番石榴叶水提取物对糖尿病小鼠小肠α-葡萄糖苷酶活性的影响

目的 研究番石榴叶水提取物对α-葡萄糖苷酶的抑制作用.方法 蒸馏水浸提、浓缩、干燥制备番石榴叶水提取物.昆明小鼠链脲佐菌素腹腔注射诱导糖尿病模型,以小鼠小肠粘膜生理盐水匀浆液作为α-葡萄糖苷酶,与双糖底物孵育,比色法测定葡萄糖产量代表α-葡萄糖苷酶的活性.比较正常小鼠和糖尿病小鼠小肠粘膜α-葡萄糖苷酶活性,以及番石榴叶水提取物对小肠粘膜α-葡萄糖苷酶活性的影响,Lineweaver-Burk作图判断水提物对α-葡萄糖苷酶抑制作用类型.结果 番石榴叶水提取物对小肠α-葡萄糖苷酶活性具有较强的抑制作用,并呈剂量效应关系;对蔗糖酶和麦芽糖酶的半数抑制浓度(IC50)分别为1.0 g/L和3.0 g/L,抑制作用类型为竞争性和非竞争性混合型.结论 番石榴叶水提取物具有抑制糖尿病小鼠小肠粘膜α-葡萄糖苷酶作用.

Effect of Psidium Guajava Leaf Extract on Alpha-glucosidase Activity in Small Intestine of Diabetic Mouse

Objective To investigate the inhibition effect of Psidium guajava linn (PGL), a leaf water-soluble extract, on the activities of alpha-glucosidases. Methods The PGL water-soluble extract (PGL WE) was obtained by the procedure of distilled water immersion, filtration, extracted fluid concentration and dry of Psidium guajava leaf. The diabetes of Kunming mice was induced by intraperitoneal injection of Streptozotocin (STZ). The small intestinal mucosa of diabetic mice was scraped to make the homogenate for the preparation of alpha-glucosidases. In vitro, the homogenates were incubated with sucrose and maltose. The formed glucose represented the activities of alpha-glucosidases. The Lineweaver-Burk plot was applied to determine the type of alpha-glucosidase activity inhibited. Results The water-soluble extract from PGL significantly inhibited, in the dose-dependent manner, the activities of alpha-glucosidase from small intestinal mucosa of diabetic mice. The PGL extract inhibition concentration (IC50) to sucrase or maltase was 1.0 g/L or 3.0 g/L respectively. The mixed inhibition type was showed to be the competitive and non-competitive inhibition. Conclusion The GPL water-soluble extract possesses the potential effect of inhibition on the alpha-glucosidase activity from the small intestinal mucosa of diabetic mouse.