香椿叶多酚的提取分离及其体外对糖尿病关键酶活性的抑制作用

Inhibitory Activities of Phenols from Toona sinensis Leaves on Key Enzyme Linked to Type 2 Diabetes in vitro

本研究从香椿叶中提取分离多酚,研究多酚对糖尿病关键酶(猪胰腺α-淀粉酶、鼠小肠蔗糖酶和麦芽糖酶)活性的影响。采用活性追踪法,运用多种分离纯化技术和色谱学分析,逐级筛选活性强的部位以及单体化合物。研究发现香椿叶多酚粗提物具有显著的酶抑制作用,猪胰腺α-淀粉酶、鼠小肠蔗糖酶和麦芽糖酶的半数抑制率(IC50)值分别为0.45 mg/mL、1.29 mg/mL和1.41 mg/mL。乙酸乙酯萃取后的70%乙醇洗脱部位为主要活性部位,其对猪胰腺α-淀粉酶、鼠小肠蔗糖酶和麦芽糖酶抑制作用的IC50值分别为0.091mg/mL、0.97 mg/mL和1.00 mg/mL。从活性部位分离出2个单体化合物,分别鉴定为:1,2,3,4,6-O-五没食子酰葡萄糖(PGG)和没食子酸乙酯(EG),其中PGG具有显著的α-淀粉酶抑制活性,IC50值为0.069 mg/mL;EG对蔗糖酶和麦芽糖酶具有一定的抑制活性,IC50值分别0.82 mg/mL和0.81 mg/mL。研究表明多酚化合物是香椿叶的有效降血糖功能成分之一,PGG和EG是主要的活性成分。

To clarify the postprandial glucose suppression effects of phenols from Toona sinensis leaves, its inhibitory effects against key enzymes（porcine pancreatic α-amylase, rat intestinal sucrase and maltase） linked to type 2 diabetes were investigated. Results showed that the crude extract of Toona sinensis leaves had significant enzyme inhibitory activities. Its IC50 values for the three key enzyme activities were 0.45, 1.29, and 1.41 mg/mL, respectively. The 70% ethanol sub-fraction of the ethyl acetate fraction was mainly responsible for enzymes inhibitory activities, which showed the strongest enzyme inhibitory activities with IC50 values of 0.091, 0.97, and 1.00 mg/mL, respectively, on porcine pancreatic α-amylase, rat intestinal sucrase and maltase. PGG（1, 2, 3, 4, 6-penta-O-galloyl-β-D-glucopyranose） and EG（ethyl gallate） isolated from 70% ethanol sub-fraction were identified as the active monomer compounds. PGG exhibited significant enzyme inhibitory activity against α-amylase with IC50 value of 0.069 mg/mL. The EG had inhibitory effects on sucrase and maltase to some extent. Its IC50 value for sucrase and maltase were 0.82 and 0.81 mg/mL, respectively. This study revealed that Toona sinensis leaves may be helpful to develop drug and functional foods for diabetes and related symptoms.