Mechanisms underlying the antidiarrheal, antispasmodic and bronchodilator activities of Fumaria parviflora and involvement of tissue and species specificity

Ethnopharmacological relevance: In the Greco-Arab (Unani) traditional medicine, Fumaria parviflora Linn. is widely used in hypreractive gut and respiratory disorders including diarrhea, abdominal cramps, indigestion and asthma but scientific studies to provide rational for these medicinal uses are sparse. This study was therefore undertaken to provide ethnopharmacological basis for its medicinal use in diarrhea, abdominal cramps and asthma. Materials and methods: The in vivo studies were conducted in mice and rats while isolated gut and tracheal preparations of rat, guinea-pig and rabbit were suspended in respective tissue baths to measure the isotonic and isometric responses, using Power Lab electronic recorder. Results: The aqueous-methanol extract of Fumaria parviflora (Fp.Cr) protected against diarrhea caused by castor oil in rats and mice, similar to loperamide and dicyclomine, and bronchospasm caused by carbachol (CCh) in rats, similar to aminophylline. In the in vitro studies, Fp.Cr relaxed CCh and isotonic high K physiological salts solutions-induced contractions in jejunum, ileum and tracheal preparations of rat, guinea-pig and rabbit. Fp.Cr was predominately more potent against CCh than isotonic high K solutions-induced contractions, similar to dicyclomine, suggesting the presence of anticholinergic and calcium channel blocking (CCB) activities, which were confirmed when Fp.Cr shifted the CCh and Ca² concentration-response curves, constructed in rat ileum and trachea, towards right. Among intestinal preparations from various species, both anticholinergic and CCB effects of Fp.Cr were exhibited at lower concentrations in rat than the other species. In tracheal preparations, Fp.Cr was the most potent in its CCB effect in rabbit. Within species, CCB effect of Fp.Cr was produced at lower concentrations in rat jejunum than ileum and trachea, whereas, anticholinergic effect was produced at higher concentration in rat trachea than intestine. Conclusion: This study, showing the presence of antidiarrheal, antispasmodic and bronchodilator activities in Fumaria parviflora possibly mediated through dual blockade of muscarinic receptors and Ca² channels, provides sound basis for its medicinal uses in diarrhea, abdominal cramps and may be used as bronchodilator in asthma. Species and tissue-dependency of these effects underscores the importance of utilizing multiple tissues and species to get more meaningful results.