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.     

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 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.     

Some neuromuscular effects of the crude extracts of the leaves of Abrus precatorius

Some neuromuscular effects of the crude extracts of the leaves of Abrus precatorius were investigated using isolated toad rectus abdominis and rat phrenic nerve-diaphragm muscle preparations as well as young chicks. The ethanol extract of the leaves inhibited acetylcholine-induced contractions of both toad rectus abdominis and rat phrenic nerve-diaphragm muscle preparations. The effects were concentration-dependent and reversible. The extract also caused flaccid paralysis when injected intravenously into young chicks. The ethanol extract had no effect on direct electrical stimulation of rat diaphragm. The inhibitory effect of the ethanol extract on the rat phrenic nerve-diaphragm preparation was potentiated in the presence of reduced calcium ions, elevated magnesium ions, or reduced potassium ions. Thus, the ethanol extract showed a similarity to d-tubocurarine in respect of the pattern of neuromuscular blockade. Both the petroleum ether and the water (cold and hot) extracts had no observable effects on the skeletal muscles used in this project. Apparently, the poisonous neuronal component of the leaves of Abrus precatorius resides mainly in the ethanol extract.     

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.     

Skeletal muscle relaxant action of an aqueous extract of Portulaca oleracea in the rat

The aqueous extract of Portulaca oleracea produced skeletal muscle relaxation in rats following i.p. or oral administration, as assessed by the prolongation of pull-up time. The i.p. route of administration was more effective. When compared with chlordiazepoxide (20 mg/kg, i.p.), diazepam (40 mg/kg, i.p.) and dantrolene sodium (30 mg/kg, oral), the extract (200-1000 mg/kg, i.p.) proved a more effective skeletal muscle relaxant. With 1000 mg/kg i.p., 80% lethality was seen. The LD50 in an acute toxicity test in mice was 1040 mg/kg i.p.     

马齿苋提取物对肝癌细胞HepG-2抑制作用的实验研究

目的观察马齿苋提取物对肝癌HepG-2的抑制作用。方法采用MTT比色法观察马齿苋提取物抑制肝癌HepG-2细胞增殖;采用流式细胞仪检测马齿苋对HepG-2细胞周期分布的影响。结果马齿苋提取物可抑制肝癌HepG-2细胞增殖,其作用具有时间和浓度依赖性;可改变细胞周期分布,多数细胞阻滞于S期,与对照组比较,细胞凋亡率差异有显著性(P<0.01)。结论马齿苋提取物可诱导肝癌HepG-2细胞凋亡,改变细胞周期分布,从而抑制细胞增殖。     

Evaluation of the gastric antiulcerogenic effects of Portulaca oleracea L. extracts in mice

Portulaca oleracea is commonly used in Iranian folk medicine. The aqueous and ethanolic extracts were studied in mice for their ability to inhibit gastric lesions induced by HCl or absolute ethanol. In addition, their effects on gastric acid secretion were measured. Both extracts showed a dose-dependent reduction in severity of ulcers. The highest dose of extracts exerted similar activity to sucralfate. The oral and intraperitoneal administration of extracts reduced the gastric acidity in pylorus-ligated mice. These results suggest that Portulaca oleracea has gastroprotective action and validates its use in folk medicine for gastrointestinal diseases.     

Effects of kava on neuromuscular transmission and muscle contractility

The effects of kava, a native drink from Oceania, on neuromuscular transmission and muscle contractility have been examined in mouse phrenic nerve-hemidiaphragm and frog sartorius muscle preparations using twitch tension and intracellular recording techniques. The extent of muscle paralysis induced by kava was similar in both directly and indirectly stimulated mouse hemidiaphragms. The neuromuscular blockade produced was poorly reversed by calcium and by neostigmine. Intracellular recordings from frog sartorius muscles showed that kava depressed the amplitude of both miniature end-plate potentials (mepps) and end-plate potentials (epps) but had no effect on the frequency of mepps. Kava greatly prolonged the duration of mepps and epps and also slowed and depressed directly elicited muscle action potentials. It is concluded that kava causes paralysis by mechanisms similar to local anaesthetics.     

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.     

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.     

马齿苋不同采收期多糖含量的测定

目的比较不同采收期马齿苋的多糖含量。方法以水提醇沉法提取马齿苋多糖,采用苯酚-硫酸法测定其含量。结果9月上旬马齿苋中多糖含量最高。结论采收期是影响马齿苋中多糖含量的重要因素。     

蚕茧、马齿苋对2型糖尿病大鼠糖脂代谢影响的实验研究

目的 探讨蚕茧、马齿苋对实验性2型糖尿病大鼠糖脂代谢的影响.方法 利用链尿佐菌素建立2型糖尿病大鼠动物模型.随机分为糖尿病模型组、蚕茧组、马齿苋组、蚕茧+马齿苋组,另设正常对照组.治疗8周,检测大鼠血糖(Glu)、三酰甘油(TG)、超氧化物歧化酶(SOD),丙二醛(MDA)和谷胱甘肽过氧化物酶(GSH-Px)含量及活性,并计算胰岛素抵抗指数(HOMA-IR).结果 与DM模型组比较,蚕茧+马齿苋联合组血糖降低了53.3%(P<0.01); TG降低了44.1%(P<0.05);HOMA-IR降低了56.1%(P<0.05);SOD、GSH分别升高了25%(P<0.01)和8.4%(P<0.05);MDA降低了53.6%(P<0.05);其余各组间差异无统计学意义.结论 蚕茧和马齿苋联合补充可明显改善糖尿病大鼠糖脂代谢、减轻胰岛素抵抗、并能有效提高其抗氧化能力、减少脂质过氧化产物的生成.     

Simple evaluation of the wound healing activity of a crude extract of Portulaca oleracea L. (growing in Jordan) in Mus musculus JVI-1

The preliminary wound healing activity of Portulaca oleracea was studied using Mus musculus JVI-1. For this purpose fresh homogenized crude aerial parts of Portulaca oleracea were applied topically on the excision wound surface as single and two doses in different amounts. Wound contraction and tensile strength measurements were used to evaluate the effect of Portulaca oleracea on wound healing. The results obtained indicated that Portulaca oleracea accelerates the wound healing process by decreasing the surface area of the wound and increasing the tensile strength. The greatest contraction was obtained at a single dose of 50mg and the second greatest by two doses of 25mg. Measurements of tensile strength and healed area were in agreement.     

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.     

Protective effects of aqueous and ethanolic extracts of Portulaca oleracea L. aerial parts on H2O2-induced DNA damage in lymphocytes by comet assay

The comet assay is a standard method for measuring DNA damage. In this study, the protective effects of ethanolic and aqueous extracts of Portulaca oleracea L. (P. oleracea) on human lymphocyte DNA lesions were evaluated with the comet assay. Lymphocytes were isolated from blood samples taken from healthy volunteers. Human lymphocytes were incubated in H(2)O(2) (50,100, and 200 μM), aqueous extract (0.05, 0.1, 0.5, 1, and 2.5mg/ml), and ethanolic extracts (0.05, 0.1, 0.5, 1, and 2.5mg/ml) of P. oleraceae aerial parts alone with a combination of H(2)O(2) (100 μM) with either 1 or 2.5mg/ml of both extracts at 4°C for 30 minutes. The extent of DNA migration was measured using the alkaline single cell gel electrophoresis approach assay, and DNA damage was expressed as percentage tail DNA. We found that the aqueous extract of P. oleracea significantly inhibited DNA damage, while there was no effect of the ethanolic extract. These data suggest that the aqueous extract of P. oleracea can prevent oxidative DNA damage to human lymphocytes, which is likely due to antioxidant constituents in the extract.     

Detection of antifungal activity in Portulaca oleracea by a single-cell bioassay system

The antifungal activity of Portulaca oleracea extracts against hyphal growth of various fungi was evaluated in real time using an automatic single-cell bioassay system. Target organisms were the filamentous fungi Aspergillus and Trichophyton and the yeast Candida. A colony of test fungi was in contact with the assay medium, or assay medium containing plant extract, in sequence. The antifungal activity of each fraction of P. oleracea was evaluated based on the dynamic hyphal growth response curves of test fungi. A crude sample obtained by EtOAc extract showed a specific and marked activity against dermatophytes of the genera Trichophyton.     

马齿苋多糖对高糖诱导的人晶状体上皮细胞发生上皮间质转化的影响

目的 观察马齿苋多糖对高糖作用下永生系人晶状体上皮细胞(SRA01/04)上皮间质转化的影响.方法 体外培养SRA01/04细胞,将传代的细胞随机分为正常对照组、高糖组、高糖+马齿苋多糖组,分别用含5.5mmol/L葡萄糖、30mmol/L葡萄糖、30mmol/L葡萄糖+0.5mg/mL马齿苋多糖的培养基培养48h,于...     

马齿苋的化学成分研究

目的:研究马齿苋Portulaca oleracea L.全草的化学成分。方法:运用各种柱色谱方法进行化学成分的分离纯化,用波谱解析方法鉴定化合物的结构。结果:从马齿苋的70%乙醇提取物中分离得到五个化合物,分别鉴定为马齿苋酰胺A(1)、马齿苋酰胺B(2)、马齿苋酰胺E(3),以及橙皮苷(4)和咖啡酸(5)。结论:化合物4和5为首次从该植物中分离得到。     

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.