Metabolic studies of four soy isoflavones in rats by HPLC–HR-MS

Abstract

In this paper, the metabolites of four soy isoflavones, daidzein, daidzin, genistein, and genistin, on perfused rat intestine–liver model were investigated by high-performance liquid chromatography coupled with high-resolution mass spectrometer/tandem mass spectrometer. Totally 16 metabolites were detected and identified based on accurate mass, fragmentation patterns, and multiple-stage mass data (MSⁿ). The metabolic site of dadzein-7-methyl ether (D-7-M) was further confirmed by nuclear magnetic resonance. Methylation, glucuronide conjugation, and sulfate conjugation were the primary metabolic processes. Among them, six metabolites, daidzin-4′,7-diglucoside, genistein-4′-glucoside, D-7-M, dadzein-4′,7-dimethyl ether, genistein-4′-methyl ether, and genistein-7-methyl ether were detected in rats for the first time and not reported in humans. The metabolic pathways of daidzein, daidzin genistein, and genistin in rats were postulated. The biological effects of these metabolites are worthy of further investigation.

Keywords::

• soy isoflavones
• metabolites
• HPLC–HR-MS/MSⁿ

Acknowledgments

This work was financially supported by the Ministry of Science and Technology of China (grant number 2012ZX09301002-001) and the Fundamental Research Funds for the Central Universities from the Institute of Materia Medica (grant number 2012RC01), Chinese Academy of Medical Sciences & Peking Union Medical College.

Notes

^1. These authors contributed equally to this work.