Polysaccharide from Ganoderma lucidum-fermented wheat pericarp: Purification, structural features, and lipid-lowering...

This study purified and characterized a polysaccharide derived from wheat pericarp via solid-state fermentation (SSF) with Ganoderma lucidum, and evaluated its lipid-lowering effects using an oleic acid (OA)-induced HepG2 cell model. After 6 days of SSF followed by incubation, soluble pentosan content reached 3.73 g/100 g - a 2.3-fold increase over untreated pericarp. A purified polysaccharide fraction designated FPP-1-a was obtained, with a molecular weight of 8.577 kDa. Monosaccharide analysis revealed that FPP-1-a consisted of fucose, arabinose, galactose, glucose, xylose, and mannose in a molar ratio of 1.54: 27.05: 19.40: 8.91: 30.35: 12.74. Structural analysis suggests that the backbone of FPP-1-a may consist of t-β-D-Xylp-(1→4)-β-D-Xylp-(1 → 4)-β-D-Xylp-(1 → 4)-β-D-Xylp-(1 → , with the C-2 positions of 1,2,3,4-β-D-Xylp substituted by t-α-L-Araf, and the C-3 positions substituted by either →1)-β-D-Xylp-(4 → or →1)-α-L-Araf-(3 → 1)-β-D-Xylp-(4 → 1)-β-D-Galp-(6→. In OA-induced HepG2 cells, FPP-1-a (100 μg/mL) significantly reduced triglyceride (TG), total cholesterol (TC), and low-density lipoprotein (LDL) levels by 52.61 %, 57.45 %, and 40.08 %, respectively, while increasing high-density lipoprotein (HDL) by 49.61 %. In addition, FPP-1-a alleviated oxidative stress and inflammation. Mechanistically, it activated the AMPK pathway, suppressing lipogenic genes while upregulating lipolytic genes. These results demonstrate FPP-1-a has potential in treatment of obesity and related metabolic disorders, while highlighting the value-added utilization of wheat processing by-products.