Pharmacological Basis for the Antidiarrheal and Antispasmodic Effects of Cuminaldehyde in Experimental Animals: In Silico, Ex Vivo and In Vivo Studies

Background: Medicinal herbs are frequently used for the management of gastrointestinal disorders because they contain various compounds that can potentially amplify the intended therapeutic effects. Cuminaldehyde is a plant-based constituent found in oils derived from botanicals such as cumin, eucalyptus, myrrh, and cassia and is responsible for its health benefits. Despite the utilization of cuminaldehyde for several medicinal properties, there is currently insufficient scientific evidence to support its effectiveness in treating diarrhea. Hence, the present investigation was carried out to evaluate the antidiarrheal and antispasmodic efficacy of cuminaldehyde, with detailed pharmacodynamics explored. Methods: An in vivo antidiarrheal test was conducted in mice following the castor oil-induced diarrhea model, while an isolated small intestine obtained from rats was used to evaluate the detailed mechanism(s) of antispasmodic effects. Results: Cuminaldehyde, at 10 and 20 mg/kg, exhibited 60 and 80% protection in mice from episodic diarrhea compared to the saline control group, whereas this inhibitory effect was significantly reversed in the pretreated mice with glibenclamide, similar to cromakalim, an ATP-dependent K+ channel opener. In the ex vivo experiments conducted in isolated rat tissues, cuminaldehyde reversed the glibenclamide-sensitive low K+ (25 mM)-mediated contractions at significantly higher potency compared to its inhibitory effect against high K+ (80 mM), thus showing predominant involvement of ATP-dependent K+ activation followed by Ca++ channel inhibition. Cromakalim, a standard drug, selectively suppressed the glibenclamide-sensitive low K+-induced contractions, whereas no relaxation was observed against high K+, as expected. Verapamil, a Ca++ channel inhibitor, effectively suppressed both low and high K+-induced contractions with similar potency, as anticipated. At higher concentrations, the inhibitory effect of cuminaldehyde against Ca++ channels was further confirmed when the preincubated ileum tissues with cuminaldehyde (3 and 10 mM) in Ca++ free medium shifted CaCl2-mediated concentration-response curves (CRCs) towards the right with suppression of the maximum peaks, similar to verapamil, a standard Ca++ ion inhibitor. Conclusions: Present findings support the antidiarrheal and antispasmodic potential of cuminaldehyde, possibly by the predominant activation of ATP-dependent K+ channels followed by voltage-gated Ca++ inhibition. However, further in-depth assays are recommended to know the precise mechanism and to elucidate additional unexplored mechanism(s) if involved.