Study on the correlation between constituents detected in serum from Rhizoma Smilacis Glabrae and the reduction of uric acid levels in hyperuricemia

Abstract

Ethnopharmacological relevance: Rhizoma Smilacis Glabrae (RSG) has been used in the clinical treatment of gout and hyperuricemia in China for thousands of years. Modern pharmacological studies have shown that RSG exhibits hypouricemic effects because of its significant inhibitory effect on the activity of xanthine oxidase.

Materials and methods: The Rhizoma Smilacis Glabrae extract (RSGE) at 1 mL/100g oral administration was demonstrated to possess in vivo potent hypouricemic effects in hyperuricemic rats pretreated with oxonic acid potassium salt (200 mg/kg, 2 mL/kg). UPLC-MS was used to identify the constituents absorbed in the serum. In addition, a bivariate correlation analysis between the changes in the relative contents of the constituents from RSGE detected by HPLC and the serum uric acid levels in hyperuricemic rats at different points in time was used to calculate their correlation coefficients.

Results: A total of 14 constituents were observed in the RSGE-treated rat serum, and 11 of these were inferred. An RSGE constituent was considered correlated with the hypouricemic effects if its correlation coefficient was above 0.5. The results suggested that only seven of the constituents absorbed in the serum of the hyperuricemic rats were correlated with hypouricemic effects, namely, palmitic acid, 3'-O-methyltaxifolin glucuronide, 3'-O-methyiastilbin glucuronide, astilbin glucuronide, 5-O-caffeoylshikimic acid glucuronide, resveratrol glucuronide, and dihydrokaempferol.

Conclusion: These findings provide potent evidence for the study on RSG as a pharmacodynamic material basis and for developing RSG as a safe and promising natural drug to prevent hyperuricemia and gout instead of allopurinol.

Keywords: Bivariate correlation analysis; HPLC; Metabolites; Rhizoma Smilacis Glabrae; UPLC–MS.