Research Article Effect of Imperatorin on the Spontaneous Motor Activity of Rat Isolated Jejunum Strips Marta Mendel, 1 Krystyna Skalicka-Wofniak, 2 Magdalena ChBopecka, 1 and Natalia Dziekan 1 1 Division of Pharmacology and Toxicology, Faculty of Veterinary Medicine, Warsaw University of Life Sciences, 8 Ciszewskiego Street, 02-786 Warsaw, Poland 2 Department of Pharmacognosy with Medicinal Plants Unit, Medical University of Lublin, 1 Chodzki, 20-819 Lublin, Poland Correspondence should be addressed to Krystyna Skalicka-Wo´ zniak; kskalicka@pharmacognosy.org Received 21 April 2015; Revised 12 June 2015; Accepted 18 June 2015 Academic Editor: Ho Lin Copyright © 2015 Marta Mendel et al. his is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Imperatorin, a psoralen-type furanocoumarin, is a potent myorelaxant agent acting as a calcium antagonist on vascular smooth muscle. Its efects on other types of smooth muscle remain unknown. herefore, the aim of this study was to investigate the hypothesized myorelaxant efect of imperatorin on gut motor activity and, possibly, to deine the underlying mechanism of action. Imperatorin was made available for pharmacological studies from the fruits of the widely available Angelica oicinalis through the application of high-performance countercurrent chromatography (HPCCC). Imperatorin generated reversible relaxation of jejunum strips dose-dependently (1–100 M). At 25 and 50 M, imperatorin caused relaxation comparable to the strength of the reaction induced by isoproterenol (Isop) at 0.1 M. he observed response resulted neither from the activation of soluble guanylate cyclase, nor from -adrenoreceptor involvement, nor from Ca 2+ -activated potassium channels. Imperatorin relaxed intestine strips precontracted with high potassium concentration, attenuated the force and duration of K + -induced contractions, and modulated the response of jejunum strips to acetylcholine. he results suggest that imperatorin probably interacts with various Ca 2+ inlux pathways in intestine smooth muscle. he types of some calcium channels involved in the activity of imperatorin will be examined in a subsequent study. 1. Introduction Imperatorin (Figure 1) is a naturally occurring furanocou- marin which is widely distributed in medicinal plants from the Apiaceae (formerly Umbelliferae) family. Due to its widespread occurrence, imperatorin was employed in several pharmacological studies aimed at understanding its efects on human and animal health. Imperatorin exerted an anxiolytic efect, improved diferent stages of memory processes [1], and protected against memory impairments induced by scopo- lamine, possessing antioxidant properties [2]. Imperatorin acts also as an anti-inlammatory [3], antiproliferative [4], anticonvulsant [5], acetyl- and butyrylcholinesterase inhi- bitor, antioxidant [6], antibacterial and anticoagulant [7], and vasodilatatory [8, 9] agent. According to studies conducted on vascular smooth mus- cle [8, 9], imperatorin inhibits Ca 2+ inlux through voltage- sensitive calcium channels, and thus it can be described as a calcium antagonist. Compounds belonging to this group of pharmacological agents afect various body functions, including muscle contractility, gland secretion, neurotrans- mitter release, gene expression, and platelet cell activity. Indeed, imperatorin acts as a calcium channel blocker in rat pituitary cells [10], mouse myocardial cells [11], and various arteries, for example, rabbit thoracic aorta [12]. Since it was established that imperatorin inluences the contractility of vascular smooth muscle, it was interesting to explore its efect on gut smooth muscle. hus, the aim of the present study was to determine the response of isolated rat intestinal strips to imperatorin treatment and to investigate the underlying mechanism of action. Since rat jejunum preparations were previously used to evaluate the calcium blocking activity of diferent compounds [13], the study also included veriication of the possible efects of imperatorin as a calcium blocker. Like many natural products, imperatorin is not routinely available in large quantities for pharmacological studies. Hindawi Publishing Corporation Evidence-Based Complementary and Alternative Medicine Volume 2015, Article ID 614849, 8 pages http://dx.doi.org/10.1155/2015/614849