African Journal of
Pharmacy and Pharmacology

  • Abbreviation: Afr. J. Pharm. Pharmacol.
  • Language: English
  • ISSN: 1996-0816
  • DOI: 10.5897/AJPP
  • Start Year: 2007
  • Published Articles: 2288

Full Length Research Paper

Extract and chloroform fraction from Syzygium cumini leaves with vasorelaxant effect mediated by inhibition of calcium channels

Rachel Melo Ribeiro
  • Rachel Melo Ribeiro
  • Pharmacology Research and Post-Graduate Laboratory, Department of Physiological Sciences, Federal University of Maranhão, Av. Portugueses, 1966, 65085-580, São Luís, Maranhão, Brazil.
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Matheus Brandão Campos
  • Matheus Brandão Campos
  • Pharmacology Research and Post-Graduate Laboratory, Department of Physiological Sciences, Federal University of Maranhão, Av. Portugueses, 1966, 65085-580, São Luís, Maranhão, Brazil.
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Ellen Julli da Silva Passos Maia
  • Ellen Julli da Silva Passos Maia
  • Laboratory of Biology, Department of Biology, Federal Institute of Education, Science and Technology of Maranhão (IFMA), BR-230, km-319, 65840-000, São Raimundo das Mangabeiras, Maranhão, Brazil.
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Gizele Oliveira Santos-Silva
  • Gizele Oliveira Santos-Silva
  • Pharmacology Research and Post-Graduate Laboratory, Department of Physiological Sciences, Federal University of Maranhão, Av. Portugueses, 1966, 65085-580, São Luís, Maranhão, Brazil.
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Iracelle Carvalho Abreu
  • Iracelle Carvalho Abreu
  • Pharmacology Research and Post-Graduate Laboratory, Department of Physiological Sciences, Federal University of Maranhão, Av. Portugueses, 1966, 65085-580, São Luís, Maranhão, Brazil.
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Vicente Ferrer Pinheiro Neto
  • Vicente Ferrer Pinheiro Neto
  • Laboratory of Experimental Surgery, Department of Medicine, CEUMA University (UNICEUMA), Av. Josué Montello, 65075-120, São Luís, Maranhão, Brazil.
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Marilene Oliveira Rocha Borges
  • Marilene Oliveira Rocha Borges
  • Pharmacology Research and Post-Graduate Laboratory, Department of Physiological Sciences, Federal University of Maranhão, Av. Portugueses, 1966, 65085-580, São Luís, Maranhão, Brazil.
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Antonio Carlos Romao Borges
  • Antonio Carlos Romao Borges
  • Pharmacology Research and Post-Graduate Laboratory, Department of Physiological Sciences, Federal University of Maranhão, Av. Portugueses, 1966, 65085-580, São Luís, Maranhão, Brazil.
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  •  Received: 06 February 2018
  •  Accepted: 05 March 2018
  •  Published: 29 March 2018

 ABSTRACT

Hypertension is associated with endothelial dysfunction characterized by decreased vasorelaxation. Our research group recently demonstrated that hydroalcoholic extract of Syzygium cumini leaves (HESc) reduces the blood pressure in spontaneously hypertensive rats (SHR). This study evaluated the ability of HESc and chloroform fraction (CF) in promoting vasorelaxation on resistance arteries rings. Endothelium-deprived superior mesenteric artery rings were suspended in organ baths containing warm perfusion medium that was continuously bubbled with carbogen and then the vasorelaxant ability of HESc and CF were assayed. The cumulative additions of HESc (0.1 to 10 mg/mL) caused a concentration-dependent relaxant response, in precontracted preparations by NE or KCl. CF (0.1 to 1.0 mg/mL) exhibited remarkable vasorelaxant activity in preparations endothelium-denuded pre-contracted with NE, in a concentration-dependent manner. The pretreatment of TEA did not decrease significantly in relaxation. The incubation of CF (0.25 and 0.5 mg/ml) reduced in a concentration-dependent way, the Emax induced by NE in mesenteric artery, however, did not altered the pD2 of the NE. Additionally, CF promoted concentration-dependent manner, maximal effect inhibition and also led to a significant rightward shift in the concentration-response curve for Ca2+ in endothelium-denuded rings. This finding indicates that S. cumini acts as a vasorelaxant agent and interfere with the responsiveness of vascular smooth muscle cell, probably acting on the regulation of intracellular Ca2+ levels through voltage-operated calcium channels.
 
Key words: S. cumini, calcium channels, vasorelaxant, medicinal plant, antihypertensive.

Abbreviation: SHR, Spontaneously hypertensive rat; HESc, Hydroalcoholic extract; CF, Chloroform fraction; NE, Norepinephrine; VSMC, Vascular smooth muscle cell; Emax, Maximum effect; ROOC’s, Receptor-operated Ca2+ channels; VOOC’s, Voltage-dependent Ca2+ channels; BKCa,   Large-conductance  Ca2+  activated  K+  channels; TEA, Tetraethylammonium.

 INTRODUCTION

Globally cardiovascular disease accounts for approximately 17 million deaths a year. Of these, complications of hypertension account for 9.4 million deaths worldwide every year. Hypertension is responsible for at least 45% of deaths due to ischemic heart disease and 51% of deaths due to stroke (WHO, 2013). The objective of antihypertensive treatment is to achieve optimal blood pressure levels during therapy to reduce hypertension-related complications. The research literature indicates that secondary metabolites of herbs and spices exhibit antihypertensive effects contributing in reducing blood pressure levels and minimizing its complications (Al Disi et al., 2016). Syzygium cumini (L.) Skeels, belongs to Myrtaceae family, is popularly known as jambolan, being is a medicinal plant known for its therapeutic properties for the treatment of different diseases such as inflammation, diabetes and hypertension (Morton, 1963; Pepato et al., 2005; Migliato et al., 2006; Dieckel et al., 2007; Abbas and Mushtaq, 2008). Its leaves are rich in phenolic compounds (Sanches et al., 2016) with great ability to act biologically in cardiometabolic disorders (Chagas et al., 2015). According to Silva et al. (2012), hydroalcoholic extract of S. cumini leaves (HESc) exhibits no chronic toxicity. Additionally, the ability of HESc to reduce blood pressure in SHR suggesting antihypertensive property were demonstrated (Ribeiro et al., 2014). In this context, this present study investigated the vasodilator effect of S. cumini leaves. This work assess the potential of HESc and and its active fraction in promoting vasorelaxation in resistance artery rings for the first time thereby, contributing to clarify the mechanism of its antihypertensive action.


 MATERIALS AND METHODS

Plant material
 
Leaves of S. cumini were collected from the campus of the Federal University of Maranhão (2°33'11.7"S 44°18'22.7"W), São Luís, Brazil, in October 2013. A voucher specimen was identified and deposited in the herbarium of “Prof. Dr. Berta Lange de Morretes” Medicinal Plant Garden, UFMA (No. 1069).
 
Preparation of the hydroalcoholic extract of S. cumini
 
Leaves were dried at room temperature and pulverized. The crude extract was prepared by maceration of the leaf powder (300 g) in 70% ethanol (1:3 w/v), and concentration in a rotary evaporator under reduced pressure at a temperature below 60°C and lyophilized. The extract thus obtained was called the hydroalcoholic extract of S. cumini leaves (HESc) with a dry weight of 49.8 g and yield 16.6% (Ribeiro et al., 2014). HESc aliquots were kept at 4ºC, protect from light, until further experimental use, when powdered HESc was resuspended in water at desired concentrations. HESc was partitioned by sequential extraction using hexane, chloroform (CF), ethyl acetate, and n-butanol. Based on previous results demonstrating that the CF was the most potent in inducing vascular relaxation in vitro (Ribeiro, 2007), we evaluated the effects of this fraction. The chloroform (CF) fraction were evaporated, with a yield 5.2% and tested to evaluate the vasorelaxant effect. In this study, phytochemical screening by CF revealed the presence of phenols.
 
Animals
 
Male 12-week-old spontaneously hypertensive rats (SHR) or normotensive (Wistar), Rattus norvegicus, weighing 250 to 300 g, obtained from the animal house of UFMA were used. The animals were housed under controlled conditions of temperature (21 ± 2°C) under a 12 h light-dark cycle, with ration and water available ad libitum. All The experimental protocols were reviewed and approved by the Animal Research Ethics Committee of UEMA, Brazil (Number 17/2012) and all the methods in this study were carried out in accordance with the approved guidelines.
 
Drugs
 
Norepinephrine hydrochloride, Acetylcholine and Tetraethylammonium chloride were purchased from Sigma Chemical Co. (St Louis, MO, USA). All other chemicals were of high analytical grade purity from Merck Darmstadt.
 
Tissue preparation
 
Preparations of the mesenteric artery were obtained as described by Borges et al. (1999), Abreu et al. (2003) and Amaechina and Omogbai (2007) and ring segments (3 to 5 mm) of the superior mesenteric artery were placed between stainless steel wires (50 𝜇m in diameter) and immersed in an organ bath chamber (5 mL) containing Krebs nutritive solution (118 mM NaCl, 5 mM KCl, 1.2 mM MgCl2, 1.2 mM NaH2PO4, 15.5 mM NaHCO3, 2 mM CaCl2, and 11mM glucose, pH 7.4) at 37°C, equilibrated with 5% CO2/ 95% O2. The preparations were first equilibrated under a tension of 1.0 g and washed at intervals of 10 min, for 60 min. Changes in the isometric tension of the preparations were measured with an isometric force transducer (PowerLab, ADInstruments Pty. Ltd., Sydney, Australia). Due to the endothelial dysfunction and the inefficient production of vasodilators by the epithelial cells present in hypertensive syndrome, we chose to perform all experiments on endothelium- denuded mesenteric arteries, to demonstrate the vascular relaxing property of the extract and fractions without the interference of endothelium-derived factors. Vascular endothelium removal was confirmed by the absence of a relaxation response by Acetylcholine (10 𝜇M) to induce more than 70% inhibition of vessels precontract with norepinephrine (NE 10 𝜇M).
 
Effect of HESc on contraction induced by NE or KCl
 
After the stabilization period, endothelium- denuded mesenteric artery rings, obtained of SHRs, were pre-contracted with NE (10 𝜇M) or KCl (80 mM) and, on the tonic phase, different concentrations of HESc (0.1, 0.25, 0.5, 5 and 10 mg/ml) were added cumulatively to organ bath. The relaxant effect was expressed as the percentage of NE or KCl induced contraction.CF on contraction induced by NE in presence or absences of K+- blocker
 
After the stabilization period, two successive contractions of similar magnitude were induced with NE (10 μM) in endothelium- denuded rings, obtained of SHR. During the tonic phase of the third contract, different concentrations of CF (0.01, 0.05, 0.10, 0.50 and 1.0 mg/mL) were added cumulatively to the organ bath. To examine the role of K+ channels in the HESc or CF induced relaxation, arteries rings pre-contract with NE (10 μM) were constructed in absence or presence of TEA (0.3 mM). The results were expressed as the percentage of NE induced contraction.
 
CF effect on arterial smooth muscle contraction induced by NE or Ca2+
 
The preparations were first equilibrated under a tension of 1.0 g and washed at intervals of 10 min. After 60 min of successive washes, cumulative dose-response curves to NE (10-9 to 10-4 M) were constructed in the absence or presence of CF (0.25 and 0.5 mg/ml). To evaluate the antagonistic action of CF against Ca2+, vascular tissue was stabilized with normal Krebs solution. After 30 min, the fluid of the preparation was replaced with Ca2+-free Krebs solution (60 mM K+, nominally Ca2+ free). Also, after 30 min of successive washes, the basal tone was recovered, permitting to obtain cumulative concentration-response curves to CaCl2 (10-6 to10-2 M) in the absence or presence of CF (0.25 and 0.5 mg/ml). The concentration necessary to elicit 50% of the maximum response (EC50) was determined using nonlinear regression analysis. The negative logarithms of the EC50 values (pD2) were used for statistical analysis. In the experiments involving high extracellular K+, Krebs solution containing 60 mM KCl was prepared by replacing an equimolar concentration of NaCl with KCl.
 
Statistical analysis
 
Results were expressed as mean ± standard error of the mean (SEM). One-way analysis of variance (ANOVA) followed by the Student-Newman-Keuls post-test was used for, multiple comparisons and Student t-test for comparison of unpaired data. A p-value < 0.05 was considered significant and the statistical analysis was performed using the GraphPad Prism® 5.0 program.


 RESULTS

In endothelium-denuded rings HESc (0.1 to 10 mg/ml) inhibited the sustained tonic contraction induced by NE 10 µM (Figure 1) in a concentration-dependent manner (Emax values= 97.20 ± 2.90%; EC 50 values= 2.82 mg/ml). Additionally, HESc also promoved a prominent vasorelaxant effect in arteries rings contracted with KCl (Figure 1), with a maximum relaxation of 100.0 ± 0.0% (EC50 1.11 mg/ml). The relaxant effect of HESc was reversible as the tissue regained its spontaneous activity at least within one hour after repeated washout. In Figure 2A was observed CF (0.1 to 1 mg/ml) also exhibited vasorelaxant activity in preparations endothelium-denuded pre-contracted with NE (10µM), in a concentration-dependent manner (Table 1). The relaxant effect of CF also was reversible after repeated washout. The vasorelaxant effect induced by HESc or CF was available in preparations with TEA (1mM). The Figure 2B showed that 30 min of TEA-pretreatment in endothelium-denuded rings did not change the vasorelaxant response of HESc (Emax values= 99.75 ± 0.25%; EC50 values= 2.24 mg/ml). In addition, in relation to vasorelaxation promoted by CF, TEA reduced relaxative effect only in concentration of 0.1 mg/mL (Figure 2A and Table 1). It was also observed that in a lower concentration CF demonstrated a potential higher vasorelaxant HESc (Figure 3). CF at concentrations of 0.25 and 0.5 mg/ml reduced the Emax value for NE in endothelium-denuded mesenteric artery (Figure 4 and Table 2). In addition, contractions induced by CaCl2 in endothelium-deprived mesenteric arterial rings were reduced in a concentration-dependent manner after incubation with 0.25 and 0.5 mg/ml CF, (Figure 5 and Table 2). There was a displacement of the CaCl2 curves to the right, changing pD2. These effects were reversed after washing with Krebs solution.
 
 
 
 
 


 DISCUSSION

This study is the first to demonstrate the vasorelaxant activity of S. cumini leaves in mesenteric artery of SHR and possibly acting involving intracellular Ca2+ stores. These results support the elucidation of possible mechanisms involved in the antihypertensive effect of this plant species, a pharmacological property recently demonstrated by our group. Structural and functional alterations occur in arterial hypertension and are important in the mechanisms that determine blood pressure and target of antihypertensive therapy (Oh et al., 2007; Oh et al., 2008). The sympathetic nervous system also participates in the development and maintenance of various forms of hypertension (Piascik et al., 1996). The magnitude of sympathetic over activity has been closely related to hypertension-related end organ damage and predicts mortality and cardiovascular outcomes (Hering and Narkiewicz, 2013). The contractile response of vascular smooth muscle cells (VSMCs) by NE is dependent on the Ca2+ influx from extracellular space through receptor-operated Ca2+ channels (ROCCs) (Karaki and Weiss, 1988; Nelson et al., 1990; Qayyum et al., 2016). In addition, potassium causes VSMCs contraction through activation of voltage dependent Ca2+ channels (VOCCs) (Thorneloe and Nelson, 2005; Ayele et al., 2010). The results presented in Figure 1 indicate that HESc promotes vasorelaxation of the pre-contracted mesenteric artery by NE and KCl, which would be suggestive of blocking Ca2+ influx through the plasma membrane. Recently, our laboratory hypothesized that HESc would prevent Ca2 + influx through VOCCs on isolated rat jejunum (Monteiro et al., 2018).
 
In VSMCs, K+ channels play important roles in the regulation of vascular tone (Tanaka et al., 2004). Large-conductance Ca2+-activated K+ channel (BKCa channels), which have been extensively studied in VSMCs, contribute to the control of vascular tone (Brenner et al., 2000) and have been therapeutic targets in the treatment of cardiovascular disease (Saponara et al., 2006). To determine if the vasorelaxant effect induced by HESc involves BKCa –channel activation, it was incubated in mesenteric artery without endothelium preparations with a selective inhibitor of this channel TEA (1mM) (Garcia and Kaczorowski, 1992; Campbell, 1993; Jackson, 2005; Eichhorn and Dobrev, 2007). Similar study was realized by Matsumoto et al. (2010) when assessing the vasodilator alkaloid isolated from Cassia siamea in mesenteric artery without endothelium preparations of rats. The results in Figure 2B showed that vasorelaxant effect of S. cumini leaves does not occur by direct activation of BKCa channels. A particular feature of phytomedicines is their complex composition, that is, the ‘phytocomplex’, with different specific effects, however a wider array of effects and healing properties are guaranteed only by the phytocomplex (Medeiros et al., 2008). In order to further characterize this effect, HESc was submitted to liquid partition, as described under material and methods. To continue the study, we decided to work with CF, whose previous results suggest potential vasorelaxant effect in mesentric arteries of normotensive rats (Ribeiro, 2007).
 
In Figure 2A and 3 it was observed that, CF in the lower concentration exhibited remarkable vasorelaxant ability in a concentration-dependent manner, when compared to HESc at the same concentration, suggesting that CF contains the active compounds present in phytocomplex and the vasorelaxant response probably implicate an endothelium-independent pathway or inhibits Ca2+ influx or by hyperpolarization produced by K+- channels (Karaki and Weiss, 1988; Eichhorn and Dobrev, 2007). Figure 2B and Table 2 suggest that the presence of TEA did not alter the vasorelaxant response pattern of CF at higher concentrations. Additionally, reduced inhibitory effect of the CF at 0.1 mg/mL by TEA showed implication of BKCa –channel activation in the induced vasorelaxation at lower concentrations of fraction (Table 1). Studies have shown that a number of plant products including polyphenols, flavonoids, and various plant extract exert antihypertensive effects that might be owing to vasorelaxant action (Curin and Andriantsitohaina, 2005; Wang et al., 2014; Van Rymenant et al., 2017). Chemical studies of S. cumini leaves were performed by Ruan et al. (2008) and showed that CF contains phenolic acids, the other complex phenolic compounds. The results of phytochemical screening showed that CF is rich in these compounds, which may be responsible for the vasorelaxant property of the plant. Previously, we have shown that the maximal response induced by α1-adrenoceptor agonist NE in SHRs, suggest that HESc contains components that interfere with the reactive response of the vascular musculature.
 
In the present study, the incubation of CF (0.25 and 0.5 mg/ml) reduced in a concentration-dependent way the Emax induced by NE in mesenteric artery, however, did not altered the pD2 of the NE, suggesting that CF contains components that interfere with the reactive response of the vascular musculature, possibly interfering with the mechanisms of Ca2+ homeostasis in VSMCs. Contractions of smooth muscles induced by high K+ have been widely used in understanding Ca2+ roles in biological systems. To check the effect of the CF in [Ca2+]i, a concentration-response curve to Ca2+ (10-6 and 10-2M) in presence of K+ - depolarizing solution (KCl 60 mM) was constructed, before and after incubation with CF 0.25 and 0.5 mg/ml, that induced concentration-dependent manner, maximal effect inhibition and also led to a significant rightward shift in the concentration-response curve for Ca2+ in endothelium-denuded rings (Figure 5 and Table 2). These findings support the notion that, the CF can block Ca- influx from the extracellular space and acts as a non-competitive Ca2+ antagonist (Figure 5). Clinically, Ca2+ antagonist are potentially used to treat hypertension (Tep-Areenan and Sawasdee, 2011).


 CONCLUSION

The results demonstrate that S. cumini L. (Skeels) causes vasorelaxant effect and interfere with the responsiveness of vascular smooth muscle cell, probably as a result of the blockade of Ca2+ channels, as demonstrated in this study. These effects can be attributed to the presence of phenolic compounds detected by phytochemical screening. The S. cumini leaves showed an excellent potential as a vasodilator agent for the treatment of hypertension. The findings may provide a possible candidate drug for clinical medical use to treat cardiovascular diseases in the future. However, further experiments are necessary to clearly elucidate this assumption.


 CONFLICT OF INTERESTS

The authors have not declared any conflict of interests.

 


 ACKNOWLEDGEMENTS

The authors thank the Brazilian funding agencies CAPES, CNPq, and FAPEMA for financial support.



 REFERENCES

Adesegun SA, Elechi NA, Coker HAB (2007). Antioxidant power of Macaranga barteri leaf. Am. J. Food Technol. 2(6):543-549.
Crossref

 

Afolayan AJ, Wintola OA, Fouche G (2016). Acute and subacute toxicological evaluation of the aerial extract of Monsonia angustifolia E. Mey. Ex. A. Rich in Wistar Rats. Evid-Based Complement. Altern. Med. 2016:4952485.

 
 

Agwu CN, Okunji CO (1986). Gastrointestinal studies of Pyrenacantha staudii leaf extracts. J. Ethnopharmacol. 15:45-55.
Crossref

 
 

Amang AP, Mezui C, Tchokomeni GS, Zondengoumba EN, Enonchong GE, Tan PV (2017). Prophylactic and healing activities of the leaves aqueous extract of Eremomastax speciosa on gastric ulcers in rats. J. Adv. Biol. Biotechnol. 12(3):1-13.
Crossref

 
 

Asiedu-Gyekye IJ, Frimpong-Manso S, Awortwe C, Antwi DA, Nyarko AK (2014). Micro-and macroelemental composition and safety evaluation of the nutraceutical Moringa oleifera leaves. J. Toxicol. 2014:1-13.
Crossref

 
 

Ateufack G, Mokam ECD, Mbiantcha M, Feudjio RBD, Nana D., Kamanyi A (2015). Gastroprotective and ulcer healing effects of Piptadeniastrum africanum on experimentally induced gastric ulcers in rats. BMC Complement. Altern. Med. 15:214-223.
Crossref

 
 

Awaad AS, El-Meligy RM, Soliman GA (2013). Natural products in treatment of ulcerative colitis and peptic ulcer. J. Saudi Chem. Soc. 17:101-124.
Crossref

 
 

Bairy KL, Roopa K, Malini S, Rao CM (2001). Protective effect of Tinospora cordifolia on experimentally induced gastric ulcers in rats. J. Nat. Remedies 2(1):49-53.

 
 

Bekro Y, Bekro J, Boua BB, Tra Bi F, Ehilé EE (2007). Etude ethnobotanique et screening phytochimique de Caesalpinia benthamiana (Baill.) Herend et Zarrucchi (Caesalpiniaceae). Sci. Nature 4(2):217-225.

 
 

Bharath KG, Divya K, Sravanthi G, Rajeshwar G, Umadevi V, Niranjan GK (2014). Antiulcer activity of ethanolic extract of Terminalia catappa leaves against gastric ulcers by pyrolic ligation induced model in rats. Int. J. Pharm. Sci. Drug Res. 6(1):38-40.

 
 

Bjarnason I, Scarpignato C, Takeuchi K, Rainsford KD (2007). Determinants of the short-term gastric damage caused by NSAIDs in man. Alimentation Pharmacol. Thermodyn. 26:95-106.
Crossref

 
 

Borrelli F, Izzo AA (2000). The plant kingdom as source of antiulcer remedies. Phytother. Res. 14:581-591.
Crossref

 
 

Bouquet A, Debray IM (1974). Plantes médicinales de côte d'Ivoire. Travaux et documents de L'O.R.S.T.0.M. No 32, Paris, France 231p.

 
 

Brown LM (2000). Helicobacter pylori: epidemiology and routes of transmission. Epidemiol. Rev. 22(2):283-297.
Crossref

 
 

Burkill HM (1985). Entry for Lasiurus hirsutus (Forssk) Boiss. Family Poaceae) in the useful plants of west tropical Africa, 2.

 
 

Chiu PJS, Gerhart C, Brown AD, Barnett A (1984). Effects of a gastric antisecretorycytoprotector2-methyl-8–(phenylmethoxy) imidazo (1,2a) -pyridine-3-acetonitrine (Sch28080) on cyteamine, reserpine and stress ulcers in rats. Gastroenterology 34:783-786.

 
 

Dashputre NL, Naikwade NS (2011). Evaluation of anti-ulcer activity of methanolic extract of Abutilon indicum Linn leaves in experimental rats. Int. J. Pharm. Sci. Drug Res. 3(2):97-100.

 
 

Deepanjana D, Devasrita D, Tatiyana M, Anup K, Bairy KL (2011). Protective effects of Moringa oleiferaon experimentally induced gastric ulcers in rats. Res. J. Pharm. Biol. Chem. Sci. 2(2):50-55.

 
 

Gbadamosi IT, Erinoso SM (2015). A review of twenty ethnobotanicals used in the management of breast cancer in Abeokuta, Ogun State, Nigeria. Afr. J. Pharm. Pharmacol. 10(27):546-564.
Crossref

 
 

Ghader JA, Vahid N, Ehsan A, Mostafa M, Hadi K (2015). Antiulcer Properties of Glycyrrhiza glabra L. extract on experimental models of gastric ulcer in mice. Iranian J. Pharm. Res. 14(4):1163-1170.

 
 

Goze NB, Kouakou KL, Bléyéré NM, Amonkan KA, Konan BA, Abo KJ-C, Yapo AP, Ehilé EE (2013). Anti-ulcerogenic effects of a hydroethanol 70% extract from stem bark of Terminalia superba engl. et diels (combretaceae) in rats and phytochemical screening. Int. J. Sci. Innov. Discov. 3(5):539-550.

 
 

Gupta MB, Nath R, Gupta GP, Bhargava KP (1985). A study of the antiulcer activity of diazepan and other tranquillose datives in albinos' rats. Clin. Exp. Pharmcol. Physiol. 12:61-63.
Crossref

 
 

Hara N, Okabe S (1985). Effects of Gefanate on acute lesions in rats. Folia Pharmacol. 85:443-448.
Crossref

 
 

Harold K, Grant DM, Mitchel J (2007). Principles of medical pharmacology. Seventh Ed. Elsevier Canada Ltd. pp. 557-559.

 
 

Hiruma-Lima CA, Akiko C, Calvo TR, Rodrigues CM, Andrade FDP, Vilegas W, Brito ARMS (2006). Antiulcerogenic activity of Alchornea castaneaefolia effects on somatostatin, gastrin and prostaglandin. J. Ethnopharmacol. 10(4):215-224.
Crossref

 
 

Kadjo K, Ouattara B, Sanogo S, Diallo AD, Adom AH, Yangni-Angate Y, Ouattara D, Niamkey EK, Beda YB (1999). Aspects épidémiologiques des ulcères gastro duodenaux. Méd. d'Afrique Noire 46(2):99-102.

 
 

Keïta BJ (1990). Ulcères gastro-duodénaux en chirurgie «B» Hôpital du point «G». Thèse de médecine, N° 18, Bamako, Mali, 69p.

 
 

Kouakou KL, Goze NB, Bleyere NM, Konan BA, Amonkan KA, Abo KJ-C, Yapo AP, Ehile EE (2013). Acute toxicity and anti-ulcerogenic activity of an aqueous extract from the stem bark of Terminalia superba Engl. and Diels (Combretaceae). World J. Pharm. Sci. 1(4):117-129.

 
 

Kumar K, Kenganora M, Satish K, Rajendran M (2013). Anti-ulcer activity of ethanol extract of the stem bark of Careya arborea Roxb. Int. Curr. Pharm. J. 2(3):78-82.
Crossref

 
 

Kunchandy J, Khanna S, Kulkarni SK (1985). The histamine H3 receptor: a target for new drugs. Arch. Int. Pharmacodyn. Ther. 275:123-126.

 
 

Oates PJ, Kakkinen JP (1988). Studies on the mechanism of ethanol induced gastric damage in rats. Gastroenterology 94:10-21.
Crossref

 
 

Organization for Economic Cooperation and Development (OECD) (2001). Guideline for testing of chemicals. Guideline 420: Acute Oral Toxicity-Fixed Dose Procedure. Http:// intp.niehs.nih.gouv/iccVam/suppdocs/feddocs/oecd/oecd_1420.pdf. Site consulté le 15/08/2016

 
 

Oliver-Bever B (1986). Medicinal plants in tropical West Africa. Cambridge University Press, Cambridge London, United Kingdom pp 240-245.
Crossref

 
 

Operations Management Suite (OMS) (2002). Promotion du rôle de la médecine traditionnelle dans le système de santé : stratégie de la région africaine. AFR/RC50/9, pp. 12-15.

 
 

Oussou NJ-B, Asiedu-Gyekye IJ, Yapo AF, N'guessan BB, Amoateng P, Kouakou KL, Asante IK, Ehile EE (2016). In-vitro scavenging activity and acute toxicity study of methanol leaves extract and fractions of Lophira lanceolata Tiegh. Ex Keay (Ochnaceae) in rats. International Journal of Phytomedicine 8(3):411-421.
Crossref

 
 

Overmier JB, Murison R (2000). Anxiety and helplessness in the face of stress predisposes, precipitates, and sustains gastric ulceration. Behavioural Brain Research10:161-174.
Crossref

 
 

Parmar NS, Desai JK (1993). A review of current methodology for the evaluation of gastric and duodenal antiulcer agents. Indian Journal of Pharmacoly 25:120-135.

 
 

Robert A, Nezamis JE, Lancaster C, Davis JP, Field SO, Hanchar AJ (1983). Mild irritants prevent gastric necrosis through 'adaptive cytoprotection' mediated by prostaglandins. American Journal of Physiology-Gastrointestinal and Liver 245:113-121.
Crossref

 
 

Sabiha S, Mohd AA, Asif M, Akhtar M (2011). Role of phenolic compounds in peptic ulcer: An overview. Journal of pharmacy and bioallied sciences 3(3):361-367.
Crossref

 
 

Sairam K, Rao CV, Dora BM, Agrawal VK, Goel RK (2002). Antiulcerogenic activity of methanolic extract of Emblica officinalis. Journal of Ethnopharmacology 82(1):1-9
Crossref

 
 

Sakat SS, Juvekar RA (2009). Antiulcer activity of methanol extract of Erythrina indica Lam. leaves in experimental animals. Pharmacognosy Research 1:396-401.

 
 

Salim AS (1990). Removing oxygen-derived free radicals stimulates healing of ethanol induced erosive gastritis in the rat. Digestion 47:24-28.
Crossref

 
 

Scheiman JM, Dubois RN, Giardiello FM (1996). NSAIDs, Eicosonoids, and the gastroenteric tract. Philadelphia Saunder 25:279-289.

 
 

Shay H, Komarov SA, Fels SS, Meranze D, Gruenstein M, Siplet H (1945). A simple method for the uniform production of gastric ulceration in the rat. Gastroenterology 5:43-61.

 
 

Sheeba MS, Sheena P, Greeshma T, Gayathri LT, Asha VV (2016). Comparative evaluation of the efficacy of Cardiospermum halicacabum Linn. on Indomethacin, Pylorus ligation and Helicobacter pylori induced gastric ulcer in rats. Annals of Phytomedicine 1: 63-72.

 
 

Soberg T, Hofstad B, Sandvik L, Johansen M, Lygren I (2010). Risk factors for peptic ulcer bleeding. Tidsskr Nor Laegeforen 130:1135-1139.

 
 

Soro KG, Mahassadi KA, Koffi GM, Kissi YH, Coulibaly A, Assohoun T, Ehua AM, Seu GS, Afum-Adjei AA, Ehua SF (2016). Postoperative morbidity and mortality of perforated peptic ulcer: retrospective Cohort study of risk factors among black africans in Côte d'Ivoire. Gastroenterology Research and Practice ID 2640730.

 
 

Takeeda M, Hayashi Y, Yamato M, Murakami M, Takeuchi K (2004). Roles of endogenous prostaglandins and cyclooxygenase isozymes in mucosal defense of inflamed rat stomach. Journal of Physiology and Pharmacology 55:193-205.

 
 

Yau S, Abdulazeez MA, Anigo KM, Garba A (2017). Gastro-protective effect of Ziziphus abyssinica root extracts in ethanol-induced acute ulcer in Wistar rats. Journal of Acute Disease 6(2):62-65.
Crossref

 
 

Yeomans ND, Hawkey CJ, Brailsford W, Næsdal J (2009). Gastroduodenal toxicity of low-dose acetylsalicylic acid: a comparison with non-steroidal anti-inflammatory drugs. Current Medical Research Opinion 25:2785-2793.
Crossref

 

 




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