Rosmarinic acid attenuates hyperuricemia via restoring hyperuricemia-induced renal and intestinal dysfunctions

The increasing incidence rate of hyperuricemia (HUA), a common chronic metabolic disease, seriously threatens public health. Previous studies have shown that rosmarinic acid (RA) has a good effect in lowering uric acid (UA). However, the exact mechanism of RA in treating HUA is still not fully understood.

To validate the therapeutic effect of RA on HUA and its potential pharmacological mechanisms through a comprehensive analysis of the gut microbiome, metabolomics and molecular interaction techniques.

A rat model of HUA was replicated with 10 % fructose water. The therapeutic effect of RA on HUA rats for 28 consecutive days was assessed through histopathology and biochemical analyses. Additionally, 16S rDNA sequencing, metabolomics, molecular docking, molecular dynamics simulation (MDS), surface plasmon resonance (SPR) and microScale thermophoresis (MST) were used to investigate the mechanisms of RA for HUA treatment.

RA could significantly reduce uric acid (UA) levels, inhibit the activities of UA synthase xanthine oxidase (XOD) and adenosine deaminase (ADA), and improve the function of intestinal and renal tissues. Furthermore, RA altered the composition of the gut microbiota in rats by reducing the Firmicutes to Bacteroidota ratio and increasing the abundance of Bacteroides at the genus level. RA could influence the levels of XOD, ADA, and other plasma metabolites. Importantly, RA modulated ABCG2 expression in the intestine and kidney, as well as URAT1 expression in the kidney. MDS proved that RA bound tightly to these transporters, the SRP results indicated that the equilibrium dissociation constants of RA with GLUT9 is 6.20 μM, RA with URAT1 is 667 nM respectively, and the MST results indicated that the equilibrium dissociation constants of RA and ABCG2 is 264.6 nM.

RA can promote UA excretion by regulating the imbalance of gut microbiota and the expressions of URAT1, GLUT9 and ABCGT2 in HUA rats. This study, for the first time, combined gut microbiota, metabolomics and molecular interaction techniques to verify the intrinsic molecular mechanism of RA in the treatment of HUA, providing a basis for the development of UA-lowering drugs.