Erodium birandianum Ilarslan & Yurdak. shows anti-gout effect through xanthine oxidase inhibition: Combination of in vitro and in silico techniques and profiling of main components by LC-Q-ToF-MS

The anti-gout effect of Erodium birandianum Ilarslan & Yurdak. was investigated through xanthine oxidase (XO) inhibition using in vitro and in silico experiments. The ethanol extract of E. birandianum (EB) with 82.26 +/- 0.10 % of XO inhibitory activity at 100 mu g/mL was sequentially fractionated. The extract and active fractions were analyzed using LC-Q-ToF-MS. Gallic, caffeic, quinic, and syringic acids, catechin, epicatechin, rutin, luteolin, apigenin, and quercetin were detected in the extract and active subfractions. In the active subfractions, presence of procyanidin derivatives having molecular weight over 850 was demonstrated through LC-Q-ToF-MS library. Catechin, caffeic acid, rutin, and quercetin were tested against XO, and the highest inhibition was caused by quercetin (98.03 +/- 2.34 %). XO inhibitory effect of gallic acid, caffeic acid, catechin, epicatechin, luteolin, apigenin, and quercetin was investigated by molecular docking experiments. Probability of their XO inhibition was estimated using PASS and Swiss Target Prediction programs. Possible toxicities were estimated by VEGA QSAR Mutagenity, CONSENSUS, ToxTREE SAR, and VEGA hepatotoxicity models. Quercetin as well as luteolin, apigenin, and gallic acid were deduced to be most likely responsible for the marked XO inhibitory effect of EB extract and active subfractions.