桦褐孔菌子实体多糖的提取及体外降血糖活性

通过响应面设计得到桦褐孔菌子实体Inonotus obliquus多糖的优化提取条件,利用酶和细胞体外实验,探究桦褐孔菌子实体多糖的降血糖活性,确定活性多糖组分,并初步分析其降糖机理及单糖组成。优化条件下多糖得率为(2.79±0.03)%。粗多糖经乙醇分级沉淀分别获得IOP30、IOP60、IOP80组分。其中IOP30显示出最强的α-葡萄糖苷酶抑制活性（IC₅₀=38.20μg/mL）,且在酶动力学上属于非竞争性抑制。HepG2细胞经0.01、0.10、1.00mg/mL的IOP30处理,葡萄糖消耗与对照组相比差异极其显著（P<0.01）;同时添加10^-7mmol/L的胰岛素和0.10、1.00mg/mL的IOP30后葡萄糖消耗增加更显著（P<0.01）。IOP30主要由鼠李糖（7.93%）、阿拉伯糖（3.12%）、木糖（11.15%）、甘露糖（19.08%）、葡萄糖（39.17%）和半乳糖（19.15%）等单糖组成。桦褐孔菌子实体IOP30多糖组分具有显著的降血糖活性,其降糖可通过抑制α-葡萄糖苷酶活性减少餐后血糖的形成,促进细胞周围组织对葡萄糖的代谢,加强肝细胞对胰岛素的敏感性。

Molecular screening of medicinal fungus Inonotus obliquus and anti-breast cancer activity of its submerged fermentation broth

The extraction conditions of polysaccharides from Inonotus obliquus(IO)fruiting body were optimized by response surface methodology(RSM).The hypoglycemic activities of the IO polysaccharides were evaluated and bioactive polysaccharide fraction(BPF)was confirmed through enzyme and cell modes in vitro.The hypoglycemic mechanism and monosaccharide composition of BPF were preliminarily analyzed.The yield of polysaccharides was(2.79±0.03)%under the optimal conditions.Fractions of IOP30,IOP60 and IOP80 were obtained from crude polysaccharide extracts by differential alcohol precipitation.Among them,IOP30 showed the strongestα-glucosidase inhibitory activity(IC50=38.20μg/mL)and acted as a noncompetitive inhibitor in enzyme kinetics.The glucose consumption rate of HepG2 cells was obviously different from that of the experimental control group(P<0.01),after treating with IOP30 of 0.01,0.10 and 1.00 mg/mL.When insulin(10-7 mmol/L)and IOP30(0.10,1.00 mg/mL)were added together,the glucose consumption rate of HepG2 cells was increased more obviously(P<0.01).IOP30 was mainly composed of rhamnose(7.93%),arabinose(3.12%),xylose(11.15%),mannose(19.08%),glucose(39.17%)and galactose(19.15%).In conclusion,IOP30 isolated from the fruiting body of IO possessed significant hypoglycemic activity by reducing the formation of postprandial blood glucose viaα-glucosidase inhibitory activity,promoting the glucose metabolism in the surrounding tissues of cells,and enhancing the sensitivity of liver cells to insulin.