Gluconic Acid-Induced Solubilization and Anticolitis Action of Alkali-Soluble Poria cocos Polysaccharide Derivatives

Abstract

For the first time, the alkali-soluble polysaccharides from Poria cocos (APCP) have been degraded using food-derived gluconic acid, and the effect depends on its concentration (≥4 mmol/mL) and specific molecular structure, rather than the acidity of the solution. Based on the differences in solubility, two components were obtained: supernatant polysaccharides from gluconic acid hydrolysis of APCP (s-GA-PCP, 61.5%) and precipitate polysaccharides from gluconic acid hydrolysis of APCP (p-GA-PCP, 38.5%). In a DSS-induced chronic colitis mouse model, both alleviated symptoms (weight/colon length recovery), restored the intestinal barrier (upregulated ZO-1/Occludin), and reduced serum TNF-α. p-GA-PCP showed better effects, while the MIX group (1:1 mixture) did not show improved efficacy compared with the p-GA-PCP alone group. Both regulated gut microbiota (enriched Lactobacillus and Bifidobacterium; reduced Bacteroidota and Verrucomicrobiota) and altered metabolic profiles. p-GA-PCP specifically enriched maslinic acid, isocitric acid, and oxoglutaric acid. Correlation analysis and in vitro experiments suggest Bifidobacterium metabolizes p-GA-PCP to produce these beneficial metabolites, exerting anti-inflammatory effects.