Effects of Dracaena arborea (Dracaenaceae) on sexual dysfunction in 4 weeks hyperglycemic male rats.

OBJECTIVE: To investigate the effects of Dracaena arborea (D. arborea) on the sexual behavior parameters in experienced type-1 diabetic rats. METHODS: Aqueous and ethanol (100 and 500 mg/kg respectively) extracts of dried root barks of D. arborea, sildenafil citrate (1.44 mg/kg), trimethylamine-N-oxide (TMAO, 20 mg/kg) and distilled water (10 mL/kg) were orally administered to 4 weeks streptozotocin-induced diabetic rats. Mount latency and frequency (ML, MF), intromission latency and frequency (IL, IF) and post-ejaculatory interval (PEI) were measured by ejaculatory series during 90 min once a week for 4 weeks. Glycemia was determined at the beginning and at the end of the treatment. RESULTS: D. arborea did not show any major antihyperglycemic effects. Compared to the control group, a significant (P<0.05-0.001) increase in MF and IF was noticed in rats treated with sildenafil citrate (89.71% and 90.07% respectively), aqueous (500 mg/kg, 88.08% and 88.74% respectively) and ethanol (100 mg/kg; 89.53% and 89.17 respectively) extracts of D. arborea after two weeks (series 1) of treatment. ML, IL and PEI were significantly (P<0.05-0.001) decreased after 4 weeks of daily treatment [sildenafil citrate (96.31, 96.31% and 34.98%), and D. arborea aqueous 500 mg/kg (94.33, 94.33% and 66.60%) and ethanol extracts 100 mg/kg (96.98, 97.08% and 64.26%)]. CONCLUSIONS: These aphrodisiac potentials of D. arborea in experienced diabetic rats could be due to the antioxidant and androgenic properties of phenols, flavonoids, saponins and sterols revealed in the plant extracts.

Analgesic and Anti-Inflammatory Properties of Extracts from the Bulbils of Dioscorea bulbifera L. var sativa (Dioscoreaceae) in Mice and Rats.

The aqueous and methanol extracts from the dry bulbils of Dioscorea bulbifera L. var sativa (Dioscoreaceae)-evaluated orally at the doses of 300 and 600 mg/kg against pain induced by acetic acid, formalin, pressure and against inflammation induced by carrageenan, histamine, serotonin and formalin in mice and rats, showed a dose dependant inhibition of pain and inflammation with a maximum effect of 56.38%, 73.06% and 42.79% produced by the aqueous extract, respectively on pain induced by acetic acid, formalin and pressure while the methanol extract at the same dose respectively inhibited these models of pain by 62.70%, 84.54% and 47.70%. The oral administration of aqueous and methanol extracts caused significant anti-inflammatory activity on paw oedema induced by histamine, serotonin and formalin. The present results show that the bulbils of Dioscorea bulbifera var sativa possess potent analgesic and anti-inflammatory activities. These activities may results from the inhibition of inflammatory mediators such as histamine, serotonin and prostaglandins. Thus, the analgesic activity of the bulbils of Dioscorea bulbifera may be at least partially linked to its anti-inflammatory activity.

In vitro inhibition of lipopolysaccharide and mycobacterium bovis bacillus Calmette Guérin-induced inflammatory cytokines and in vivo protection from D-galactosamine/LPS -mediated liver injury by the medicinal plant Sclerocarya birrea.

Sclerocarya birrea is a medicinal plant used for the treatment of inflammatory- and bacterial-related diseases. The present study investigated in vitro and in vivo the effects of the stem bark methanol extract of S. birrea. Nitrite, TNF, IL-1beta, IL-6 and IL-12p40 production by bone marrow-derived macrophages (BMDM) pre-incubated with or without S. birrea, and stimulated with Lipopolysaccharide (LPS) or infected with live Mycobacterium bovis Bacillus Calmette Guérin (BCG) was evaluated. S. birrea extract inhibited, in a concentration-dependent manner, nitrite, TNF, IL-1beta, IL-6 and IL-12p40 production by BMDM stimulated with LPS or infected with live BCG. The iNOS expression was reduced by S. birrea after stimulation of BMDM with LPS. In addition, S. birrea inhibited the nuclear factor kB (NF-kB) activation by both LPS and BCG. The effects of the plant extract were also evaluated in an in vivo model of liver injury induced by D-galactosamine/LPS (D-GalN/LPS) administration in mice. S. birrea limited D-GalN/LPS-liver injury as assessed by a reduction in transaminases and TNF, IL-1beta, IL-6 serum levels, and translocation of NF-kB to the nucleus. Taken together, our data indicate that stem bark methanol extract of S. birrea possesses anti-inflammatory properties by inhibiting NF-kB activation and cytokine release induced by inflammatory or infectious stimuli.

Hypertensive effects of oral administration of the aqueous extract of Solanum torvum fruits in L-NAME treated rats: evidence from in vivo and in vitro studies.

ETHNOPHARMACOLOGICAL RELEVANCE: Solanum torvum fruits are commonly used in Cameroonian traditional medicine for treatment of arterial hypertension. It has been previously shown that intravenous administration of aqueous extract from dried fruits (AEST) reduced blood pressure. AIM: The present work evaluates acute toxicity and effects of oral administration of AEST in chronic arterial hypertension induced by L-NAME. Effects of AEST were also evaluated on isolated aorta. MATERIALS AND METHODS: AEST (200 mg/kg/day, p.o.) was given solely or concomitantly with L-NAME (40 mg/kg/day, p.o.) for 30 consecutive days. Animal body weight, systolic blood pressure and heart rate were measured before stating the treatment and at the end of each week. Urinary volume and urinary sodium and potassium contents were quantified before and at days 1, 15 and 30 of the treatment. Aorta from treated animals was tested for their sensitivity to noradrenaline and carbachol. Aorta from normal untreated rats was used to evaluate the in vitro vascular effect of AEST. RESULTS: The results showed that AEST did induce neither mortality nor visible signs of toxicity. When given solely or in co-administration with L-NAME, AEST significantly reduced animal's body weight. It amplified the hypertensive and cardiac hypertrophy effect of L-NAME and did not affect these parameters in normotensive animals. AEST increased the sensitivity to noradrenaline in normotensive and significantly reduced it in hypertensive animals. AEST significantly increased urinary volume and sodium excretion in L-NAME treated animals while reducing the sodium excretion in normotensive. In vitro, AEST induced a potent partial endothelium-dependent contraction of aortic ring; contractions that were partially antagonized by prazosin and verapamil and were not relaxed by carbachol. CONCLUSION: These results suggest that oral chronic administration of AEST induced potentiation of arterial hypertension and cardiac hypertrophy in L-NAME treated rats. These effects may result from a reduction in sensitivity to vasorelaxant agents and increase in hypersensitivity to contractile factors. AEST possess potent in vitro vasocontractile activity that may result from activation of both alpha(1)-adrenergic pathway and calcium influx.

Anti-hypertensive effects of the methanol/methylene chloride stem bark extract of Mammea africana in l-NAME-induced hypertensive rats.

AIM OF THE STUDY: The methanol/methylene chloride (CH(3)OH/CH(2)Cl(2)) extract from the stem bark of Mammea africana was showed to possess vasodilating effect in the presence and the absence of N(omega)-nitro-l-arginine methyl ester (l-NAME). The present study was designed to evaluate the effects of the methanol/methylene chloride from the stem bark of Mammea africana. MATERIALS AND METHODS: The extract (200 mg/(kg day)) was administered orally in rats treated concurrently with l-NAME (40 mg/(kg day)). l-Arginine (100 mg/(kg day)) and captopril (20 mg/(kg day))were used as positive controls. Bodyweight, systolic arterial blood pressure and heart rate were measured weekly throughout the experiment period (28 days). At the end of treatment, animals were killed and the cardiac mass index evaluated. The aorta was used to evaluate the endothelium-dependant relaxation to carbachol. The aorta contraction induced by noradrenalin was also examined and expressed as a percentage of that induced by KCl. RESULTS: The extract neither affected the body weight nor the heart rate. The extract as captopril completely prevented the development of arterial hypertension. Both the substances failed to restore the endothelium-dependent vascular relaxation and increased the vascular contraction to norepinephrine in relation to KCl contraction. They also significantly reduced the left ventricular hypertrophy induced by l-NAME. CONCLUSION: These findings are in agreement with the traditional use of Mammea africana in the treatment of arterial hypertension and indicate that it may have a beneficial effect in patients with NO deficiency but will be unable to improve their endothelium-dependent vasorelaxation.

Vasodilator effect of the extracts and some coumarins from the stem bark of Mammea africana (Guttiferae).

CH(2)Cl(2) fraction obtained from the stem bark of Mammea africana inhibited noradrenaline (NA) or KCl-induced contraction in isolated guinea pig and rat aorta. The vasorelaxant potency of the CH(2)Cl(2) fraction of Mammea africana was diminished by a pre-treatment with Nitro-L-arginine methyl ester (L-NAME), an inhibitor of NO synthase, which was however not affected by indomethacin pre-treatment. These findings indicated that the vasorelaxant effect of Mammea africana may be partially endothelium dependent, mediated by nitric oxide and that vasoactive prostanoids might not be contributing to the vasorelaxation effect. Three bioactive compounds were isolated from this CH(2)Cl(2) fraction and identified as 4-n-propylcoumarins (1) (mammea B/BB), 4-phenylcoumarins (2) (mammea A/AA or mammeisin) and (B/BA) (3) and might involved in the vasorelaxant effect of the extract. The mechanisms of the vasorelaxant effect might therefore be multiple, including endothelium dependence and the mechanisms, which interfere with the liberation of Ca(2+) into the muscle cell.

Vasorelaxant effects of Brillantaisia nitens Lindau (Acanthaceae) extracts on isolated rat vascular smooth muscle.

Brillantaisia nitens Lindau (Acanthaceae) is traditionally used in Cameroon for the treatment of many diseases including cardiovascular disorders. We have studied its vasorelaxant effects in rat vascular smooth muscle. In this study, aqueous, methylene chloride, methanol, and methylene chloride/methanol leaves extracts of Brillantaisia nitens were tested for their relaxing ability in vitro. Strips of rat aorta, with or without intact endothelium, were mounted in tissue baths, contracted with KCl (60mM) or norepinephrine (10(-4)M), and then exposed to the plant extracts. These extracts exhibited concentration-dependent vasorelaxations of norepinephrine-induced contractions of intact aortic strips. The EC(50) were 0.42+/-0.01mg/ml (aqueous extract), 0.63+/-0.02mg/ml (methylene chloride extract), 0.73+/-0.02mg/ml (methanol extract) and 0.36+/-0.02mg/ml (methylene chloride/methanol extract). The methylene chloride/methanol (CH(2)Cl(2)/CH(3)OH) extract was the most potent relaxing extract. It caused a concentration-dependent and endothelium-independent relaxation of the rat aortic strips contracted by KCl or norepinephrine. On the NE-induced contraction, its maximal relaxant activity (109%) due to the dose of 1.5mg/ml, was not significantly modified by the pretreatment of aortic strips with indomethacin (89%, P>0.05) or with l-NAME (103%, P>0.05). This suggests that the vasorelaxation elicited by CH(2)Cl(2)/CH(3)OH extract was not mediated via endothelium-derived prostacyclin or nitric oxide. In contrast, this relaxation was markedly reduced by tetraethylammonium, a blocker of non-selective K(+) channels and glibenclamide, a blocker of ATP-sensitive K(+) channels. The CH(2)Cl(2)/CH(3)OH extract significantly inhibited Ca(2+)-induced concentration-contraction and the Ca(2+) influx in aortic strips incubated with 60mM KCl. These results indicate that the vasorelaxant effect of the CH(2)Cl(2)/CH(3)OH extract of Brillantaisia nitens is due to an inhibition of Ca(2+) influx, possibly via the activation of ATP-sensitive K(+) channels.

Analgesic and anticonvulsant effects of extracts from the leaves of Kalanchoe crenata (Andrews) Haworth (Crassulaceae).

Kalanchoe crenata Andr. (Crassulaceae) is a fleshy herbaceous plant used in the African traditional medicine as remedies against otitis, headache, inflammations, convulsions and general debility. In the present work, the analgesic effects of methylene chloride/methanol (1:1) (CH(2)Cl(2)/CH(3)OH) extract and its hexane, methylene chloride (CH(2)Cl(2)), ethyl acetate, n-butanol fractions and aqueous residue have been evaluated using acetic acid, formalin and pressure test. The anticonvulsant effects of the CH(2)Cl(2)/CH(3)OH extract were also investigated on seizures induced by pentylenetetrazol (PTZ 70 mg/kg), strychnine sulphate (STN 2.5 mg/kg) and thiosemicarbazide (TSC 50 mg/kg). CH(2)Cl(2)/CH(3)OH extract and its fractions, administered orally at the doses of 150 and 300 mg/kg, exhibited protective effect of at least 30% on the pain induced by acetic acid. The CH(2)Cl(2) fraction at 300 mg/kg showed a maximal effect of 78.49%. The CH(2)Cl(2)/CH(3)OH extract and its CH(2)Cl(2) fraction at the doses of 150 and 300 mg/kg significantly reduced the first phase of pain induced by formalin while the second phase was completely inhibited. The CH(2)Cl(2) fraction produced more than 45% reduction in the sensitivity to pain induced by pressure. The CH(2)Cl(2)/CH(3)OH extract of Kalanchoe crenata significantly increased the latency period in seizures induced by PTZ and significantly reduced the duration of seizures induced by the three convulsant agents. The extract protected 20% of animals against death in seizures induced by TSC and STN. These results suggest a peripheral and central analgesic activities as well as an anticonvulsant effect of the leaves of Kalanchoe crenata.

Relaxant effects of the neutral extract of the leaves of Bidens pilosa Linn on isolated rat vascular smooth muscle.

The long-lasting antihypertensive effect of a neutral extract of Bidens pilosa has been suggested to be due to vasodilation. The present work was undertaken to assess this hypothesis. The vasorelaxant effect of a neutral extract (NBp) of the leaves of B. pilosa was evaluated in vitro on isolated rat aorta contracted with KCl or norepinephrine. NBp induced a concentration-dependent vasorelaxation of the rat aorta precontracted with KCl (60 mM) by 25%-105% at the respective concentrations of 0.25-1.5 mg/mL. The maximal concentration of 1.5 mg/mL provoked 88% relaxation of norepinephrine-induced contractions. There were no significant differences between the effects of the extract on the aorta strips with or without endothelium. In the presence of indomethacin or pyrilamine maleate, the relaxant response induced by the plant extract was significantly inhibited at the lower concentrations. The plant extract was able to reduce the aorta resting tone, inhibit the KCl-induced contractions (90% at 1.5 mg/mL) and the CaCl2-induced contractions by 95% at a concentration of 0.75 mg/mL. These results demonstrate the vasodilating properties of the neutral extract of Bidens pilosa and indicate that it may act as a calcium antagonist.

Analgesic properties of the aqueous and ethanol extracts of the leaves of Kalanchoe crenata (Crassulaceae).

The aqueous and ethanol extracts of the dry leaves of Kalanchoe crenata (300 and 600 mg/kg) were evaluated for their analgesic properties on the pain induced by acetic acid, formalin and heat in mice and by pressure on rats. The ethanol extract of K. crenata at a dose of 600 mg/kg produced an inhibition of 61.13% on pain induced by acetic acid and 50.13% for that induced by formalin. An inhibition of 67.18% was observed on pain induced by heat 45 min after the administration of the extract. The aqueous extract administered at a dose of 600 mg/kg produced a maximum effect of 25% on pain induced by pressure. These activities were similar to those produced by a paracetamol-codeine association, while indomethacin exhibited a protective effect only against the writhing test. Our results suggest that the leaves of K. crenata could be a source of analgesic compounds.

Possible mechanisms of action of the neutral extract from Bidens pilosa L. leaves on the cardiovascular system of anaesthetized rats.

The aim of this study was to investigate the hypotensive and cardiac effects of the neutral extract from Bidens pilosa leaves. Intravenous administration of the extract resulted in a biphasic dose-related hypotensive activity. In normotensive rats (NTR), B. pilosa decreased systolic blood pressure by 18.26%, 42.5% and 30% at doses of 10, 20 and 30 mg/kg, respectively. In spontaneously hypertensive rats (SHR), the decrease in systolic blood pressure was 25.77%, 38.96% and 28.64% at the above doses, respectively. These doses induced hypotension by 27%, 34.13% and 18.73% respectively in salt-loaded hypertensive rats. In NTR, B. pilosa reduced heart rate by 23.68% and 61.18% at doses of 20 and 30 mg/kg, respectively. The force of contraction of the heart was only affected at 30 mg/kg. The initial phase of hypotensive response was partially inhibited by atropine while propranolol increased this effect. These results suggest that B. pilosa exhibited its fi rst hypotensive effects by acting on the cardiac pump efficiency and secondly through vasodilation.

Anti-inflammatory and analgesic properties of the stem bark extracts of Erythrophleum suaveolens (Caesalpiniaceae), Guillemin & Perrottet.

The MeOH stem bark extract of Erythrophleum suaveolens dissolved in water and shaken up with ethylacetate (EtOAc) and fractionated on a polyamide column with methanol as eluent produced five principal fractions. These fractions were designated as fraction A (74.8 mg yield and rich in alkaloids), fraction B (36.6 mg), fraction C (7.8 mg yield, monomeric procyanidin), fraction D (26.6 mg yield, rich in monomeric and oligomeric procyanidin), and fraction E (18.1 mg yield, rich in polymeric procyanidin). The original MeOH extract administered (100 mg/kg po) produced about 47% inhibition of carrageenin-induced paw oedema 1 h after administration. Fraction D, obtained from the ethylacetate extract and rich in procyanidins produced over 33% inhibition of carrageenan-induced paw oedema while a dose of 19.2 microg/ml produced 100% inhibitory effect on 5-lipoxygenase. A dose of 100 mg/kg of the MeOH extract also produced over 30% reduction of the sensitivity to pain while 50 mg/kg of fraction D rich in procyanidins produced over 45% analgesic effects. These results were judged significant compared to those obtained with indomethacin and acetylsalicylic acid. These findings suggest that extracts of the bark of Erythrophleum suaveolens possess potent anti-inflammatory and analgesic property and that the procyanidins lead to the observable pharmacological effects.

[Hypotensive effects of a methanol extract of Bidens pilosa Linn on hypertensive rats]. / Effets hypotensifs de l'extrait au méthanol de Bidens pilosa Linn chez les rats hypertendus.

Bidens pilosa Linn is highly regarded in some parts of Cameroon in traditional folk medical practices. The hypotensive effects of the leaf methanol extract from Bidens pilosa Linn (Asteraceae) were evaluated in spontaneously hypertensive rats (SHR), salt-loading hypertensive rats (SLHR) and normotensive Wistar rats (NTR) using the indirect (tail-cuff) method. Acute changes in urine volume and urinary excretion of Na+ and K+ were also studied. The hypotensive effect of the extract was more remarkable in hypertensive than in normotensive rats. Bidens pilosa did not provoke significant changes in the heart rate and urine volume. Urinary excretion of Na+ was decreased by 36% in spontaneously hypertensive rats and the excretion of K+ increased by 35% in normotensive rats but the effects were not statistically significant. These results suggest that the extract is a useful antihypertensive drug which has no effect on the heart frequency. The hypotensive effects of the extract may be induced by vasodilation.