Hypotensive and spasmolytic activities of ethanolic extract of Capparis cartilaginea

An ethanolic extract of Capparis cartilaginea (CC) at a dose of 1–10 mg/kg caused a dose-dependent fall in blood pressure and heart rate in anaesthetized rats. These effects were not blocked by atropine (1 mg/kg) and pretreatment with CC did not alter the pressor response to norepinephrine, indicating that the cardiovascular effects of CC are independent of cholinergic or adrenergic receptor involvement. In spontaneously beating guinea-pig atria, CC induced a concentration-dependent (0.1–1 mg/mL) decrease in force and rate of atrial contractions. In rabbit thoracic aorta, CC caused inhibition of norepinephrine or K⁺-induced contractions. In guinea-pig ileum, CC (1 mg/mL) inhibited submaximal contractions induced by acetylcholine, histamine or 5-HT. Spontaneous contractions of rat uterus were also abolished when CC was added to the tissue bath at similar concentrations. These results suggest that the direct relaxant action of CC on myocardium and blood vessels may be responsible for its hypotensive and bradycardiac effects observed in the in vivo studies. Moreover, CC exhibits general spasmolytic activity in different smooth muscle preparations.     

Antidiarrheal and Antispasmodic Activities of Buddleja polystachya are Mediated Through Dual Inhibition of Ca++ Influx and Phosphodiesterase Enzyme

This study describes the antidiarrheal and antispasmodic activities of the hydro‐alcoholic extract of Buddleja polystachya (Bp.Cr) with possible mode of action explored along with activity‐directed fractionation. Bp.Cr and its aqueous (Bp.Aq) and organic fractions, petroleum ether (Bp.Pet), dichloromethane (Bp.DCM), ethylacetate (Bp.EtAc) and butanol (Bp.But), were tested using the in‐vivo and in‐vitro assays. The crude extract (100–300 mg/kg) showed 20 and 60% protection of castor oil‐induced diarrhea in mice. In isolated rabbit jejunum, Bp.Cr like papaverine inhibited spontaneous and high K⁺ (80 mM)‐induced contractions equi‐potently. In guinea‐pig ileum, Bp.Cr showed a moderate spasmogenic effect. The activity‐directed fractionation revealed that the spasmolytic activity was concentrated in the organic fractions and spasmogenic component in the aqueous fraction. Amongst the organic fractions, BP.DCM and Bp.Pet inhibited spontaneous and high K⁺‐induced contractions equi‐potently, while Bp.But, like verapamil was more potent against high K⁺. The crude extract and its organic fractions caused rightward shift in the Ca⁺⁺‐concentration response curves (CRCs), similar to verapamil, and all except Bp.But potentiated the isoprenaline‐inhibitory CRCs to the left, similar to papaverine. The results of this study indicate that the crude extract of B. polystachya possesses antidiarrheal and antispasmodic activities, mediated possibly through dual inhibition of Ca⁺⁺ influx and phospodiesterase enzyme. Copyright © 2015 John Wiley & Sons, Ltd.     

Pharmacological studies on hypotensive and spasmolytic activities of pure compounds from Moringa oleifera

Bioassay directed fractionation of an ethanolic extract of Moringa oleifera (MO) leaves resulted in the isolation of four pure compounds, niazinin A (1), niazinin B (2), niazimicin (3) and niaziminin A + B (4 + 5). Intravenous administration of either one of the compounds (1–10 mg/kg) produced hypotensive and bradycardiac effects in anaesthetized rats. Pretreatment of the animals with atropine (1 mg/kg) completely abolished the hypotensive and bradycardiac effects of acetylcholine (ACh), whereas cardiovascular responses to the test compounds remained unaltered, ruling out the possible involvement of muscarinic receptor activation. In isolated guinea-pig atria all the compounds (50–150 μg/mL) produced negative inotropic and chronotropic effects. Each compound inhibited K⁺ -induced contractions in rabbit aorta as well as ileal contractions induced by ACh or histamine at similar concentrations. Spontaneous contractions of rat uterus were also inhibited equally by all compounds. These data indicate that the direct depressant action of these compounds exhibited on all the isolated preparations tested is probably responsible for its hypotensive and bradycardiac effects observed in vivo. Moreover, spasmolytic activity exhibited by the constituents of the plant provides a scientific basis for the traditional uses of the plant in gastrointestinal motility disorders.     

Studies on spasmogenic and spasmolytic activities of Calendula officinalis flowers

The aqueous-ethanol extract of Calendula officinalis flowers (Co.Cr) was studied for its possible spasmolytic and spasmogenic effects in isolated gut preparations. In rabbit jejunum, Co.Cr caused a dose-dependent (0.03-3.0 mg/mL) relaxation of spontaneous and K+-induced contractions, suggestive of calcium channel blockade (CCB). In a few preparations, a mild non-reproducible spasmogenic effect was observed at lower doses, followed by relaxation. The CCB effect was confirmed when pretreatment of the jejunum preparations with Co.Cr produced a dose-dependent rightward shift in the Ca(++) dose-response curves, similar to that of verapamil. Activity-directed fractionation revealed that the spasmolytic activity of the plant was concentrated in its organic fractions. The aqueous fraction exhibited a marked atropine sensitive spasmogenic effect but was found to be devoid of any spasmolytic effect. These data indicate that the crude extract of Calendula officinalis flowers contains both spasmolytic and spasmogenic constituents, exhibiting these effects through calcium channel blocking and cholinergic activities and this study provides a scientific base for its traditional use in abdominal cramps and constipation.     

Presence of cholinergic and calcium antagonist constituents in Saussurea lappa explains its use in constipation and spasm

This study was carried out to provide a scientific basis for the traditional use of Saussurea lappa, in constipation and spasms. Isolated tissue preparations were used to see if the aqueous-methanol crude extract of the S. lappa root (Sl.Cr) contains gut stimulatory and inhibitory constituents. In isolated guinea-pig ileum, a quiescent preparation, Sl.Cr caused a concentration-dependent (0.3-5.0 mg/mL) spasmogenic effect, with the maximum effect reaching 91% of the acetylcholine maximum. A further increase in concentration caused a declining effect, indicating the presence of spasmolytic constituent(s). The spasmolytic effect was more marked in the spontaneously contracting rabbit jejunum and in the atropinized preparations. The spasmolytic effect was mediated through calcium channel blocking (CCB) activity, as evident by its inhibitory effect against high K(+) (80 mm)-induced contraction and displacement of the Ca(++) concentration-response curves to the right. These data indicate that the crude extract of Sl.Cr contains gut stimulatory constituent(s) of cholinergic-type providing a scientific basis for its use in constipation. The presence of spasmolytic constituents of CCB-type more evident in the spontaneous contracting gut preparation may explain its use in spasms.     

Cholinomimetic and calcium channel blocking activities of Carthamus oxycantha

The crude extract of Carthamus oxycantha (Co.Cr) and its fractions were studied in vitro for their possible spasmogenic and spasmolytic activities. Co.Cr (0.03-10 mg/mL) caused an atropine sensitive spasmogenic effect in guinea-pig ileum. In spontaneously contracting rabbit jejunum preparations, Co.Cr caused a dose-dependent (0.03-3.0 mg/mL) spasmogenic effect, followed by relaxation at the next higher doses of 5.0-10.0 mg/mL. In the presence of atropine, the spasmogenic effect was blocked and the relaxant effect was observed at lower doses (0.1-5.0 mg/mL), shifting the inhibitory dose-response curves to the left. Co.Cr also inhibited K(+) (80 mm)-induced contractions in atropinized preparations at similar doses, suggesting calcium channel blockade (CCB) activity. The CCB effect was further confirmed when pretreatment of the tissue with Co.Cr produced a dose-dependent shift in the Ca(++) dose-response curves to the right, similar to that caused by verapamil. Activity-directed fractionation revealed that the spasmolytic effect was concentrated in organic fractions in the following order of potency: hexane > ethylacetate > chloroform, while the aqueous fraction exhibited spasmogenic and weak spasmolytic effects. These results indicate that Carthamus oxycantha contains a combination of spasmogenic (cholinergic) and spasmolytic (calcium antagonist) constituents.     

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.     

Isoliquiritigenin,a flavonoid from licorice,plays a dual role in regulating gastrointestinal motility in vitro and in vivo

Licorice root has been used for years to regulate gastrointestinal function in traditional Chinese medicine. This study reveals the gastrointestinal effects of isoliquiritigenin, a flavonoid isolated from the roots of Glycyrrhiza glabra (a kind of Licorice). In vivo, isoliquiritigenin produced a dual dose‐related effect on the charcoal meal travel, inhibitory at the low doses, while prokinetic at the high doses. In vitro, isoliquiritigenin showed an atropine‐sensitive concentration‐dependent spasmogenic effect in isolated rat stomach fundus. However, a spasmolytic effect was observed in isolated rabbit jejunums, guinea pig ileums and atropinized rat stomach fundus, either as noncompetitive inhibition of agonist concentration‐response curves, inhibition of high K⁺ (80 mM)‐induced contractions, or displacement of Ca²⁺ concentration‐response curves to the right, indicating a calcium antagonist effect. Pretreatment with N^ω‐nitro‐L‐arginine methyl ester (L‐NAME; 30 µM), indomethacin (10 µM), methylene blue (10 µM), tetraethylammonium chloride (0.5 mM), glibenclamide (1 µM), 4‐aminopyridine (0.1 mM), or clotrimazole (1 µM) did not inhibit the spasmolytic effect. These results indicate that isoliquiritigenin plays a dual role in regulating gastrointestinal motility, both spasmogenic and spasmolytic. The spasmogenic effect may involve the activating of muscarinic receptors, while the spasmolytic effect is predominantly due to blockade of the calcium channels. Copyright © 2008 John Wiley & Sons, Ltd.     

Analgesic and Uterine Relaxant Effects of Isoliquiritigenin,a Flavone from Glycyrrhiza glabra

Shaoyao‐gancao‐tang, a Chinese medicinal formula consisting of peony and licorice has been used for the treatment of dysmenorrhea for thousands of years. The purpose of the present study was to demonstrate the analgesic and uterine relaxant effects of isoliquiritigenin (ISL), a flavonoid isolated from the roots of Glycyrrhiza glabra (a type of licorice). In vitro, isoliquiritigenin caused concentration‐dependent inhibition of spontaneous contraction of isolated rat uterus and the contraction induced by various types of stimulants, such as acetylcholine (Ach, 10 µm ), KCl (40 mm ) and oxytocin (1 mU/mL). The uterine contractile response to cumulative concentrations of CaCl₂ was blocked by 0.1 and 1 mm of isoliquiritigenin. The isoliquiritigenin‐induced relaxation was partly inhibited by the nitric oxide synthase (NOS) inhibitor N^ω‐nitro‐l ‐arginine methylester (l ‐NAME, 100 µm ) and the COX‐1/COX‐2 inhibitor indomethacin (10 µm ). In vivo, isoliquiritigenin could cause a significant reduction in the acetic acid‐induced writhing response and hot‐plate test at the high dose. These results indicate that isoliquiritigenin, a flavonoid isolated from the roots of Glycyrrhiza glabra, not only has a spasmolytic effect on uterine contraction, which is in relation to Ca²⁺ channels, NOS and COX, but also an effective activity in reducing pain. Copyright © 2012 John Wiley & Sons, Ltd.     

Antispasmodic,bronchodilator and blood pressure lowering properties of Hypericum oblongifolium – possible mechanism of action

The crude extract of Hypericum oblongifolium (Ho.Cr), which tested positive for flavonoids, saponins and tannins caused concentration‐dependent (0.1–1.0 mg/mL) relaxation of spontaneous and high K⁺ (80 mM)‐induced contractions in isolated rabbit jejunum preparations, suggesting a Ca⁺⁺ antagonistic effect, which was confirmed when pretreatment of the tissue with Ho.Cr produced a rightward shift in the Ca⁺⁺ concentration‐response curves, like that caused by verapamil. Ho.Cr relaxed carbachol (1 μM) and high K⁺‐induced contractions in guinea pig tracheal preparations. It caused a dose‐dependent (3–100 mg/kg) fall in arterial blood pressure of rats under anesthesia. In isolated guinea pig atria, Ho.Cr caused inhibition of both atrial force and rate of spontaneous contractions. When tested in rabbit aortic rings, Ho.Cr exhibited a vasodilator effect against phenylephrine (1 μM) and high K⁺‐induced contractions. These results indicate that Ho.Cr possesses gastrointestinal, respiratory and cardiovascular inhibitory effects, mediated via a Ca⁺⁺ antagonist mechanism. Copyright © 2009 John Wiley & Sons, Ltd.     

Antidiarrhoeal and spasmolytic activities of the methanolic crude extract of Alstonia scholaris L. are mediated through calcium channel blockade

This study was aimed to provide a pharmacological basis to the medicinal use of Alstonia scholaris as an antidiarrhoeal and antispasmodic by using in vivo and in vitro techniques. In the in vivo study the crude extract of Alstonia scholaris (As.Cr), which tested positive for the presence of alkaloids, provided 31–84% protection against castor oil‐induced diarrhoea in mice at 100–1000 mg/kg doses, similar to loperamide. In isolated rabbit jejunum preparation, the As.Cr caused inhibition of spontaneous and high K⁺ (80 mm )‐induced contractions, with respective EC₅₀ values of 1.04 (0.73–1.48) and 1.02 mg/mL (0.56–1.84; 95% CI), thus showing spasmolytic activity mediated possibly through calcium channel blockade (CCB). The CCB activity was further confirmed when pretreatment of the tissue with the As.Cr (0.3–1 mg/mL) caused a rightward shift in the Ca⁺⁺ concentration‐response curves similar to verapamil, a standard calcium channel blocker. Loperamide also inhibited spontaneous and high K⁺ precontractions as well as shifted the Ca⁺⁺ CRCs to the right. These results indicate that the crude extract of Alstonia scholaris possesses antidiarrhoeal and spasmolytic effects, mediated possibly through the presence of CCB‐like constituent(s) and this study provides a mechanistic base for its medicinal use in diarrhoea and colic. Copyright © 2009 John Wiley & Sons, Ltd.     

Pharmacological Studies on the Antispasmodic,Bronchodilator and Anti‐Platelet Activities of Abies webbiana

This study evaluated the antispasmodic, bronchodilator and anti‐platelet activities of Abies webbiana to rationalize some of its folk uses in gut and airways disorders and inflammation. The crude extract of A. webbiana (Aw.Cr) caused a complete relaxation of both spontaneous and K⁺ (80 mM)‐induced contractions in isolated rabbit jejunum in a concentration‐dependent manner. Aw.Cr shifted the Ca⁺⁺ concentration–response curves (CRCs) to the right, in a fashion similar to verapamil, confirming its Ca⁺⁺ channel blocking (CCB) effect. In isolated rabbit tracheal preparations, it caused relaxation of carbachol (1 μM) and K⁺ (80 mM)‐induced contractions comparable to verapamil suggesting that the bronchodilatory effect may possibly be mediated through CCB activity. Aw.Cr was found to be the inhibitor of both ADP‐ and epinephrine‐induced aggregation of human platelets thereby suggesting therapeutic potential in this plant against thrombo‐embolic conditions. The exhibited anti‐platelet effect was observed at low doses against epinephrine as compared to ADP. This study confirmed the presence of spasmolytic activity in Abies webbiana through possible blockade of Ca⁺⁺ channels providing evidence for its folkloric use in gut and respiratory disorders in addition to anti‐platelet activity. Copyright © 2014 John Wiley & Sons, Ltd.     

Asparagus PR cannot compete with first‐line diuretics in lowering the blood pressure in treatment‐requiring antihypertensives

A six week clinical surveillance of 163 patients receiving maximally tolerable doses of Asparagus P^®, a proprietary mixture pulversied dried asparagus root and parsley leaf, has not indicated any clinically useful antihypertensive effect. The profile of adverse events (with 7 patients leaving the surveillance early because of renally related complaints) contraindicates its use in hypertension or to promote flushing of the efferent tract in rental inflammatory conditions or urolithiasis. Copyright © 2009 John Wiley & Sons, Ltd.     

Blood pressure lowering and anti‐inflammatory effects of hesperidin in type 2 diabetes; a randomized double‐blind controlled clinical trial

Elevated levels of reactive oxygen species under diabetic condition lead to vascular complications and inflammation. This study aimed to examine the effects of hesperidin supplement on blood pressure and inflammatory markers in type 2 diabetes. In this research, 64 patients were randomly allocated to receive 500 mg/day hesperidin or placebo capsules for 6 weeks. Data on systolic blood pressure (SBP), diastolic blood pressure, serum total antioxidant capacity (TAC), tumor necrosis factor alpha, interleukin 6 (IL‐6), and high‐sensitivity C‐reactive protein (hs‐CRP) were collected at the baseline and at the end of the study. In the hesperidin group, SBP (122.7 ± 8.5 vs. 119.0 ± 7.4; p = .005), mean arterial blood pressure (94.2 ± 5.5 vs. 91.8 ± 5.5; p = .009), IL‐6 (8.3 ± 2.1 vs. 7.4 ± 1.8; p = .001), and hs‐CRP (1.9 ± 1.2 vs. 1.1 ± 0.9; p < .000) decreased whereas TAC increased (0.74 ± 0.1 vs. 0.82 ± 0.1; p < .000) in comparison to the baseline values. There was a significant difference in mean percent change of SBP, diastolic blood pressure, mean arterial blood pressure, serum TAC, and inflammatory markers (tumor necrosis factor alpha, IL‐6, and hs‐CRP) between hesperidin and control groups following intervention in adjusted models (p < .05). These results suggest that hesperidin may have antihypertensive and anti‐inflammatory effects in type 2 diabetes.     

Hypotensive and cardio-chronotropic constituents of Tinospora crispa and mechanisms of action on the cardiovascular system in anesthetized rats

Ethnopharmacological relevance

Tinospora crispa has been used in folkloric medicine for the control of blood pressure. We previously found that an extract of Tinospora crispa stems decreased the mean arterial blood pressure (MAP) with a transient decrease, followed by an increase in the heart rate (HR) in rats.

Aim of the study

To identify the active components of the Tinospora crispa extract and investigate the mechanisms of action on blood pressure and heart rate in anesthetized rats.

Materials and methods

The active components of Tinospora crispa extract were separated by column chromatography and a preparative HPLC. The effects and mechanisms of the active compounds on blood pressure and heart rate were studied in anesthetized, normal and reserpinized rats in vivo.

Results

5 active compounds: adenosine, uridine, salsolinol, higenamine and tyramine were isolated. Adenosine decreased MAP and HR and this effect was inhibited by DMPX (A_2A adenosine receptor antagonist). Uridine increased MAP and decreased HR and this was inhibited by suramin but not by DMPX. Salsolinol decreased the MAP and HR and this was inhibited by phentolamine but not by ICI-118,551 (β₂-adrenoceptor antagonist) or atropine. In reserpinized rats, salsolinol had a hypertensive effect that was inhibited by prazosin and phentolamine, but not by atenolol, and caused an increase in HR that was inhibited by atenolol, but not by prazosin or phentolamine. Higenamine decreased the MAP with an increase in HR. The hypotensive effect was inhibited by ICI-118,551 or atenolol, whereas the increase in HR was not inhibited by ICI-118,551. Atenolol inhibited the increase in HR at a small dosage of higenamine but potentiated it at a higher dosage. In reserpinized rats, a small dosage of higenamine tended to potentiate the effect but at a higher dosage it caused inhibition. ICI-118,551 significantly inhibited this hypotensive effect. Tyramine caused an increase in MAP and HR and these effects almost disappeared in reserpinized rats.

Conclusions

The results demonstrate that these 5 compounds from Tinospora crispa acted in concert on the cardiovascular system of anesthetized rats. Salsolinol, tyramine and higenamine acted via the adrenoreceptors, whereas uridine and adenosine acted via the purinergic adenosine A₂ and P₂ receptors to decrease blood pressure with a transient decrease of HR followed by an increase.     

Blood pressure lowering effect of the aqueous extract of the stem of Ipomoea acanthocarpa (convolvulaceae) in spontaneously and salt-loaded hypertensive rats

Spontaneously hypertensive (SHR) and salt-loaded hypertensive rats (SLHR) were submitted to a daily treatment by gavage of 2 mL/100 g body weight of the aqueous extract of the stem of Ipomoea acanthocarpa (30 mg/mL stock solution). A fall in blood pressure of nearly 13% was observed after two successive administrations of the aqueous extract. After 14 days of treatment, the blood pressure fell by more than 30±8%. The hypotensive effect might be due to a direct vascular smooth muscle effect or to its already observed high diuretic effects or might be acting by some other mechanism.     

四逆汤对失血性休克大鼠心功能和血压调节的肾上腺素受体机制研究

 目的观察四逆汤对失血性休克大鼠心功能的保护作用及其机制探讨。方法以血流动力学为指标，观察四逆汤对失血性休克大鼠的治疗作用,及α和β受体阻断剂对其作用的影响。结果四逆汤能改善失血性休克大鼠的左心室收缩压(LVSP)、左心室等容期压力最大变化速率(±dp/dtmax)和平均动脉压(MAP)的降低，α和β受体阻断剂可不同程度地阻断四逆汤对失血性休克大鼠的保护作用。结论四逆汤对失血性休克大鼠有强心、升压作用，其作用机制可能与调节肾上腺素α和β受体有关。     

Dual Inhibition of Ca+2 Influx and Phosphodiesterase Enzyme Provides Scientific Base for the Medicinal Use of Chrozophora prostrata Dalz. in Respiratory Disorders

The crude ethanolic extract of Chrozophora prostrata (Cp.Cr) was tested using in vivo and ex vivo assays for its possible bronchodilatory effects in order to validate its medicinal use in respiratory disorders, like asthma and cough. Cp.Cr exhibited dose‐dependent inhibition of carbachol (CCh)‐induced bronchospasm in anesthetized rats, similar to aminophylline. When tested on guinea‐pig tracheal preparations, Cp.Cr caused relaxation of both CCh (1 μM) and high K⁺ (80 mM)‐induced contractions with comparable potencies, similar to papaverine, a dual inhibitor of phosphodiesterse (PDE) and Ca⁺² influx. Pre‐treatment of the tracheal tissues with Cp.Cr resulted in potentiation of the inhibitory effect of isoprenaline on CCh‐induced contractions, like that caused by papaverine indicative of PDE inhibitory activity, which was confirmed when Cp.Cr concentration dependently (1 and 3 mg/mL) increased intracellular cAMP levels of the tracheal preparations, like papaverine. Cp.Cr shifted concentrationresponse curves of Ca⁺² constructed in guinea‐pig tracheal preparation towards right with suppression of the maximum response, similar to both verapamil and papaverine. These data indicate bronchodilator activity of Chrozophora prostrata mediated possibly through dual inhibition of PDE and Ca⁺² influx, thus, showing therapeutic potential in asthma with effect enhancing and side‐effect neutralizing potential Copyright © 2016 John Wiley & Sons, Ltd.     

大风子科植物的化学和生物活性研究进展

综述了近10年来与我国药用资源有关的大风子科12属植物的化学成分和生物活性的研究进展。该科植物主要含有芳香苷、木脂素苷、二萜、环戊烯氰醇苷等主要成分,其生物活性包括抗菌、抗病毒、抗肿瘤、降血脂、降血糖等作用。我国的大风子科植物中山羊角属、栀子皮属和山桂花属的研究尚属空白,对这些属植物进行系统的化学及生物活性研究,对新的天然产物和新的活性成分的发现,以及对该属植物的分类均有重要意义。     

A Review of the Receptor Binding and Pharmacological Effects of N‐methyltyramine

N‐methyltyramine (NMT) is a protoalkaloid isolated from various plant species. It is assumed that NMT is an adrenergic agonist with pharmacological properties similar to other structurally related biogenic amines. Current research studies indicate that NMT is an α‐adrenoreceptor antagonist, and exhibits modest inhibitory (antagonistic) activity with respect to the breakdown of fats (lipolysis). Furthermore, NMT has been shown to enhance appetite and digestion of foods through its stimulatory effects on gastrin and pancreatic secretions. As a consequence, NMT is not an ingredient that should be used in dietary supplements designed to promote weight loss. It may result in an increase in perceived energy by promoting appetite and the digestion and absorption of nutrients while inhibiting the breakdown to fats to energy. Copyright © 2014 The Authors Phytotheraphy Research Published by John Wiley & Sons, Ltd.