MS/MS and UPLC-MS profiling of triterpenoid saponins from leaves and roots of four red beet (Beta vulgaris L.) cultivars

Abstract

Triterpene saponins from the leaves of red beet (Beta vulgaris L.) were qualitatively profiled using electrospray ionization tandem mass spectrometry (ESI-MS/MS). Results indicated that red beet leaves contain 11 saponins, including oleanolic acid aglycone and a varying number of sugars plus acetyl or methyl groups. We identified and studied two additional saponins other than the nine reported previously from red beets. Relative quantification was undertaken of saponins in leaves, compared to those in the roots of four cultivars (Egyptian, Forono, Red Sphere, and Round Dark Red). Saponins were quantitated using ultra-performance reverse-phase liquid chromatography (UPLC) coupled with ESI-MS/MS. Leaves of Egyptian and Round Dark Red contained higher total amount of saponins than the roots, whereas relatively higher levels of saponins were observed in roots in cultivars Red Sphere and Forono. The differential accumulation of specific triterpene saponins is indicative of spatially differentiated biosynthesis and/or biological function.