基于酶活力和细胞模型分析广佛手多糖降血糖活性及作用机制

佛手（Citrus medica ‘Fingered’）是一种药食同源的芸香科柑桔属植物，产自广东的佛手称为广佛手。本研究以广佛手多糖为对象，采用酶活力和细胞模型探究其体外降血糖活性及机制。结果表明，广佛手多糖FCP-2-1对α-葡萄糖苷酶、α-淀粉酶和血管紧张素转化酶（angiotensin converting enzyme，ACE）活力的半抑制质量浓度（half-maximal inhibitory concentration，IC50）分别为2.74、0.87 mg/mL和0.85 mg/mL。在3T3-L1脂肪细胞中，广佛手多糖各分离纯化组分均能显著促进细胞葡萄糖转运，改善细胞的脂代谢，降低肿瘤坏死因子（tumor necrosis factor，TNF）-α的分泌量。其机制可能是FCP-2-1通过促进磷脂酰肌醇3激酶（phosphatidylinositol 3-kinase，PI3K）/蛋白激酶B（protein kinase B，PKB，也称AKT）通路中PI3K、葡萄糖转运体4、AKT和磷酸化-AKT蛋白的表达，缓解细胞的胰岛素抵抗，恢复细胞正常代谢。

Hypoglycemic Effect and Mechanism of Polysaccharides from Finger Citron from Guangdong Province Based on Enzyme Activities and Cell Model

Finger citron (Citrus medica ‘Fingered’) is a medicinal and edible plant belonging to the genus Citrus of the family Rutaceae. Finger citron grown in Guangdong is called Guang Foshou. The present study explored the in vitro hypoglycemic activity and mechanism of polysaccharides extracted from Guang Foshou by measuring enzyme activities as well as using cell model. The results showed that the half-maximal inhibitory concentrations (IC50) of the polysaccharide fraction FCP-2-1 for α-glucosidase, α-amylase and angiotensin converting enzyme (ACE) were 2.74, 0.87 and 0.85 mg/mL, respectively. All the polysaccharides remarkably promoted glucose transport in 3T3-L1 adipocytes, improved lipid metabolism and reduced the secretion of tumor necrosis factor (TNF)-α. The mechanism might be that FCP-2-1 could promote the expression of phosphatidylinositol 3-kinase (PI3K), glucose transporter 4 (GLUT4), protein kinase B (PKB or AKT) and phosphorylated AKT (p-AKT) in the PI3K/AKT signaling pathway to alleviate insulin resistance and restore normal cellular metabolism.