荞麦壳提取物有效组分的分离及体外抗糖尿病活性

摘要

目的:研究荞麦壳提取物经大孔树脂分离纯化后各组分的体外活性.方法:荞麦壳提取物(buckwheat hull extract,BHE)、一次纯化后获得的精制物(purified buckwheat hull extract,PBHE)、二次纯化后分为的5 个组分(BHE-M1、BHE-M2、BHE-M3、BHE-M4、BHE-M5)分别用于测定α-葡萄糖苷酶活力和蛋白质糖基化终末产物(advanced glycation end products,AGEs)抑制率.结果:BHE一次纯化后荞麦壳总黄酮含量从30.8 g/100 g升高到65.3 g/100 g,二次纯化后BHE-M4组分总黄酮含量最高,为89.2 g/100 g.当质量浓度为1.000 mg/mL时各组分的α-葡萄糖苷酶活力抑制率分别为16.03%(BHE)、24.39%(PBHE)、18.04%(BHE-M2)、25.46% (BHE-M3)、28.23%(BHE-M4)、26.24%(BHE-M5),显著高于阳性对照组阿拉伯糖;抗AGEs活性实验结果显示,在葡萄糖-牛血清白蛋白、果糖-牛血清白蛋白体系中除BHE-M1组分外,其余组分活性均高于阳性对照胺基胍,其中BHE-M4组分活性最高;BHE-M4组分的高效液相色谱-质谱联用分析结果显示,BHE-M4中含有的黄酮类化合物可能为山奈酚-3-O-β-D-葡萄糖苷或山奈酚-3-O-β-D-半乳糖苷、牡荆素、芦丁、异槲皮苷或金丝桃苷、槲皮苷.结论:荞麦壳提取物经纯化后高黄酮组分的α-葡萄糖苷酶抑制活性以及抗AGEs活性最高,即荞麦壳黄酮是荞麦壳抗糖尿病活性的主要组成成分.%The purpose of this investigation was to evaluate the in vitro bioactivity of buckwheat hull extract (BHE). BHE was purified and separated into 5 fractions: BHE-M1, BHE-M2, BHE-M3, BHE-M4 and BHE-M5 by sequential chromatography on macroporous resins. The inhibitory activity against α-glycosidase and advanced glycosylation end products (AGEs) formation of these fractions was assessed. The results indicated that the purity of BHE was increased from 30.8 to 65.3 g/100 g after purification and BHE-M4 had the highest purity of 89.2 g/100 g among the five fractions. The percentage inhibition of α-glycosidase by BHE, purified BHE, BHE-M2, BHE-M3, BHE-M4 and BHE-M5 at a concentration of 1.000 mg/mL were 16.03%, 24.39%, 18.04%, 25.46%, 28.23% and 26.24%, respectively, which were significantly higher than that of the positive control arabinose. In glucose-bovine serum albumin (G-BSA) and fructose-bovine serum albumin (F-BSA) systems, all samples except BHE-M1 had a stronger inhibitory effect on AGEs formation than amino guanidine with BHE-M4 being the mwost effective. High performonce liquid chromatography-mass spectrometry (HPLC-MS) results indicated that flavonoids identified in BHE-M4 were kaempferol-3-O-β-D-glucoside or kaempferol-3-O-β-D-galactosidase, vitexin, rutin, isoquercitrin or hyperoside and quercitrin. Conclusively, flavonoid-rich extracts from buckwheat hull possessed a stronger inhibitory effect on α-glycosidase activity and AGEs formation, implying that flavonoids are the major antidiabetic components in buckwheat hull.