Study On The Fermentation Process Optimization And Anti-diabetic Effects Of Polysaccharide From Inonotus Obliquus

Inonotus obliquus is worldwild traditional medicinal fungi, with high medical value, polysaccharides-enriching Inonotus obliquus extract is commonly used to the prevention and treatment of a variety of diseases, such as antidiabetic, anticancer, anti-oxidation. Present study aims to optimize the culture and polysaccharide extraction conditions of Inonotus obliquus. In vivo, streptozocin(STZ) was used to establish the type 1 diabetic mouse model, and the anti-diabetic effects of polysaccharide from Inonotus obliquus were investigated.The chemometrics methods were applied to optimize the fermentation medium of Inonotus obliquus. The optimum fermentation medium consisted of: glucose 26.24 g/L, yeast extract 20 g/L, KH2PO4 0.22 g/L,MgSO4·7H2O 0.24 g/L,ZnCl2 0.011 g/L,VB1 0.1 g/L. The average polysaccharide content of three validation experiments was 13.11%.The study was performed to optimize the polysaccharides water-assisted extraction conditions from the mycelium of Inonotus obliquus by response surface methodology. The effects of various experimental parameters in extraction step including extraction time, extraction temperature, liquid-solid ratio were studied using the method of single factor test design. On the results of single factor test design, a 15-run Box-Behnken design was performed to optimize the extraction conditions of the polysaccharides. The experimental results of Box-Behnken design were analyzed by response surface methodology。The optimum conditions for polysaccharides extraction obtained by the response surface methodology were extraction time 4.25 h,extraction temperature 66.5℃ and liquid-solid ratio 34.41 mL·g-1.The extraction ratio odtained by the regression analysis was 10.99 %.The type 1 diabete mice induced by STZ were used to study the effect of polysaccharide fraction on diabetic. Polysaccharide from Inonotus obliquus could effectively recover the levels of weight, blood glucose of diabete mice and enhance the contents of insulin, pyruvate kinase. They could also effectively increase the level of hepatic glycogen, muscle glycogen, superoxide dismutase, glutathione peroxidase, catalase and decrease the malondialdehyde accumulation. The mechanism by which polysaccharide provides prevention of diabetic may be attributable to inhibition of catabolism of glucose and enhancing of anti-oxidant. Polysaccharide are able to down-regulate the release of interleukin-2, Nuclear factor-kappa B, and up-regulate interleukin-2 receptor, thus inhibiting the inflammatory reaction. The effect of the polysaccharide high dose group was most obvious, and the results were most close to Metformin Hydrochloride positive control group. The results indicated that polysaccharide fraction from Inonotus obliquus can effectively alleviate STZ induced hyperglycemia, immune inflammation and reduce the oxidative damage of diabete mice.