title: Cholinomimetic and calcium channel blocking activities of Carthamus oxycantha.
abstract: 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.
authors.affiliation: Department of Biological and Biomedical Sciences, The Aga Khan University Medical College, Karachi-74800, Pakistan. anwar.gilachi@aku.edu
authors.forename: Anwar H
authors.initials: AH
authors.lastname: Gilani
authors.forename: Ishfaq A
authors.initials: IA
authors.lastname: Bukhari
authors.forename: Rafeeq A
authors.initials: RA
authors.lastname: Khan
authors.forename: Arif-ullah
authors.initials: AU
authors.lastname: Khan
authors.forename: Farman
authors.initials: F
authors.lastname: Ullah
authors.forename: Viqar U
authors.initials: VU
authors.lastname: Ahmad
mesh_terms: D000818:Animals; D032701:Biomimetics; D002121:Calcium Channel Blockers / Q000494:pharmacology*; D020013:Calcium Signaling; D031178:Carthamus / Q000737:chemistry*; D004305:Dose-Response Relationship, Drug; D005260:Female; D006168:Guinea Pigs; D007082:Ileum / Q000187:drug effects; D007583:Jejunum / Q000187:drug effects; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects; D010936:Plant Extracts / Q000737:chemistry* / Q000494:pharmacology*; D011817:Rabbits
chemical_list: D002121:Calcium Channel Blockers; D010936:Plant Extracts