Determination of isoflavone glucoside malonates in Trifolium pratense L. (red clover) extracts: quantification and stability studies.
Isoflavones, their glucosides and their glucoside malonates were determined in red clover leaf extracts using reversed-phase LC coupled to atmospheric pressure chemical ionisation mass spectrometry (APCI-MS), UV and fluorescence detectors and the stability of the malonates was investigated. Extracts can be stored at least 1-2 weeks at -20 degrees C without loss of malonates. In LC-separated fractions the malonates are most stable when stored at low temperature after evaporation to dryness. The concentrations of eight major isoflavones ranged from 0.04 to 5 mg/g leaves.
De Rijke
E
E
Department of Analytical Chemistry and Applied Spectroscopy, Free University, Amsterdam, The Netherlands.
Zafra-Gómez
A
A
Ariese
F
F
Brinkman
U A
UA
Gooije
C
C
D001274:Atmospheric Pressure; D005960:Glucosides / Q000032:analysis*; D007529:Isoflavones / Q000032:analysis*; D008314:Malonates / Q000032:analysis*; D013050:Spectrometry, Fluorescence; D013056:Spectrophotometry, Ultraviolet; D029921:Trifolium / Q000737:chemistry*
D005960:Glucosides; D007529:Isoflavones; D008314:Malonates