An UPLC - Q - Orbitrap method for pharmacokinetics and tissue distribution of four triterpenoids in rats after oral administration of Poria cocos ethanol extracts

Abstract

Poria cocos (Schw.) Wolf, is a fungus that is widely used as medicine and dietary supplement in China. But its action mechanism is still not very clear. In this paper, a rapid, specific and sensitive high performace liquid chromatography coupled with hybrid quadrupole - orbitrap mass sepctrometry (UPLC - Q - Orbitrap MS) method has been developed and validated to simultaneously determine of four triterpenoids including Dehydrotumulosic acid (DTA), Dehydropachymic acid (DPA), Pachymic acid (PA), Dehydrotrametenolic acid (DMA) from Poria cocos in rat plasma and tissues. The analyte was extracted from rat plasma and tissue homogenates by protein precipitation with acetonitrile using glibenclamide as the internal standard (IS). Chromatographic separation was carried out on ACQUITY UPLC BEH - C₁₈ column (2.1 mm × 50 mm, 1.7 μm) with a mobile phase composed of acetonitrile - water (containing 1.0 mmol/L ammonium acetate) using gradient elution at a flow rate of 0.2 mL/min. Electrospray ionization (ESI ^-) under negative ion mode was used, and its quantization was performed with multiple reaction monitoring (MRM) mode. The method was fully validated and successfully applied to pharmacokinetics and tissue distribution study in rats after oral administration of ethanol extracts of Poria cocos. Compared with that of plasma exporsure, triterpenoids could be detected in various tissues with a relatively high degree of tissue distribution. After oral administration, the concentration orders in seven different tissues were ranked as DTA > PA > DPA > DMA in intestine and stomach, wheras DTA > DMA > PA > DPA in heart, liver, spleen, lung and kidney tissues, which is speculated that DPA, PA may be converted into DMA in vivo. In conclusion, this results may provide a material basis for study of the pharmacological actions of triterpenoids in Poria cocos.

Keywords: Dehydropachymic acid; Dehydrotrametenolic acid; Dehydrotumulosic acid; Pachymic acid; Pharmacokinetics and tissue distribution; Poria cocos; UPLC - Q - Orbitrap MS.