Deep Eutectic Solvent Extraction Assisted Ligand Affinity Assay for α-Glucosidase Inhibitors Screening From the Plasma of Rats Administrated Pueraria lobata Extracts

In this work, for the first time, a deep eutectic solvent assisted ligand affinity assay was proposed. Several critical parameters affecting the analysis performance were investigated and the optimized DES extract conditions were as follows: the solution of tetrabutylammonium chloride–ethylene glycol (1:2) was prepared as an extract solution. A total of 1.4 mol/L sodium citrate (pH = 6.6) was used for phase separation, and the vortex extraction time was 5 min. Analytes could be enriched in the phase of deep eutectic solvent after phase separation. Then, they could be analyzed by α-glucosidase immobilized magnetic beads affinity assay directly. Results showed the proposed method could detect luteolin (a positive control) from plasma selectively. The LOD was 2 µg/mL. The intraday precision and the interday precision were 7.86% and 6.66%, respectively. By using the proposed method as a tool, plasma of the rats that administrated the extract of Pueraria lobata was analyzed. The bio-active flavonoids absorbed in the body such as puerarin, daidzin, daidzein, and a metabolite of puerarin (puerarin glucuronide) were found. The method has the benefits of a simplified analytic process, high resolution, and is a reliable method.