龙眼叶不同极性部位对2型糖尿病小鼠的降血糖作用研究

Study on Hypoglycemic Effects of Different Polar Parts from the Leaves of Dimocarpus longan on Type 2 Diabetes Mellitus Mice

目的:优选龙眼叶对2型糖尿病小鼠降血糖的活性部位,为龙眼叶的药效物质基础研究提供参考。方法:龙眼叶经95%乙醇渗漉提取得到总提物,在确定总提物的降血糖作用后,将总提物浸膏用水混悬,然后依次用石油醚、乙酸乙酯、正丁醇萃取得相应部位提取物(分别记为ST、YT、ZT和WT)。采用高糖高脂饲料联合链脲佐菌素法复制2型糖尿病小鼠模型。将成模小鼠随机分为模型组(蒸馏水),阳性对照组(二甲双胍,0.1 g/kg),ST低、中、高剂量组(22.2、29.6、44 g/kg,以生药计,下同),YT低、中、高剂量组(10.7、16、32 g/kg),ZT低、中、高剂量组(10.5、15.8、31.6 g/kg)和WT低、中、高剂量组(18.5、24.6、37 g/kg),每组10只;并另选10只正常小鼠作为正常组(蒸馏水)。各组小鼠均每天灌胃给药1次,连续给药28 d。观察并记录小鼠的生长情况及体质量变化,检测小鼠空腹血糖值,对小鼠进行葡萄糖耐量实验,并测定小鼠血清中总胆固醇(TC)、三酰甘油(TG)、高密度脂蛋白(HDL-C)和低密度脂蛋白(LDL-C)的含量。结果:与正常组比较,模型组小鼠的体质量和血清中HDL-C含量降低,空腹血糖值和给予葡萄糖0.5、1、2 h后小鼠的血糖值以及糖耐量曲线下面积升高,且血清中TC、TG和LDL-C含量升高,差异均有统计学意义(P<0.01)。与模型组比较,给药28 d后YT高剂量组小鼠体质量升高,YT各剂量组和ZT中、高剂量组小鼠空腹血糖值降低(P<0.05或P<0.01),给予葡萄糖1 h后YT中、高剂量组和ZT高剂量组小鼠血糖值以及给予葡萄糖2 h后YT高剂量组小鼠血糖值均降低,YT各剂量组和ZT高剂量组小鼠糖耐量曲线下面积以及血清中TC含量均降低、血清中HDL-C含量均升高,YT高剂量组和ZT高剂量组小鼠血清中TG、LDL-C含量以及YT中剂量组小鼠血清中TG含量均降低,ZT中剂量组小鼠血清中HDL-C含量升高,差异均有统计学意义(P<0.05或P<0.01)。结论:龙眼叶乙酸乙酯部位和正丁醇部位对2型糖尿病小鼠有较好的降血糖作用。

OBJECTIVE:To optimize the hypoglycemic active parts from the leaves of Dimocarpus longan for type 2 diabetes mellitus mice,and to provide reference for material basis study of it.METHODS:Total extract was obtained from the leaves of D.longan with 95%ethanol percolation extraction.After confirming hypoglycemic effect of total extract,extract was suspended with water.Relevant extract was obtained by using petroleum ether,ethyl acetate and n-butanol in turn(respectively marked as ST,YT,ZT and WT).The model of type 2 diabetes mellitus mice was established by high glucose and high fat diet combined with STZ.Model mice were randomly divided into model group(distilled water),positive control group(metformin,0.1 g/kg),ST low-dose,medium-dose and high-dose groups(22.2,29.6,44 g/kg,calculated by crude drug,similarly hereinafter),YT low-dose,medium-dose and high-dose groups(10.7,16,32 g/kg),ZT low-dose,medium-dose and high-dose groups(10.5,15.8,31.6 g/kg),WT low-dose,medium-dose and high-dose groups(18.5,24.6,37 g/kg),with 10 mice in each group.Other 10 normal mice were included in normal group(distilled water).Those groups were given relevant medicine intragastrically,once a day,for consecutive 28 d.The growth of mice and the change of body weight were observed and recorded.Fasting blood glucose(FBG)of mice was detected,and glucose tolerance test of mice was conducted.The contents of TC,TG,HDL-C and LDL-C in serum of mice were also determined.RESULTS:Compared with normal group,body weight and serum content of HDL-C in model group were decreased;FBG and the blood sugar after giving glucose for 0.5,1,2 h and area under glucose tolerance curve of mice were increased,and serum contents of TC,TG and LDL-C were alse increased,with statistical significance(P<0.01).compared with model group,body weight of mice in YT high-dose group after administration of 25 d was increased,FBG of mice in YT groups and ZT medium-dose,high-dose groups were decreased(P<0.05 or P<0.01);blood sugar of mice in YT medium-dose,high-dose groups and ZT high-dose group after giving glucose for 1 h as well as blood sugar of mice in YT high-dose group after giving glucose for 2 h were all decreased;area under glucose tolerance curve of mice and serum content of TC were decreased in YT groups and ZT high-dose group,while serum content of HDL-C was increased.Serum content of TG and LDL-C in YT high-dose group and ZT high-dose group as well as serum content of TG in YT medium-dose group were all decreased,serum content of HDL-C in ZT medium-dose group was increased,with statistical significance(P<0.05 or P<0.01).CONCLUSIONS:The ethyl acetate part and n-butanol part from the leaves of D.longan show good hypoglycemic effect on type 2 diabetes mellitus mice.