Comprehensive assessment of the antidiarrheal properties of polyphenols from Psidium cattleianum Sabine's aerial parts.

ETHNOPHARMACOLOGICAL RELEVANCE

Diarrhea is associated with high morbidity and mortality rates in developing countries and is ranked the second leading cause of infant mortality worldwide. Psidium cattleianum Sabine leaves have been traditionally used as an anti-diarrheal remedy, however, no scientific study has thoroughly investigated its anti-diarrheal potential.

AIM OF THE STUDY

To unravel the polyphenolic profile and explore the antidiarrheal potential of the defatted aqueous methanol extract (DAME) of Psidium cattleianum Sabine aerial parts through in vivo and in vitro experiments, alongside an inclusive in-silico analysis.

MATERIALS AND METHODS

The major polyphenolic compounds were purified and identified using chromatographic and spectroscopic techniques. The antidiarrheal activity was assessed using castor oil-induced diarrhea, gastrointestinal motility test, and castor oil-induced enteropooling in vivo models. Bacterial strains associated with diarrhea were used for the in vitro study. Molecular docking was investigated using Autodock Vina and OpenBabel tools. Moreover molecular dynamics study was performed using GROMACS, PyMOL and Bio3D package in R Studio.

RESULTS

Twelve polyphenols were isolated for the first time from the aerial parts of the Egyptian Psidium cattleianum Sabine and identified as; castalagin (1), rutin (2), kaempferol 3-O-β-D-rutinoside (3), guaijaverin (4), avicularin (5), quercetin 3-O-β-(3'-O-galloylxylopyranoside (6), verbascoside (7), quercetrin (8), gallic acid (9), methyl gallate (10), quercetin (11) and kaempferol (12). DAME (200, 400, and 800 mg/kg) significantly delayed the diarrheal onset by 1.5, 1.8, and 2.3 folds, respectively. The diarrheal inhibition percentage was 63.47, 82.69, and 92.31, respectively. The content of intestinal transit decreased by 27.38 %, 45.11 %, and 50.06 %. The Antidiarrheal index was 43.28, 66.74, and 84.22. E. coli, S. enterica, L. monocytogenes, and S. aureus demonstrated sensitivity to DAME, exhibiting inhibition zones (IZ) ranging from 10 to 25 mm. The docking conclusion shows that all identified polyphenols bind to the Kappa Opioid Receptor (KOR) and Beta-ketoacyl-acyl carrier protein synthase III (FabH), with promising results that confirm the credibility of the biological findings. Then, we selected the top-ranked phytocompounds verbascoside (7) based on their highest binding affinity scores for KOR and FabH -10.33 and -8.91 (Kcal/mol), respectively. Furthermore, 200 ns MD simulations performed on the KOR and FabH ligand-protein complexes, computed RMSD, RMSF, RG, PCA, DCCM, and free energy landscape (FEL), revealed stable conformations of the ligand-protein interactions throughout the simulations. These findings support that DAME is a promising alternative for managing diarrheal and bacterial infections related to gastrointestinal disorders. Our future direction is to formulate the extract in a suitable dosage form and implement clinical studies, while scaling up the in silico active phenolics for detailed mechanistic study is a promising approach.