Optimizing conditions of polysaccharide extraction from Shiitake mushroom using response surface methodology and its regulating lipid metabolism

• Process conditions of SMP were optimized using the response surface method (RSM).
• Contour maps showed that all variables significantly affected the yield.
• The effect of SMP on oxidative damage in mice was done in vivo.
• The SMP decreases blood lipid level.
• SMP is useful for animal fed with HCD.

Process conditions (extraction time, extraction temperature, water/solid ratio and incubation time) of Shiitake mushroom polysaccharides (SMP) were optimized by conducting experiments at three different levels using the response surface method (RSM). A second-order polynomial response surface equation was developed indicating the effect of variables on polysaccharides yield. Contour maps generated using the response surface equation showed that all the experimental variables significantly affected the yield. The effect of SMP on oxidative damage in mice fed by high cholesterol diet (HCD) was done in vivo. Results showed that SMP can decreased serum total cholesterol (TC), triglyceride (TG), low density lipoprotein (LDL-c) levels, and increased high density lipoprotein (HDL-c) levels in HCD mice. Treatment with SMP reduced blood, liver lipid peroxidation level and increased antioxidant enzymes activities. Thus it can be concluded that SMP can improve lipid metabolism and decreased oxidative damage in HCD mice.