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Profiling isoflavonoids found in legume root extracts using capillary electrophoresis
Author(s) -
Baggett Brandi R.,
Cooper John D.,
Hogan Eric T.,
Carper Jason,
Paiva Nancy L.,
Smith Joel T.
Publication year - 2002
Publication title -
electrophoresis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.666
H-Index - 158
eISSN - 1522-2683
pISSN - 0173-0835
DOI - 10.1002/1522-2683(200206)23:11<1642::aid-elps1642>3.0.co;2-y
Subject(s) - isoflavonoid , capillary electrophoresis , formononetin , micellar electrokinetic chromatography , chemistry , chromatography , high performance liquid chromatography , legume , medicago truncatula , medicago sativa , kaempferol , daidzein , flavonoid , biochemistry , botany , biology , genistein , genetics , symbiosis , bacteria , antioxidant , endocrinology
Legumes such as alfalfa ( Medicago sativa L.), barrel medic ( Medicago truncatula ), white sweet clover ( Melilotus alba ) and fenugreek ( Trigonella graecum ), normally accumulate (–)‐medicarpin and its malonated glucose conjugate as natural inhibitors of fungal pathogens. These plants also accumulate the biosynthetic precursor formononetin as well as the malonated glycoside. We were interested in developing a robust high‐throughput method to quantitate the levels of these two isoflavonoids, both free and conjugated, in legume root extracts, for use in screening for mutant plants accumulating altered levels of these compounds. Capillary electrophoresis was examined as an alternative to current high‐performance liquid chromatography (HPLC) methods to generate isoflavonoid profiles. The developed assay used micellar electrokinetic capillary chromatography (MEKC) to provide the required selectivity in complex root extracts. The addition of 1,2‐hexanediol to the sodium dodecyl sulfate (SDS) electrolyte provided improved resolution of adjacent isoflavonoids. We examined the role of several factors including sample preparation, buffer composition, buffer pH, and organic component in the injected sample. The use of capillaries with longer path lengths were also examined to increase sensitivity. A comparison of results obtained using MEKC and HPLC showed good correlation in the relative amounts of the isoflavonoids studied.