Metabolism of secondary metabolites isolated from Tartary buckwheat and its extract

The metabolism of Tartary buckwheat was investigated using a strategy from single bioactive compounds to complex Tartary buckwheat extract. Firstly, the metabolites of different structural compounds were investigated by an in situ liver-intestinal perfusion model and the metabolic pathways were proposed. Furthermore, Tartary buckwheat extract in rats was elucidated on the basis of the metabolism information of single compounds. High-performance liquid chromatography coupled with high resolution mass and multiple-stage mass spectrometry (HPLC-HRMS/MSn) was performed to characterise and identify 19 metabolites in perfusate and intestinal content after administration of single compounds to an in situ liver/intestinal perfusion model and 16 metabolites and 6 components in rat faeces, urine, bile, and plasma after oral administration of Tartary buckwheat to rats. Five new metabolites were identified as the glucuronidation and sulfation products of N-trans-feruloyltyramine and the methylation product of quercetin-3-0-[beta-D-xyloxyl-(1 -> 2)-alpha-iota-rhamnoside]. The metabolic pathways of phenylpropanoid glycosides and N-trans-feruloyltyramine were proposed for the first time. (C) 2014 Elsevier Ltd. All rights reserved.