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 stembark and leaf extracts of Bridelia ferruginea on skeletal muscle

The ethanolic extracts of the leaves and stembark of Bridelia ferruginea were separately investigated for their effects on skeletal muscle using the phrenic nerve-hemidiaphragm muscle preparation from rats. The bark extract inhibited twitch tension induced by direct electrical stimulation (muscle) (MS) but not indirect electrical stimulation (nerve) (NS) of the diaphragm. It inhibited tetanus tension to both nerve (TNS) and muscle stimulation (TMS), had no effect on K⁺-induced contracture and reduced the minimal fusion frequency (MFF). The leaf extract had no effect on twitch tension to NS and MS or K⁺-induced contracture but increased tetanus tension to TNS or TMS as well as MFF. These findings suggest that the bark extract does not affect influx of extracellular Ca²⁺ but inhibits the intracellular mobilization of Ca²⁺. The leaf extract also had no effect on influx of extracellular Ca²⁺ but most likely facilitated the intracellular mobilization of Ca²⁺. Thus, the intracellular action of the bark extract is opposite to that of the leaf extract.     

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.     

Effects of extracts of seed and leaf of Piper guineense on skeletal muscle activity in rat and frog

The pharmacological effects of leaf and seed extracts of Piper guineense were investigated on phrenic nerve hemidiaphragm activity following electrical stimulation in vitro. The Leaf and seed extracts (10 micrograms-1 mg/mL) and (50-800 micrograms/mL) respectively produced biphasic effects consisting of an initial enhancement followed by secondary transient or prolonged depression of twitch tension in response to electrical stimulation of both muscle and nerve. These effects were similar to that of decamethonium (2-800 mg/mL). An increased concentration of extracellular Ca2+ in vitro reversed the twitch contraction inhibited by the leaf and seed extracts in a dose related pattern following electrical stimulation. It is concluded that the leaf and seed extracts of Piper guineense possess among other pharmacological properties, a depolarizing neuromuscular blocking action.     

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.     

Effects on rat uterine and aorta strip smooth muscle of Thymus leptophyllus extract

The diethylether extract from Thymus leptophyllus was found to be more active on uterine smooth muscle than on aorta strips. Rat uterus experiments with and without extracellular calcium, yielded similar IC₅₀ values. A non-specific mechanism for the relaxant activity can therefore be postulated. In rat aorta and in the presence of extracellular calcium the extract inhibited the contractile response induced by K⁺ depolarizing solution and had a less inhibitory effect on noradrenaline (NA) contraction. In a Ca²⁺-free solution the extract strongly reduced the Ca²⁺-release induced by NA, but it did not affect the transient contraction caused by caffeine (CAF).     

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.     

Preliminary antifungal and cytotoxicity studies of extracts of Ritchiea capparoides var. longipedicellata

Crude extracts obtained from the leaves, stem bark and roots of Ritchiea capparoides var. longipedicellata were screened for in vitro antifungal activity using the agar tube dilution method. The leaf hexane, leaf methanol, stem bark methanol and root methanol extracts were tested using ten clinical strains of fungi at a concentration of 200 and 400 μg/ml, respectively. At 400 μg/ml, all four extracts inhibited the growth of six of the ten test fungi used in the study. Inhibition of the growth of Aspergillus niger by the extracts was also seen but the activity was low and the leaf hexane and root methanol extracts inhibited the growth of Drechslera rostrata. Only the leaf hexane extract was active against Curvularia lunata, while the growth of Candida albicans was not inhibited by any of the extracts. The inhibition of growth of almost all the microorganisms decreased at 200 μg, griseofulvin was included as a reference compound and methanol as the control. Preliminary cytotoxicity tests were done with the four extracts using the larvae of the brine shrimp, Artemia saline. The extracts were however found to be relatively non-toxic as each extract had an LD₅₀ value greater than 1000 μg/ml.     

Effects of leaf extract of Caesalpinia bonduc (Caesalpiniaceae) on the contractile activity of uterine smooth muscle of pregnant rats

The calcium dependency and the cholinergic effect of the leaf extract of Caesalpinia bonduc Roxb. (Caesalpiniaceae) was studied in isolated pregnant rat myometrium preparations. Isometric contractions were recorded. The extract (Cebo) increased the contractile force in the isolated strips in a concentration-dependent manner. The effects were comparable to those obtained with acetylcholine. Contractions induced by Cebo or acetylcholine were inhibited in the presence of atropine. The stimulating action of Cebo on the contractile responses of isolated myometrium preparations inhibited by atropine may be mediated by cholinergic receptors. In calcium-free solution Cebo induced a tonic contraction (contracture) of the muscle. Moreover, in high-potassium calcium-free solution Cebo caused contracture of the uterine smooth muscle. Cebo was still able to elicit contractions in calcium-free solution containing EDTA or EGTA. These findings suggest the existence of cholinergic receptors sensitive to Cebo which could influence the influx of calcium (phasic contraction) and mobilization of calcium from cellular stores (tonic contraction), both of which are responsible for the increase of contractile activity and development of the contracture of uterine smooth muscle.     

Active-oxygen scavenging activity of traditional nourishing-tonic herbal medicines and active constituents of Rhodiola sacra

The active-oxygen scavenging activity of 70 traditional herbal medicines used in China and Japan as nourishing tonics were evaluated by electron spin resonance (ESR) technique, in order to evaluate their effectiveness for anti-aging and to search for new active-oxygen scavengers from natural resources. Most of the 70 herbal medicines showed scavenging activity with various intensities. Areca catechu (methanol extract), Dendrobium plicatile (methanol extract), Juglans regia (water extract), Paeonia lactiflora (methanol extract), Psychotria serpens (water and methanol extracts), Rhodiola sacra (water and methanol extracts) and Uncaria rhynchophylla (water extract) especially showed strong scavenging activity against superoxide anion radical (*O2-), while J. regia (water and methanol extracts), Morus alba (water extract) and Schisandra chinensis (water extract) revealed strong scavenging activity against hydroxyl radical (HO*). In addition, the active-oxygen scavenging activities of 19 compounds isolated from R. sacra were also examined, and hydroquinone (1), caffeic acid (3), protocatechuic acid (6), gallic acid (7), (-)-epigallocatechin 3-O-gallate (8), 3-O-galloylepigallocatechin-(4beta-->8)-epigallocatechin+ ++ 3-O-gallate (10), heterodendrin (17) and gallic acid 4-O-beta-D-glucopyranoside (19) were found to show mild or strong inhibitory activity against superoxide anion radical (*O2-), while 4-hydroxybenzoic acid (2), 3, 4-hydroxycinnamic acid (4), 6-8 and 19 inhibited hydroxyl radical (OH*). These active-oxygen scavengers may contribute, to different extents, to their anti-aging action.     

Screening of Chinese herbal drug extracts for inhibitory activity on nitric oxide production and identification of an active compound of Zanthoxylum bungeanum

Sixty-eight water and methanol extracts from 34 Chinese herbal drugs, most of which are used for inflammatory diseases, were screened for their inhibitory effects on nitric oxide (NO) production in lipopolysaccharide (LPS)-stimulated J774.1 macrophages and in LPS/interferon (IFN)-gamma-stimulated mouse peritoneal exudate macrophages. Among the extracts, methanol extracts of Myristica fragrans, Plantago asiatica, Rubia cordifolia, and Zanthoxylum bungeanum showed significant inhibition in J774.1 macrophages, while in mouse peritoneal exudate macrophages, water extracts of Ru. cordifolia and Scutellaria baicalensis and methanol extracts of Angelica megaphylla, My. fragrans, and Z. bungeanum inhibited the NO production. Among them, inhibition of water extract of Sc. baicalensis was found to be mainly due to direct scavenging of NO radicals, through an examination of its scavenging activity on PAPA NONOate-generated NO radicals, while water extract of Ru. cordifolia and methanol extracts of An. megaphylla, My. fragrans, P. asiatica, and Z. bungeanum showed inhibition on iNOS mRNA expression. At last, an inhibitory compound on iNOS mRNA expression was isolated from a methanol extract of Z. bungeanum and identified as 4-O-beta-D-glucopyranosyldihydroferulic acid by NMR spectral analyses and chemical synthesis.     

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.     

Studies on diuretic and hypouricemic effects of Orthosiphon stamineus methanol extracts in rats

AIM OF THE STUDY: Orthosiphon stamineus (Labiatae) is a traditional folk medicine widely used in Southeast Asia for the treatment of several kidney disorders, gout and as a diuretic. This study was conducted to examine the diuretic and hypouricemic effects of Orthosiphon stamineus leaf extracts. MATERIALS AND METHODS: The diuretic effect of different methanol extracts was examined by treating different groups of Sprague-Dawley rats with single (2g/kg) oral doses of methanol and methanol:water (1:1) extracts. Hydrochlorothiazide (10mg/kg) was used as positive control in acute study. Methanol and methanol water (1:1) extracts at 0.5 g/kg were administered for a period of 7 consecutive days. Cumulative urine volume and electrolytes (Na+ and K+) concentrations at different time intervals were measured. On the other hand, hypouricemic activity of methanol:water extract (1:1) was experimented using different oral single doses (0.25, 0.5, 1 and 2g/kg). Allopurinol was used as positive control. Uric acid concentration in serum was analyzed by using RP-HPLC at 280 nm. RESULTS: Sodium and potassium excretion increased significantly (p<0.05 and <0.01) in the first 8h of treatment with a single dose (2g/kg) of the extracts in a pattern comparable to that of the known diuretic hydrochlorothiazide. Meanwhile, repeated administration of 0.5 g/kg methanol:water (1:1) extract showed a significant increase in urine volume (from day 3 to day 7) (p<0.01) and electrolytes excretion (Na+ and K+) from day 2 to day 7 (p<0.05 and <0.01). On the other hand, 0.5, 1 and 2g/kg of methanol:water (1:1) extract and the standard allopurinol reduced the serum urate level in hyperuricemic rats at hour 6. CONCLUSION: These results provided an evidence of the high tendency of methanol:water (1:1) extract of Orthosiphon stamineus towards diuretic and hypouricemic effects in rats.     

Antienterobacterial activity of Hemidesmus indicus R. Br. root extract

The antienterobacterial activity of the chloroform and methanol extracts of Hemidesmus indicus root was demonstrated using a variety of methods and different enterobacterial strains. Although the constituents were similar in the chloroform extract (CHI) and the fatty substance separated (ME1) from the methanol extract (MHI), ME1 was found to be more effective than CHI as evident from the disc diffusion method. ME1 was found to be more active than MHI, followed by CHI. This may be due to the inefficient diffusion of CHI into the medium. In a modified agar well diffusion and swab method the activity of the extract against different strains was observed in a single plate. The extracts inhibited growth in a dose dependent manner; both MHI and CHI were most effective against S. flexneri, least effective against S. dysenterie and moderately effective against the other strains. The presence of antimicrobial trace elements such as copper and zinc, along with other active constituents may contribute to the antienterobacterial activity of Hemidesmus indicus root.     

Anti-influenza virus activity of Chaenomeles sinensis

AIM OF THE STUDY: This investigation evaluated anti-influenza virus activity of 50% ethanol extract of the fruit of Chaenomeles sinensis K(OEHNE), which is widely used as a traditional Chinese medicine to treat throat diseases. MATERIAL AND METHODS: Type A and B influenza viruses were treated with the extract at various concentrations for 1h at room temperature; then the plaque titers of the treated viruses were determined. The neutralizing component in the extract was partially purified using HP20 column chromatography. RESULTS: Treatment with the extract at concentrations greater than 5mg/ml reduced the plaque titers of the both viruses to less than 10% of those of untreated viruses. The treatment inhibited viral hemagglutination activity, too. When the 50mg/ml extract was added to the culture medium after inoculation of the virus, viral NS2 protein synthesis was selectively inhibited and progeny virus was not detected in the infected cell medium. Partial purification showed that the neutralizing component consisted of high molecular weight polyphenols. CONCLUSION: High molecular weight polyphenols in the fruits of C. sinensis neutralizes influenza virus by inhibiting hemagglutination activity and by suppressing NS2 protein synthesis.     

Evaluation of the anti-asthmatic property of Asystasia gangetica leaf extracts

The leaf of Asystasia gangetica T. Adams (Acanthaceae) is used in many parts of Nigeria for the management of asthma. This study was aimed at investigating the anti-asthmatic property of hexane, ethylacetate, and methanol extracts of the leaves of Asystasia gangetica, obtained by successive sohxlet extraction. The results indicated that the extracts did not exhibit contractile or relaxant activity in isolated tissue preparations; however, they inhibited the contraction evoked by spasmogens; the IC(50) were calculated, where possible. The extracts relaxed histamine-precontracted tracheal strips in the following degree of potency-ethylacetate extract>hexane extract=methanol extract. The extracts also exhibited anti-inflammatory activity in the order of magnitude-methanol extract>hexane extract>ethylacetate extract. Acute toxicity test estimated an i.p. LD(50) of 2150 mg/kg in mice for methanol extract while phytochemical screening showed the presence of carbohydrates, proteins, alkaloids, tannins, steroidal aglycones, saponins, flavonoids, reducing sugars, and triterpenoids, with the methanol extract having the highest number of constituents. The study justified the use of the leaf of Asystasia gangetica in the management of asthma in Nigerian folk medicine.     

胚胎肢芽提取液对失神经肌肉的作用

目的:本实验用大鼠胚胎肢芽为材料,提取生物活性物质,研究其对失神经支配肌肉的保护作用,以期为胚胎肢芽营养蛋白有效成分的研究提供依据,探索延缓失神经肌肉萎缩的方法和途径。方法:切除大鼠右侧坐骨神经0.5cm,缝合伤口。实验组采用生物化学方法提取的胚胎肢芽中营养蛋白(embryoniclimbbudextract,ELBE)0.1ml/天(1mg/ml)注射至失神经支配的趾长伸肌中,对照组注射生理盐水0.1ml/天。分别于术后7天、14天两时间段取材,进行肌张力、肌湿重,总蛋白含量和肌纤维横截面积测定。结果:失神经支配趾长伸肌应用ELBE后7天、14天时,单收缩力和强直收缩力均较对照组增加(30%~60%)(P<0.05),肌湿重和蛋白含量下降减慢率在7天时,实验组优于对照组,两者差异有显著性意义(P<0.05)。14天时,实验组明显高于对照组,两者差异有显著性意义(P<0.01,P<0.05)。7天、14天时实验组的肌纤维截面积均较对照组增多(P<0.05)。结论:胚胎肢芽提取液(ELBE)可减缓失神经肌肉的萎缩。除了已知的其对神经营养作用外,ELBE具有减少失神经肌肉形态和功能改变的肌营养作用。     

Spasmogenic effect of Datura metel root extract on rat uterus and rectum smooth muscles

The effect of Dautura metel leaf and root extracts, scopolamine and acetylcholine was studied on isolated smooth muscle preparations. Datura metel leaf extract and scopolamine showed antispasmodic effects, whereas Datura metel root extract and acetylcholine caused contracture in isolated rat uterus and rectum whole muscle. This suggests the presence of a spasmogenic factor in Datura metel root extract.     

Effects of Thymus species extracts on rat duodenum isolated smooth muscle contraction

The diethylether, ethylacetate and butanolic extracts from Thymus webbianus and Thymus leptophyllus were tested for spasmolytic activity. Pre-incubation of the isolated rat duodenum with these extracts for 10 min produced a concentration-dependent inhibition of acetylcholine-induced contractions. This effect was at least ten times greater with the apolar extracts than with the polar extracts.     

Potent suppressive activity of fresh and dried peels from Satsuma mandarin Citrus unshiu (Marcorv.) on hydroperoxide generation from oxidized linoleic acid

The effects of various extracts prepared from fresh and dried peels of Satsuma mandarin (Citrus unshiu Marcov.) on hydroperoxide generation from oxidized linoleic acid were compared under different extraction conditions. The cold-and hot-water extracts of fresh peels showed significant suppressive activity against hydroperoxide generation in a dose-dependent manner. However, the methanol or acetone extract of fresh peels did not exhibit significant suppressive effects. The commercially available ascorbic acids equivalent to their concentrations in the water extracts of fresh peels showed roughly equal antioxidative activities compared with those of the water extracts of fresh peels. Although the cold- and hot- water extracts of dried peels indicated a considerable reduction of ascorbic acid concentration, they exhibited much higher antioxidative activities than those of the fresh peels. The methanol extract of dried peels also showed significant antioxidative activities, but did not contain significant ascorbic acid. These results suggest that the fresh peels of Satsuma mandarin have potential antioxidant activities, and the drying treatment of fresh peels caused an enhancement of the antioxidant activity. The pharmacological significance of this finding is discussed.