荞麦壳提取物有效组分的分离及体外抗糖尿病活性

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/m L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。

Isolation and Anti-Diabetic Activity in Vitro of Flavonoids from Buckwheat Hull

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.