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

• Published in: Molecules (Basel, Switzerland) Vol. 23; no. 10; p. 2719
• Main Authors: Liu, Xiao-Xiao, Sun, Shi-Wei, Yuan, Wen-Jing, Gao, Hua, Si, Yue-Yue, Liu, Kun, Zhang, Shuang, Liu, Yang, Wang, Wei
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 22.10.2018; MDPI
• Subjects: Bioassays; Chromatography; Chromatography, High Pressure Liquid; Clover; Drug dosages; Enzyme Activation - drug effects; Enzyme Inhibitors - chemistry; Enzyme Inhibitors - isolation & purification; Enzyme Inhibitors - pharmacology; Flavonoids; Flavonoids - chemistry; Flavonoids - isolation & purification; Flavonoids - pharmacology; Gramineae; Gramineae species; High performance liquid chromatography; Hypoxanthine; Inhibitors; Intestine; Kinetics; Legumes; Liquid chromatography; Liver; Melilotus - chemistry; Melilotus albus; Melilotus albus Medic. ex Desr; Metabolism; Models, Molecular; Molecular Conformation; Pharmacy; Plant Extracts - chemistry; Plant Extracts - pharmacology; Protein Binding; Rheumatism; Solubility; Spectrum analysis; Straw; Structure-Activity Relationship; tricin; Uric acid; Wheat; Xanthine oxidase; Xanthine Oxidase - antagonists & inhibitors; China; Melilotus albus Medic. ex Desr; Gramineae species; tricin; xanthine oxidase
• ISSN: 1420-3049; 1420-3049
• DOI: 10.3390/molecules23102719

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 ( ) 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 IC value of 4.13 μM. Further inhibition kinetics data indicated it to be a mixed-type inhibitor and and 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.