Phytochemical investigation, antimicrobial activities, and molecular docking studies on endemic <i>Gelasia sericea</i> (Aucher ex DC.) Zaika, Sukhor. &amp; N.Kilian grown in Türkiye

In this study, activity-guided isolation of the endemic <i>Gelasia sericea</i> (Aucher ex DC.) Zaika, Sukhor. & N.Kilian yielded five new compounds (8-<i>O</i>-<i>β</i>-<i>D</i>-glucopyranosyl-6-hydroxy-3-(4-hydroxyphenyl)-1<i>H</i>-isochromen-1-one (<b>1</b>), <i>rel.</i> (3 <i>R</i>,3'<i>S</i>)-8,8'-oxy<i>bis</i>[6-hydroxy-3-(4-hydroxyphenyl)-3,4-dihydro-1<i>H</i>-isochromen-1-one] (<b>2</b>), 3-<i>O</i>-(4-<i>O</i>-glyceryl)-<i>α</i>-<i>D</i>-xylopyranosyl-5-methyl-4<i>H</i>-pyran-4-one (<b>3</b>), 2-carboxyl-3-hydroxy-4'-methoxy-5-<i>O</i>-(3-<i>O</i>-glyceryl)-<i>β</i>-<i>D</i>-xylopyranosylbibenzyl (<b>4</b>), and 2-carboxyl-3,4'-dihydroxy-5-<i>O</i>-(<i>β</i>-<i>D</i>-apiofuranosyl)-(1→6)-<i>β</i>-D-glucopyranosylbibenzyl (<b>5</b>). Five known compounds as <i>p</i>-coumaric acid (<b>6</b>), scorzopigmecosite (<b>7</b>), scorzocreticin (<b>8</b>), quercetin (<b>9</b>), and kelampayoside A (<b>10</b>). Spectroscopic methods were used to characterise the structures of compounds <b>1-10</b>. All the isolated compounds, except compound <b>10</b>, exhibited an inhibition zone diameter of 10-12 mm against at least one of the nine different microorganisms tested. Compound <b>8</b> was found to be the most effective with an MIC value of 12.5 μg/mL against <i>Pseudomonas aeruginosa</i>. Additionally, molecular docking analysis of compounds <b>1-10</b> was performed, targeting <i>P. aeruginosa</i> RhlR and DNA gyrase B enzymes. Among the identified compounds, compound 2 exhibited the most promising inhibitory activity against both targets, with binding energies of -12.0 and -11.3 kcal/mol, respectively.