Objective The purpose of this study is to optimize the extraction process of intracellular polysaccharides from liquid fermented P. eryngii var. ferulae mycelium by response surface analysis and explore the effects of polysaccharides on the proliferation and antioxidant effects of WRL68 cells.

Methods Taking the P.eryngii var. ferulae strain as the research object, a single-factor experiment combined with response surface methodology was used to optimize the extraction process of intracellular polysaccharides from P.eryngii var.ferulae. The solid-liquid ratio, temperature, ultrasonic time, extraction time and extraction times were selected for single factor experiments, and the intracellular polysaccharide extraction process of P. eryngii var. ferulae was optimized by the response surface method. Meanwhile, tetrazolium salt method was used to analyze its protective effect on WRL68 cell injury.

Results Single factor and response surface optimization experiments were carried out on the mycelial polysaccharides of P. eryngii var. ferulae to optimize the polysaccharide extraction process. After optimization, the extraction process of P. eryngii var. ferulae mycelium polysaccharide was 40:1 mL/g liquid ratio, the extraction temperature was 68 ℃, the ultrasonic time was 38 min, the extraction time was 2 h, the extraction was repeated 4 times. Finally, the yield of polysaccharides under optimized process conditions was 30.8%, which was 150.2% higher compared to that before the optimization. At the same time, the scavenging ability of polysaccharides to DPPH, ·OH^- and ·O₂^- free radicals was measured, and the results showed that P. eryngii var. ferulae polysaccharides had good antioxidant activity in vitro. In addition, 600 μg/mL concentration of P. eryngii var. ferulae polysaccharides significantly promoted the proliferation of WRL68 cells with a cell survival rate reaching 147.528% and had a significant protective effect on hepatocyte oxidative damage caused by H₂O₂.

Conclusion The optimized extraction process can significantly improve the extraction rate of mycelial polysaccharides from P. eryngii var. ferulae and the polysaccharides have a significant protective effect on oxidative stress damage in hepatocytes. This study could provide extraction process parameters for the development and utilization of P. eryngii var. ferulae polysaccharides by liquid deep fermentation and offer experimental reference for the development of hepatoprotective drugs of P. eryngii var. ferulae polysaccharides.