Metabolic profiling of saponins in Medicago sativa and Medicago truncatula using HPLC coupled to an electrospray ion-trap mass spectrometer.
Triterpene saponins isolated from Medicago sativa (alfalfa) and Medicago truncatula roots were separated, profiled and identified using an optimized, reversed-phase HPLC with on-line photodiode array detection and electrospray ionization mass spectrometry method (HPLC/PDA/ESI/MS). ESI source polarity and solvent conditions were compared. The effects of these parameters on mass spectral attributes were determined. Ion structures were confirmed using tandem mass spectrometry (MS/MS). Fifteen saponins were identified in alfalfa (cultivars Apollo, Radius, and Kleszczewska) based upon negative-ion HPLC/PDA/ESI/MS, HPLC/PDA/ESI/MS/MS and literature data. In addition, the identification of two new malonated saponins in alfalfa are proposed. Negative-ion HPLC/PDA/ESI/MS and HPLC/PDA/ESI/MS/MS spectra were utilized along with HPLC retention times to profile and identify 27 saponins in M. truncatula (cultivar Jemalong, A17). M. truncatula yielded a much more complex mixture of saponins than observed for alfalfa. The authors are not aware of any previous reports identifying saponin glycosides in M. truncatula.
Huhman
David V
DV
Plant Biology Division, The Samuel Roberts Noble Foundation, 2510 Sam Noble Parkway, Ardmore, OK 73401, USA.
Sumner
Lloyd W
LW
D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D029902:Medicago / Q000737:chemistry*; D012503:Saponins / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*
D012503:Saponins