Deep Eutectic Solvent: Improve the Constituents in <i>Plantago asiatica</i> L. ( <i>PAL</i> ) Extract Oral Absorption in Rats

Plantago asiatica L. (PAL) is a prevalent perennial herb utilized for both culinary and medicinal purposes. This article examines the impact of deep eutectic solvent (DES, composed of choline chloride and lactic acid) on the pharmacokinetics of chemical constituents in PAL extract. An ultra-high performance liquid chromatography coupled with triple quadrupole mass spectrometry (UHPLC-MS/MS) method, characterized by high sensitivity and specificity, was developed and validated for the simultaneous quantification of luteolin, oleanolic acid, ursolic acid, verbascoside, apigenin, aucubin, and plantamajoside in rat plasma following oral administration of PAL extract. The chromatographic separation employed an XBridge BEH C18 column, utilizing a mobile phase system composed of a 0.1% (v/v) formic acid aqueous solution and methanol with gradient elution. The devised approach was effectively used in the pharmacokinetic investigation of these seven analytes from PAL extract in rats. The pharmacokinetic characteristics, including C_max, AUC_(0- _t ₎, and AUC_(0-∞), of PAL extract dissolved in 15% DES (v/v) via oral administration were superior to those dissolved in water. The findings indicated that DES may enhance the absorption of constituents in PAL extract, extend the duration and concentration of chemical components in vivo, and possibly improve the therapeutic efficacy.