Histone deacetylase inhibitory properties of metabolites from leaves of <i>Quercus pontica</i> K. Koch and its metabolites

The infusions prepared from some <i>Quercus</i> L. species are used in folk medicine for medicinal purposes and consumed as tea. <i>Quercus pontica</i> K. Koch was selected in this study, for which no phytochemical isolation studies have been performed so far. Quercetin 3-<i>O</i>- β-D-glucopyranoside, kaempferol 3-<i>O</i>-(6""-<i>O</i>-galloyl)-β-D-glucopyranoside, kaempferol 3-<i>O</i>-β-D-glucopyranoside, kaempferol 3-<i>O</i>-(6"'-coumaroyl-β-D-glucopyranoside, phlorizin, rosmarinic acid, and catechin were isolated from the titled plant for the first time. Some polyphenolic compounds have been shown to inhibit histone deacetylase (HDAC) enzymes. However, there is no study on the any activities of <i>Quercus</i> species in the literature. In this study, we demonstrated that the extract has <i>in vitro</i> pan-HDAC inhibition activity. Through a virtual screening study, the compounds were found to inhibit HDAC7 more strongly than the other HDAC isoforms; therefore, the HDAC7 inhibition activities were studied <i>in vitro</i>. Kaempferol 3-<i>O-β</i>-D-glucopyranoside and kaempferol 3-<i>O</i>-(6'"-coumaroyl-<i>β</i>-D-glucopyranoside) showed the best anti-HDAC7 activity with 37% and 41% inhibition at 500 μM.