Analysis of Quinoa Saponin Extract and Blood Constituents Based on UPLC-Q-Exactive-MS/MS

The main chemical components of saponins extracted from quinoa and the components in the blood of rat after oral administration were analyzed and identified by ultra-performance liquid chromatography coupled with Q-Exactive mass spectrometry (UPLC-Q-Exactive-MS/MS). Hypersil Gold VANQUISH C₁₈ column (2.1 mm×100 mm, 1.8 μm) was used. The mobile phase was formic acid water-formic acid acetonitrile gradient elution, the column temperature was 30 ℃, the analysis time was 35 min, the flow rate was 0.3 mL·min⁻¹. Electrospray ion source (ESI), positive and negative ion sources and Full ms/dd-ms² mode were used for detection. The results showed that the recovery rate, matrix effect, precision and stability of the method met the requirements of biological samples. A total of 15 saponins were identified in the saponin extract of quinoa, which were divided into three oleanolic acid saponin types, five hederagenin saponin types, six phytolaccagenic acid saponin types and one serjanic acid saponin type according to the configuration of aglycones. Male Sprague Dawley (SD) rats were selected as the experimental object, after intragastric administration of quinoa saponin extract at 175.5 mg·kg⁻¹, at 0, 0.5, 1, 2 and 4 hours after administration, blood was taken from the orbit, the plasma of rats took buspirone hydrochloride as the internal standard, precipitated protein with methanol, centrifuged, filtered by microporous membrane, and then injected for analysis. The results showed that six prototype saponins and trace hydrolyzed hederagenin and serjanic acid glycosides were detected in the blood components of rat plasma. Through the analysis of the components of the extract and the components entering the blood, 15 saponins in quinoa saponins were identified and their cleavage laws were found, and the changes in the relative contents of the components into the blood of rat plasma were found. The chemical composition and metabolic characteristics of triterpenoid saponins in quinoa were preliminaries elucidated, which provided a theoretical basis for further research and application of quinoa.