Classification of structural characteristics facilitate identifying steroidal saponins inAlliums using ultra-high performance liquid chromatography high-resolution massspectrometry

Authors: Geng, Ping; Chen, Pei; LIN, LONG-ZE - Retired Non ARS Employee; Sun, Jianghao; HARRINGTON, PETER - Ohio University; Harnly, James - Jim

Submitted to: Journal of Food Composition and Analysis
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/6/2021
Publication Date: 5/25/2021
Citation: Geng, P., Chen, P., Lin, L., Sun, J., Harrington, P., Harnly, J.M. 2021. Classifi cation of structural characteristics facilitate identifying steroidal saponins inAlliums using ultra-high performance liquid chromatography high-resolution massspectrometry . Journal of Food Composition and Analysis. 102:103994. https://doi.org/10.1016/j.jfca.2021.103994.
DOI: https://doi.org/10.1016/j.jfca.2021.103994

Interpretive Summary: Saponins are ubiquitous in plants and have a diverse range of attributes including sweetness and bitterness, serve as emulsifiers, and have pharmacological, hemolytic, antimicrobial, and insecticidal properties. Saponins are readily soluble in water and, at sufficiently high concentrations, are toxic to fish, insects, and even mammals. They are generally considered to be environmentally sensitive compounds used for plant defense against microbes and fungi. Saponins are used in a wide of beverage, confectionery, cosmetic and pharmaceutical products, primarily as emulsifying agents. Saponins extracted from the soapbark tree (Quillaja) have been used as biological reagents. Structurally, saponins are generally classified as either a triterpene or a steroidal sapogenin glycoside. Chemical studies of saponins in over 40 Allium plants have reported more than 300 steroidal saponins. A structure classification guided analytical method was developed and identified putatively142 saponins from Alliums vegatables (leeks, scallions and onions) in this study.

Technical Abstract: A strategy was developed for 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 sapogenin (saponin aglycones) in Allium based on their structure characteristics. The approach has been successfully applied to putatively identify a total of 142 steroidal saponins in scallions, giant green onions, petite sweet Vidalia onions, and leeks using HRAM mass values and diagnostic fragmentation ions, and 36 of them were reported for the first time.