Isolation of Tricin as a Xanthine Oxidase Inhibitor from Sweet White Clover (Melilotus albus) and Its Distribution in Selected Gramineae Species

作者：Xiao-Xiao Liu, Shiwei Sun, Wenjing Yuan, Hua Gao, Yueyue Si, Kun Liu, Shuang Zhang, Yang Liu, Wei Wang · 发表于：Molecules · 年份：2018 · DOI：10.3390/molecules23102719 · 被引用次数：16 · 研究领域：Gout, Hyperuricemia, Uric Acid、Plant pathogens and resistance mechanisms、Porphyrin Metabolism and Disorders

Xanthine oxidase, an enzyme present in significant levels in the intestine and liver, metabolizes hypoxanthine to xanthine and xanthine to uric acid in the purine catabolic pathway. An inhibitory compound acting against xanthine oxidase was isolated from sweet white clover (Melilotus albus) by bioassay and high-performance liquid chromatography guided separation. It was identified as tricin by spectroscopic analysis. Tricin possessed a potent xanthine oxidase inhibitory activity with an IC50 value of 4.13 μM. Further inhibition kinetics data indicated it to be a mixed-type inhibitor and Ki and KI values were determined to be 0.47 μM and 4.41 μM. To find a rich source of tricin, the distribution of tricin in seven different tissues from four Gramineae species was investigated by high-performance liquid chromatography analysis. The highest amount (1925.05 mg/kg dry materials) was found in the straw of wheat, which is considered as a potentially valuable source of natural tricin.