东方栓孔菌多糖对小鼠的降血糖和降血脂作用

Glucose-lowering effect of Trametes orientalis polysaccharides in hyperglycemic and hyperlipidemic mice

目的探讨东方栓孔菌多糖组分的降血糖和降血脂作用。方法东方栓孔菌粗多糖经DEAE纤维素柱分离,利用水和0.5 mol/L NaCl溶液冲洗,收集其中多糖含量较高的组分DEAE-水和DEAE-盐,两部分分别经Sephadex G-100凝胶柱得到4个多糖组分TOPW-1,TOPW-2,TOPS-1,TOPS-2。通过2,2'-联氮-双-3-乙基苯并噻唑啉-6-磺酸(ABTS)法考察各多糖组分抗氧化活性,对紫外检测信号一致的收集液TOPW-1,TOPS-1利用HPGPC测定相对分子质量,对均一的TOPW-1通过酸水解结合HPLC分析测定单糖组成。体外检测TOPW-1,TOPS-1对DPP4(二肽基肽酶-4)抑制活性,脂肪细胞摄取葡萄糖能力和对胰脂肪酶的抑制活性,初步判断降糖作用,并建立高脂饲料高血脂小鼠模型和链脲霉素(STZ)高血糖小鼠模型,实验动物分为正常组,模型组,模型+TOPS-1高、中、低剂量组(0.1,0.2,0.4 g/kg),模型+丹参(0.5 g/kg)组和模型+消渴丸(5丸/kg)组,后两组为阳性对照组,灌胃给药。采用血糖测试仪和全自动生化分析仪分别测定血清血脂指标[总胆固醇(TC)、三酰甘油(TG)、低密度脂蛋白胆固醇(LDL-C)、高密度脂蛋白胆固醇(HDL-C)]和血糖水平,评价TOPS-1降血糖和降血脂作用,探讨可能的作用机制。结果TOPW-1为均一组分,是由D-甘露糖、D-葡萄糖、D-半乳糖及D-岩藻糖组成的多糖,但TOPW-1的抗氧化及体外降血糖作用均不显著。TOPS-1为非均一多糖,具有较强的抗氧化能力(在500μg/mL浓度下,其清除率达到90.15%),对胰脂肪酶有一定的促进作用,进一步动物实验表明TOPS-1中剂量组(0.2 g/kg)能显著降低高血糖小鼠的空腹血糖值及高血脂小鼠的TC、TG和LDL-C含量,且给药过程中未出现小鼠死亡。TOPS-1低、高剂量组降血糖作用不显著,高剂量组给药存在一定增加小鼠死亡率的可能。结论东方栓孔菌多糖具有抗氧化,降血糖和调血脂的作用,推测其降糖作用与降低氧化应激水平,减少糖尿病人脂肪代谢紊乱有关。

Objective To explore the glucose-lowering effect of the polysaccharide fractions of Trametes orientalis.Methods The crude polysaccharides of T.orientalis were chromatographed on DEAE cellulose column using H2O and 0.5 mol/L NaCl solution as the eluent and DEAE-water and DEAE-salt with high polysaccharide contents were collected.The two fractions were separated using Sephadex G-100 gel column to obtain 4 polysaccharide fractions TOPW-1,TOPW-2,TOPS-1,and TOPS-2.The anti-oxidation activity of the polysaccharide fractions was investigated with ABTS method.The fractions TOPW-1 and TOPS-1 with consistent UV detection signals were collected and HPGPC was used to determine their relative molecular mass.The monosaccharide composition in homogeneous TOPW-1 was determined by acid hydrolysis combined with HPLC.The in vitro inhibitory activities of TOPW-1 and TOPS-1 against DPP4,adipocyte glucose intake and lipase activity were tested to preliminarily assess their glucose-lowering effect.In a mouse model of hyperglycemic and hyperlipidemic,the glucose-lowering effect of TOPS-1(0.1,0.2,and 0.4 g/kg)and its effect on blood lipid metabolism were investigated in comparison with Xiaoke pills(5 pills/kg)and Danshen tablets(0.5 g/kg).Results TOPW-1 was a homogeneous polysaccharide composed mainly of D-mannose,D-glucose,D-galactose,and D-fucose,with weak antioxidant and hypoglycemic effects.TOPS-1 was not a single polysaccharide and at the concentration of 500μg/mL showed an high ABTS clearance rate(90.15%).In the mouse model of hyperglycemia and hyperlipidemia,treatment with TOPS-1(0.2 g/kg)enhanced the activity of lipase and significantly reduced fasting glucose level and serum contents of total cholesterol,triacylglycerol,and low-density lipoprotein cholesterol without causing death in the mice.The glucose-lowering effects of TOPS-1 was not significant at the low(0.1 g/kg)or high(0.4 g/kg)dose,and a high dose tended to increase the mortality of the mice.Conclusion T.orientalis polysaccharides have anti-oxidation,glucose-lowering and lipid-lowering effects in mice,and their glucose-lowering effect is probably medicated by reducing oxidative stress and ameliorating lipid metabolism disorder.