Glycolipids from Polygala sibirica var. megalopha and their in vitro inhibitory activity on xanthine oxidase / 中草药

ABSTRACT

Objective: To investigate the glycolipids from Polygala sibirica var. megalopha and their structure-activity relationship of xanthine oxidase (XO) inhibitory activity. Methods: The 75% EtOH extract of P. sibirica var. megalopha was chromatographied with D101 macroporous resins column by water, 35% EtOH, 65% EtOH, and 95% EtOH, successively. Compared to other elution parts, the 65% EtOH elution part exhibited stronger XO inhibition. Further bioassay-guided separation led to the isolation of four known glycolipids, which demonstrated potent XO inhibition. Results: Four compounds were identified to be tenuifoliside A (1), 3,6'-disinapoyl sucrose (2), 3'-E-3,4,5-trimethoxycinnamoyl-6-benzoyl sucrose (3), and 3'-E-3,4,5-trimethoxycinnamoyl-4-benzoyl sucrose (4) through spectroscopic data analysis. All compounds were obtained from this plant for the first time. This enzyme inhibition was dose dependent and the IC50 values of compounds 1, 3, and 4 were 9.5, 10.2, and 7.7 μmol/L, respectively. Among them, compound 2 had significantly higher XO inhibitory activity than that of the control allopurinol (IC50=11.2 μmol/L). It was speculated that the styryl side chain linking with sugar base played an important role on the XO inhibitory activity. Conclusion: Glycolipides as a novel series of XO inhibitors, may be developed into a promising remedy for human gout.