eCommons@AKU Department of Biological & Biomedical Sciences Medical College, Pakistan February 2008 Gastrointestinal, selective airways and urinary bladder relaxant effects of Hyoscyamus niger are mediated through dual blockade of muscarinic receptors and Ca(2+) channels Anwarul Hassan Gilani Aga Khan University Arif-Ullah Khan Aga Khan University Mustafa Raoof Aga Khan University Muhammad Nabeel Ghayur Aga Khan University Bina S. Siddiqui See next page for additional authors Follow this and additional works at: http://ecommons.aku.edu/pakistan_fhs_mc_bbs Part of the Physiology Commons Recommended Citation Gilani, A., Khan, A., Raoof, M., Ghayur, M., Siddiqui, B., Vohra, W., Begum, S. (2008). Gastrointestinal, selective airways and urinary bladder relaxant effects of Hyoscyamus niger are mediated through dual blockade of muscarinic receptors and Ca(2+) channels. Fundamental & Clinical Pharmacology, 22(1), 87-99. Available at: http://ecommons.aku.edu/pakistan_fhs_mc_bbs/76 Authors Anwarul Hassan Gilani, Arif-Ullah Khan, Mustafa Raoof, Muhammad Nabeel Ghayur, Bina S. Siddiqui, Waseem Vohra, and Sabira Begum This article is available at eCommons@AKU: http://ecommons.aku.edu/pakistan_fhs_mc_bbs/76 doi: 10.1111/j.1472-8206.2007.00561.x ORIGINAL Gastrointestinal, selective airways and ARTICLE urinary bladder relaxant effects of Hyoscyamus niger are mediated through dual blockade of muscarinic receptors and Ca2+ channels Anwarul Hassan Gilania*, Arif-ullah Khana,b, Mustafa Raoof a, Muhammad Nabeel Ghayura,c, Bina S. Siddiquid, Waseem Vohrad, Sabira Begumd aNatural Product Research Division, Department of Biological and Biomedical Sciences, The Aga Khan University Medical College, Karachi – 74800, Pakistan bDepartment of Pharmacology, Faculty of Pharmacy, University of Karachi, Karachi, Pakistan cDepartment of Medicine, McMaster University, St. Joseph’s Hospital, Hamilton, ON, Canada dHEJ Research Institute of Chemistry, University of Karachi, Karachi – 75270, Pakistan Keywords ABSTRACT airways and bladder selec- tivity, This study describes the spasmolytic, antidiarrhoeal, antisecretory, bronchodilatory anticholinergic, and urinary bladder relaxant properties of Hyoscyamus niger to rationalize some of Ca2+ antagonist, its medicinal uses. The crude extract of H. niger seeds (Hn.Cr) caused a complete Hyoscyamus niger concentration-dependent relaxation of spontaneous contractions of rabbit jejunum, similar to that caused by verapamil, whereas atropine produced partial inhibition. + Hn.Cr inhibited contractions induced by carbachol (1 lM) and K (80 mM)ina Received 21 June 2007; revised 13 September 2007; pattern similar to that of dicyclomine, but different from verapamil and atropine. 2+ accepted 13 November 2007 Hn.Cr shifted the Ca concentration–response curves to the right, similar to that caused by verapamil and dicyclomine, suggesting a Ca2+ channel-blocking mechanism in addition to an anticholinergic effect. In the guinea-pig ileum, Hn.Cr *Correspondence and reprints: produced a rightward parallel shift of the acetylcholine curves, followed by a non- [email protected] parallel shift with suppression of the maximum response at a higher concentration, similar to that caused by dicyclomine, but different from that of verapamil and atropine. Hn.Cr exhibited antidiarrhoeal and antisecretory effects against castor oil- induced diarrhoea and intestinal fluid accumulation in mice. In guinea-pig trachea and rabbit urinary bladder tissues, Hn.Cr caused relaxation of carbachol (1 lM) and + K (80 mM) induced contractions at around 10 and 25 times lower concentrations than in gut, respectively, and shifted carbachol curves to the right. Only the organic fractions of the extract had a Ca2+ antagonist effect, whereas both organic and aqueous fractions had anticholinergic effect. A constituent, b-sitosterol exhibited Ca2+ channel-blocking action. These results suggest that the antispas- modic effect of H. niger is mediated through a combination of anticholinergic and Ca2+ antagonist mechanisms. The relaxant effects of Hn.Cr occur at much lower concentrations in the trachea and bladder. This study offers explanations for the medicinal use of H. niger in treating gastrointestinal and respiratory disorders and bladder hyperactivity. ª 2008 The Authors Journal compilation ª 2008 Blackwell Publishing Ltd. Fundamental & Clinical Pharmacology 22 (2008) 87–99 87 88 A. H. Gilani et al. INTRODUCTION MATERIALS AND METHODS Hyoscyamus niger Linn. (Solanaceae), commonly Plant material, preparation of crude extract and known as ‘Henbane’ and ‘Ajwain-i-khurasani’ locally fractions in Pakistan, grows wildly throughout the Himalayan The seeds of H. niger (5 kg) were purchased from the range at altitudes of 8000–11 000 feet and in local market, cleaned and coarsely ground. The pow- many other parts of the world [1]. Its seeds are used dered material was extracted four times with 98% in traditional medicine for treating a variety of methanol at room temperature. The soaked material ailments including asthma, cough, colic, diarrhoea was filtered through a muslin cloth and then through and genito-urinary complaints such as irritable blad- Whatman qualitative grade 1 filter paper [17]. This der [2,3]. procedure was repeated thrice and the combined filtrate Phytochemical studies revealed the presence of was evaporated with a rotary evaporator under reduced hyoscine (scopolamine), hyoscyamine, anisodine, pressure to a thick syrupy mass, the crude extract anisodamine [4,5], aesculetin, coumarin, kaempferol, (Hn.Cr), at a yield of approximately 19.6%. Activity- quercetin, rutin, cuscohygrine, chlorogenic acid, lino- guided fractionation of the parent extract was carried leic acid, myristic acid, oleic acid, stearic acid, pyridine, out by using solvents of increasing polarity. Hn.Cr was trimethylamine [6], b-sitosterol, grossamide, canna- partitioned between ethyl acetate and water. The ethyl bisin D & G, daucosterol, N-trans-feruloyltyramine, acetate phase was dried over Na2SO4 (anhydrous), then 1-O-octadecanoyl glycerol, 1-O-(9Z,12Z-octadecadienoyl) concentrated at reduced pressure to yield an ethyl glycerol, 1-O-(9Z,12Z-octadecadienoyl)-3-O-(9Z-octa- acetate residue. The water layer was dried to obtain decenoyl) glycerol, vanillic acid [7], calystegines [8] the aqueous fraction (Hn.Aq). The ethyl acetate residue and withanolides [9]. The plant is known to possess was treated with petroleum ether to obtain the petro- antispasmodic, analgesic [10], mydriatic [11] and leum ether fraction (Hn.PE) and insoluble fraction. The sedative [12] properties. latter was treated with ethyl acetate to give the ethyl Hyoscine and hyoscyamine, previously identified acetate fraction (Hn.EtAc). The fraction left after as the anticholinergic constituents in H. niger, are extraction with ethyl acetate was dissolved in metha- considered responsible for its antispasmodic effect [13]. nol to obtain the methanolic fraction (Hn.MeOH). However, it is generally believed that the plant Stock solutions of the plant materials were prepared contains multiple compounds acting on different sites. in 10% ethanol, and subsequent dilutions in distilled The aim of this study was to see if H. niger has an H2O/saline. antispasmodic effect on the gut, airways and urinary bladder through a combination of mechanisms. Plants Chemicals with medicinal use in hyperactive gut and airway Acetylcholine chloride, atropine sulphate, b-sitosterol, disorders usually possess a Ca2+ channel-blocking carbachol, chlorogenic acid, coumarin, dicyclomine, action in combination with other spasmolytic mecha- loperamide hydrochloride, scopolamine, vanillic acid nisms [14–16]. In this investigation, we report the and verapamil hydrochloride were purchased from presence of a combination of anticholinergic and Ca2+ Sigma Chemicals Co (St Louis, MO, USA). Hyoscyamine antagonist effects in H. niger seed extract, studied in sulphate and castor oil were obtained from ChromaDex tissues relevant to gastrointestinal, airway and urinary (Santa Ana, CA, USA) and KCl Pharma (Karachi, systems. Activity-directed fractionation revealed that Pakistan) respectively. Chemicals used for making the anticholinergic component(s) was widely distrib- physiological salt solutions were potassium chloride uted both in the organic and aqueous fractions, while (Sigma Chemicals Co), calcium chloride, glucose, Ca2+ antagonist was concentrated only in the organic magnesium chloride, magnesium sulphate, potassium fraction. Apart from the crude extract and its resultant dihydrogen phosphate, sodium bicarbonate, sodium fractions, the pure compounds of H. niger namely dihydrogen phosphate (Merck, Darmstadt, Germany) b-sitosterol, scopolamine, hyoscyamine, coumarin, and sodium chloride from BDH Laboratory Supplies chlorogenic acid and vanillic acid were also studied. (Poole, UK). All chemicals used were of analytical grade b-sitosterol was found to exhibit spasmolytic effect via and solubilized in distilled H2O except, b-sitosterol which Ca2+ antagonist mechanism. was dissolved in 10% ethanol; subsequent dilutions were ª 2008 The Authors Journal compilation ª 2008 Blackwell Publishing Ltd. Fundamental & Clinical Pharmacology 22 (2008) 87–99 2+ Anticholinergic and Ca antagonist activities of Hyoscyamus niger 89 2+ prepared in distilled H2O. Vehicles used had no effect on To confirm the Ca antagonist action of the test tissue contractility in control experiments. substance, the tissue was allowed to stabilize in normal Tyrode’s solution, which was then replaced with