Phytochemistry, Laxative, Prokinetic and Spasmolytic Verification of Withania somnifera (L.) Dunal Using In-Vitro, In-Vivo and In-Silico Approaches

Background: Withania somnifera (L.) Dunal is traditionally used as laxative, diuretic and sedative remedy. The current study was aimed to perform phytochemical analysis, antioxidant, cholinesterase inhibitory, laxative, prokinetic and spasmolytic potentials of the plant using in -vitro, in -vivo and in-silico approaches. Methods: Phytochemical analysis was performed using Gas Chromatography -Mass Spectrometry (GC -MS). In -vitro cholinesterase inhibitory and antioxidant studies were performed using standard procedures. The laxative effect was evaluated using pigeons and rabbits whereas the spasmolytic study was performed using rabbits jejunal slices. In-silico study was performed against the identified compounds using Discovery studio version 4.1. Results: The GC -MS revealed the presence of several bioactive compounds. Methanolic extract (MEWS) and n-butanol fraction (NBFWS) showed antioxidant potential using 2,2 '-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS) and 2,2-Diphenyl-1picrylhydrazyl (DPPH) assays with half maximal inhibitory concentration (IC50) values of (90 mu g mL-1, 180 mu g mL-1) and (170 mu g mL-1, 169 mu g mL-1) respectively. Furthermore, they inhibited acetylcholinesterase (AChE) with IC50 values of 50 and 150 mu g mL-1 respectively. Both samples exhibited prokinetic effects in metronidazole and loperamide hydrochloride -induced constipation models. Metronidazole was found to be effective by reducing the percentage of wet feces as compared to loperamide hydrochloride. Both samples promoted intestinal transit (propulsion) compared to distilled water. The NBFWS showed significant spasmolytic activity with an effective concentration (EC50 = 0.85 +/- 0.31 mg mL-1) in rabbit jejunum when compared with MEWS (EC50 = 4.3 +/- 0.5 mg mL-1). Similarly, NBFWS exhibited significant relaxing activity in potassium chloride (KCl)induced (80 mM) contraction (EC50 = 3.41 +/- 0.67 mg mL-1) compared to MEWS (EC50 of 9.6 +/- 0.4 mg mL-1). In-silico molecular docking study against the active site of AChE enzyme revealed that 8 -cis Octadecenoic acid methyl ester exhibited C -docker energy of -50.0022 Kcal/mol relative to the co -crystallized ligand (-43.6427 Kcal/mol). Conclusions: The purpose of the current study was to find a natural remedy which can overcome the problem associated with constipation and to regulate the GIT motility. The results validated the use of Withania somnifera(W. somnifera) in the treatment of gastrointestinal disorders like constipation and spasms, yet further work is warranted to isolate and therapeutically validate its bioactive phytochemicals.