Siraj Munir, Uzair Ali Khalid, Mudassir Asrar and Anwarul Hassan Gilani contributed equally to this work.
The authors declare that they have no competing interests.
MHM designed the project, supervised the study and drafted final manuscript. SM and UAK carried out literature search, experimental work and data acquisition. AHG contributed in study design and review of the manuscript. MA identified and procured the plant material and reviewed the manuscript for publication. All authors read and approved the final manuscript for publication.
MHM is an Assistant Professor at Natural Product Research Division,Department of Biological and Biomedical Sciences, Faculty of Health Sciences, Medical College, The Aga Khan University, Stadium Road, P.O. Box 3500, Karachi 74800, Pakistan. SM and UAK are undergraduate medical students at Medical College, The Aga Khan University, Stadium Road, P.O. Box 3500, Karachi 74800, Pakistan. AHG is a Professor of Pharmacology at Natural Product Research Unit, Department of Biological and Biomedical Sciences, The Aga Khan University Medical College, Karachi-74800, Pakistan. MA is Professor at Department of Botany, University of Balochistan, Quetta.
Matricaria chamomilla commonly known as “Chamomile” (Asteraceae) is a popular medicinal herb widely used in indigenous system of medicine for a variety of ailments. However, there is no detailed study available showing its effectiveness in hyperactive gut disorders like, abdominal colic and diarrhoea. This study was designed to determine the pharmacological basis for the folkloric use of Matricaria chamomilla in diarrhoea.
The crude aqueous-methanolic extract of Matricaria chamomilla (Mc.Cr) was studied for its protective effect in mice against castor oil-induced diarrhoea and intestinal fluid accumulation. The isolated rabbit jejunum was selected for the in-vitro experiments using tissue bath assembly coupled with PowerLab data acquisition system.
Oral administration of Mc.Cr to mice at 150 and 300 mg/kg showed marked antidiarrhoeal and antisecretory effects against castor oil-induced diarrhoea and intestinal fluid accumulation, simultaneously, similar to the effects of cromakalim and loperamide. These effects of plant extract were attenuated in animals pretreated with K+ channel antagonist, glibenclamide (GB) or 4-aminopyridine (4-AP). When tested in isolated rabbit jejunum, Mc.Cr caused a dose-dependent (0.3-3 mg/ml) relaxation of spontaneous and low K+ (25 mM)-induced contractions, while it exhibited weak inhibitory effect on high K+ (80 mM). The inhibitory effect of Mc.Cr on low K+-induced contractions was partially inhibited in the presence of GB, while completely blocked by 4-AP. Cromakalim, an ATP-sensitive K+ channel opener, caused complete relaxation of low K+-induced contractions with little effect on high K+. Pretreatment of tissues with GB blocked the inhibitory effects of cromakalim on low K+, while the presence of 4-AP did not alter the original effect. Verapamil, a Ca++ channel antagonist, caused complete relaxation of both low and high K+-induced contractions with similar potency. The inhibitory effect of verapamil was insensitive to GB or 4-AP. When assessed for Ca++ antagonist like activity, Mc.Cr at high concentrations caused rightward shift in the Ca++ concentration-response curves with suppression of the maximum response, similar to the effect of verapamil, while cromakalim did not show similar effect.
This study indicates that Matricaria chamomilla possesses antidiarrhoeal, antisecretory and antispasmodic activities mediated predominantly through K+-channels activation along with weak Ca++ antagonist effect.