Pharmacokinetic comparisons of six components from raw and vinegar-processed Daphne genkwa aqueous extracts following oral administration in rats by employing UHPLC-MS/MS approaches

A sensitive UHPLC-MS/MS approach was developed and validated for the quantification of genkwanin, 3′-hydroxygenkwanin, apigenin, luteolin, yuanhuacine and genkwadaphnin in biological samples after oral administration of raw and vinegar-processed Daphne genkwa. Liquiritin and glycyrrhetinic acid were employed as internal standards. Six components were extracted by using protein precipitation with acetonitrile. Chromatographic separation was achieved on a Waters BEH C18 column (50 mm × 2.1 mm, 1.7 μm) by using a mobile phase composed of water (containing 0.1% formic acid) and acetonitrile. Mass spectrometric detection was conducted using multiple reaction monitoring (MRM). The intra- and inter-day precisions of the six analytes were below 4.87%, and the accuracies were within ±5.0%. The extraction recoveries of the six constituents were determined between 97.5% and 105.4% and the matrix effects ranged from 97.3% to 103.7%. All the samples showed satisfactory precision and accuracy after various stability tests. The established approach was successfully applied to the comparative pharmacokinetic study. Compared to the raw group, the parameters of Cmax and AUC0−t of genkwanin, 3′-hydroxygenkwanin, apigenin and luteolin elevated remarkably (p < 0.05) after oral delivery of vinegar-processed Daphne genkwa while the parameters of Cmax and AUC0−t of yuanhuacine and genkwadaphnin decreased significantly (p < 0.05). The results revealed that vinegar-processing could enhance bioavailability of genkwanin, 3′-hydroxygenkwanin, apigenin and luteolin but reduce the bioavailability of yuanhuacine and genkwadaphnin.