Bisnordihydrotoxiferine and vellosimine from Strychnos divaricans root: Spasmolytic properties of bisnordihydrotoxiferine

Bisnordihydrotoxiferine and vellosimine, two tertiary indole alkaloids have been isolated from the root of Strychnos divaricans. Bisnordihydrotoxiferine antagonized in a nonspecific manner, oxytocin and acetylcholine induced contractions in the rat uterus and acetylcholine and histamine responses in the guinea-pig ileum. Bisnordihydrotoxiferine, like verapamil, produced effects on voltage dependent Ca²⁺ channels. For example in guinea-pig ileum, bisnordihydrotoxiferine (pD'₂ 3.92±0.09) and verapamil (pD'₂ 6.00±0.11) inhibited KCl induced contractions. Furthermore, bisnordihydrotoxiferine (pD'₂ 4.37±0.02) and verapamil (pD'₂ 6.83±0.10) also antagonized CaCl₂ induced contractions of K⁺-depolarized rat uterus. When compared with sodium nitroprusside, an antagonist of receptor operated Ca²⁺ channels, bisnordihydrotoxiferine had no effect. However, in the aorta, the alkaloid (IC₅₀, 6.10 × 10^?6M) antagonized the intracellular calcium dependent transient contractions of noradrenaline and it was about four times more potent than procaine (IC₅₀, 2.30 × 10^?5M), a known inhibitor of the release of Ca²⁺ from intracellular stores. Bisnordihydrotoxiferine may produce nonspecific spasmolytic actions mainly by inhibiting intracellular calcium mobilization and to a lesser extent by inhibiting voltage dependent calcium channels in smooth muscles.     

Spasmolytic actions of warifteine,a bisbenzylisoquinoline alkaloid isolated from the root bark of Cissampelos sympodialis Eichl. (menispermaceae)

Warifteine, a bisbenzylisoquinoline alkaloid isolated from the root bark of Cissampelos sympodialis Eichl., produced a reversible, nonspecific and noncompetitive antagonism of histamine, carbachol and bradykinin induced contractions of the guinea-pig ileum. The corresponding pD'₂ values (mean±SE) were 4.90±0.15, 4.95±0.20 and 5.03±0.11. Warifteine also antagonized oxytocin and bradykinin induced contractions of the rat uterus in a similar manner with pD'₂ values of 4.30±0.26 and 3.76±0.06 respectively. In the guinea-pig trachea, the alkaloid inhibited spontaneous tone (IC₅₀, 1.1 × 10^?5M) as well as carbachol induced sustained contractions (IC₅₀, 2.9 × 10^?5M). As warifteine antagonized KCI induced contractions of the guinea-pig ileum (pD'₂ value 4.57±0.10), inhibition of Ca⁺⁺ influx through voltage operated Ca⁺⁺ channels may be partially responsible for its antispasmodic activity. However, the reported local anaesthetic property of warifteine may not contribute to the observed muscle relaxation as procaine failed to reduce the spontaneous tone or consistently antagonize carbachol induced contractions of the trachea and was inactive in inhibiting voltage operated Ca⁺⁺ channels in the ileum.     

Effect of ambrein on smooth muscle responses to various agonists

The pharmacological effects of ambrein (isolated from ambergris) on the contractile responses induced by some agonists in smooth muscle preparations were investigated. Ambrein in the concentration range of 10, 50 and 250 μg/ml decreased the spontaneous contraction of the isolated rabbit jejunum, rat uterus and guinea-pig vas deferens. Ambrein-induced antagonism to acetylcholine (Ach) in the guinea-pig ileum was abolished when the concentration of calcium chloride in the Tyrode's solution was increased to 5 mM/l. Furthermore, ambrein did not antagonise nicotine-induced contractions in the isolated rabbit jejunum or serotonin-induced contractions in the isolated guinea-pig ileum and vas deferens or the rat uterus. However, ambrein in the concentration range of 10, 50 and 250 μg/ml antagonised prostaglandins (PGs) E₂, D₂, F_2α, and oxytocin-induced contractions in the rat uterus in vitro. Ambrein also antagonised (±) noradrenaline and (−) adrenaline-induced contractions in the isolated guinea-pig vas deferens. It is concluded that ambrein-induced non-selective dose-dependent antagonism to the effects of some agonists (Ach, adrenaline, noradrenaline, PGs and oxytocin) in some smooth muscles may be due to the ability of this compound to interfere with the mobilisation of extracellular Ca²⁺ required for muscular contractions induced by these agonists.     

Further studies on the antidiarrhoeal activity of bisnordihydrotoxiferine,a tertiary indole alkaloid in rodents

The dimeric tertiary indole alkaloid bisnordihydrotoxiferine isolated from the root bark of Strychnos trinervis (Vell.) Mart. inhibited, on i.p. administration, Escherichia coli-induced diarrhoea and cholera toxin-stimulated intestinal fluid accumulation in mice. The respective ED₅₀ values were 10.6 and 20.0 mg/kg. The activity of bisnordihydrotoxiferine was unaffected by nalorphine or yohimbine, suggesting that the opioid and α₂-adrenoceptors respectively, are not important for its antidiarrhoeal action. In smooth muscle studies, bisnordihydrotoxiferine antagonized in a noncompetitive and reversible manner, the contractions produced by histamine, acetylcholine and substance P in guinea-pig ileum and by 5-hydroxytryptamine and arachidonic acid in rat fundic strip. The respective pD'₂ values (mean ± SEM) were 5.21 ± 0.29, 5.20 ± 0.29, 5.35 ± 0.12, in the ileum and 4.95 ± 0.13 and 3.66 ± 0.12 in the fundic strip. The values of slopes of the regression lines differed significantly from unity in all cases. Bisnor was inactive against PGE₂-induced contractions in the ileum. The mechanism of action of the alkaloid may be related to nonspecific antagonism of gastrointestinal smooth muscle stimulant activity of several endogenous substances.     

Bronchodilator Activity of Aerial Parts of Polygonatum verticillatum Augmented by Anti‐inflammatory Activity: Attenuation of Ca2+ Channels and Lipoxygenase

Polygonatum verticillatum is commonly used for the treatment of asthma and inflammation. The current study was aimed to scrutinize the pharmacological profile of methanolic extract of the aerial parts (PA). Isolated tracheal preparations were used for the evaluation of bronchodilatory activity, whilst the in vivo carrageenan‐induced paw oedema test and an in vitro lipoxygenase (LOX) inhibitory assay were used for the assessment of the anti‐inflammatory profile of PA. When tested against carbachol and K⁺ (80 mM)‐induced contractions, PA caused complete inhibition of isolated rabbit tracheal preparations in a dose‐dependent mode, similar to verapamil. While elucidating possible mechanism, PA shifted the Ca²⁺ concentration–response curves to the right, analogous to that produced by verapamil, confirming a Ca²⁺ channel blocker‐like activity. PA provoked profound reduction in paw oedema with a maximum protection of 60.87% at 200 mg/kg i.p. in a dose‐dependent manner which was augmented by its prominent LOX inhibitory activity (IC₅₀: 125 µg/mL). These findings authenticated its therapeutic potential in the treatment of asthmatic and inflammatory conditions. Copyright © 2012 John Wiley & Sons, Ltd.     

Endothelium‐Independent Vasorelaxation Effects of Sigesbeckia glabrescens (Makino) Makino on Isolated Rat Thoracic Aorta

The present study aimed to investigate the vasorelaxant effect of the methanol extract of Sigesbeckia glabrescens (Makino) Makino (MESG) on rat aortic rings and mechanism of action. MESG inhibited both noradrenaline bitartrate (NA)‐ and potassium chloride (KCl)‐induced contraction of endothelium‐intact aortic rings in a concentration‐dependent manner. Removal of the endothelium did not influence the effect of MESG on NA‐precontracted aortic rings. Pretreatment with MESG (250 µg/mL) inhibited calcium chloride‐induced vasocontraction of NA‐ or KCl‐precontracted endothelium‐denuded aortic rings. It also relaxed phorbol‐12‐myristate‐13‐acetate‐induced contraction of aortic rings in a concentration‐dependent manner. In addition, Bay K8644 (an L ‐type calcium channel opener) vasocontracted in MESG pretreated aortic rings. On the other hand, the inositol 1,4,5‐triphosphate receptor, the ryanodine receptor, the Rho‐kinase inhibitor (Y‐27632), a soluble guanylyl cyclase blocker (1‐H‐[1,2,4]‐oxadiazolo‐[4,3a]‐quinoxalin‐1‐one), and K⁺ channel blockers (glybenclamide, tetraethylammonium, and 4‐aminopyridine) did not affect the effect of MESG. These results suggested that the mechanism underlying the vasorelaxant effect of MESG is mediated by endothelium‐independent pathways. This specifically refers to blockade of the influx of extracellular Ca²⁺ via receptor‐operative Ca²⁺ channels and voltage‐dependent Ca²⁺ channels and inhibition of a protein kinase C‐mediated cellular pathway. Copyright © 2012 John Wiley & Sons, Ltd.     

New Findings on the Effects of Tannic Acid: Inhibition of L‐Type Calcium Channels,Calcium Transient and Contractility in Rat Ventricular Myocytes

Tannic acid (TA) is a group of water‐soluble polyphenolic compounds that occur mainly in plant‐derived feeds, food grains and fruits. Many studies have explored its biomedical properties, such as anticancer, antibacterial, antimutagenic, antioxidant, antidiabetic, antiinflammatory and antihypertensive activities. However, the effects of TA on the L‐type Ca²⁺ current (I_Ca‐L) of cardiomyocytes remain undefined. The present study examined the effects of TA on I_Ca‐L using the whole‐cell patch‐clamp technique and on intracellular Ca²⁺ handling and cell contractility in rat ventricular myocytes with the aid of a video‐based edge detection system. Exposure to TA resulted in a concentration‐ and voltage‐dependent blockade of I_Ca‐L, with the half maximal inhibitory concentration of 1.69 μM and the maximal inhibitory effect of 46.15%. Moreover, TA significantly inhibited the amplitude of myocyte shortening and peak value of Ca²⁺ transient and increased the time to 10% of the peak. These findings provide new experimental evidence for the cellular mechanism of action of TA and may help to expand clinical treatments for cardiovascular disease. Copyright © 2016 John Wiley & Sons, Ltd.     

Smooth muscle relaxant activities of compounds isolated from malaysian medicinal plants on rat aorta and guinea-pig ileum

Muscle relaxant activities of six compounds isolated from Malaysian medicinal plants were investigated on the smooth muscles of the rat aorta and longitudinal muscle of the guinea-pig ileum. Except for goniothalamin, the other five compounds exhibited varying degrees of muscle relaxant activities on the two smooth muscles. Dicentrine, isocorydine, altholactone and usnic acid reduced the contractions to KCI and phenylephrine in the rat aorta, whilst atranorin slightly reduced the contractions to phenylephrine but not KCI. In addition, dicentrine and isocorydine markedly reduced the contractile response to phenylephrine in Ca²⁺-free Krebs solution. In the longitudinal muscle of the guinea-pig ileum, altholactone, atranorin, dicentrine and isocorydine inhibited to a greater extent the phasic than the tonic responses to KCI. All four compounds similarly inhibited the contractions induced by ACh. The results suggest that the relaxant activities of the compounds are attributed mainly to inhibition of Ca²⁺ influx via the calcium channels in the membrane of the smooth muscles. Furthermore, the greater sensitivity of dicentrine, isocorydine and altholactone against phenylephrine-induced contractions or KCI-induced phasic contractions are due to their abilities to inhibit intracellular Ca²⁺ release in these muscles.     

Effect of Wine Polyphenol Resveratrol on the Contractions Elicited Electrically or by Norepinephrine in the Rat Portal Vein

We investigated the effects of resveratrol on rat portal vein (RPV) contractility without endothelium. Contractions were produced by electrical field stimulation of perivascular nerves (EFS), norepinephrine (NE), adenosine 5′‐triphosphate (ATP), high K⁺ solution and by calcium chloride (CaCl₂) in Ca²⁺‐free and high K⁺, Ca²⁺‐free solution. The EFS‐evoked contractions were more sensitive to resveratrol and to NS1619‐selective openers of big calcium‐sensitive (BK_Ca) channels, than NE‐evoked contractions. Effects of resveratrol on the ATP‐evoked contractions were weak. Blockers of BK_Ca channels partly inhibited the effect of resveratrol only in EFS‐contracted preparations. Western blotting showed that RPV expressed K_Ca1.1 protein. Inhibitors of ATP‐ and voltage‐sensitive K⁺ channels did not modify the effects of resveratrol. None of the antagonists of K⁺ channels affected the resveratrol inhibition of NE‐evoked contractions and effect of high concentrations of resveratrol on the EFS‐evoked contractions. Resveratrol more potently inhibited CaCl₂ than potassium chloride contractions of RPV. Thus, BK_Ca channels partly mediate the inhibitory effect of resveratrol on the neurogenic contractions of RPV. The smooth muscle Ca²⁺ channels and/or Ca²⁺ mobilizing through cells might be involved in the effects of resveratrol on the contractility of RPV. Our results are important for better understanding the impact of resveratrol on the portal circulation. Copyright © 2013 John Wiley & Sons, Ltd.     

Spasmolytic Activity of Cissampelous mucronata Leaf Extract

The aqueous leaf extract of Cissampelous mucronata (Menispermaceae) was studied for spasmolytic properties. The extract inhibited the responses of histamine, acetylcholine and nicotine on the guinea-pig ileum in a dose-related manner. The extract completely abolished the spontaneous pendular movement of the rabbit jejunum reversibly, and decreased gastrointestinal motility in mice. It did not modify the effect of Ca²⁺ on the guinea-pig ileum. Acute toxicity tests in mice established the i.p. LD₅₀ value of the extract to be 1698.24±77 mg/kg.     

环维黄杨星D对心肌细胞缺氧/复氧损伤的保护作用和对心肌细胞内游离钙浓度的影响

目的:研究环维黄杨星D(CVB-D)对培养乳鼠心肌细胞缺氧/复氧损伤的保护作用和对急性分离大鼠心肌细胞内游离Ca²⁺浓度的影响。方法:采用培养的乳鼠心肌细胞建立缺氧/复氧损伤模型,测定心肌细胞搏动频率、细胞存活率、肌酸激酶(CK)的含量;应用特异性荧光指示剂Fluo-3/AM负载急性分离的大鼠心肌细胞,用激光共聚焦显微镜检测胞内游离钙的变化。结果:缺氧/复氧损伤+环维黄杨星D组(H/R+CVB-D)乳鼠心肌细胞搏动频率、细胞存活率与缺氧/复氧损伤组比较明显升高,CK含量与缺氧/复氧损伤组比较明显下降。对急性分离大鼠心肌细胞内[Ca²⁺]i逐步升高,并呈剂量依赖性;在有外钙和无外钙时,CVB-D对胞内钙的升高有显著差异(P<0.05);在无外钙并加入内罗啶孵育后,CVB-D引起的胞内[Ca²⁺]i轻度升高,但与无钙组相比无显著性差异(P>0.05)。结论:环维黄杨星D对培养乳鼠心肌细胞缺氧/复氧损伤有保护作用,对急性分离大鼠有升高心肌细胞内游离钙离子浓度的作用,[Ca²⁺]的升高既源于内钙释放又源于外钙内流。     

Evidence of the mechanism of action of Erythrina velutina Willd (Fabaceae) leaves aqueous extract

Ethnopharmacological relevance

Erythrina velutina is traditionally used for sleepiness, convulsions and nervous system excitation in Brazil. Although central effects have been reported for Erythrina velutina, little is known about its mechanism of action.

Aim of the study

To investigate the pharmacological evidences of mechanism of action of Erythrina velutina leaves aqueous extract (AE).

Materials and methods

Terminal segments of the guinea-pig ileum (n = 5–8) were mounted in an organ bath and isotonic contractions were recorded. Phytochemical screening was carried out on AE.

Results

AE (0.025–2.50 mg/ml) produced contractile response in the guinea-pig ileum, yielding typical concentration–response curves (EC₅₀ = 0.63 mg/ml). Electrically evoked contractions were significantly increased in the presence of AE. AE-elicited contractions were significantly reduced by bicuculline, tetrodotoxin, atropine, verapamil or incubation in low calcium–high potassium solution. Atropine along with verapamil abolished AE contractile response. Alkaloids, catechins, steroids, flavonols, flavononols, flavonoids, phenols, saponins, tannins, triterpenoids, and xanthones were detected in AE.

Conclusions

AE contains important constituents for pharmacological activities. AE-induced contractions seem to involve GABA_A receptor activation, acetylcholine release, muscarinic receptor activation, augmentation of Ca²⁺ entry through L-type calcium channels, and calcium release from the intracellular stores. These findings provide further support for Erythrina velutina traditional uses.     

葛根素对氧糖剥夺大鼠海马神经细胞Ca2+和NO的影响

 目的研究葛根素(puerarin,Pur)对缺氧缺糖状态下海马神经细胞内Ca²⁺和NO水平的影响。方法选用新生大鼠体外培养8 d的海马神经细胞,进行3 h的氧糖剥夺(oxygen/glucose deprivation,OGD)或30 min的L-谷氨酸(0.5mmol·L^-1)处理后再正常培养24 h,Pur处理组在OGD或谷氨酸处理的同时和以后24 h给予不同剂量(40,100μmol·L^-1)Pur,Annexin V联合流式细胞仪检测细胞的凋亡率和坏死率;以Fluo-3或DAF-2为荧光标记,用激光共聚焦显微镜观测30 min的OGD过程中海马神经细胞Ca²⁺和NO的动态变化以及Pur的影响。结果OGD诱导海马神经细胞Ca²⁺和NO水平快速升高,其最高值分别达正常对照组的2.9和1.9倍;Pur明显减缓OGD期间神经细胞Ca²⁺内流和NO合成,与OGD组相比,40和100μmol·L^-1的Pur分别使细胞Ca²⁺峰值降低29.2%和37.1%(P<0.05和P<0.01),NO峰值降低23%和33%(P<0.05和P<0.01),显著抑制细胞内Ca²⁺和NO水平的升高;同时Pur可有效抑制OGD和谷氨酸引起的神经细胞死亡。结论Pur可通过抑制神经细胞谷氨酸/Ca²⁺/NO通路的活动而有效保护缺氧缺糖对神经细胞的损伤作用。     

白藜芦醇对大鼠离体胸主动脉环的舒张作用

目的:观察白藜芦醇(resveratrol,RVL)对大鼠离体胸主动脉血管的舒张作用并探讨其机制。方法:采用离体血管环灌流方法,观察RVL在含Ca²⁺或无Ca²⁺ Krebs液孵育条件下对去甲肾上腺素(NA)引起的血管平滑肌收缩的影响;同法观察RVL对30,80mmol·L^-1的KCl引起的血管平滑肌收缩的影响;RVL对NA引起的依赖于细胞内钙和细胞外钙收缩反应的影响,以及加入N-G-硝基-L-精氨酸(L-NNA)和优降糖后RVL舒张大鼠离体主动脉环效应的变化。结果:RVL呈浓度依赖性舒张NA引起的血管收缩;无Ca²⁺ 组RVL抑制NA所致血管平滑肌收缩效应大于含Ca²⁺ 组;RVL能够拮抗NA诱发的依内钙的收缩反应,而对外钙收缩无抑制。RVL对80,30mmol·L^-1 的KCl引起的血管平滑肌收缩均有抑制作用,且前者量效曲线明显上移。L-NNA使RVL舒血管效应降低(26.0±4.6)%;优降糖组的血管舒张受抑程度与对照组无显著差别(P>0.05)。结论:RVL可呈内皮依赖性舒张血管平滑肌,其作用机制可能与该药促进NO合成释放,开放钙激活的钾通道以及抑制血管平滑肌细胞外钙内流和内钙释放有关。     

有机硒化合物的抗炎及抗变态反应作用

 目的：有机硒化合物具有多种活性，为此研究3种合成的有机硒化合物的抗炎作用和抗变态反应作用,并分析构效关系。方法：药物对小鼠巴豆油性耳肿胀的影响;对组胺(histamine,His)、过敏性慢反应物质(slow-reacting substance of anaphylaxis SRS-A)所致离体豚鼠回肠收缩的影响;致敏豚鼠肺中SRS-A的提取及药物的拮抗实验。结果：3种化合物能不同程度地抑制小鼠巴豆油性耳肿胀(〖WTBX〗P＜0.05或P〖WTBZ〗＜0.01)。50%抑制离体豚鼠回肠收缩时的药物浓度(IC₅₀)分别为对His:1.25×10^-5,1.58×10^-4，1.25×10^-4 mol/L,对SRS-A:8.9×10^-6，1.25×10^-4，1.12×10^-4mol/L。致敏豚鼠肺释放SRS-A的抑制浓度:10^-4mol/L。结论：3药中9108对受体的拮抗作用最强。该类化合物的化学结构中苯环(B)邻位酯基取代的化合物具有强的受体拮抗作用。它们的抗炎及抗免疫作用与其对His及SRS-A的受体拮抗作用及SRS-A的阻释作用有关。     

灵芝多糖对小鼠腹腔巨噬细胞胞浆游离Ca2+浓度的影响

 目的:探讨灵芝多糖(GLP)对免疫细胞信号转导过程的影响?方法:采用激光扫描共聚焦显微镜(LSCM)技术,动态监测GLP均一体组分GLB₇对小鼠腹腔巨噬细胞(MΦ)胞浆游离Ca²⁺浓度([Ca²⁺]i)的影响?结果:GLB₇(20μg·ml^-1)引起小鼠腹腔MΦ中[Ca²⁺]i明显升高,升高值为(248±18)%(n=6);GLB₇引起小鼠腹腔MΦ外钙内流及MΦ内IP₃敏感和IP₃非敏感钙池释放Ca²⁺,[Ca²⁺]i升高值分别为(76±10)%,(58±10)%,(41±8)%(n=6);GLB₇对MΦ[Ca²⁺]i的影响与K⁺通道及其引起的膜电位变化无关?结论:MΦ是灵芝多糖作用的靶细胞;GLB₇引起MΦ中[Ca²⁺]i快速升高,可能是灵芝多糖产生作用的重要途径?     

龙葵碱诱导HepG2细胞凋亡的线粒体通路研究

 目的观察龙葵碱诱导HepG₂细胞凋亡与线粒体通路的关系。方法MTT法测定龙葵碱对HepG₂细胞的细胞毒作用;AO/EB双染,激光共聚焦扫描显微镜观察龙葵碱对HepG₂细胞形态学的影响;TMRE和Fluo-3/AM双染,激光共聚焦扫描显微镜同时观察细胞线粒体膜电位和细胞内[Ca²⁺]_i的变化。结果龙葵碱对HepG₂细胞有细胞毒作用;龙葵碱诱导HepG₂细胞形态出现凋亡形态时TMRE和Fluo-3/AM双染观察表明,龙葵碱在降低线粒体膜电位的同时能够升高细胞内[Ca²⁺]_i浓度。结论龙葵碱降低膜电位,开放细胞膜PT通道,使细胞内Ca²⁺顺浓度梯度转运,从而升高细胞内Ca²⁺浓度启动细胞凋亡机制。     

Mechanisms of Vasorelaxation Induced by Hexahydrocurcuminin Isolated Rat Thoracic Aorta

This study was designed to examine the vasorelaxant effects of hexahydrocurcumin (HHC), one of the major natural metabolites of curcumin from Curcuma longa, on rat isolated aortic rings, and the underlying mechanisms. Isometric tension of the aortic rings was recorded using organ bath system. HHC (1 nM to 1 mM) relaxed the endothelium‐intact aortic rings pre‐contracted with PE and KCl in a concentration‐dependent manner. Removal of the endothelium did not alter the effect of HHC‐induced relaxation. In Ca²⁺‐free Krebs solution, HHC significantly inhibited the CaCl₂‐induced contraction in high K⁺ depolarized rings and suppressed the transient contraction induced by PE and caffeine in a concentration‐dependent manner. HHC was also observed to relax phobal‐12‐myristate‐13‐acetate (PMA), an activator of protein kinase C (PKC), precontracted aortic rings in a concentration‐dependent manner with EC₅₀ values equivalent to 93.36 ± 1.03 μM. In addition, pre‐incubation with propranolol (a β‐adrenergic receptor blocker) significantly attenuated the HHC‐induced vasorelaxation. These results suggest that the vasorelaxant effect of HHC is mediated by the endothelium‐independent pathway, probably because of the inhibition of extracellular Ca²⁺ influx through voltage‐operated Ca²⁺ channels and receptor‐operated Ca²⁺ channels, the inhibition of Ca²⁺mobilization from intracellular stores, as well as inhibition of PKC‐mediated Ca²⁺‐independent contraction. Moreover, HHC produces vasorelaxant effects probably by stimulating the β‐adrenergic receptor. Copyright © 2015 John Wiley & Sons, Ltd.     

Different Effects of Some Isoquinoline Alkaloids from Argemone mexicana on Electrically Induced Contractions of Isolated Guinea-pig Ileum

The present study examines the effects of the extracts [petroleum ether, CHCl₃, CHCl₃/MeOH (9:1) and MeOH], partially purified fractions and pure compounds from Argemone mexicana on the electrically induced contractions of the isolated guinea-pig ileum (E.C.I.). The results of the experiments indicate that CHCl₃/MeOH (9:1) and MeOH extracts, tested at a concentration of 400, 200 and 100 μg/mL, dose-dependently reduced the guinea-pig ileum contractions, whereas the petroleum ether and CHCl₃ extracts did not affect it. Furthermore, the partially purified fractions II–V from the MeOH extract, each tested at concentrations of 200, 100 and 50 μg/mL also inhibited E.C.I. Finally the pure compounds 1–2 (5×10⁻⁶–1×10⁻⁵–5×10⁻⁵ M ) isolated and purified from the above fractions significantly reduced, in a dose dependent manner, the electrical contractions of the ileum, whereas compound 3 (5×10⁻⁶–1×10⁻⁵×10⁻⁵ M ) increased them. Since the active compounds 1–3 were respectively identified as protopine, allocryptopine and berberine by NMR, the observed effects could be related mainly to these compounds. © 1997 by John Wiley & Sons, Ltd.     

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.