Comparative pharmacokinetic studies of five C-glycosylflavones in normal and urolithiasis model rats following administration of total flavonoids from Desmodium styracifolium by liquid chromatography-tandem mass spectrometry.

The total flavonoids of Desmodium styracifolium are the flavonoid extracts purified from Desmodii Styracifolii Herba, which has conventionally been used for treating urolithiasis in China. In this study, a sensitive and simple liquid chromatography-tandem mass spectrometry method was developed to simultaneously determine five active components of the extracts in rat plasma. Chromatographic separation of the analytes (schaftoside, vicenin-1, vicenin-2, vicenin-3, and isovitexin) was performed on an ACQUITY UPLC HSS T3 Column under gradient elution conditions. The calibration curves were linear over ranges from 0.5 to 100 ng/ml for schaftoside, vicenin-1, vicenin-2, and vicenin-3, and 0.2-20 ng/ml for isovitexin. The relative standard deviation of intra- and inter-day precisions were ≤6.8% and ≤8.3%, respectively, and the accuracies (relative error) were within ±7.6%. The recoveries of the analytes ranged between 97.3% and 100.3%, and the matrix effects ranged from 98.6% to 113.8%. The method was successfully applied to the pharmacokinetic studies of the five active ingredients of Desmodium styracifolium, for the first time, in both normal and urolithiasis model rats. Results revealed that the plasma levels of these components were significantly increased under the pathological state. This study provided valuable information facilitating the clinical investigation of this medicine.