In vitro cholinomimetic effect of Loranthus ferrugineus in isolated guinea pig ileum.
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.
Ameer
Omar Ziad
OZ
Department of Physiology & Pharmacology, School of Pharmaceutical Sciences, Universiti Sains Malaysia, Penang, Malaysia. omar_3m@yahoo.com
Salman
Ibrahim M
IM
Siddiqui
Mohammad Jamshed Ahmad
MJ
Yam
Mun Fei
MF
Sriramaneni
Raghava Naidu
RN
Sadikun
Amirin
A
Ismail
Zhari
Z
Shah
Amin Malik
AM
Asmawi
Mohd Zaini
MZ
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
D018678:Cholinergic Agents; D018727:Muscarinic Antagonists; D010936:Plant Extracts; D011976:Receptors, Muscarinic