Inhibitory effects of Santolina chamaecyparissus extracts against spasmogen agonists

Several extracts of Santolina chamaecyparissus ssp. squarrosa antagonized in a concentration-dependent way the contractions of rat duodenum, guinea-pig ileum, rat vas deferens and rat uterus as induced by acetylcholine, histamine, noradrenaline, oxytocin and serotonin. Polar extracts were less active than apolar extracts, and it was necessary to assay the former at higher concentrations. Only the lyophilized aqueous extract produced a slight hypotensive effect when given intravenously at 150 mg/kg to urethananesthetized rats.     

Effect of ambrein on smooth muscle responses to various agonists

The pharmacological effects of ambrein (isolated from ambergris) on the contractile responses induced by some agonists in smooth muscle preparations were investigated. Ambrein in the concentration range of 10, 50 and 250 μg/ml decreased the spontaneous contraction of the isolated rabbit jejunum, rat uterus and guinea-pig vas deferens. Ambrein-induced antagonism to acetylcholine (Ach) in the guinea-pig ileum was abolished when the concentration of calcium chloride in the Tyrode's solution was increased to 5 mM/l. Furthermore, ambrein did not antagonise nicotine-induced contractions in the isolated rabbit jejunum or serotonin-induced contractions in the isolated guinea-pig ileum and vas deferens or the rat uterus. However, ambrein in the concentration range of 10, 50 and 250 μg/ml antagonised prostaglandins (PGs) E₂, D₂, F_2α, and oxytocin-induced contractions in the rat uterus in vitro. Ambrein also antagonised (±) noradrenaline and (−) adrenaline-induced contractions in the isolated guinea-pig vas deferens. It is concluded that ambrein-induced non-selective dose-dependent antagonism to the effects of some agonists (Ach, adrenaline, noradrenaline, PGs and oxytocin) in some smooth muscles may be due to the ability of this compound to interfere with the mobilisation of extracellular Ca²⁺ required for muscular contractions induced by these agonists.     

Antispasmodic and hypotensive effects of Ferula asafoetida gum extract

The effects of Ferula asafoetida gum extract on the contractile responses of the isolated guinea-pig ileum induced by acetylcholine, histamine and KCl, and on the mean arterial blood pressure of rat were investigated. In the presence of extract (3 mg/ml), the average amplitude of spontaneous contractions of the isolated guinea-pig ileum was decreased to 54 +/- 7% of control. Exposure of the precontracted ileum by acetylcholine (10 microM) to Ferula asafoetida gum extract caused relaxation in a concentration-dependent manner. Similar relaxatory effect of the extract was observed on the precontracted ileum by histamine (10 microM) and KCl (28 mM). However, when the preparations were preincubated with indomethacin (100 nM) and different antagonists, such as propranolol (1 microM), atropine (100 nM), chlorpheniramine (25 nM) then were contracted with KCl, exposure to the extract (3 mg/ml) did not cause any relaxation. Furthermore, Ferula asafoetida gum extract (0.3-2.2 mg/100g body weight) significantly reduced the mean arterial blood pressure in anaesthetised rats. It might be concluded that the relaxant compounds in Ferula asafoetida gum extract interfere with a variety of muscarinic, adrenergic and histaminic receptor activities or with the mobilisation of calcium ions required for smooth muscle contraction non-specificly.     

Pharmacological basis for the use of the antivenene water soluble extract of Diodia scandens as a laxative, oxytocic agent and a possible aphrodisiac in traditional medicine practice in eastern nigeria.

The effects of the antivenene fraction of an ethanol extract of Diodia scandens on some mammalian smooth muscles were investigated. On the guinea-pig ileum, the extract was shown to be a partial agonist acting via muscarinic receptors. Acetylcholine (ACh) was 2.5 x 10(5) times more potent. On the pregnant guinea-pig uterus, the extract induced concentration-dependent increases in the force of contraction and tonus. Oxytocin and ergometrine were respectively 10(6) and 10(3) times more potent. The extract, at subliminal concentrations, potentiated ACh and adrenaline-induced contractions in the guinea-pig was deferens. It also induced dose-related vasodilatation in the rat hindquarters and depressed the blood pressure in the anaesthetized cat. It was concluded that these pharmacological actions offer some scientific explanation for the use of Diodia scandens in traditional medicine as a laxative and as an oxytocic agent. It is suggested that the extract could enhance erection and ejaculatory processes in the male, thus accounting for its regular use by some elderly males.     

Globularia alypum L. extracts reduced histamine and serotonin contraction in vitro

The present study analyses in in vitro models the pharmacological activity of methanol and dichloromethane extracts (1, 10 and 100 microg/mL) obtained from the leaves and stems of Globularia alypum L. Preincubation of the guinea-pig ileum and rat uterus with both extracts produced a dose dependent abolition of the contractile effects of histamine and serotonin, respectively. At the same doses, neither methanol nor dichloromethane extract reduced the contractile effects of acetylcholine on rat duodenum or noradrenaline on rat vas deferens.     

Antiinflammatory activity and effects on isolated smooth muscle of extracts from different Teucrium species

The present study analyses the antiinflammatory effects and the action on in vitro motility of methanol and dichloromethanol extracts and stems of four Teucrium species (T. flavum, T. cartaginenses, T. buxifolium and T. pumillum). The antiinflammatory activity was tested in the carrageenan-induced paw oedema in rats. T. flavum methanol (200 mg/kg, i.p.) and dichloromethanol (138 mg/kg, i.p.) extracts showed a significant anti-inflammatory effect through the 24 h experimental period and reduced the E_max induced by histamine and serotonin in vitro on guinea-pig ileum and rat uterus respectively. These extracts did not modify the contractile effects induced by acetylcholine on rat duodenum and noradrenaline on rat vas deferens. The methanol extracts of T. pumillum (50 mg/kg, i.p.) and T. buxifolium (26 mg/kg, i.p.) exhibited significant antiinflammatory effects only in the acute phase of the oedema (2 h) without affecting the chronic phase (24 h). In guinea-pig ileum, rat uterus and rat vas deferens, the methanol extract of T. pumillum reduced the maximal effect induced by histamine, serotonin and noradrenaline, respectively, whereas the methanol extract of T. buxifolium lacked any effect on the contractile activity induced by various agonists in vitro. When tested for antiinflammatory activity the methanol (200 mg/kg, i.p.) and dichloromethanol (200 mg/kg, i.p.) extracts of T. cartaginenses did not modify the oedematous response induced by carrageenan administration.     

Toxicological evaluation of Nerium oleander on isolated preparations

In vitro toxicological evaluation of Nerium oleander was carried out using different isolated preparations. The methanolic leaf extract potentiated both spontaneous and electrically evoked contractions of vas deferens of rats and guinea-pig ileum in a concentration dependent manner. The effect was not antagonized by the adrenergic blocker, tolazoline. The extract inhibited electrically stimulated neurogenic twitch responses of rat phrenic nerve diaphragm preparation. The dose dependent inhibition of twitch response in this preparation could not be reversed by the anticholinesterase drug, neostigmine. The extract evoked a persistent depolarizing effect on the phrenic nerve diaphragm preparation. The extract exhibited its most potent action on the isolated right atrial preparation of rat. It inhibited the rate of spontaneously beating atria in a concentration dependent manner. The negative chronotropic effect was not antagonized either by antimuscarinic drug or adrenergic agonist.     

Effects on Arterial Blood Pressure of the Methanol and Dichloromethanol Extracts from Schinus molle L. in Rats

The effects on arterial blood pressure of the methanol and dichloromethanol extracts from Schinus molle L. were analysed in urethane anaesthetized rats. In normotensive rats, the mean arterial blood pressure was significantly reduced by the i.v. administration of both extracts. The dichloromethanol extract inhibited the effects of noradrenaline on arterial blood pressure in the anaesthetized rat and it reduced the maximal contractile effect ( E _max) induced by noradrenaline on rat vas deferens in the organ bath. However, the methanol extract did not modify the effects of noradrenaline in the evaluated tests.     

Effect of Extract of Leaf and Seed of Piper guineense on Some Smooth Muscle Activity in Rat,Guinea-pig and Rabbit

Extracts of the leaf and seed of Piper guineense were separately prepared and their pharmacological effects screened using smooth muscle of the gastrointestinal tract and uterus. The leaf extract enhanced both the frequency and tone of spontaneous contractions of rabbit jejunum and induced contraction of guinea-pig ileum, which were blocked by atropine. The seed extract had the opposite effect on rabbit jejunum, an inhibition which was antagonized by prazocin, and little or no effect on guinea-pig ileum. Both extracts had a stimulant effect on rat uterine muscle, the seed extract to a lesser extent.     

Chemical and pharmacological analysis of the crude aqueous/alcoholic extract from Cordyline dracaenoides

Chemical analysis of Cordyline dracaenoides (Kunth) demonstrated the presence of steroidal saponins and anthocyanidins in the stem, rhizome and root. Small amounts of tannins were also detected in its stem and rhizome. Pharmacological analysis revealed different effects according to the part of the plant used. Crude aqueous/alcoholic extract (CE) from the rhizome inhibited carrageenan-induced rat paw oedema, while the CE obtained from the root significantly decreased the locomotor activity and potentiated barbiturate-induced hypnosis in mice. The CE from the roots inhibited noradrenaline-induced contraction in the rat vas deferens in a concentration-dependent and a noncompetitive manner, while the CE from the rhizome caused a parallel displacement to the left of noradrenaline concentration response curves. In the isolated rat stomach, the CE from the roots promoted a concentration-dependent displacement to the right of the serotonin concentration response curve allied to a marked inhibition of its maximal response, while the CE from the rhizome produced only an inhibition of about 40% of serotonin-contractile responses. These results suggest that the CE from C. dracaenoides exhibits a potent and long lasting antioedematogenic effect, has central depressant effects and potentiates noradrenaline-induced contractile responses of the isolated rat vas deferens. All these effects may be, at least in part, related to the presence of steroidal saponins in this plant.     

Calcium antagonistic activity of Bacopa monniera on vascular and intestinal smooth muscles of rabbit and guinea-pig.

The present study demonstrates the calcium antagonistic activity in ethanol extract of Bacopa monniera. The plant extract inhibited the spontaneous movements of both guinea-pig ileum (IC50 = 24+/-4 microg/ml) and rabbit jejunum (IC50 = 136+/-9 microg/ml). A marked reduction in acetylcholine- and histamine-induced responses (0.0001-10 microM) in the ileum was evident in the presence of extract (260 microg/ml). The acetylcholine (1 microM)-induced contraction in the ileum was also inhibited by the extract (100-700 microg/ml) in a concentration dependent way (IC50 = 285+/-56 microg/ml). All these results indicate a direct action of the extract on smooth muscles. Calcium chloride-induced responses in the rabbit blood vessels and jejunum were attenuated in the presence of plant extract (10-700 microg/ml) implying a direct interference of plant extract with influx of calcium ions in the cells. However, the lack of modification of either noradrenaline- or caffeine-induced contractions in the presence of extract suggests that extract has no detectable effect on mobilization of intracellular calcium. These results indicate that spasmolytic effect of the B. monniera extract in smooth muscles is predominantly due to inhibition of calcium influx via both voltage and receptor operated calcium channels of the cell membrane.     

麸煨肉豆蔻不同提取物对大鼠离体肠平滑肌的影响

目的研究麸煨肉豆蔻不同提取物对大鼠离体肠管自发活动的影响。方法采用RM6240B多道生理信号采集处理系统及大鼠离体十二指肠平滑肌进行实验,观察麸煨肉豆蔻不同提取物对离体肠运动功能的影响。结果麸煨肉豆蔻挥发油、醇提物、醇提物的石油醚提取物及乙酸乙酯提取物对离体大鼠十二指肠自主运动有抑制作用,抑制率分别为51.2%、29.2%、47.8%和59.2%(P<0.01);水提物、正丁醇提取物及醇提取物萃取后的水层无抑制作用。结论麸煨肉豆蔻的挥发油、醇提物的石油醚、乙酸乙酯提取物可能为麸煨肉豆蔻止泻的有效部位。     

Terminalia arjuna,an ayurvedic cardiotonic,increases contractile force of rat isolated atria

The direct effects of aqueous, ethanolic, chloroform and petroleum ether extracts of Terminalia arjuna (family: Combretaceae) bark, an ayurvedic remedy for cardiovascular disorders, were studied on isolated atria of rats. The aqueous extract produced a substantial positive inotropic effect (EC₅₀ = 0.25 mg/mL) but no change in the rate. The ethanol, chloroform and petroleum ether extracts all decreased the rate of contraction. A slight increase in force was seen with ethanol and chloroform extracts. Higher concentrations of the chloroform extract had a negative inotropic effect. The ethanol extract decreased the maximum following frequency of the left atria. It is concluded that Terminalia arjuna has a significant positive inotropic property on rat atria in vitro which could contribute to its efficacy in treating cardiovascular disorders.     

Antihypertensive and vasodilator effects of methanolic and aqueous extracts of Tribulus terrestris in rats

The effects of methanolic and aqueous extracts of Tribulus terrestris on rat blood pressure (BP) and the perfused mesenteric vascular bed were investigated. The extracts dose-dependently reduced BP in spontaneously hypertensive rats (SHRs) with the aqueous fraction being more potent than the methanolic fraction at all doses tested. In vitro, the methanolic but not aqueous extract produced a dose-dependent increase in perfusion pressure of the mesenteric vascular bed. When perfusion pressure was raised with phenylephrine (10(-5) M), the aqueous extract produced a dose-dependent reduction in perfusion pressure at all doses. A low dose of the methanolic extract produced a vasoconstrictor effect while higher doses produced dose-dependent reduction in perfusion pressure. L-NAME (10(-4) M) significantly reduced but did not abolish vasodilation induced by the extracts. Vasodilator responses to aqueous and methanolic fractions were significantly reduced in preparations where perfusion pressure was raised with KCl (60 mM). A combination of KCl and L-NAME abolished the vasodilator responses induced by the extracts. It was concluded that methanolic and aqueous extracts of Tribulus terrestris possess significant antihypertensive activity in spontaneously hypertensive rats. The antihypertensive effects appeared to result from a direct arterial smooth muscle relaxation possibly involving nitric oxide release and membrane hyperpolarization.     

Hystological and pharmacological study of Thymus piperella (L.)

Histological and pharmacological assays have been carried out with methanol, hexane, dichloromethane and butanol extracts of Thymus piperella (L.) leaves. All the extracts were considered innocuo in the toxicity test. Methanol and also hexane, dichlorometane and butanol fractions, inhibited significantly the contractions induced by acetylcholine in isolated rat ileum in a concentration-dependent manner and the hexane extract was the most potent. However, the methanol extract did not modify the contractile effect of noradrenaline and histamine on isolated rat aorta and guinea-pig trachea respectively at the assayed dose (10, 100, 200 microg/mL). These results contribute to explain in part the use of this plant in folk medicine. In addition, morphological and histological structures characteristic of this species have been described for the first time.     

Chemical constituents of Aristolochia constricta: antispasmodic effects of its constituents in guinea-pig ileum and isolation of a diterpeno-lignan hybrid

Twenty constituents were isolated from the n-hexane and chloroform extracts of Aristolochia constricta, a plant whose aerial parts have been used empirically in folk medicine for various purposes. The inhibitory effects of these constituents on smooth muscle contraction in isolated guinea-pig ileum were studied in order to observe their antispasmodic effects. 3,4-Dibenzyldihydrofuran-type lignans [(-)-cubebin, (-)-hinokinin, and (-)-pluviatolide] and a kaurene-type diterpene [(-)-kaur-16-en-19-oic acid] were isolated as active principals. They inhibited electrically induced and acetylcholine-induced contraction in the isolated guinea-pig ileum. In addition, 9- O-[(-)-kaur-15-en-17-oxyl]cubebin was isolated as a new diterpeno-lignan hybrid, although this constituent did not exhibit antispasmodic activity.     

Evaluation of Alstonia scholaris leaves for broncho-vasodilatory activity

The present study demonstrates that the ethanol extract of Alstonia scholaris (Apocynaceae) leaves induced pronounced bronchodilatory activity in anaesthetized rats with the probable involvement of prostaglandins. However, in vitro preparations of guinea-pig trachea did not confirm this property, indicating that bronchodilation is not due to the direct tracheal smooth muscle relaxation. The vasodilatory activity of the extract was independent of adrenergic or muscarinic receptors or prostaglandins but was mainly via endothelial-derived relaxing factor, nitric oxide. The extract inhibited the spontaneous movements of rabbit jejunum and contractile effects of acetylcholine and histamine on guinea-pig ileum. Additionally, the extract caused marked reduction of barium chloride-, potassium chloride- and calcium chloride-induced contraction on guinea-pig ileum and pulmonary artery, implying a direct interference of plant extract with the influx of calcium ions into cells. However, the extract has no detectable effect on mobilization of intracellular calcium. These results coupled with the in vivo effects of ethanol extract reveal that the Alstonia scholaris leaves possess broncho-vasodilatory activity mediated presumably by prostaglandins, calcium antagonism and endothelium-derived relaxing factor(s).     

Antispasmodic property of the aqueous extract of Aristolochia albida Duch

The antispasmodic property of the underground parts of Aristolochia albida Duch (family: Aristolochiaceae) was evaluated. The evidence was provided by the aqueous extract of the plant's rhizome which exhibited significant relaxation of the spontaneous pendular contraction of isolated rabbit duodenum. The extract at moderate doses abolished acetylcholine (Ach), histamine and 5-hydroxytryptamine (5-HT) induced contractions on isolated rabbit duodenum and guinea-pig ileum. The effects of the extract mimicked antagonists (atropine, mepyramine and methysergide). Therefore, the extract evoked its antispasmodic actions by antagonism via muscarinic, histaminic and 5-HT receptors. © 1997 John Wiley & Sons, Ltd.     

Effect of an aqueous extract of Portulaca oleracea leaves on smooth muscle and rat blood pressure

An aqueous extract of Portulaca oleracea leaves and stems produced a dose-dependent relaxation of guinea pig fundus, taenia coli and rabbit jejunum and a dose-dependent contraction of the rabbit aorta. On spontaneously-beating rabbit right atria and electrically-paced left atria, the extract produced a dose-dependent negative inotropic and chronotropic effects. On rat blood pressure, the extract produced dose-dependent pressor responses. Phentolamine reduced the relaxant effect of the extract on gut smooth muscle and abolished the contractile response on the aorta as well as the pressor response on blood pressure. Guanethidine and tetrodotoxin had no effect on extract-induced relaxant or contractile responses. On rat blood pressure atropine and cyproheptadine had no effect on extract-induced pressor response, whereas propranolol slightly reduced the pressor response. An increase in extracellular calcium reversed the inhibitory effect of the extract on the rabbit atria. The extract may, therefore, act in part on postsynaptic alpha-adrenoceptors and by interference with transmembrane calcium influx.     

Pharmacological effects of Agapanthus africanus on the isolated rat uterus.

The Agapanthus africanus plant is used by South African traditional healers as a phytomedicine in herbal remedies to treat pregnancy-related ailments and to augment labour. It has already been shown that an aqueous extract of A. africanus causes smooth muscle contractions in the isolated uterus and ileum preparations. In the present study, the effects of an aqueous extract of A. africanus leaves was examined on receptor systems involved in contraction of the uterine smooth muscle in order to determine the mechanism of its pharmacological effect relevant to its ethnic use to augment labour. The extract was tested on the isolated rat uterus preparation. The aqueous extract of A. africanus leaves was found to exhibit agonist activity on uterine muscarinic receptors and to promote the synthesis of prostaglandins in the oestrogenized rat uterus. Some pharmacological justification for the ethnic use of A. africanus as a herbal oxytocic in prolonged labour has been provided.