UHPLC-MS profiles and antidiarrheal activity for two Quercus species grown in Egypt

<em>Quercus</em> L. genus (Oak) belongs to the family Fagaceae and their galls are used commercially in leather tanning, dyeing, and ink preparation. Several <em>Quercus</em> species were used traditionally in the management of wound healing, acute diarrhea, hemorrhoid, and inflammatory diseases. The present study aims to investigate the phenolic content of the 80% aqueous methanol extract (AME) of <em>Q.</em> <em>coccinea</em> and <em>Q. robur</em> leaves as well as to assess their anti-diarrheal activity. Twenty-five and twenty-six polyphenolic compounds were tentatively identified in <em>Q.</em> <em>coccinea</em> and <em>Q. robur </em>AME, respectively using UHPLC/MS. The identified compounds are related to quercetin, kaempferol, isorhamnetin, and apigenin glycosides and their aglycones. In addition, hydrolyzable tannins, phenolic acid, phenyl propanoides derivatives, and cucurbitacin F were also identified in both species.