美国豆芋花总皂苷制备及其α-葡萄糖苷酶抑制活性

为高效利用美国豆芋花皂苷类化合物,以皂苷得率和纯度为指标,研究美国豆芋花总皂苷的提取工艺及大孔树脂纯化工艺,并对制备的美国豆芋花总皂苷的抗氧化及α-葡萄糖苷酶活性抑制能力进行研究。结果表明,美国豆芋花总皂苷的提取工艺为提取溶剂90%乙醇,料液比1∶20,温度70℃,提取时间2 h。得到的提取物石油醚脱脂后用水饱和正丁醇萃取,D-101大孔树脂吸附柱纯化的工艺为上样皂苷质量浓度1 mg·m L~(-1),上样量40 m L·g~(-1)树脂,洗脱剂为80%乙醇(pH值6),洗脱剂用量4 BV(树脂柱体积)。制备的美国豆芋花总皂苷样得率4.24%,纯度达65.35%,比粗提物(纯度15.27%)提高了约3倍;抗氧化性能(清除DPPH和ABTS自由基IC50值分别为51.08、29.24μg·m L~(-1))和α-葡萄糖苷酶活性抑制能力(IC50值为83.62μg·m L~(-1))也均优于粗提物(清除DPPH、ABTS自由基IC50值分别为286.51、69.92μg·m L~(-1),α-葡萄糖苷酶的抑制浓度(IC50)值为1 043.57μg·m L~(-1)),表明该工艺可用于高活性美国豆芋花总皂苷的富集和纯化。此外,美国豆芋花总皂苷抑制α-葡萄糖苷酶活性的抑制类型为竞争型抑制,抑制常数为49.68μg·m L~(-1)。本研究结果为开发具有降血糖功能的医药中间体或功能性食品提供了新资源和实践基础。

Preparation of Saponin From the Apios Americana Medikus Flower and Its glucosidase Inhibitory Ability

To efficiently use the saponin from the Apios Americana Medikus flower,we taking saponin yield and purity as response indicators,the reflux extraction and macroporous resin purification were used in the present study to explore an appropriate extraction technology.The antioxidant and α-glucosidase inhibition activity were also studied for the refined saponin.The results showed that the optimal reflux conditions were ethanol concentration 90％,material/liquid ration 1:20,extraction temperature 70 ℃,and extraction duration 2 h.,The crude saponin was then partitioned in a separatory funnel with n-butanol after defatted and before washed through the D-101 macroporous resin.The optimum purification condition are 1 mg· mL-1 of saponons eluted by 80％ ethanol at pH value 6 with a volume of 4 BV (resin bed volume),and the loaded amount was 40 mL· g-1 resin.The yield of the refined saponin was 4.24％ while the purity reached 65.35％,which was 3 times higher than that of crude extract.The refined saponin showed strong DPPH and ABTS radical scavenging capacity,IC50 index for each assay was 51.08 μg·mL-1 and 29.24 μg· mL-1,respectively.Furthermore,it possessed stronger o-glucosidase inhibitory ability than the positive control of acarbose,IC50 index was 83.62 μg· mL-1.All the active indices were better than that of crude extract (IC50 index for DPPH,ABTS radical scavenging capacity and α-glucosidaseinhibitory ability were 286.51 μg· mL-1,69.92 μg· mL-1,and 1 043.57 μg· mL-1 respectively.).The result showed that the above reflux extraction and macroporous resin purification method was feasible in thepreparation of saponin from the Apios americana Medikus flower.Kinetic analysis showed that the inhibitory mechanism of the saponin from the flower of Apios Americana Medikus on α-glucosidase was a typical competitive inhibition.The inhibitory constant was 49.68 μg·mL-1.The result would provide new resources and practical basis for the further development of the hypoglycemic pharmaceutical intermediates or functional foods.