Structural Characterization of Corn Silk and Pueraria lobata Polysaccharides and Hypolipidemic Activity and Intestinal Microbiota Modulation in Obese Mice

This study characterized the structural properties of corn silk polysaccharides (CSP) and Pueraria lobata Ohwi polysaccharides (PLP), evaluating their lipid-lowering efficacy and modulatory effects on the gut microbiota in obese mice. Structural elucidation included monosaccharide composition, molecular weight distribution, spectroscopic analysis (UV and FT-IR), and surface micromorphology. Diet-induced obesity was established in mice via a high-fat diet (HFD). General physiological indices, liver pathological sections, lipid-metabolism indices, 16S rRNA gut microbiota, and short-chain fatty acids were determined and analyzed. The subjects were subsequently treated with CSP, PLP, and a CSP-PLP complex. Compositional analysis revealed that CSP was a 10.257 kDa heteropolysaccharide comprising mannose, rhamnose, glucuronic acid, glucose, xylose, galactose, and arabinose. Morphological evaluation via SEM showed that CSP exhibitd a characteristic rough surface and an amorphous, sheet-like ultrastructure. The monosaccharide composition of Pueraria lobata polysaccharide (PLP) consisted of mannose, rhamnose, galacturonic acid, galactose, xylose, arabinose and fucose. It had a relative molecular weight of 20.62 kDa and was a polysaccharide with a smooth-surfaced, massive structure. Administration of the CSP-PLP complex effectively attenuated weight gain in obese mice. Compared to the HFD-fed model group, the CSP-PLP complex significantly suppressed (P<0.05) hepatic lipid accumulation, epididymal fat mass, and serum levels of TC, TG, LDL-C, and MDA. Conversely, HDL-C concentrations and CAT enzymatic activity were markedly elevated (P<0.05), suggesting improved lipid profiles and antioxidant capacity. Concurrently, the CSP-PP complex modulated gut microbiota homeostasis, as evidenced by significant shifts in α- and β-diversity. Specifically, treatment promoted the relative abundance of beneficial taxa, including Dubosiella, Muribaculum, and Akkermansia. These microbial alterations were accompanied by a significant increase (P<0.05) in fecal short-chain fatty acids (SCFAs), particularly butyric and isovaleric acids. The synergistic administration of corn silk and Pueraria polysaccharides effectively mitigates obesity in mice, a process mediated by the modulation of systemic metabolism, gut microbiota architecture, and short-chain fatty acid (SCFA) profiles. These findings elucidate a novel therapeutic strategy for obesity management and provide a theoretical foundation for the development of polysaccharide-based functional foods.