大黄中α-淀粉酶抑制因子的研究

Study on inhibitors of α-amylase in rhubarb

采用甲醇粗提、石油醚、二氯甲烷、乙醚、乙酸乙酯、乙醇索氏极性梯度提取、pH梯度萃取以及硅胶制备板纯化并结合各组分α-淀粉酶抑制活性跟踪方法对大黄中α-淀粉酶抑制因子的分布进行了系统研究。结果表明,乙酸乙酯和乙醇组分对α-淀粉酶的抑制率分别为35.0%和26.9%;前者的pH梯度萃取组分为NaHCO3、Na2CO3、NaOH、剩余乙酸乙酯,对α-淀粉酶的抑制率依次为:66.5%、46.7%、58.1%和49.0%。其中NaHCO3组分用硅胶制备板纯化并水解,经薄层分析认定其苷元是大黄酸。纯化后对α-淀粉酶的抑制率不升反降的事实暗示了粗样中杂质的协同作用。

α amylase inhibitory factors in rhubarb were studied systematically by the method of a combination of extraction with methanol,Soxhlet pH gradient extraction,purification by using preparative silica gel plates,and α amylase inhibitory activity monitoring of the various components. The results showed that ethyl acetate and ethanol components of the α amylase inhibition rates were 35. 0% and 26. 9%,respectively. α amylase inhibitory rates of the pH gradient components of ethyl acetate,NaHCO3,Na2CO3,NaOH,and the remaining ethyl acetate were：66. 5%,46. 7%,58. 1% and 49. 0% respectively. The NaHCO3 fraction was purified by using preparative silica gel plates,then hydrolyzed and analyzed with thin layer silica gel. The result indicated that its aglycone was rhein. The fact of a reducing inhibitory rate after purification implied that impurities in crude samples may have synergetic effect with the major ingredient.