Effect of Rumex dentatus on Gastrointestinal Protection and Toxicology in Rodents via Investigating H+/K+-ATPase, Calcium Channels, and PDE Mediated Signaling

Abstract

This present study aims to delineate Rumex dentatus crude extract (Rd.Cr), n-Hexane, ethyl acetate, aqueous fractions (Rd.n-Hex, Rd.ETAC, and Rd.Aq), and emodin for antidiarrheal, antisecretory effects, anti-spasmodic, gastrointestinal transient time, anti-H. pylori, antiulcer effects, and toxicology. Plant extracts attributed dose-dependent protection against castor oil-induced diarrhea and dose-dependently inhibited intestinal fluid secretions in mice. They decreased the distance transverse by charcoal in the gastrointestinal transit model in rats. In rabbit jejunum preparations, it causes a concentration-dependent relaxation of both spontaneous and K+ (80 mM)-induced contraction, Rd.n-Hex and verapamil were relatively potent against K+-induced contractions and shifted the Ca2+ concentration-response curves (CRCs) to the right, Rd.Cr and Rd.ETAC shifted the isoprenaline-induced inhibitory CRCs to the left, showing potentiating effect similar to papaverine. Rd.n-Hex showed anti-H. pylori effect. Extracts and emodin also show an inhibitory effect against H+/K+-ATPase. Rumex dentatus showed a gastroprotective and antioxidant effect. Histopathological evaluation showed improvement in cellular architecture and decrease in the expression of inflammatory markers such as cyclooxygenase (COX2), tumor necrosis factor (TNF-α), and phosphorylated nuclear factor kappa B (p-NFƙB), validated through immunohistochemistry, ELISA, and western blot techniques. In RT-PCR, it decreases H+/K+-ATPase mRNA levels. Rumex dentatus was analyzed for certain safety aspects and exhibited a relative safety profile as no impairment was observed in kidneys, heart, liver, and brain further assisted by biochemical and hematological analysis. Docking studies revealed that emodin against H+/K+-ATPase pump and voltage gated L-type calcium channel showed E-value of −7.9 and −7.4 kcal/mol, respectively. MD simulations and molecular mechanics Poisson Boltzmann surface area and molecular mechanics Generalized Born surface area MMPBSA/GBSA findings are consistent with the in-vitro, in-vivo, and docking results. In conclusion, Rumex dentatus extracts and its phytoconstituent could be considered a potent antioxidant and anti-inflammatory drug candidates that possess anti-diarrheal, anti-secretary, antispasmodic, anti-H. pylori, and anti-ulcer potential. Toxicity studies were done according to OECD standards 425. It belongs to group 5 (LD50 > 2000 mg/kg), which suggests that it is in the lower toxicity class.