Metabolic regulatory effects of licorice: A bile acid metabonomic study by liquid chromatography coupled with tandem mass spectrometry

Licorice is one of the most popular herbal medicines worldwide, and is mainly used to moderate the characteristics of other herbs in Traditional Chinese Medicine. It is hypothesized that licorice exerts this role by regulating systemic metabolism. Bile acids play a critical role in lipid digestion and cholesterol metabolism, and are sensitive biomarkers for hepatic function. In this study, the regulatory effects of licorice on bile acid metabonome in rats were investigated using liquid chromatography coupled with tandem mass spectrometry. After oral administration of a clinical dosage of licorice water extract, the levels of 21 fully identified and 41 tentatively characterized bile acid analogs in rat plasma were determined by a fully validated method. Following partial least squares discriminant analysis, the results showed that licorice treatment led to dose-dependent up-regulation of free and glycine-conjugated bile acids excretion. Particularly, the plasma levels of cholic acid (1465.33 ± 915.93–7156.46 ± 3490.49 ng/mL, p = 0.0027) and β-muricholic acid (228.19 ± 163.95–1284.40 ± 775.62 ng/mL, p = 0.0045) increased significantly 48 h after administration. As licorice is widely used as a detoxifying drug, the regulation of plasma bile acids may be an important evidence to interpret its mechanism.

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► Metabolic regulatory effect of licorice was studied through bile acid metabonomics.
► Sixty-two bile acid analogs were determined by LC-SRM/MS and analyzed by PLS-DA.
► Licorice intake led to dose-dependent up-regulation of free and glycine-bile acids.
► The results could contribute to interpret the detoxification mechanism of licorice.