml in broth cultures). It is enriched in saturated alkyl phenolic acids (C15:0, C16:0, C17:0 C19:0) which represents a novel source of these compounds with potent anti-Helicobacter pylori activity. The promising use of anacardic acids and Amphipterygium adstringens bark in the development of an integral treatment of Helicobacter pylori diseases is discussed.

Constituents and antiulcer effect of Alchornea glandulosa: activation of cell proliferation in gastric mucosa during the healing process

Alchornea glandulosa (Euphorbiaceae) is a plant used in folk medicine as an antiulcer agent. Rats pretreated with methanolic extract obtained from the leaves of A. glandulosa (AG) showed a dose-dependent effect and significant reduction of gastric ulcers induced by absolute ethanol at the doses of 500 (57%) and 1000 mg/kg (85%) in relation to the control group. Pretreatment of mice with AG (500, 1000 mg/kg, p.o.) showed dose-dependent activity and significantly decreased the severity of lesions caused by HCl/ethanol and by non steroidal anti inflammatory drug-induced gastric lesions. Pretreatment with AG also induced antisecretory action via local and systemic routes and a significant decrease in the total gastric acid content. The gastroprotective effects of AG involved the participation of nitric oxide and increased levels of endogenous sulfhydryl compounds, which are defensive mechanisms of the gastrointestinal mucosa against aggressive factors. The ability of AG to heal gastric ulcers was evaluated after 14 consecutive days of treatment. The results showed that single oral administrations of AG (250 mg/kg/once daily) potently stimulates gastric epithelial cell proliferation that contributes to the accelerated healing of gastric ulcers induced by acetic acid. In addition, no subacute toxicity (body weight gain, vital organs, and serum biochemical parameters) was observed during treatment with AG. Phytochemical investigation of AG led to the isolation of myricetin-3-O-alpha-L-rhamnopyranoside, quercetin-3-O-alpha-L-arabinopyranoside, quercetin-3-O-beta-D-galactopyranoside, quercetin, amentoflavone, methyl gallate, gallic acid, and pterogynidine. We also established the phytochemical profile of AG with the quantification of total phenolic compounds. These compounds may contribute to the observed antiulcerogenic effects of AG.

Gastroprotective effect and cytotoxicity of terpenes from the Paraguayan crude drug "yagua rova" (Jatropha isabelli)

A new jatrophone derivative (6), jatrophone (3), jatropholone A (4) and jatropholone B (5), acetyl aleuritolic acid (1), cyperenoic acid (2) and a monoterpene were isolated from the rhizomes of the Paraguayan crude drug Jatropha isabelli. The compounds were characterized by spectroscopic means. The gastroprotective effect of jatrophone, jatropholone A and B as well as 9beta,13alpha-dihydroxyisabellione 6 and the triterpene 1 was assessed in the HCl/EtOH-induced gastric lesions model in mice. Jatrophone elicited a strong gastroprotective effect with no significant differences between 25, 50 or 100 mg/kg and reducing lesions from 88 to 93%. The jatropholones A and B showed remarkable differences in the gastroprotective assay. Jatropholone A presented a dose-related response, with maximum effect (54% lesion reduction) at the highest dose (100 mg/kg), jatropholone B showed a strong action at all the doses, reducing lesions by 83-91%. The cytotoxicity of the compounds was assessed towards fibroblasts and AGS cells. Jatrophone was toxic against both cell lines (IC50 values: 2.8 and 2.5 microM, respectively). Jatropholone B (5) was not cytotoxic while jatropholone A (4) displayed a selective effect against AGS cells (IC50: 49 microM). The relevance of stereochemistry in the biological effects is clear comparing the effect of jatropholone A and B against AGS cells, with IC50 values of 49 and > 1000 microM for the beta and alpha C-16 isomers, respectively. The results provide scientific support for the use of "yagua rova" as a gastroprotective crude drug in Paraguayan traditional medicine.

Pharmacological and toxicological studies of Drimys angustifolia Miers. (Winteraceae)

Drimys angustifolia Miers. (Winteraceae) is a Brazilian medicinal plant used as analgesic, antiulcer and anti-inflammatory without studies to assure its efficacy and safety Leaf and stem bark extracts were evaluated to determine the antiulcer, analgesic, antiinflammatory and antioxidant activities. Preliminary toxic effects and qualitative phytochemical profile were also performed. The antiulcer activity was detected in both extracts. Administration of the leaf extract at 250 mg/kg inhibited total lesion area by 76.50% (p < 0.01 in ethanol/HCl method), while carbenoxolone at 250 mg/kg reduced lesions by 69.48%. Stem bark extract (250 mg/kg) inhibited lesion by 81.42%, while carbenoxolone by 74.10%. Similar effects were observed in the ethanol-induced ulcer method, but no activity was observed in piroxican model. The effects involve nitric oxide in gastric protection, since the L-NAME treatment reversed the protection given by the extracts. Antioxidant effects suggest an involvement against oxidative stress. In the pain (writhing, tail-flick and hot-plate tests) and inflammation (carrageenan-induced paw edema) models, the extracts did not present any effect. The phytochemical studies demonstrated that both extracts contain flavonoids, saponins, glycosilated triterpenoids, fixed acids, cyanogenic glycosides, quinones, tannins, xanthone and steroidal aglycones. Toxicological studies showed that the extracts are safe at the effective antiulcer doses.

Effect of Mouriri pusa extracts on experimentally induced gastric lesions in rodents: role of endogenous sulfhydryls compounds and nitric oxide in gastroprotection

Several plants are used in folk medicine to treat gastrointestinal disorders. Mouriri pusa Gardn. (Melastomataceae) is a medicinal plant commonly used in the central region of Brazil against gastric ulcer. Two organic extracts methanolic (MeOH) and dichloromethane (DCM) obtained by sequential extraction from the leaves of Mouriri pusa were evaluated for their ability to protect the gastric mucosa against injuries caused by necrotizing agents (0.3M HCl/60% EtOH, absolute ethanol, non-steroidal anti-inflammatory drug, stress and pylorus ligature) in mice and rats. The best results were obtained after pretreatment with MeOH extract whereas the DCM extract did not show the same significant antiulcerogenic activity. No acute toxicity was observed in animals treated with 5 g/kg, p.o. of MeOH extract. The mechanism involving the antiulcerogenic action of MeOH extract seemed to be related to NO generation and also suggested the effective participation of endogenous sulfhydryl group in the gastroprotective action. Phytochemical investigation of the MeOH extract of Mouriri pusa yielded tannins, flavonoids and (-)-epicatechin. The presence of these phenolic compounds probably would explain the antiulcerogenic effect of the polar extract of Mouriri pusa leaves.

Gastroprotective effect of Astragaloside IV: role of prostaglandins, sulfhydryls and nitric oxide

This investigation evaluated the gastroprotective activity of Astragaloside IV, a cycloartane-type triterpene glycoside isolated from Astragalus zahlbruckneri. Gastric mucosal damage was induced in rats by intragastric ethanol (1 mL/rat). Rats treated orally with Astragaloside IV suspended in Tween 80 at 3, 10 and 30 mg kg(-1), showed 15, 37 and 52% gastroprotection, respectively. The gastroprotection observed at 30 mg kg(-1) for this compound was attenuated in rats pretreated with N(G)-nitro-L arginine methyl ester (70 mg kg(-1), i.p), a nitric oxide (NO)-synthase inhibitor, suggesting that the gastroprotective mechanism of this glycoside involves, at least in part, the participation of NO. The gastroprotective effect of Astragaloside IV was not affected by the inhibition of prostaglandin synthesis with indometacin (10 mg kg(-1), s.c.) nor by the block of endogenous sulfhydryls with N-ethylmaleimide (NEM, 10 mg kg(-1), s.c.). Carbenoxolone was used as a gastroprotective model drug and showed a dose-dependent gastroprotective effect (25, 43 and 88% of gastroprotection, at 3, 10 and 30 mg kg(-1), respectively). The partial participation of prostaglandins, sulfhydryls and NO was observed in the gastroprotective mechanism of carbenoxolone.

Can the aqueous decoction of mango flowers be used as an antiulcer agent?

This study was designed to determine the effect of Mangifera indica flowers decoction, on the acute and subacute models of induced ulcer in mice and rats. A single oral administration of the aqueous decoction (AD) from M. indica up to a dose of 5 g/kg, p.o. did not produce any signs or symptom of toxicity in the treated animals. The oral pre-treatment with AD (250, 500 and 1000 mg/kg) in rats with gastric lesions induced by ethanol, decreased the gastric lesions from 89.0+/-6.71 (control group) to 9.25+/-2.75, 4.50+/-3.30 and 0, respectively. Pretreatment with AD (250, 500 and 1000 mg/kg) to mice with HCl/ethanol- or stress-induced gastric lesions resulted in a dose-dependent significant decrease of lesion index. In the piroxicam-induced gastric lesions, the gastroprotective effect of AD was reducing with the increase of the AD dose. In the pylorus-ligature, AD (p.o.) significantly decreased the acid output indicating the antisecretory property involved in the gastroprotective effect of M. indica. Treatment with AD during 14 consecutive days significantly accelerated the healing process in subacute gastric ulcer induced by acetic acid in rats. Pretreatment with N-nitro-l-arginine methyl ester (l-NAME), an inhibitor of NO-synthase, did not abolish the gastroprotective effects (99% with saline versus 80% with l-NAME) of AD against ethanol-induced gastric lesions. Pretreatment with N-ethylmaleimide (NEM), a blocker of endogenous sulphydryl group, significantly abolished the protective effects of AD against ethanol-induced gastric ulcers (95% with saline versus 47% with NEM). Phytochemical screening showed the presence of steroids, triterpenes, phenolic compounds and flavonoids. Estimation of the global polyphenol content in the AD was performed by Folin-Ciocalteu method and showed approximately 53% of total phenolic on this extract. These findings indicate the potential gastroprotective and ulcer-healing properties of aqueous decoction of M. indica flowers and further support its popular use in gastrointestinal disorders in Caribbean.

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Gastroprotective activity of Pradosia huberi on experimentally induced gastric lesions in rodents: role of endogenous sulphydryls and nitric oxide

Pradosia huberi is a medicinal plant very common in the Amazonian forest population. The research interest in this plant is justifiable because of its potential medicinal value in gastritis and gastric ulcer mentioned in local folk medicine. In this paper, we evaluated the acute toxicity and antiulcerogenic effect of a hydroalcoholic extract (HAE) obtained from Pradosia huberi barks in rodents. No acute toxicological sign or symptom was observed in animals treated with the highest dose (5000 mg/kg, p.o.) of Pradosia huberi. In the HCl/EtOH-induced gastric ulcer model, HAE demonstrated significant inhibition of the ulcerative lesion index by 73% (500 mg/kg) and 88% (1000 mg/kg), respectively, in relation to the control value (p<0.05). The gastric damage induced by absolute ethanol in rats was effectively reduced by 84, 88 and 81% (250, 500 and 1000 mg/kg) when compared with the control group (p<0.01). In the NSAID-induced lesion model, HAE also showed antiulcerogenic effect with decrease in gastric lesions of 56% (250 mg/kg), 57% (500 mg/kg) and 67 % (1000 mg/kg) when compared with animals treated with vehicle (p<0.05). In the gastric ulcer induced by pylorus ligature model, the administration of HAE by oral and intraduodenal routes inhibited the gastric lesion index by 79 and 52% (500 mg/kg), respectively. HAE administered orally or intraduodenally was able to change gastric juice parameters (pH, volume and acid output) as well as those treated with cimetidine. The treatment with HAE (p.o.) significantly increased gastric volume, the pH values and promoted reduced acid output (p<0.01). By comparative effect (intraduodenal and oral route), we observed that HAE was better for local activity in gastric mucosa than in systemic action. HAE also has a non-specific activity when found to be the inhibitor of intestinal motility (p>0.01). The mechanism of action of HAE did not seem to be related to the NO-inhibitor but showed the participation of endogenous sulphydryl group in the gastroprotective action.

Cytotoxic activity and effect on nitric oxide production of tirucallane-type triterpenes

Hexane extract from the bark of Amphipterygium adstringens, as well as its principal constituents, masticadienonic acid and 3alpha-hydroxymasticadienolic acid, inhibited the growth of five human cancer cell lines. Derivatives of, namely 24,25 S-dihydromasticadienonic acid and masticadienolic acid, were also evaluated. The results showed that both and had greater activity than on colon cancer cell lines. The effects of on the production of nitric oxide (NO) from both resting and lipopolysaccharide-activated macrophages were determined. It was found that and caused an increase in NO release from resting macrophages; in lipopolysaccharide-activated macrophages, only and caused an increase in NO production.