Structure characteristics of a polysaccharide fraction from Brassica rapa L. and its protective effect on hyperuricemia.

Brassica rapa L., a medicinal and edible plant commonly used by the Uyghur population in Xinjiang, China, is rich in bioactive polysaccharides. In this study, a novel polysaccharide fraction, BRPA-1, with a weight-average molecular weight of 57.56 kDa was extracted and purified from B. rapa L. roots. Methylation and NMR analyses suggested that BRPA-1 was a branched glucan-rich polysaccharide fraction. The anti-hyperuricemic effects of BRPA-1 were evaluated in a hyperuricemic mouse model. BRPA-1 significantly reduced serum uric acid, suppressed xanthine oxidase and adenosine deaminase activities, and alleviated renal oxidative stress and inflammation. BRPA-1 treatment was also accompanied by changes in gut microbiota composition, increased cecal short-chain fatty acid levels, and enrichment of beneficial genera such as Lactobacillus and Blautia. These microbial and metabolic changes were associated with its hypouricemic and renoprotective effects. These findings suggest that BRPA-1 may be a promising functional dietary ingredient for managing hyperuricemia, with gut microbiota- and short-chain fatty acid-related changes possibly contributing to its beneficial effects.