title: Antispasmodic effect of Acorus calamus Linn. is mediated through calcium channel blockade.
abstract: Acorus calamus Linn. (Araceae) is a native of Central Asia and Eastern Europe and has widespread use in the traditional system of medicine for gastrointestinal disorders such as colic pain and diarrhoea. This study was aimed at providing a possible pharmacological basis to the use of this plant as an antispasmodic and antidiarrhoeal. In the isolated rabbit jejunum preparation the crude extract (Ac.Cr), which tested positive for the presence of alkaloid, saponins and tannins, caused inhibition of spontaneous and high K(+) (80 mm)-induced contractions, with respective EC(50) values of 0.42 +/- 0.06 and 0.13 +/- 0.04 mg/mL (mean +/- SEM; n = 6-8), thus showing spasmolytic activity, mediated possibly through calcium channel blockade (CCB). The CCB activity was confirmed when pre-treatment of the tissue with Ac.Cr (0.3-1.0 mg/mL) caused a rightward shift in the Ca(++) dose-response curves similar to that caused by verapamil, a standard calcium channel blocker. Activity-directed fractionation revealed that the CCB activity was concentrated in the n-hexane fraction while the ethylacetate fraction was less potent. These results suggest that the spasmolytic effect of the plant extract is mediated through the presence of CCB-like constituent(s) which is concentrated in the n-hexane fraction and this study provides a strong mechanistic base for its traditional use in gastrointestinal disorders such as colic pain and diarrhoea.
authors.affiliation: Department of Biological and Biomedical Sciences, The Aga Khan University Medical College, Karachi-74800, Pakistan. anwar.gilani@aku.edu
authors.forename: Anwar Ul Hassan
authors.initials: AU
authors.lastname: Gilani
authors.forename: Abdul Jabbar
authors.initials: AJ
authors.lastname: Shah
authors.forename: Manzoor
authors.initials: M
authors.lastname: Ahmad
authors.forename: Farzana
authors.initials: F
authors.lastname: Shaheen
mesh_terms: D029023:Acorus / Q000737:chemistry*; D000818:Animals; D000930:Antidiarrheals / Q000494:pharmacology; D002118:Calcium / Q000032:analysis; D002121:Calcium Channel Blockers / Q000494:pharmacology*; D015220:Calcium Channels / Q000187:drug effects*; D005260:Female; D020128:Inhibitory Concentration 50; D007583:Jejunum / Q000187:drug effects*; D008297:Male; D051379:Mice; D009119:Muscle Contraction / Q000187:drug effects; D010276:Parasympatholytics / Q000494:pharmacology*; D010936:Plant Extracts / Q000737:chemistry / Q000494:pharmacology*; D011817:Rabbits; D023382:Toxicity Tests, Acute / Q000379:methods; D014700:Verapamil / Q000494:pharmacology
chemical_list: D000930:Antidiarrheals; D002121:Calcium Channel Blockers; D015220:Calcium Channels; D010276:Parasympatholytics; D010936:Plant Extracts; D014700:Verapamil; D002118:Calcium