Response Surface Optimization of the Alkaline ExtractionProcess of Ganoderma lucidum Polysaccharides and PreliminaryStudy on Their Immunological Activity

Objective: To investigate and optimize the alkaline extraction process of Ganoderma lucidum polysaccharides, and to preliminarily explore their immunological activity.Methods: Ganoderma lucidum was used as the raw material for the extraction of polysaccharides.A single-factor experiment was conducted to examine the effects of NaOH concentration, temperature, and extraction time on the total sugar content of the polysaccharides.Based on these results, response surface methodology was applied to optimize the extraction process.The total polysaccharide content, uronic acid content, monosaccharide composition, molecular weight, and cell viability were measured.Results: The optimal extraction conditions were found to be a temperature of 93 C, NaOH concentration of 0.40 mol/L, and extraction time of 172 min, yielding a total polysaccharide content of 47.66%.The monosaccharide composition of the extracted polysaccharides included mannose, glucuronic acid, glucose, galactose, arabinose, and fucose.Molecular weight analysis revealed two average molecular weights, 3.15 10 4 Da and 1.014 10 4 Da, indicating the polysaccharides were relatively small.Infrared spectroscopy showed the presence of -type glycosidic linkages in the polysaccharides.In the cell viability assay, GLCP-1 enhanced the viability of RAW264.7 cells and significantly inhibited the viability of HepG2 cells.However, the specific regulatory mechanism remains unclear.Conclusion: The study successfully optimized the alkaline extraction of Ganoderma lucidum polysaccharides and demonstrated their potential immunological activity, providing a foundation for the future exploration of their bioactivity and industrial production.