打瓜干皮中多糖的含量测定及降血糖作用机制

Determination of Polysaccharide Content in Dried Peel of Seeding Watermelon and Its Mechanism of Lowering Blood Glucose

目的测定打瓜干皮中多糖的含量,探讨打瓜多糖的降血糖机制。方法采用苯酚-硫酸法测定打瓜干皮中多糖的含量,淀粉和蔗糖负荷法测定打瓜多糖对淀粉和蔗糖负荷小鼠血糖的影响,采用对硝基酚法测定打瓜多糖对α-葡萄糖苷酶活性的抑制作用。结果打瓜多糖标准曲线为A=0.066 4 C+0.022 6,R^2=0.999 5,测得打瓜干皮中多糖含量4.45%(n=10,RSD=1.80%);50,100和150 mg·kg^(-1)打瓜多糖均可以显著降低淀粉负荷小鼠的血糖;100和150 mg·kg^(-1)打瓜多糖可显著降低蔗糖负荷小鼠血糖;打瓜多糖在浓度18 mg·m L-1时能显著抑制α-葡萄糖苷酶的活性,抑制率(73.19±3.45)%(n=10)。结论打瓜多糖对淀粉和蔗糖负荷小鼠均有降血糖作用,且对α-葡萄糖苷酶有明显的抑制作用。

Objective Determination of polysaccharide content in dried peel seeding watermelon, and its mechanism of lowering blood glucose.Methods The content of polysaccharides in dried peel of seeding watermelon was determined by the method of phenol-sulfuric acid.Mice were given starch and sucrose load,and the mouse blood glucose was examined.The inhibitory activities of seeding watermelon against α-glucosidase were tested by the colorimetry of pNPG.Results The calibration of polysaccharide was A=0.066 4 C＋0.022 6, R2=0.999 5, the content of polysaccharide in dried peel of seeding watermelon was 4.45% （n=10,RSD=1.80%）;50,100 and 150 mg·kg-1 of polysaccharide could significantly reduce the starch load in mice blood glucose（P〈0.01）;100 and 150 mg·kg-1 of polysaccharide significantly reduced sucrose load blood glucose（P〈0.01）;polysaccharide concentration in 18 mg·mL-1 could significantly inhibit the activity of α-glucosidase as the inhibitory rate was （73.19±3.45）% （n=10）.Conclusion Seeding watermelon polysaccharide has effect on lowering blood glucose in starch and sucrose load mice, and inhibits α-glucosidase significantly.