Classification of structural characteristics facilitate identifying steroidal saponins in Alliums using ultra-high performance liquid chromatography high-resolution mass spectrometry

Abstract A strategy was developed for the identification of saponins in Alliums using ultra-high performance liquid chromatography high-resolution accurate-mass/multi-stage mass spectrometry (UHPLC-HRAM/MSn). The identification process was facilitated by a systematic classification of 152 previously reported sapogenins (saponin aglycones) in Allium based on their structural characteristics. The approach was successfully applied to putatively identify a total of 108 steroidal saponins in scallions, giant green onions, petite sweet Vidalia onions, and leeks using HRAM mass values and diagnostic fragmentation ions rapidly. Seventeen of the saponins are reported in genus Allium for the first time.