Determination and pharmacokinetic study of two triterpenoid saponins in rat plasma after oral administration of the extract of Aralia elata leaves by UHPLC-ESI-MS/MS.

Aralia elata (Miq.) Seems (A. elata) grow in Northeast China and the total saponins of A. elata is used to auxiliary treatment for the acute hepatitis, chronic hepatitis and the transaminase on the high side. Aralia-saponinV and Aralia-saponinVI are the major bioactive saponins in A. elata leaves. A selective and sensitive UHPLC-MS/MS method was developed and validated for the determination and pharmacokinetic study of Aralia-saponinV and Aralia-saponinVI indwelling the extract in rat plasma in this article. The sample pretreatment involved a one-step extraction of 0.2mL plasma with methanol. Shengmaxinside C was used as internal standard (I.S.). The separation was carried out on an Agilent SB-C18 column (1.8μm, 50mm×2.1mm) at 30°C with a mobile phase of acetonitrile-5mM ammonium acetate (90:10, v/v) at a flow rate of 0.2mL/min. The detection was performed on a triple quadrupole tandem mass spectrometer by multiple reaction monitoring (MRM) mode via electrospray ionization (ESI) source operating in the negative ionization mode. The optimized mass transition ion-pairs (m/z) monitored for Aralia-saponinV, Aralia-saponinVI and I.S. were 1103.2/941.2, 1119.2/957.0 and 707.0/647.1, respectively. The current UHPLC-MS/MS assay method was validated for linearity, intra-day and inter-day precisions, accuracy, extraction recovery and stability, and it was suitable for the pharmacokinetic studies of the two saponins after oral administration of extract of A. elata leaves. The lower limits of quantification were 5.70ng/mL for Aralia-saponinV and 6.15ng/mL for Aralia-saponinVI. Intra-day and inter-day precisions were less than 7.4% and the accuracy range was from 1.19% to 8.60%. The mean extraction recoveries of analytes and I.S. from rat plasma were all more than 89.5%. This paper described a simple, sensitive and validated UHPLC-MS/MS method for simultaneous determination of Aralia-saponinV and Aralia-saponinVI in rat plasma after oral administration of the extract of A. elata leaves, and investigated on their pharmacokinetic studies as well.