甘草酸提取废液α-葡萄糖苷酶抑制剂的筛选与鉴定

Screening and Identification of α-Glucosidase Inhibitor in Waste Liquid from Glycyrrhizic Acid Extraction

将甘草酸提取废液用正己烷、氯仿、乙酸乙酯、正丁醇进行梯度萃取,检测各萃取相对α-葡萄糖苷酶的抑制作用,筛选出活性最强的萃取相;根据双倒数曲线图判断其对α-葡萄糖苷酶的抑制作用类型,采用联合作用指数分析其与阿卡波糖的协同作用;通过超高效液相色谱-二极管阵列检测-质谱检测方法分析,结合酸水解以及与标准品相对照的方法,初步鉴定其主要成分的化学结构,并测定主要成分的含量。结果表明:在甘草酸提取废液各溶剂萃取物中,乙酸乙酯萃取相对α-葡萄糖苷酶的抑制作用最强,为竞争性抑制,半抑制浓度为0.152 9 g/L,抑制常数Ki为0.085 1 g/L;与阿卡波糖有协同抑制效应;其主要成分为甘草素、柚皮素、异甘草素以及芒柄花素的单糖苷和二糖苷。甘草素类、柚皮素类、异甘草素类和芒柄花素类的黄酮含量总计分别为28.08%、2.95%、11.80%和4.38%;黄酮总含量为47.21%。

Waste liquid from glycyrrhizic acid extraction was extracted with n-hexane, chloroform, ethyl acetate and n-butyl alcohol sequentially. The inhibitory effects of the resulting extracts on α-glucosidase were studied compared to identify the one with the highest inhibitory effect. The inhibition type was evaluated based on the Lineweaver-Burk plot and synergistic interaction between the selected extract and acarbose was analyzed by combination index. The chemical structure and amounts of the major components of the extract were determined using ultra-high performance liquid chromatography-diode array detection-mass spectrometry following acid hydrolysis by comparison with standards. The results showed that the ethyl acetate extract had the strongest inhibitory activity against α-glucosidase through competitive inhibition with an half maximal inhibitory concentration value of 0.152 9 g/L and an inhibition constant（Ki） value of 0.085 1 g/L, and synergistic effect existed between acarbose and the ethyl acetate extract. The major constituents of the extract were monoglucosides and diglucosides of glycyrrhizin, naringenin, isoliquiritigenin and formononetin. The contents of the flavonoids glycyrrhizin, naringenin, isoliquiritigenin and formononetin were 28.08%, 2.95%, 11.80% and 4.38% respectively. The content of total flavonoids was 47.21%.