Determination and Pharmacokinetics of WGA in Rat Plasma by LC-MS After Oral Administration of Xanthoceras sorbifolia Bunge Extract.

3-O-(3-O-angeloyl-6-O-β-D-glucopyranosyl)-β-D-glucopyranosyl-28-O-(2-α-L-rhamnopyranosyl-6-O-β-D-glucopyranosyl)-β-D-glucopyranosyl-16-deoxybarringtogenol A (WGA) is a potential anti-AD (Alzheimer's disease) active compound isolated from the husks of Xanthoceras sorbifolia Bunge. A rapid and accurate high-performance liquid chromatography-mass spectrometry (LC-MS) method was developed and validated for the quantification of WGA in rat plasma. Digoxin was used as internal standard (IS). Sample preparation was performed by liquid-liquid extraction using ethyl acetate-isopropanol (1:1, v/v). HPLC separation was carried out using a Venusil MP C18 column (150 mm × 4.6 mm, 5 μm). Isocratic elution was performed using methanol: water (70:30, v/v) as the mobile phase, at a flow rate of 0.8 mL/min. Analysis was performed in selected ion monitoring mode with a positive electrospray ionization interface. No endogenous interference was observed at the retention time of the analyte because of the high specificity of selected ion monitoring mode. The assay was validated to demonstrate the selectivity, linearity, recovery, accuracy, precision and stability. The lower limit of quantification (LLOQ) was 10.0 ng/mL. The developed and validated method has been successfully applied to the quantification and pharmacokinetic study of WGA in rats after oral administration of X. sorbifolia Bunge extract.