title: In vitro cholinomimetic effect of Loranthus ferrugineus in isolated guinea pig ileum.
abstract: This study aimed to elucidate the mechanism(s) of the spasmogenic action of Loranthus ferrugineus in isolated guinea pig ileum. Thus the contractile responses of guinea pig ileum to graded additions of either L. ferrugineus methanol extract or its n-butanol fraction were tested in the presence and absence of various pharmacological interventions. The data showed that L. ferrugineus methanol extract and the n-butanol fraction produced a concentration-dependent spasmogenic effect in isolated guinea pig ileum segments. These effects were significantly inhibited in the presence of 1 microM atropine. In contrast, the response to the lowest concentrations of L. ferrugineus methanol extract (0.25, 0.5 and 1 mg/mL) and n-butanol fraction of L. ferrugineus (0.125, 0.25 and 0.5 mg/mL) were considerably enhanced in the presence of 0.05 microM neostigmine. Neither L. ferrugineus methanol extract nor n-butanol fraction contractile responses were affected upon the incubation of the ileal segments with 100 microM hexamethonium. The results of this study show that the spasmogenic effect of L. ferrugineus is possibly mediated through a direct action on intestinal muscarinic receptors. It is suggested that the bioactive constituents of L. ferrugineus serve as a substrate for acetylcholinesterase.
authors.affiliation: Department of Physiology & Pharmacology, School of Pharmaceutical Sciences, Universiti Sains Malaysia, Penang, Malaysia. omar_3m@yahoo.com
authors.forename: Omar Ziad
authors.initials: OZ
authors.lastname: Ameer
authors.forename: Ibrahim M
authors.initials: IM
authors.lastname: Salman
authors.forename: Mohammad Jamshed Ahmad
authors.initials: MJ
authors.lastname: Siddiqui
authors.forename: Mun Fei
authors.initials: MF
authors.lastname: Yam
authors.forename: Raghava Naidu
authors.initials: RN
authors.lastname: Sriramaneni
authors.forename: Amirin
authors.initials: A
authors.lastname: Sadikun
authors.forename: Zhari
authors.initials: Z
authors.lastname: Ismail
authors.forename: Amin Malik
authors.initials: AM
authors.lastname: Shah
authors.forename: Mohd Zaini
authors.initials: MZ
authors.lastname: Asmawi
mesh_terms: D000818:Animals; D018678:Cholinergic Agents / Q000378:metabolism / Q000494:pharmacology*; D005260:Female; D006168:Guinea Pigs; D007082:Ileum / Q000187:drug effects* / Q000378:metabolism; D066298:In Vitro Techniques; D028183:Loranthaceae / Q000737:chemistry*; D008297:Male; D018727:Muscarinic Antagonists / Q000378:metabolism / Q000494:pharmacology; D010936:Plant Extracts / Q000378:metabolism / Q000494:pharmacology*; D011485:Protein Binding; D011976:Receptors, Muscarinic / Q000378:metabolism
chemical_list: D018678:Cholinergic Agents; D018727:Muscarinic Antagonists; D010936:Plant Extracts; D011976:Receptors, Muscarinic