BackgroundMareya micrantha (Benth.) Müll. Arg. (Euphorbiaceae) is a shrub that is commonly used in Côte d'Ivoire (West Africa) for the treatment of constipation and as an ocytocic drug. The present study was carried out to investigate the laxative activity of Mareya micrantha in albino's Wistar rats.MethodsRats were divided in 5 groups of 5 animals each, first group as control, second group served as standard (sodium picosulfate) while group 3, 4 and 5 were treated with leaf aqueous extract of Mareya micrantha at doses of 100, 200 and 400 mg/kg body weight (b.w.), per os respectively. The laxative activity was determined based on the weight of the faeces matter. The effects of the leaves aqueous extract of Mareya micrantha and castor oil were also evaluated on intestinal transit, intestinal fluid accumulation and ions secretion.ResultsPhytochemicals screening of the extract revealed the presence of flavonoids, alkaloids, tannins, polyphenols, sterols and polyterpenes. The aqueous extract of Mareya micrantha applied orally (100, 200 and 400 mg/kg; p.o.), produced significant laxative activity and reduced loperamide induced constipation in dose dependant manner. The effect of the extract at 200 and 400 mg/kg (p.o.) was similar to that of reference drug sodium picosulfate (5 mg/kg, p.o). The same doses of the extract (200 and 400 mg/kg, p.o.) produced a significant increase (p < 0.01) of intestinal transit in comparison with castor oil (2 mL) (p < 0.01). Moreover, the extract induced a significant enteropooling and excretion of Cl-, Na+, K+ and Ca2+ in the intestinal fluid (p < 0.01).ConclusionsThe results showed that the aqueous extract of Mareya micrantha has a significant laxative activity and supports its traditional use in herbal medicine.

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Dans cette étude, nous avons évalué, d'une part, l'influence d'un extrait méthanolique de Mitragyna ciliata (MYTA) [rubiacées] sur l'activité mécanique du coeur isolé de rat, grâce au dispositif amélioré de Langerdorff et, d'autre part, la pression artérielle carotidienne de lapin grâce au dispositif de Ludwig. MYTA induit un effet inotrope positif qui varie de 0 à 35 ± 0,89 % d'augmentation pour des concentrations allant de 10 -5 mg/ml à 5 Â 10 -1 mg/ml et à une concentration très élevée de 1 mg/ml, le coeur s'arrête avec une amplitude de plus de 50 ± 1,29 % d'augmentation par rapport au témoin. Il induit aussi un effet chronotrope négatif dose-dépendant qui diminue jusqu'à 48 ± 0,79 %, avant de s'annuler avec la concentration de 1 mg/ml. De plus, MYTA régularise progressivement l'activité cardiaque pour des arythmies induites par l'atropine et l'hypothermie. Ainsi, MYTA renforce, régularise et ralentit l'activité cardiaque. MYTA induit une chute de tension dose-dépendante qui varie de 140 mmHg (valeur normale) à 129 mmHg pour une dose allant de 10 à 40 mg/kg de poids corporel (PC). Mots clés : MYTA -Cardiovasculaire -CardiotoniqueHypotensifEffect of Mitragyna ciliata (MYTA) on cardiovascular system of rat Abstract : In this study, we evaluate the influence of a methanolic extract of Mitragyna ciliata (MYTA) [Rubiaceae] on the mechanics of isolated rat heart, thanks to improved Langerdorff's device and carotid arterial pressure of rabbits with Ludwig's device. MYTA, in concentrations ranging from 10 -5 mg/ml to 5 Â 10 mg/ml induces a drop in blood pressure with inotropic effect that varies from 0 to 35 ± 0.89% increase in concentrations ranging from 10 -5 mg/ml at 5 Â 10 -1 mg/ml and a very high concentration of 1 mg/ml stops the heart with a magnitude of more than 50 ± 1.29% increase compared with the control. It also induces a dosedependent negative chronotropic effect decreasing to 48 ± 0.79% before vanishing with the concentration of 1 mg/ ml. In addition, MYTA gradually regulates the activity of cardiac arrhythmia induced by atropine and hypothermia. Thus, MYTA strengthens, regulates, and slows the activity of heart. MYTA induces dose-dependent hypotension ranging from 140 mmHg (normal) to 129 mmHg for a dose of 40-mg/kg body weight.

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Purpose: In previous studies, the aqueous extract of Combretum molle was shown to inhibit disturbances of breathing induced by acetylcholine. The aim of this study was to elucidate the mechanism of this inhibition. Methods: The aqueous extract of Combretum molle and an anti-asthmatic, salbutamol (reference), were tested at varying concentrations for their inhibitory effects on breathing. Acetylcholinesterase (AChE) was extracted from rabbit duodenum and its activity determined by Ellman's assay using acethylthiocholine iodide (ACTH) as substrate. The rate of hydrolysis of acetylcholinesterase was spectrophotometrically monitored at 412 nm. Results: The results indicate that in the presence of C. molle extract, a considerable reduction in the variation of breathing amplitudes occurred. Furthermore, the extract probably contains anti-AChE substances. C. molle exerted non-competitive inhibition of acetylcholinesterase with Michaelis-Menten constant (K M) of 192 µM and velocity at maximal concentration of substrate (V max) of 4444 µM/min. Conclusion: These results support the use of C. molle leaf in the Pharmacopoeia of Ivory Coast as an anti-asthmatic, in view of its inhibitory effect on breathing disturbances.

Cette étude a été consacrée à l'analyse des effets inhibiteurs de l'extrait aqueux de Combretum molle sur les variations des amplitudes respiratoires et la toux. Nous avons observé que l'injection de cet extrait aux doses testées (3,33 mg/kg, 7,14 mg/kg) ne produit aucun effet sur la respiration normale du lapin. Par ailleurs, l'injection de 0,2 ml d'acétylcholine (714.10 -3 mg/kg) a induit un pourcentage estimé à -100 %. Toutefois, l'injection combinée de l'acétyl-choline (0,2 ml, 714.10 -3 mg/kg) et de doses croissantes d'extrait aqueux de Combretum molle (3,33 mg/kg, 3,5 mg/kg, 7,14mg/kg) a induit une réduction du pourcentage de variation des amplitudes respiratoires de -100 % à -20 ± 0,5 %. En outre, nous avons testé les effets de l'extrait aqueux sur la toux. Les cobayes non traités par cet extrait de Combretum molle donnent en moyenne 10,25 ± 0,95 toux sur dix minutes. Ce lot constitue le témoin. En revanche, le prétraitement des cobayes par 3 mg/kg d'extrait total a provoqué 8,25 ± 0,45 toux pendant dix minutes. Alors qu'avec 30 mg/kg la réduction est passée de 10,25 ± 0,95 à 4,5 ± 0,25 toux. Ces résultats nous ont permis de conclure que l'extrait aqueux présente des effets inhibiteurs sur la toux et les bronchoconstrictions induites par l'acétylcholine.Abstract: In this work, we studied the inhibitory effects of Combretum molle extract on respiratory disturbances and coughs. Injection of 3.33 mg/kg and 7.14 mg/kg of Combretum molle had no effect on a rabbit's breathing. Injection of acetylcholine (0.2 ml; 714.10 -3 mg/kg) induced a percentage estimated at -100%. But a combined injection of acetylcholine and increasing doses of Combretum molle reduced this percentage from -100% to -20 ± 0.5%. We also studied the inhibitory effects of the crude extract on coughs. Guinea pigs which were not treated produced 10.25 ± 0.95 in 10 minutes. But treating the guinea-pigs with 3 mg/kg of crude extract resulted in 8.25 ± 0.45 coughs for 10 min. With 30 mg/kg, however, coughing was reduced to 4.5 ± 0.25. We could therefore conclude that the extract presents some inhibitory effects on coughing and bronchial contraction induced by acetylcholine.