Determination of polyphenolic compounds in lucerne by supercritical fluid extraction coupled with ultra‑performance liquid chromatography‑tandem mass spectrometry

Abstract

Abstract A method was developed to determine 23 biologically active compounds, including 13 flavonoids and 10 phenolic acids, in various morphological parts (flowers, leaves, stems, seeds, and roots I and III cut) of the lucerne plant using a simple, fast high performance liquid chromatography with tandem mass spectrometry detection. The separation was achieved using a pentafluorophenyl stationary phase and a gradient elution with 0.1% formic acid in water and acetonitrile. The calibration curves exhibited good linearity (r2 value from 1.0 to 0.9925). The limit of detection (LOD) and limit of quantification (LOQ) for 23 compounds range from 0.01-50 ng/mL and 0.033-165 ng/mL, respectively. The main flavonoids found in the extracts were apigenin (765.96 ± 29.08 µg/g), luteolin (545.21 ± 14.64 µg/g), quercetin (169.90 ± 16.69 µg/g), and esculetin (130.99 ± 6.72 µg/g). Salicylic acid (2960.89 ± 11.00 µg/g) and 4-hydroxybenzoic acid (1561.42 ± 38.62 µg/g) were the most abundant in the analyzed extracts. The roots of the third cut and the stems were found to be the richest in polyphenolic compounds. These findings suggest that different morphological parts of lucerne could be used as food additives or supplement components due to their nutritional properties.