Comparison of the skeletal muscle relaxant properties of Portulaca oleracea extracts with dantrolene sodium and methoxyverapamil

The effects of aqueous (AEE), dialysable (DIF) and methanol (MEE) extracts of Portulaca oleracea stems and leaves were compared with those of dantrolene sodium and methoxyverapamil (D-600) with respect to inhibition of twitch tension on the rat phrenic nerve-hemidiaphragm and with respect to contracture induced by nicotinic agonists on the frog rectus abdominis preparations. The extracts, dantrolene and D-600 inhibited twitch tension due to indirect electrical stimulation via the phrenic nerve (NS) on hemidiaphragm muscle, whereas the extracts and dantrolene inhibited, in addition, twitch amplitude due to direct muscle stimulation (MS). The extracts, dantrolene and D-600 also attenuated K+- and caffeine-induced contractures with the extracts and D-600 also reducing the time taken for the K+-induced contracture to fall to basal tension. In addition, the tetanic tension due to NS and MS was attenuated with only the extracts and dantrolene reducing the twitch/tetanus ratio (MS). There was a non-significant but consistent tendency for mutual potentiation between the extracts and dantrolene with respect to their inhibitory effect on twitch amplitude (MS) resulting in a shift to the left of the concentration-response curves to the extracts or dantrolene. This was not evident with the extracts and D-600 or dantrolene and D-600. Simultaneous addition of the extracts and dantrolene resulted in an increase in the rate of twitch tension inhibition and a decrease in the time to maximum relaxation of twitch amplitude (MS). The extracts and D-600 proved more effective in attenuating nicotinic agonist (acetylcholine, carbachol and nicotine)-induced contractures on the rectus abdominis muscle than dantrolene. From these observations, it appears that the Portulaca oleracea extracts mimic, in part, the effect of D-600 and dantrolene on the rat hemidiaphragm and frog rectus abdominis muscles; therefore, the muscle relaxant properties of the extracts may be due, in part, to inhibition of trans-membrane Ca influx, interference with the Ca-induced Ca release process and/or inhibition of the release of intracellular Ca from stores in the sarcoplasmic reticulum.     

Effects of extracts of Portulaca oleracea on skeletal muscle in vitro

Extracts of Portulaca oleracea inhibited twitch tension due to direct (MS) and indirect electrical stimulation via the phrenic nerve (NS) of the rat hemidiaphragm muscle. The rank order of potency was dialysable extract greater than or equal to methanol extract greater than diethylether extract, although all exhibited equal efficacy. The non-dialysable extract did not inhibit twitch tension due to MS or NS. The dialysable, methanol and diethylether extracts inhibited tetanus tension, and attenuated the area under the K+- and caffeine-induced contracture. The contracture induced by nicotinic agonists and K+ on the rectus abdominis muscle was significantly inhibited by these extracts.     

Investigation of the antispasmodic potential of Hibiscus sabdariffa calyces

Addition of an aqueous extract of Hibiscus sabdariffa calyces (2.5 ml/bath approximately 125 mg of starting crude material) inhibited the tone of various isolated muscle preparations (rabbit aortic strip, rhythmically contracting rat uterus, guinea-pig tracheal chain and rat diaphragm). Other muscles were stimulated (quiescent rat uterus and frog rectus abdominis). Intravenous injection of the extract to anaesthetized cats lowered the blood pressure in a dose-response manner. The inhibitory effects were resistant to a number of standard receptor blockers but the hypotensive influence was partially blocked by atropine and the tonic effects on rat uterus were partially reduced by hydrocortisone and indomethacin.     

Pharmacological effects of Synclisia scabrida alkaloid B on some isolated muscle preparations

Alkaloid B reversibly blocked the responses of rat diaphragm to electrically induced stimulations via the phrenic nerve. The alkaloid had no effect on the responses of the diaphragm elicited by direct electrical stimulation. The responses of frog rectus abdominis muscle to acetylcholine were inhibited by alkaloid B.Alkaloid B reversibly antagonised the responses of rabbit duodenum to exogenously applied acetylcholine. The contractile effect of oxytocin on rat uterus was specifically inhibited by alkaloid B. The effects of alkaloid B on isolated muscle preparations were concentration-dependent. However, the effect of dopamine and noradrenaline on rat vas deferens was not altered by alkaloid B.     

Effects of Daniellia oliveri stem bark and leaf extracts on rat skeletal muscle.

The stem bark and leaves of Daniellia oliveri were screened phytochemically and the effects of their respective methanol extracts on the skeletal muscle of rats were investigated using the isolated phrenic nerve hemidiaphragm muscle preparation. Both were found to contain tannins, cardiac and saponin glycosides. In addition, the bark, but not leaves, contained cyanogenetic glycosides. The methanol extracts were found to possess neuromuscular blocking properties. The leaf extract appeared to act primarily by inhibiting the influx of extracellular Ca(2+) principally by inhibiting K(+) channels. The inhibitory action of the bark extract appeared to be mediated by interference with transmitter release and an action on multiple sites.     

Skeletal muscle relaxant properties of the aqueous extract of Portulaca oleracea

The skeletal muscle relaxant properties of an aqueous extract of Portulaca oleracea were examined on the twitch and tetanus tension evoked by electrical stimulation using the rat phrenic nerve-hemidiaphragm and frog sciatic nerve-sartorius muscle preparations and on contractures induced by nicotinic agonists using the rat rectus abdominis muscle preparation. The extract (5-50 X 10(-4) g/ml) produced a dose-dependent initial enhancement, followed by a longer lasting depression of twitch tension as induced by indirect electrical stimulation (NS) as well as direct stimulation (MS) of the diaphragm and sartorius muscle preparations. The augmentation of twitch amplitude (MS) produced by the extract was not significantly antagonised or potentiated by d-tubocurarine (5-50 X 10(-8) M) or physostigmine (5-50 X 10(-8) M) at concentrations which blocked or potentiated NS-induced twitch contractions. Furthermore, tetrodotoxin (5 X 10(-7) g/ml) alone or in combination with d-tubocurarine did not significantly attenuate extract-induced augmentation of twitch contractions to MS. In addition, the depression of twitch tension due to NS was not antagonised by physostigmine but was reversed and/or abolished by Ca2+ (2-5 X 10(-3) M) or potassium thiocyanate (1 X 10(-3) M). Contractures induced by K+ (80 mM) or by tetanic stimulation (20-60 Hz) were significantly reduced by the extract whereas, contracture induced by caffeine (2.5-6.0 mM) was not affected. Ca2+-free Tyrode's solution and EDTA (1.25 X 10(-3) g/ml) potentiated extract-induced depression of twitch tension to MS. On the rectus abdominis, contractures induced by nicotinic agonists (acetylcholine, 3-500 X 10(-7) M; carbachol, 5-500 X 10(-7) M and nicotine, 5-500 X 10(-8) M) were significantly attenuated and/or abolished by the extract (5-10 X 10(-3) g/ml). These observations indicate that the aqueous extract possesses unique skeletal muscle relaxant properties which do not appear to involve interference with cholinoceptor mechanism(s). It appears that the mechanism of action of the extract may involve interference with Ca2+ mobilization in skeletal muscle.     

Evaluation of plant extracts for sweetness using the Mongolian gerbil

Extracts of Thladiantha grosvenorii fruits, Stevia rebaudiana leaves, and Abrus precatorius leaves were investigated using Mongolian gerbil electrophysiological and conditioned taste aversion procedures, which were designed to respond to sucrose. A close correlation was observed between extracts of these sweet plants known to contain sweet principles and those extracts indicated as being sweet by a combination of these gerbil bioassays. The methods employed seem to be suitable for use in aiding the purification of highly sweet compounds of plant origin.     

Isolation of a neuromuscular junctional blocking agent from Cleistanthus collinus plant leaf extract

A potent neuromuscular junctional blocking agent was isolated from chloroform extracts of poisonous Cleistanthus collinus leaf by a combined chromatographic—cholinesterase inhibition technique. An amorphous yellowish green extract was eluted from paper or micro thin layer chromatographic plates. This compound caused a 93% fade on nerve evoked muscle tension and a 95% decrement in nerve evoked muscle action potentials and least change in muscle evoked muscle action potentials and tension in a rat phrenic nerve—diaphragm preparation, suggesting the presence of a potent pharmacologically active ingredient causing neuromuscular blockade which is irreversible.     

Acetylcholine and choline in common spices

Aqueous extracts obtained from seven commonly used spices (cardamon, coriander, cumin, black pepper, red pepper, anise and fennel) showed cholinomimetic effects when tested on rat blood pressure, rat jejunum and frog rectus abdominis preparations. This effect was observed mostly when the spices were roasted. Chemical estimation using gas chromatography/mass spectrometry confirmed the presence of large amounts of acetylcholine and its precursor choline.     

Effects of essential oil of Croton zehntneri,and of anethole and estragole on skeletal muscles

Extracts of the essential oil of Croton zehntneri (CzEO) yield a mixture of substances in which the major components are anethole and estragole. The action of CzEO and of pure anethole and estragole (at 0.05–1.0 mg/ml) were studied in muscle preparations of the toad and rat. All three oils blocked twitches evoked by nerve stimulation. In the rat diaphragm direct stimulation resulted in enhanced twitches (CzEO), partially depressed twitches (estragole) and anethole did not induce a significant change. The response of toad rectus to acetylcholine was reduced by all three oils. Caffeine contractions of the rectus abdominis and sartorius muscles were enhanced by all oils. This enhancement in the case of the sartorius was blocked by procaine. Lowering the temperature to 4°C in the presence of CzEO, anethole or estragole provoked a contraction which could be blocked by procaine. CzEO, anethole or estragole alone sometimes caused contractions. The occurrence of this response was increased by elevation of calcium (to 22 mM). Other divalent cations and La³⁺ were also effective, in order: La³⁺ > Ca²⁺ > Mn²⁺ > Ba²⁺ > Mg²⁺ except in the case of anethole where the order of Ca²⁺ and Mn²⁺ are interchanged. CzEO- and estragole-induced contractions were blocked by procaine. The data suggest that CzEO, anethole and estragole may have two sites of action on muscle fibers: the post junctional membrane, by blocking neuromuscular transmission, and on the sarcoplasmic reticulum (SR), by increasing myoplasmic calcium.     

The muscle relaxant properties of Portulaca oleracea are associated with high concentrations of potassium ions

The juice and aqueous extracts from the plant Portulaca oleracea have been used in West Africa for a variety of medical purposes, and extracts were previously shown to have muscle relaxant properties on isolated nerve-muscle preparations. We have attempted to characterise the components responsible for this activity. Ethanolic extracts caused an initial augmentation of twitch height in chick biventer cervicis preparations and then blockade which appeared to be mediated by an action directly on muscle fibres rather than on neuromuscular transmission. Solvent fractionation of the crude ethanolic extract followed by bioassay on the chick biventer cervicis preparation showed that muscle paralysis increased with increasing polarity: i.e. water fraction > butanol > ethyl acetate crude extracts. These fractions contained 28%, 18%, 12.2% and 9%, respectively, of potassium by weight of dried extract. Similar concentrations of KC1 reproduced the same effect as the extracts on muscle activity, and when the most active fraction (water fraction) was desalted, it had no neuromuscular activity even at 10 times higher concentration than used previously. We conclude that the neuromuscular activity of extracts of Portulaca oleracea is caused by high concentrations of potassium ions.     

Preliminary phytochemical, pharmacological and antibacterial studies of the alkaloidal extracts of the leaves of Synclisia scabrida Miers

Preliminary phytochemical investigation of the leaves of Synclisia scabrida indicated the presence of two alkaloids in the water extracts and five alkaloids in the ethanol extracts. The alkaloidal fraction obtained from the cold ethanol extract furnished on column-chromatography, a homogeneous amorphous solid which has been designated as alkaloid C. Alkaloid C showed positive test for alkaloids. The UV and IR spectra and colour reactions of alkaloid C indicated that the compound may be a phenolic bisbenzylisoquinoline alkaloid. All the extracts delayed the onset and shortened the duration of apomorphine-induced stereotyped behaviour in chicks. In addition, 40 mg kg-1 i.p. of the ethanolic extract induced catalepsy in rats. The cold water extract (CWE) synchronized the EEG of the hyperstriatum, optic tectum and the reticular formation while the EMG activity was slightly enhanced. The hot ethanol alkaloidal extract (HEE) inhibited the growth of Pseudomonas aeruginosa and Staphylococcus aureus. The minimum inhibitory concentration of HEE on Pseudomonas aeruginosa strains I and II were 5 and 2.5 micrograms/ml while for Staphylococcus aureus strains I and II were 5 and 10 micrograms/ml, respectively. Up to 1 g kg-1 i.p. of the extract failed to induce any lethal effect in chicks and rats. These effects of the leaf extracts of Synclisia scabrida Miers support some of the local uses of the plant by traditional medical practitioners.     

Post-testicular antifertility effects of Abrus precatorius seed extract in albino rats

Oral administration of a 50% ethanol extract of Abrus precatorius seeds (250 mg/kg) in albino rats for 30 and 60 days induced an absolute infertility in males which was reversible. Suppression of sperm motility in the cauda epididymis was the most pronounced effect of the treatment. Such treatment may affect the oxidative/energy metabolism of the cauda epididymis. Histological and histocytometric observations in testis and parareproductive tissues appeared normal while the protein, sialic acid, acid phosphatase and succinic dehydrogenase levels were significantly depleted.     

Anthelmintic screening of Zimbabwean plants traditionally used against schistosomiasis

Extracts of 23 plant species used popularly against schistosomiasis in Zimbabwe were screened for their anthelmintic effect. Schistosomules of the trematode Schistosoma mansoni and cysticercoids of the cestode Hymenolepis diminuta were studied in vitro. The material consisted of 58 plant extracts, of which 37 killed the newly excysted cysticercoids within an hour, when incubated in a culture medium. Lethal concentrations varied from 0.8 to 103 mg/ml. All plant extracts showed activity against the tapeworms after 24 h. Ten of the best extracts were also tested against schistosomules. Five of these extracts showed activity. Lethal concentrations varied from 0.6 to 33.8 mg/ml of dry plant material. Extracts of stem and root from Abrus precatorius (Fabaceae), of root bark and leaves from Ozoroa insignis (Anacardiaceae) and of root bark from Zizyphus mucronata (Rhamnaceae) gave the best results against tapeworms. The best results against schistosomules were obtained with stem and root extracts from Abrus precatorius (Fabaceae) and stem bark from Elephantorrhiza goetzei (Mimosaceae). Although the activity of root and root bark extracts commonly used in traditional medicine was verified in this study, our results showed that also extracts from leaf and stem can be effective anthelmintics.     

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).     

鸡骨草醇提物抗菌活性研究

目的对鸡骨草的醇提物进行体外抗菌活性的研究。方法采用四种常用菌杯碟法进行测定。结果发现提取液对大肠埃希菌和铜绿假单胞菌均有抑菌效果,对金黄色葡萄球菌和肺炎克雷伯氏菌则几乎没有抑菌效果,其中对铜绿假单胞菌抑菌效果最为明显,如以1 g鸡骨草提取1 mL提取液为标准,则其提取液对铜绿假单胞菌的抗菌活性与0.1 mg/mL的盐酸四环素溶液相当。结论鸡骨草醇提物具有抑菌活性。     

Neuromuscular effects and acute toxicity of an ethyl acetate extract of Spigelia anthelmia Linn

An ethyl acetate extract of Spigelia anthelmia (EASa), with validated anthelmintic activity, was evaluated for its acute toxicity and general effects in albino Swiss mice and for neuromuscular relaxant activity in the frog sciatic-gastrocnemius and rectus abdominis preparation. The extract induced a dose-related myotonia and muscular paralysis of rapid onset at higher doses. The calculated LD50 after oral and intraperitoneal administration was 345.9 [241.4-484.7] mg/kg and 60.8 [47.4-80] mg/kg, respectively. In broilers, intramuscular injection of EASa-induced spastic paralysis qualitatively similar to that obtained after succinylcholine administration and contrasting to the flaccid paralysis induced by D-tubocurarine. The contraction elicited by direct stimulation of the gastrocnemius was blocked by EASa by 54.3+/-4.7% (IC50 = 21.4 [11.2-35.8] microg/ml) and the twitches evoked by stimulation of the sciatic nerve were blocked by 69.1+/-7.4% (IC50 = 17.9 [4.5-34.23] microg/ml). EASa also blocked acetylcholine-induced contractions in the frog rectus abdominis by 58.6+/-7.4% (IC50 = 7.4 [1.7-15.28] microg/ml) but did not decrease tonic contractions induced by a high-potassium Ringer solution. In summary, the ethyl acetate extract of Spigelia anthelmia induces tonic paralysis in vivo, and decreases amplitudes of twitches and increases tonus of skeletal muscle in vitro.     

Effect of orally administered shao-yao-gan-cao-tang (Shakuyaku-kanzo-to) on muscle cramps in maintenance hemodialysis patients: a preliminary study

Muscle cramps are one of the most common complications of hemodialysis (HD), and often are a source of great pain in spite of various clinical measures. The traditional herbal medicine, shao-yao-gan-cao-tang (Japanese name: Shakuyaku-kanzo-to), consists of equal amounts of paeony and licorice roots, and has been used in Japan and China for muscle pain or skeletal muscle tremors. To determine whether this medicine is able to prevent frequent and unendurable muscle cramps in patients undergoing HD, Shakuyaku-kanzo-to at 6 g per day was prospectively administered for 4 weeks to five patients on HD who were suffering from frequent muscle cramps. The frequency and severity of cramping before and after the treatment treatment were carefully observed and compared. Skeletal muscle cramps completely disappeared in two of the treated patients after the start of oral administration of Shakuyaku-kanzo-to. Moreover, the frequency of cramping was significantly decreased in two of the remaining three patients after persistent administration. The severity of muscle cramps was also decreased by this treatment in the responsive patients. No serious side effects were detected during the treatment period. The inhibitory effect of Shakuyaku-kanzo-to on muscle contraction was also experimentally examined by using phrenic nerve-diaphragm preparations from male Wistar rats. Differences between the twitch responses were determined when the diaphragms and the nerves were stimulated in the presence and absence of the extract of Shakuyaku-kanzo-to. The results demonstrated that extracts of paeony and licorice roots inhibit contraction of skeletal muscles in rats. Taken together, we suggest that administration of Shakuyaku-kanzo-to is a safe, effective treatment for preventing muscle cramps in patients undergoing HD.     

Potential antifilarial activity of the leaves and seeds extracts of Psoralea corylifolia on cattle filarial parasite Setaria cervi

The effect of aqueous and alcohol extracts of the leaves and seeds of Psoralea corylifolia, on the spontaneous movements of both the whole worm and the nerve muscle preparation of Setaria cervi and on the survival of microfilariae in vitro was studied. Alcohol extracts of both leaves and seeds caused the inhibition of spontaneous movements of the whole worm and the nerve muscle preparation of S. cervi, characterised by initial, short lasting small increase in tone of contractions followed by paralysis. The initial stimulatory effect was not observed by alcohol extract of leaves on nerve muscle preparation. The concentrations required to inhibit the movements of whole worm and nerve muscle preparations for alcohol extracts of leaves and seeds were 160, 30, and 150, 20 microg/ml, respectively suggesting a cuticular permeability barrier. Alcohol extracts of both leaves and seeds caused death of microfilariae in vitro, LC(50) and LC(90) being 15 and 25 ng/ml for alcohol extract of leaves and 12 and 18 ng/ml for alcohol extract of seeds, respectively.     

Pharmacological activities of extracts of Daniellia oliveri (Rolfe) Hutch. and Dalz. (Leguminosae)

Extracts of the stem bark of Daniellia oliveri using hexane, ethyl acetate and methanol were tested for analgesic, antipyretic and antiinflammatory activities. The hexane extract exhibited a dose related analgesic activity whilst the methanolic extract was active in the induced inflammatory condition. The ethyl acetate extract was relatively inactive and none of the extracts showed any antipyretic activity. Metabolic cage studies showed that a 70% ethanolic extract of the bark caused significant decreases in body weight, food intake, urine and stool output of rats. This extract also exhibited a competitive antagonism on histamine-induced contractions of the guinea-pig ileum and a non-competitive inhibition of acetyl choline-induced contraction of the frog rectus abdominis muscle.