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Flavonoid analysis of buckwheat sprouts.

Food chemistry (2014-10-13)
Tae-Gyu Nam, Sun Mi Lee, Ji-Hae Park, Dae-Ok Kim, Nam-in Baek, Seok Hyun Eom
ABSTRACT

It is known that common buckwheat sprouts contain several flavonoids, including orientin, isoorientin, vitexin, isovitexin, rutin, and quercetrin, whereas tartary buckwheat sprouts contain only rutin. In this study, we evaluated flavonoids present in buckwheat sprouts and identified a previously unreported flavonoid. Simultaneous detection by HPLC was used to separate rutin and a compound that was not separated in previous studies. We used a novel HPLC elution gradient method to successfully separate rutin and the previously unidentified compound, for which we performed structural analysis. The identification of six flavonoids by HPLC was confirmed using HPLC-ESI-MS/MS analysis. The newly identified compound, [M+H](+) =611.17, was identified by NMR as the rutin epimer quercetin-3-O-robinobioside. Unlike common buckwheat sprout, tartary buckwheat sprout contained rutin as a main flavonoid, whereas other flavonoids appeared only in trace amounts or were not detected. Quercetin-3-O-robinobioside was not detected in tartary buckwheat sprout.

MATERIALS
Product Number
Brand
Product Description

Supelco
Vitexin, analytical standard
Sigma-Aldrich
Isovitexin, ≥98.0% (HPLC)
Isovitexin, primary reference standard
Vitexin, primary reference standard
Isoorientin, primary reference standard
Sigma-Aldrich
Isoorientin, ≥98% (HPLC)