title: Intestinal and vascular smooth muscle relaxant effect of Viscum album explains its medicinal use in hyperactive gut disorders and hypertension.
abstract: BACKGROUND
  Viscum album has shown inhibitory effect on different smooth muscles but underlying mechanisms in gut and vascular smooth muscles are not well defined. Additionally, the plant has also importance in managing hyperactive gut and cardiovascular disorders. The current study was aimed to probe a pharmacological base of the smooth muscle relaxant effect of V. album in gut and vascular preparations.
  
  
  METHODS
  V. album crude extract (Va. Cr) and its ethyl acetate fraction (Va. EtAc) were studied using in vitro techniques. The antispasmodic activity was performed using isolated rabbit jejunum while the vasorelaxant effects were studied in rabbit aortic rings.
  
  
  RESULTS
  Va. Cr and Va. EtAc inhibited spontaneous and high K(+)-induced contractions with EC50 values of 0.31 mg/mL (0.15-0.57) and 0.62 mg/mL (0.3-0.95), respectively. This advocates an antispasmodic effect probably operated through calcium channels blockade (CBB). The proposed mechanism was confirmed by a pretreatment of the tissue with Va. Cr (0.01-0.3 mg/mL), which shifted the Ca(++) concentration-response curves (CRCs) rightward, similar to verapamil. Moreover, Va. Cr showed a partial relaxation against high K(+) and PE (1 μM) induced contractions in isolated rabbit aorta rings. Va. EtAc caused complete relaxation of high K(+) precontraction and partially relaxed PE (1 μM) induced contractions, suggesting inhibitory effect on Ca(++) entry, in addition to other possible mechanisms. CRCs were shifted to the right correspondingly to verapamil when the aortic rings were pretreated with Va. Cr and Va. EtAc.
  
  
  CONCLUSIONS
  These data indicated that Va. Cr possesses smooth muscle relaxant effect mediated through voltage-dependent Ca(++) channel blockade (CCB), which explains its spasmolytic and vasorelaxant activity. The CCB activity is concentrated more in Va. EtAc. This study provides an evidence for the medicinal importance of V. album in gut spasm and possibly hypertension.
authors.affiliation: Department of Pharmacy, COMSATS Institute of Information Technology, Abbottabad, 22060, Pakistan. taouskhan@ciit.net.pk.
authors.forename: Taous
authors.initials: T
authors.lastname: Khan
authors.affiliation: Department of Pharmacy, COMSATS Institute of Information Technology, Abbottabad, 22060, Pakistan.
authors.forename: Sayyad
authors.initials: S
authors.lastname: Ali
authors.affiliation: Department of Pharmacy, COMSATS Institute of Information Technology, Abbottabad, 22060, Pakistan.
authors.forename: Rahila
authors.initials: R
authors.lastname: Qayyum
authors.affiliation: Department of Pharmacy, COMSATS Institute of Information Technology, Abbottabad, 22060, Pakistan.
authors.forename: Izhar
authors.initials: I
authors.lastname: Hussain
authors.affiliation: Department of Environmental Sciences, COMSATS Institute of Information Technology, Abbottabad, 22060, Pakistan.
authors.forename: Fazli
authors.initials: F
authors.lastname: Wahid
authors.affiliation: Department of Pharmacy, COMSATS Institute of Information Technology, Abbottabad, 22060, Pakistan.
authors.forename: Abdul Jabbar
authors.initials: AJ
authors.lastname: Shah
mesh_terms: D000818:Animals; D001011:Aorta / Q000187:drug effects*; D002121:Calcium Channel Blockers / Q000494:pharmacology; D006973:Hypertension; D007583:Jejunum / Q000187:drug effects*; D009131:Muscle, Smooth, Vascular / Q000187:drug effects; D010276:Parasympatholytics / Q000494:pharmacology*; D010936:Plant Extracts / Q000737:chemistry* / Q000494:pharmacology*; D011817:Rabbits; D014665:Vasodilator Agents / Q000494:pharmacology; D028182:Viscum album / Q000737:chemistry*
chemical_list: D002121:Calcium Channel Blockers; D010276:Parasympatholytics; D010936:Plant Extracts; D014665:Vasodilator Agents
keywords: Ca++ antagonist; Fraction; Gut spasm; Rabbit jejunum and aorta; Vasorelaxation; Viscum album