The skeletal muscle relaxant action of Portulaca oleracea: role of potassium ions

An aqueous extract of the stems and leaves of Portulaca oleracea abolishes the twitch contraction of the directly stimulated rat hemidiaphragm preparation. The effects of the extract mimic qualitatively the action of potassium oxalate — a known constituent of Portulaca oleracea — on the diaphragm. Removal of K⁺ ions from the methanol extract by passing it through a cation exchange resin reduced the inhibitory effect of the extract. There was a positive correlation between the concentration of K⁺ ions in the extract and the effects of potassium chloride of similar molarity. It is concluded that the K⁺ ion content of Portulaca oleracea is at least partly responsible for the relaxant effect observed on the isolated rat diaphragm.     

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.     

Antiviral activity of Sanicula europaea L. extracts on multiplication of human parainfluenza virus type 2.

The antiviral activity of Sanicula europaea L. extracts against human parainfluenza virus type 2 (HPIV-2) was examined. The extract prepared from the leaves of the plant and a fraction separated from the crude extract with gel filtration chromatography were found to inhibit HPIV-2 replication without any toxic effect on Vero cells. The acidic fraction obtained from the crude extract of S. europaea leaves was found to be the most active fraction with plaque inhibition assay at non-cytotoxic concentrations. Unfortunately, antiviral activity was not detected in the molecules purified from the crude ethanol extract of Sanicula leaves.     

Activity of aqueous extract of the bark of Vitex doniana on uterine muscle response to drugs

The activity of Vitex doniana on the uterine muscle response was investigated. The bark of Vitex doniana was extracted in boiled water at 100 degrees C, and the extracted solution filtered and centrifuged with refrigeration. The extract prepared from the dry powder extract was tested on uterine muscle strip preparations. The bark extract of Vitex doniana was analysed elementally and found to contain much more potassium and phosphate than calcium, magnesium, zinc and iron. The presence of potassium ions in excess may also be partly responsible for the effect of the crude extract on uterine muscle activity. In another study, Vitex doniana extract induced graded uterine muscle contractions and also potentiated the contractile effects of prostaglandins, ergometrine and oxytocin. However, the potentiating effect was not significant on the contractile responses to acetylcholine and potassium chloride. The investigation therefore suggests that the effect of the Vitex doniana bark extract may be not only voltage operated but may act via uterotonic receptors. Therefore, the use of Vitex doniana to control postpartum bleeding after child birth may be justified.     

New evidences of antimalarial activity of Bidens pilosa roots extract correlated with polyacetylene and flavonoids

Bidens pilosa is among the several plants used in Brazil to treat malaria. It was demonstrated that crude extracts from roots prepared with 80% ethanol by percolation are active in vitro against Plasmodium falciparum and the activity is correlated with the presence of polyacetylene and flavonoids. This extract was submitted to column chromatography with ether and ether methanol (1:1) and two fractions, enriched in polyacetylene and flavonoids, respectively, were obtained. The extract and the fractions were assessed by HPLC/DAD analysis and antimalarial tests in vivo. Ethanol extract showed by HPLC the presence of several peaks for polyacetylene and flavonoids, compounds corresponding to quercetin-3,3'-dimethoxy-7-0-rhamnoglucopyranose and the acetylene 1-phenyl-1,3-diyn-5-en-7-ol-acetate, previously identified in this extract. The peaks for flavonoids were absent in ether fraction and those ones for polyacetylene in ether:methanol. In in vivo tests, ethanol extract caused 36% of reduction of parasitaemia at fifth day, and 29% at seventh day. Ether:methanol fraction caused 38% of reduction at fifth day but was inactive at day 7. The survival of the animals treated with 80% ethanol extract was higher than in the fractions. The results showed that the in vivo activity of ethanol extract depends on the presence of polyacetylene and flavonoids.     

千斤拔总黄酮提取工艺的优化及其萃取相体外抗氧化活性研究

目的 优化千斤拔中总黄酮乙醇回流提取工艺条件,并探讨其体外抗氧化活性。方法 通过单因素实验、响应面法优化千斤拔中总黄酮的提取工艺;采用优化后的提取条件对千斤拔进行乙醇回流提取,提取液减压浓缩以水分散,依次用等量的石油醚、环己烷、乙酸乙酯,以及正丁醇萃取,通过冷冻干燥得到各萃取物。采用紫外可见分光光度法测定各萃取物的总黄酮含量,采用1,1-二苯基-2-苦肼基(1,1-diphenyl-2-picrylhydrazyl,DPPH)清除实验、羟基自由基清除实验和铁离子还原能力实验(FRAP法),对千斤拔总黄酮粗提物中不同极性组分的抗氧化活性进行测定。结果 提取温度91.75 ℃、提取时间127.79 min,料液比1∶19.6 g·mL^-1,体积分数80%乙醇,为千斤拔中总黄酮的最佳提取工艺,在此条件下总黄酮的得率为0.366 08%,与预测值0.366 138%相接近;千斤拔总黄酮提取物的不同极性组分均含有黄酮类化合物,并具有一定的抗氧化活性,各组分抗氧化活性的顺序为:正丁醇>水相>乙酸乙酯>石油醚>环己烷。结论 本实验所建立的千斤拔总黄酮乙醇提取工艺,方法稳定、高效;极性萃取物抗氧化活性的高低与其黄酮含量相关,正丁醇萃取物的抗氧化活性最强,该研究可为千斤拔开发利用提供实验依据。     

Chronic toxicity study of Portulaca grandiflora Hook

We investigated the toxic effects of Portulaca grandiflora aqueous extract given to male and female Wistar rats for 6 months. The rats were divided into five groups of each sex that were control groups, three experimental groups and recovery groups. The control groups received 5 ml of distilled water/kg per day. The experimental groups were orally given the water extract of Portulaca grandiflora at doses of 10, 100 and 1000 mg/kg per day. The recovery groups received 1000 mg/kg per day for 6 months and were continued husbandry without giving the extract for further 14 days. Changes in the body weights, actual and relative organ weights were not significantly demonstrated in all groups throughout the study. No significant alteration in hematological, biochemical and histopathological parameters was observed in all female groups given the extract. It was found that any significant changes in hematological and biochemical parameters in the male rats at the doses of 100 and 1000 mg/kg per day were not dose-related. In addition, no histopathological lesions were observed in the male animals. Our results suggested that the water extract of Portulaca grandiflora at the doses given in the study did not induce any detrimental effects in the rats.     

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.     

In vitro activity of Rutaceae species against the trypomastigote form of Trypanosoma cruzi

The activity of crude plant extracts of nine species of Rutaceae against the trypomastigote form of Trypanosoma cruzi was evaluated at 4 mg/ml. Thirty-two crude extracts were tested and eight of them showed significant activity (>80%). The most active extract was obtained from the stems of Pilocarpus spicatus (97.3%). Fractionation of the active crude extracts provided 25 fractions which were tested against the trypomastigote form of T. cruzi at 2 mg/ml. Of these six showed significant activity (>80%). The most active fractions (100%) were obtained from the leaves of Almeidea coerulea (butanol fraction) and Conchocarpus inopinatus (dichloromethane fraction).     

Pharmacological actions of the gut active principles in Croton penduliflorus hutch. Seed on isolated smooth and skeletal muscles and on blood pressure

The effects of Croton penduliflorus seed crystals (CP crystals) were investigated on isolated guinea-pig ileum, chick biventer cervicis muscle and frog rectus abdominis muscle. The effect of the crystals on flood pressure of normotensive Sprague Dawley rats was also investigated. CP crystals induced concentrations-dependent contractions in the guinea-pig ileum with EC₅₀ of 2.39 × 10⁶ g/mL. Contractions induced by CP crystals in the guinea-pig ileum were not inhibited by atropine (2 × 10^?7-1.2 × 10^?6 g/mL), tetrodotoxin (3 × 10^?8-2 × 10^?7 g/mL), hexamethonium (7 × 10^?6-2.8 × 10^?5 g/mL), mepyramine (2 × 10^?7 g/mL) and noradrenaline (2 × 10^?5 g/mL) but were completely (100%) inhibited by indomethacin (7.2 × 10^?6 g/mL). CP crystals (1.0 × 10^?6-5.0 × 10^?4 g/mL) could not elicit contractions in either chick biventer cervicis or frog rectus abdominis muscle. The mean blood pressure of normotensive Sprague Dawley rats was significantly reduced by CP crystals (1.6 × 10^?4-2.5 × 10^?3 g/mL) while the heart rate was significantly reduced by an intravenous infusion of the crystals (2.5 × 10^?3 g/kg) after 2min. The methods employed and the significance of the results obtained are discussed.     

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??OBJECTIVE To evaluate the antimalarial activity of Isodon yuennanensis for the development of neo-style antimalarial drugs or lead compounds from plants. METHODS The crude extract and compounds from I. yuennanensis were screened for antimalarial activities by ??-hematin formation inhibition assay, and the RESULTS were expressed as IC₅₀ values. RESULTS The crude extract, as well as some compounds, showed ??-hematin formation inhibition activities in different degrees. CONCLUSION The ethyl acetate fraction derived from the 70% acetone extract of I. yuennanensis and the compounds 2, 12, and 13 obtained from the ethyl acetate fraction are worthy of deeper research due to their significant antimalarial activities.     

CNS activity of the methanol extract of Mallotus peltatus (Geist) Muell Arg. leaf: an ethnomedicine of Onge

The aim of the present study was to investigate several neuropharmacological effects of the methanol extract and different fractions of Mallotus peltatus (Geist) Muell Arg. var acuminatus (Euphorbiaceae) leaves in Wistar albino rats and Swiss albino mice. General behavior, exploratory behavior, muscle relaxant activity and phenobarbitone sodium-induced sleeping time were studied. The results revealed that the crude extract at 200-300 mg kg(-1) p.o. and its fractions A and B at 50 mg kg(-1) caused a significant reduction in spontaneous activity (general behavioral profile), remarkable decrease in exploratory behavioral pattern (Y-maze and head dip tests), a reduction in muscle relaxant activity (rotarod, 30 degrees inclined screen and traction tests), and also significantly potentiated phenobarbitone sodium-induced sleeping time. The phytochemical study of crude leaf extract revealed the presence of tannin, triterpenoid, flavonoid, sterol, alkaloid and reducing sugar. Further fractionation and purification yielded two major fractions A (ursolic acid) and B (beta-sitosterol) with some fatty acids as the major compounds. The psychopharmacological activity of the crude leaf extracts appeared to be either due to fraction A (50 mg kg(-1)) or a combination of fractions A and B (50 mg kg(-1)) along with some fatty acids present in the n-butanol part of methanol extract of M. peltatus leaf (MEMPL).     

Bronchodilatory effect of Acorus calamus (Linn.) is mediated through multiple pathways

Aim of the study

This study was undertaken to provide a pharmacological basis for traditional use of Acorus calamus in airways disorders.

Materials and methods

Isolated guinea-pig trachea and atria were suspended in organ baths bubbled with carbogen and mechanisms were found using different parameters.

Results

In isolated guinea-pig tracheal segments, crude extract of Acorus calamus was more effective than carbachol in causing relaxation of high K⁺ (80 mM) precontractions, similar to verapamil, suggesting blockade of calcium channels. The n-hexane fraction was equipotent against both precontractions, similar to papaverine, while ethylacetate fraction was more potent against carbachol precontractions but had a negligible dilator effect against K⁺, similar to atropine and or rolipram. Pretreatment of tracheal preparations with n-hexane or ethylacetate fractions potentiated isoprenaline-induced inhibitory concentration-response curves, similar to papaverine or rolipram. Pretreatment of tracheal preparations with ethylacetate fraction caused a rightward parallel shift in carbachol response curve at lower concentration (0.003 mg/mL) similar to atropine and a non-parallel shift at higher concentrations (0.01 mg/mL), with reduction of maximum response, similar to rolipram. In isolated guinea-pig atrial preparations, crude extracts, its fractions and papaverine inhibited force and rate of contractions at higher concentrations than the smooth muscle while verapamil was equipotent.

Conclusion

These data indicate the presence of unique combination of airways relaxant constituents in crude extract of Acorus calamus, a papaverine-like dual inhibitor of calcium channels and phosphodiesterase in n-hexane fraction and a novel combination of anticholinergic, rolipram-like phosphodiesterase4 inhibitor in ethylacetate fraction and associated cardiac depressant effect, provide a pharmacological basis for traditional use of Acorus calamus in disorders of airways.     

Inhibitory activity of extracts of Alternanthera brasiliana (amaranthaceae) against the herpes simplex virus

Five extracts from A. brasiliana, obtained through different procedures, showed anti-HSV activity. The best activity was detected in a fraction (B) that was obtained from the crude cold aqueous extract on Sephadex G₁₅. Fraction B showed low cellular toxicity and inhibition from 32.4% to 99.9% at concentrations from 6.2 to 50.0 μg/mL, exhibiting a therapeutic index of 32. Fractions obtained on Sephadex G₁₀₀ and reversed-phase column also showed considerable inhibition. Fraction B did not show any virucidal activity, however, its inhibitory activity was revealed during the later stages of the virus replication cycle. This fraction showed activity on DNA synthesis of infected cells.     

Anti-inflammatory and immunomodulatory activities of polysaccharide from Chlorella stigmatophora and Phaeodactylum tricornutum

Crude polysaccharide extracts were obtained from aqueous extracts of the microalgae Chlorella stigmatophora and Phaeodactylum tricornutum. The crude extracts were fractionated by ion-exchange chromatography on DEAE-cellulose columns. The molecular weights of the polysaccharides in each fraction were estimated by gel filtration on Sephacryl columns. The crude polysaccharide extracts of both microalgae showed anti-inflammatory activity in the carrageenan-induced paw edema test. In assays of effects on the delayed hyper-sensitivity response, and on phagocytic activity assayed in vivo and in vitro, the C. stigmatophora extract showed immunosuppressant effects, while the P. tricornutum extract showed immunostimulatory effects.     

In vitro cytotoxic, antileishmanial and antifungal activities of ethnopharmacologically selected Gabonese plants

Seventy-seven crude extracts from leaves and stem barks of 15 Gabonese plants used in traditional medicine were evaluated for their cytotoxic, antileishmanial and antifungal activities. Most of the extracts exhibited cytotoxic activities toward human monocytes, and most particularly the hydromethanolic 50% (v/v) fraction of Ganophyllum giganteum leaves (IC(50)=1.3 microg/ml) as well as the methanolic extracts of Polyalthia suaveolens, Dioscorea preussii, Augouardia letestui leaves and Cola lizae stem barks (IC(50)<5 microg/ml). The methanolic extract of Polyalthia suaveolens displayed a strong antiproliferative activity against the promastigote form of Leishmania infantum parasites and presented a good antifungal activity on all the tested strains (IC(50)<1mg/ml). This extract was divided into six fractions: fraction F6 demonstrated a cytotoxic activity stronger than those of the crude extract (IC(50)=0.6 microg/ml), fractions F4 and F5 were devoid of cytotoxicity (IC(50)>100 microg/ml) and displayed interesting antileishmanial activity against the intracellular amastigote form of the parasite (IC(50)=5.6 and 12.4 microg/ml), respectively. However, the antifungal activity observed for the crude extract could not be recovered in the corresponding fractions.     

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 characterization and chemical fractionation of a liposterolic extract of saw palmetto (Serenoa repens): Effects on rat prostate contractility

Ethnopharmacological relevance

Saw palmetto (Serenoa repens) was first used medicinally by native American Indians to treat urological disorders. Nowadays, saw palmetto extracts are widely used in Europe and North America to treat the urinary symptoms associated with benign prostatic hyperplasia even though its mechanisms of action are poorly understood. This study aimed to characterize the bioactive constituents of a lipid extract of saw palmetto that are able to affect contractility of the rat prostate gland. The mechanism of action will also be investigated.

Materials and methods

A commercially available lipid extract of saw palmetto was subjected to fractionation using normal phase column chromatography. Composition of fractions was assessed by proton nuclear magnetic resonance spectroscopy (¹H NMR) and mass spectrometry (MS). Contractile activities of these fractions were evaluated pharmacologically using isolated preparations of rat prostate gland and compared to the activity of the crude extract.

Results

Saw palmetto extract inhibited contractions of the rat prostate gland which were consistent with smooth muscle relaxant activity. Only the ethyl acetate fraction resulting from chromatography inhibited contractions of isolated rat prostates similarly to the inhibition produced by the crude lipid extract. Comparison with authentic samples and analysis of NMR data revealed that this bioactivity was due to the fatty acid components present in the ethyl acetate fraction. Bioassay using various pharmacological tools identified multiple contractile mechanisms which were affected by the bioactive constituents.

Conclusion

A fatty acid component of saw palmetto extract causes inhibition of prostatic smooth muscle contractions via a non-specific mechanism.     

Anti-inflammatory and anti-angiogenic activities of Gastrodia elata Blume

Gastrodia elata Blume rhizome has been traditionally used as a folk medicine for centuries in Oriental countries. Its ethanol extract (GEE) and subsequent fractions were used to evaluate anti-angiogenic, anti-inflammatory and related activities of Gastrodia elata. GEE potently inhibited angiogenesis in the chick chorioallantoic membrane assay, and its n-butanol fraction (BuOH) exerted the higher inhibitory effect. In a dose-dependent manner, GEE inhibited vascular permeability induced by acetic acid. GEE and its BuOH fraction exerted an inhibitory activity on exudate production, leukocyte migration and nitric oxide (NO) level in rat air-pouch model. GEE caused a dose-dependent inhibition of acetic acid-induced abdominal writhing in mice. In addition, GEE inhibited NO production and expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) upon stimulation by lipopolysaccharide (LPS) in RAW264.7 macrophages. In summary, we demonstrate some novel pharmacological activities of Gastrodia elata, such as anti-angiogenic, anti-inflammatory and analgesic activities, and in vivo and in vitro inhibitory activity on NO production.     

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.