Spasmolytic action of Lepechinia caulescens is through calcium channel blockade and NO release

The present study was undertaken to elucidate the mode of action of methanol extract from aerial parts of L. caulescens (TC-MELc) as spasmolytic agent on in vitro rat ileum test, and investigate the possible antibacterial activity of different extracts from the plant. TC-MELc induced a concentration-dependent (0.001 to 100microg/mL) antispasmodic effect on spontaneous contractions. TC-MELc also (IC50 11.2microg/mL) induced a marked depression on cumulative concentration-response curve for carbachol (Emax=2.3+/-0.3g vs. 0.66+/-0.1g) and serotonin (Emax=1.1+/-0.3g vs. -0.01+/-0.09g). Besides, extract decreased and displaced to the right KCl and CaCl2 concentration-response curves. Moreover, TC-MELc (11.2microg/mL) provoked a total relaxation when ileum strips were contracted with carbachol (1microM) in calcium-free Krebs solution. Pre-treatment with l-NAME (10microM) produced a significant change of the relaxant response and activity was markedly inhibited. Additionally, hexanic (HELc), dichloromethanic (DELc) and methanolic (MELc) extracts from aerial parts were studied to determine their antibacterial activity. DELc showed antibacterial activity on all bacterial strains assayed (相似文献   

The relaxant activity of the methanolic extract of Acanthus montanus on intestinal smooth muscles

The effects of the methanolic extract of Acanthus montanus on different smooth muscle preparations have been investigated. The extract (6.25-100 microg/ml) produced a concentration-dependent relaxation and inhibition of the spontaneous contraction of the rabbit jejunum which was reversed by CaCl2 (0.1-1mM). This effect of the extract was not blocked by propranolol (3 x 10(-7) M) but partially antagonised by phentolamine (10(-6)-3 x 10(-6) M), procaine (10(-3) M) and methylene blue (10(-5) M). The extract also caused a concentration-dependent relaxation of the KCl-precontracted taenia coli of the guinea-pig which was partially blocked by propranolol (3 x 10(-5) M) that completely blocked isoprenaline (10(-8)-3 x 10(-4) M) relaxation of the tissue. Methylene blue (10(-5) M) and procaine (10(-3) M) completely blocked the direct relaxant effects of the extract and isoprenaline on the guinea-pig taenia coli. The extract (0.1-1mg/ml) shifted the concentration-response curves of CaCl2 to the right in a concentration-dependent manner on the guinea-pig taenia coli. These effects of the extract suggest a non specific smooth muscle relaxant activity.     

Nitric oxide-dependent vasodilatation by ethanolic extract of Hancornia speciosa via phosphatidyl-inositol 3-kinase

The vasodilator effect of the ethanolic extract of leaves from Hancornia speciosa Gomes (HSE) was studied in rat aortic rings. HSE produced a concentration-dependent vasodilatation (pIC(50)=5.6+/-0.1), which was completely abolished in endothelium-denuded vessels. The endothelium-dependent vasodilatation induced by HSE was abolished by l-NAME (100 microM), a nitric oxide (NO) synthase inhibitor, but not atropine (1 microM; pIC(50)=5.6+/-0.2), a muscarinic receptor antagonist, nor indomethacin (10 microM; pIC(50)=5.4+/-0.2), a cyclooxygenase inhibitor. The concentration-response curve of HSE was significantly shifted to the left by superoxide dismutase (SOD; 300U/mL). In addition, while SOD displaced the 3-morpholino-sidnonimine (SIN-1; P<0.05) concentration-effect curve to the left, HSE (50 microg/mL) had no effect. Finally, wortmannin (0.3 microM), an inhibitor of phosphatidyl-inositol 3-kinase (PI3K), dramatically reduced the vasodilator effect of HSE. Together, these findings lead us to conclude that HSE induces a NO- and endothelium-dependent vasodilatation in rat aortic preparations, likely by a mechanism dependent on the activation of PI3K.     

Antimicrobial activity of the essential oil and extracts of Cordia curassavica (Boraginaceae)

In traditional Mexican medicine Cordia curassavica (Jacq) Roemer & Schultes is used to treat gastrointestinal, respiratory and dermatological disorders in Zapotitlán de las Salinas, Puebla (México). The aim of this work was to investigate antimicrobial activity of the essential oil, obtained by using Clevenger distillation apparatus, and hexane, chloroform and methanol extracts from aerial parts of Cordia curassavica. Antimicrobial activity was evaluated against 13 bacteria and five fungal strains. The oil and extracts exhibited antimicrobial activity against Gram-positive and Gram-negative bacteria and five fungal strains. Sarcina lutea and Vibrio cholerae were the strains more sensitive to the essential oil effect (MIC=62 microg/mL) and Vibrio cholerae for the hexane extract (MIC=125 microg/mL). Rhyzoctonia solani was the strain more sensitive to the essential oil effect (IC(50)=180 microg/mL) and Trichophyton mentagrophytes for the hexane extract (IC(50)=230 microg/mL). The essential oil was examined by GC and GC-MS. A total 11 constituents representing 96.28% of the essential oil were identified: 4-methyl,4-ethenyl-3-(1-methyl ethenyl)-1-(1-methyl methanol)cyclohexane (37.34%), beta-eudesmol (19.21%), spathulenol (11.25%) and cadina 4(5), 10(14) diene (7.93%) were found to be the major components. The present study tends to confirm the use in the folk medicine of Cordia curassavica in gastrointestinal, respiratory and dermatological diseases.     

Constituents, biological activities and quality control parameters of the crude extract and essential oil from Arracacia tolucensis var. multifida

Bioassay guided fractionation of an antimycobacterial extract of Arracacia tolucensis var. multifida (Umbelliferae) led to the isolation of isoimperatorin (1), osthol (2), suberosin (3), 8-methoxypsoralen (8-MOP) (4), herniarin (5), scoparone (6), umbelliferone (7), dihydroxypeucedanin (8), 5-methoxypsoralen (5-MOP) (9), isoscopoletin (10) and scopoletin (11). The isolates were tested against Mycobacterium tuberculosis and only 1-4 showed significant activity with MIC values of 64, 32, 16 and 128 microg/mL, respectively. The essential oil showed moderate in vitro antibacterial activity against representative Gram-positive and Gram-negative bacteria. The volatile oil of Arracacia tolucensis var. multifida was analyzed by GC-MS and found to be composed mainly by 2 and 3. The essential oil (IC(50)=116.4+/-23.2 microg/mL) and the extract (IC(50)=1153.1+/-53.2 microg/mL) of the plant provoked concentration dependent inhibition of the tone and amplitude of the guinea-pig ileum spontaneous contractions; the latter activity was related with the high coumarin content of this species. A suitable (novel and rapid) HPLC method to quantify the major active coumarins of the plant was developed. The method provides also a reproducible fingerprint useful for identity tests of this plant.     

Antimicrobial and general toxicity activities of Gymnosperma glutinosum: a comparative study

Gymnosperma glutinosum (Spreng.) Less (Asteraceae) is an important, and an effective herbal medicine which is wide used for the treatment of diarrhoea in Mexico. We examined and compared the antibacterial and antifungal activities through the dilution method and for general toxicity activity by the brine shrimp lethality assay of two samples of Gymnosperma glutinosum from two localities of Mexico: San Rafael-Coxcatlan (Puebla State) and Tepeji del Rio (Hidalgo State). In addition, two bioactive compounds (-)-17-hydroxy-neo-clerod-3-en-15-oic acid (1) and 5,7-dihydroxy-3,6,8,2',4',5'-hexamethoxyflavone (2) were isolated. From the hexane extract from both places was obtained a MeOH partition M(2). M(2) of Tepeji del Rio showed the least MICs (<125 microg/ml) in the majority of the bacterial strains. Sarcina lutea was the most sensitive bacteria (MIC< 125 microg/ml). The hexane extract of both localities showed antifungal activity against all tested fungi. San Rafael's hexane extract was significant more activity than Tepeji del Rio. Aspergillus niger (IC(50)=23.79 microg/ml) and Trichophyton mentagrophytes (IC(50)=90.25 microg/ml) were the more sensitive fungus strains. The strongest general toxicity activity was observed with the M(2) partition from Tepeji del Rio (LC(50)=503.7 microg/ml). The results obtained in this investigation, showed differences between the antimicrobial activities of the samples of plants collected in San Rafael (Puebla) and Tepeji del Rio (Hidalgo).     

Effect of Gnaphalium conoideum HBK on guinea pig airway smooth muscle: role of L-type Ca2+ channels

Plants from the Gnaphalium genus have been used in the Mexican traditional medicine for digestive and respiratory complaints. In the present study, the effect of methanolic extract from Gnaphalium conoideum HBK on the responses to contractile agonists was assessed in guinea pig tracheas, and the possible role of L-type Ca2+ channels was explored in tracheal guinea pig isolated myocytes. Cumulative concentration-response curves to carbachol or histamine, as well as contractile responses to 60 mM KCl were evaluated with or without 30 min preincubation with 20 or 100 microg ml(-1) Gnaphalium conoideum. Likewise, intracellular Ca2+ concentrations were measured by microfluorometric method (fura-2 AM) in isolated tracheal myocytes with or without preincubation with 0.1, 0.31 or 1 microg ml(-1)Gnaphalium conoideum. We found that methanolic extract from Gnaphalium conoideum significantly diminished the contractile responses to histamine, but not to carbachol or KCl. In isolated myocytes, Gnaphalium conoideum significantly reduced the intracellular Ca2+ rise induced by 60 mM KCl. Because histamine contractile responses are largely dependent on extracellular Ca2+, and KCl responses are mainly mediated through L-type Ca2+ channels, our results suggested that methanolic extract from Gnaphalium conoideum might be acting as a partial blocker of these Ca2+ channels.     

Anti-proliferative effect of Euphorbia stenoclada in human airway smooth muscle cells in culture

The ethanolic extract of a Malagasy species Euphorbia stenoclada (ES) (Euphorbiaceae), traditionally used as a herbal remedy against asthma and acute bronchitis, was tested to evaluate possible anti-proliferative activity on human airway smooth muscle cells (HASMC). The ES ethanolic extract totally abolished the interleukin-1beta (IL-1beta) induced proliferation of HASMC (IC(50)=0.73+/-0.08 microg/mL). No cytotoxic effect was observed up to 20 microg/mL. A bioassay-guided fractionation of the ethanolic extract was performed by reversed-phase (RP) flash chromatography, giving five fractions (FA to FE) where fraction FE was the only active one (IC(50)=0.38+/-0.02 microg/mL). The purification of this bioactive fraction FE was carried out by RP-HPLC affording six sub-fractions 1-6, and only sub-fraction 5 kept the anti-proliferative activity. Its major constituent was identified as quercetin (IC(50)=0.49+/-0.12 microg/mL) by means of HPLC/UV/MS and co-elution with the authentic standard. Quercitrin was also identified in the fraction FE but was inactive. A structure-activity relationship with flavonols determined that methylation reduced the anti-proliferative activity whereas glycosylation abolished it. The present study shows that the anti-proliferative properties of Euphorbia stenoclada are mediated through the presence of quercetin that may explain the traditional use of this plant as a remedy against asthma.     

Hypoglycemic, vasorelaxant and hepatoprotective effects of Cochlospermum vitifolium (Willd.) Sprengel: a potential agent for the treatment of metabolic syndrome

Cochlospermum vitifolium (Willd.) Sprengel is a Mexican medicinal plant that is used in the folk medicine for the treatment of hypertension, diabetes, hepatitis and related diseases. The purpose of the present study was to assess the pharmacological properties of different extracts from Cochlospermum vitifolium bark as potential agent for the treatment of some factors related with metabolic syndrome (MS), a complex disease produced for several pathophysiological factors such as visceral fat obesity, insulin resistance, hypertension, dyslipidemia and liver steatosis. Hexane (HECv), dichloromethane (DECv) and methanol (MECv) extracts were subjected to some pharmacological assays to determine their vasorelaxant and hypoglycemic activity. On the other hand, MECv was also evaluated to determine its hepatoprotective effect on sub-chronic experimental assay. HECv showed a significant endothelium-independent relaxation on rat aorta rings (intact endothelium: IC(50)=14.42+/-5.90 microg/mL, E(max)=92.71+/-8.9%; denuded endothelium: IC(50)=27.94+/-4.0 microg/mL, E(max)=78.68+/-4.6%) and MECv produced an endothelium-dependent relaxation (IC(50)=21.94+/-6.87 microg/mL, E(max)=79.12+/-7.80%) on this tissue. Furthermore, HECv (at a dose of 120 mg/kg) also showed a significant decrease of blood glucose levels (p<0.05) on normoglycemic rats. Moreover, MECv (at a dose of 100 mg/kg) also was administered to bile duct-obstructed rats to determine its hepatoprotective activity, showing a statistically significant decrease of serum glutamic-pyruvic transaminase (PGT, 45%) and alkaline phosphatase (APh, 15%) (p<0.05). Finally, we obtained a crystalline polyphenolic compound from MECv by spontaneous precipitation. Those crystals were identified as (+/-)-naringenin by X-ray diffraction, NMR, IR and GC-MS techniques. Results suggest that Cochlospermum vitifolium could be used as a potential agent against MS since it shows hypoglycemic, vasorelaxant and hepatoprotective properties.     

药对麻黄地龙配比及平喘作用机制的研究

目的:考察药对麻黄、地龙用量配比及可能的平喘作用机制。方法:观察麻黄、地龙3种用量配比(1∶1,1∶3,1∶9)水煎液对10μmol.L-1卡巴胆碱(carbachol,CCh),10μmol.L^-1组胺(histamine,His)引起离体气管平滑肌张力增加的松弛作用,以及对10μmol.L^-1CCh引起的离体气管上皮短路电流增加的抑制作用。结果:对于10μmol.L^-1CCh引起的离体大鼠气管平滑肌收缩,麻黄地龙3种配比水提物的舒张作用随剂量增加而增强,1∶1,1∶3水提物的IC50分别为7.5,15 mg.mL^-1,1∶9水提物不能产生对CCh引发最大收缩抑制50%的效应;对于10μmol.L^-1His所引起的离体豚鼠气管平滑肌收缩,麻黄地龙3种配比水提物的舒张作用随剂量增加而增强,1∶9,1∶3,1∶1水提物的IC50分别为0.19,0.61,1.8 mg.mL-1;在抑制CCh引起的离体大鼠气管上皮短路电流增加方面,三者的作用强度顺序为1∶3>1∶1>1∶9,三者没有显著性差异。结论:麻黄、地龙药对具有舒张离体气管平滑肌和抑制气管上皮离子分泌的作用,其作用机制包括抗CCh和抗His作用。1∶3是麻黄、地龙药对中的最适配比。     

In vitro purgative effect of Ruellia praetermissa. Sceinf.ex.Lindau (Acanthaceae)

Methanol, ethylacetate and aqueous extracts of Ruellia praetermissa initiated spontaneous contractions in the quiescent and increased contraction on the electrically stimulated ileal strip at a concentration of 30 microg/ml. The extracts produced concentration-related contractions both in amplitude and tone up till 750 microg/ml with IC(50) of 360 microg/ml (methanol extract), 425 microg/ml (ethylacetate extract) and 540 microg/ml (aqueous extract). Acetylcholine also produced a concentration-related (IC(50)=18 microg/ml) contractions of the isolated ileum. Atropine in concentrations of 3.4 x 10(-6)-3 x 10(-3) microg/ml antagonized progressively the response of the isolated ileum to acetylcholine (32 x 10(-2) microg/ml) and the methanol extract (650 microg/ml) induced contractions suggesting a mode of action via cholinergic system. Luteolin and apigenin and iridoid glucosides (taxiphilin and 8-epi-deoyganic acid) might be responsible at least in part for the observed effect.     

Antispasmodic and relaxant effects of the hidroalcoholic extract of Pimpinella anisum (Apiaceae) on rat anococcygeus smooth muscle

The present work describes the mechanisms involved in the muscle relaxant effect of ethanol:water (40:60, 60:40 and 80:20) aerial parts extracts of Pimpinella anisum. Three hidroalcoholic extracts in which the proportion of ethanol was 40% (HA(40%)), 60% (HA(60%)) or 80% (HA(80%)) were tested for activity in the rat anococcygeus smooth muscle. The three extracts (50 microg/mL) inhibited acetylcholine-induced contraction. The extract HA(60%) (5-50 microg/mL) concentration dependently relaxed acetylcholine-pre-contracted tissues (31.55+/-3.56%). Conversely, HA(40%) and HA(80%) did not exert relaxant action. Pre-incubation of the preparations with N(G)-nitro-L-arginine methyl ester (L-NAME, 100 microM), 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (ODQ, 3 microM) and oxyhemoglobin (10 microM) reduced the relaxation induced by HA(60%) (percentage of relaxation: 6.81+/-1.86%, 13.13+/-5.87% and 2.12+/-1.46%, respectively). Neither indomethacin (10 microM) nor tetraethylammonium (1 mM) affected the relaxation induced by HA(60%). Incubation of the tissues with L-NAME significantly enhanced the maximal contraction induced by acetylcholine, indicating an inhibitory role for NO in the modulation of the contractile response of anococcygeus smooth muscle to acetylcholine. However, simultaneous addition of L-NAME and HA(60%) resulted in an effect similar to that observed with L-NAME alone, further confirming the observation that Pimpinella anisum acts by realizing NO. Additionally, HA(60%) did not alter CaCl(2)-induced contraction. Collectively, our results provide functional evidence that the effects elicited by the hidroalcoholic extract of Pimpinella anisum involve the participation of NO and subsequent activation of the NO-cGMP pathway. The relaxant action displayed by Pimpinella anisum justifies its use in the folk medicine as an antispasmodic agent.     

Isolation of a muscarinic alkaloid with ocular hypotensive action from Trophis racemosa

A muscarinic alkaloid with a quaternary nitrogen was isolated from Trophis racemosa. Aqueous solutions (0.5%-2%) of the chloride salt of the alkaloid produced dose-dependent reductions of intra-ocular pressure ranging from 6.6 +/- 0.7 mmHg to 15.7 +/- 0.3 mmHg, (p < 0. 001, n = 5) in dogs. Atropine (0.1 mL of a 1% solution) and pirenzepine at a non selective antagonist dose (0.1 mL of 0.5% solution) for M(1) and M(3) receptors blocked the reduction of intra-ocular pressure, but alpha-adrenoceptor blockade with phenoxybenzamine (0.1 mL of a 1% solution) did not block the reduction of intra-ocular pressure. On the isolated guinea-pig ileum and trachea, the alkaloid produced contractions which were inhibited by atropine (6 x 10(-7) M or 0.4 microg/mL) and by pirenzepine at a non-selective antagonist dose (3.1 x 10(-6) M or 1.3 microg/mL) for M(1) and M(3) receptors. But neither selective blockade of M(2) receptors with gallamine (1.7 x 10(-6) M or 1.5 microg/mL) nor selective blockade of M(1) receptors with pirenzepine (7 x 10(-9) M or 3 ng/mL) inhibited the alkaloid-induced contractions. There was also no inhibition of the alkaloid-induced contractions in the presence of ganglionic nicotinic receptor blockade with pentolinium (5.6 x 10(-7) M or 0.3 microg/mL) and hexamethonium (1.7 x 10(-6) M or 0.6 microg/mL), but nicotine-induced contractions were inhibited by these ganglionic blockers. These results suggest that a muscarinic alkaloid from Trophis racemosa produced ocular hypotension via M(3) receptor stimulation in dogs.     

Cytotoxic activity of Typhonium flagelliforme (Araceae)

The plant Typhonium flagelliforme (Araceae), commonly known as the 'rodent tuber', is often included as an essential ingredient in various herbal remedies recommended for cancer therapies in Malaysia. Various extracts prepared from either the roots, tubers, stems or leaves were tested for cytotoxic activity on murine P388 leukaemia cells using the MTT assay method. Both the chloroform (IC50 = 6.0 microg/mL) and hexane (IC50 = 15.0 microg/mL) extract from the 'roots and tubers' exhibited weak cytotoxic activity. The hexane extract (IC50 = 65.0 microg/mL) from the 'stems and leaves' exhibited weaker cytotoxic activity than the chloroform extract (IC50 = 8.0 microg/mL). Although the juice extract from the 'roots and tubers' is frequently consumed for cancer treatment, it exhibited poor cytotoxic activity. Further analysis using an amino acid analyser revealed that the juice extract contained a high concentration of arginine (0.874%). A high tryptophan content (0.800%) was confirmed by NMR and HPLC analysis.     

Spasmogenic effect of a Solanummelongena leaf extract on guinea pig tracheal chains and its possible mechanism(s)

The methanol extract of fresh leaves of Solanum melongena L. (Solanaceae) was evaluated for its capacity to alter the tone of isolated, pre-contracted guinea pig tracheal chains, as well as for its possible mechanism(s) of action. Using serial dilutions between 0.0025 and 2.5 mg/mL, the extract was found to cause a dose-dependent increase in the force of muscle contraction. The EC(50) value was 0.46 +/- 0.01 mg/mL. The concomitant use of acetylcholine 10(-5) M did not significantly affect the force of contraction induced by the extract. Histamine 10(-5) M added at about 40% to, and salbutamol 10(-6) M antagonized by about 30% its constrictive effect. Chlorpheniramine 10(-6) M, propanolol 10(-5) M, and nifedipine 10(-6) M did not significantly influence the extract-induced force of contraction, but atropine 3 x 10(-7) M reduced it by approximately 60%. These data suggest that the Solanum melongena extract exerted a bronchospasmogenic rather than a bronchospasmolytic effect, probably through muscarinic receptor stimulation.     

Presence of calcium antagonist activity explains the use of Syzygium samarangense in diarrhoea

Syzygium samarangense (Family; Myrtaceae) or 'makopa', as it is commonly known, is native to Malaysia, some islands of Indonesia and to Far East in general. This study was undertaken to rationalize the use of this plant in hypermotility states of the gut. The hexane extract of S. samarangense (Ss.Hex) was found to dose-dependently (10-3000 microg/mL) relax the spontaneously contracting isolated rabbit jejunum. When tested for a possible calcium channel blocking (CCB) activity, the extract (10-1000 microg/mL) relaxed the high K+-induced contractions and also decreased the Ca++ dose-response curves in a dose-dependent manner (30-100 microg/mL), confirming the CCB activity. Four flavonoids isolated from the hexane extract were tested for a possible spasmolytic activity. All flavonoids, identified as: 2'-hydroxy-4',6'-dimethoxy-3'-methylchalcone (SS1), 2',4'-dihydroxy-6'-methoxy-3',5'-dimethylchalcone (SS2), 2',4'-dihydroxy-6'-methoxy-3'-methylchalcone (SS3) and 7-hydroxy-5-methoxy-6,8-dimethylflavanone (SS4), showed dose-dependent (10-1000 microg/mL) spasmolytic activity with SS2 being the most potent. These results indicate that the presence of compounds with spasmolytic and calcium antagonist activity may be responsible for the medicinal use of the plant in diarrhoea.     

Hypotensive and vasorelaxant effects of the procyanidin fraction from Guazuma ulmifolia bark in normotensive and hypertensive rats

THE AIM OF THE STUDY: was to investigate the in vivo and in vitro cardiovascular activity of a procyanidin fraction (PCF) obtained from acetone extract of Guazuma ulmifolia bark which has traditionally been used as an antihypertensive agent. RESULTS: 10 mg/kg PCF doses orally administered to sugar-fed hypertensive rats decreased both the systolic arterial pressure and the heart rate, whereas the same doses intravenously administered induced arterial hypotension which was attenuated by NG-nitro-L-arginine methylester (L-NAME 31 mg/kg) pretreatment. In these experiments we employed carbachol as a positive control test. The PCF reduced the contraction induced by norepinephrine (1x10(-7) M) in isolated aortic rings of normotensive (IC50=35.3+/-12.4 ng/mL) and sugar-fed hypertensive (IC50=101.3+/-57.2 ng/mL) rats. This relaxant activity was inhibited by either vascular endothelium removal or L-NAME (30 microM) pretreatment, while indomethacin (10 microM) or atropine (10 microM) had no effect. Preliminary analysis of the PCF by HPLC-DAD-MS and FAB+ mass spectrometry allowed the detection of the main components such as the complex of procyanidin oligomers consisting mainly of tetramers and trimers. CONCLUSIONS: Guazuma ulmifolia bark possesses long-lasting antihypertensive and vasorelaxing properties linked to the endothelium related factors, where nitric oxide is involved.     

In vitro antiplasmodial activity of Brazilian Cerrado plants used as traditional remedies

Twenty-seven species of native Brazilian Cerrado plants commonly used by traditional healers to treat malaria and other diseases were collected and 204 hexanic and ethanolic extracts were obtained by maceration. The antiplasmodial activity of the extracts was tested in vitro against a chloroquine resistant strain (FcB1) of Plasmodium falciparum, and cytotoxicity against the cell lines L-6 of rats and MRC-5 of human was evaluated. Thirty-two extracts showed significant inhibition rates of Plasmodium falciparum growth and of these six showed cytotoxicity against the cell lines. The strongest antiplasmodial activity was found for the hexanic extracts of Xylopia aromatica root wood (IC(50)=4.7 microg/ml), Xylopia emarginata root bark (IC(50)=4.9 microg/ml), Casearia sylvestris var. lingua leaves, stem wood and stem bark, and root wood and root bark (IC(50) values from 0.9 to 2.3 microg/ml), and Cupania vernalis leaves (IC(50)=0.9 microg/ml); and for the ethanolic extract of Aspidosperma macrocarpon root bark (IC(50)=4.9 microg/ml). However, the best selectivity towards Plasmodium falciparum was observed for the hexanic root bark extract of Matayba guianensis (IC(50) on Plasmodium falciparum=6.1 microg/ml, SI=16.4 for MRC-5) and the ethanolic root bark extract of Aspidosperma macrocarpon (IC(50) on Plasmodium falciparum=4.9 micro/ml, SI=16.2 for MRC-5).     

Isolation of a bronchodilator flavonoid from the Thai medicinal plant Clerodendrum petasites

The ethanolic extract of Clerodendrum petasites was tested to evaluate the spasmolytic activity on isolated guinea-pig tracheal smooth muscle. The crude extract (2.25-9.0 mg/ml) dose-dependently caused relaxation of tracheal smooth muscle which was contracted by exposure to histamine. A bioassay-guided fractionation of the crude extract was performed by means of partitioning and centrifugal partition chromatography. Finally the active principle was isolated and identified as the flavonoid hispidulin (EC(50): (3.0+/-0.8)x10(-5) M). These results suggest that hispidulin may be beneficial in the treatment of asthma.     

Pharmacological study of antispasmodic activity of Mirabilis jalapa Linn flowers

INTRODUCTION: Mirabilis jalapa Linn is a well-studied plant. The indigenous people of Mexico use Mirabilis jalapa to cure many infirmities including dysentery, diarrhea, muscular pain and abdominal colic. In the present investigation, we have further characterized some pharmacological properties of an extract of Mirabilis jalapa flowers; therefore, we intend to contribute to understand the pharmacological effects and clarify the complex use of this medicinal plant. RESULTS: The extract of Mirabilis jalapa (1-1000 mug/mL) exhibits an inhibitory effect (IC(50)=18+/-0.7 micorg/mL) on gut smooth muscle contractility whereas it stimulates the contraction of rabbit aortic muscle (EC(50)=11.60+/-0.26 micorg/mL) in a concentration-dependent manner. CONCLUSIONS: These effects were not due to either ACh or HIS receptors blockage, IP(3), cAMP, cGMP, Ca(2+) release from intracellular storage, or protein kinase mediated contraction-relaxation mechanisms. The effects inducted by the Mirabilis jalapa extract may involve a serotoninergic mechanism, which, in turn, interacts with other adrenergic systems. Further studies are necessary to identify the active compounds within the extract and to elucidate the mechanism of action.