Quantitative analysis of phenolic metabolites from different parts of Angelica keiskei by HPLC-ESI MS/MS and their xanthine oxidase inhibition.

Angelica keiskei is used as popular functional food stuff. However, quantitative analysis of this plant's metabolites has not yet been disclosed. The principal phenolic compounds (1-16) within A. keiskei were isolated, enabling us to quantify the metabolites within different parts of the plant. The specific quantification of metabolites (1-16) was accomplished by multiple reaction monitoring (MRM) using a quadruple tandem mass spectrometer. The limit of detection and limit of quantitation were calculated as 0.4-44 μg/kg and 1.5-148 μg/kg, respectively. Abundance and composition of these metabolites varied significantly across different parts of plant. For example, the abundance of chalcones (12-16) decreased as follows: root bark (10.51 mg/g)>stems (8.52 mg/g)>leaves (2.63 mg/g)>root cores (1.44 mg/g). The chalcones were found to be responsible for the xanthine oxidase (XO) inhibition shown by this plant. The most potent inhibitor, xanthoangelol inhibited XO with an IC50 of 8.5 μM. Chalcones (12-16) exhibited mixed-type inhibition characteristics.