荞麦麸皮提取物对α-葡萄糖苷酶活性的影响

Effects of Different Solvent Extracts from Buckwheat Bran on α-Glucosidase Activity

本实验分别用乙醇和水从荞麦麸皮中提取到了以荞麦黄酮为主要成分的乙醇粗提物和以荞麦糖醇为主要成分的水粗提物,并将乙醇粗提物经高压水解,获得乙醇粗提物的水解物。研究这3种提取物对α-葡萄糖苷酶活性的影响,并以阿卡波糖和D-手性肌醇为参照。比色法和液相色谱法测得,苦荞麸皮乙醇粗提物的主要成分为苦荞黄酮,黄酮含量为74.0%,其中86.5%为芦丁,槲皮素和异槲皮素微量;乙醇粗提物经高压水解后,总黄酮含量为76.2%,其中,芦丁、槲皮素和异槲皮素分别占60.6%、25.2%、13.5%。甜荞麸皮水粗提物的主要成分为D-手性肌醇、肌醇,其含量分别为43.6%、2.9%。3种荞麦麸皮提取物均具有抑制α-葡萄糖苷酶的活性,作用强度分别为:乙醇粗提物的水解物>乙醇粗提物>水粗提物,IC50分别为0.0085、0.0578、17.3551g/L。苦荞黄酮经高压水解后,抑制α-葡萄糖苷酶活性显著提高,与阿卡波糖IC50(0.0335g/L)相比,约是它的1/4;水粗提物在低质量浓度下抑制效果不明显,在较高的质量浓度下则表现出抑制活性。

The respective effects of buckwheat bran ethanol extract mainly composed of flavonoids and its high-pressure hydrolysate as well as the water extract from the material mainly composed of fagopyritols on α-glucosidase activity were measured using acarbose or D-chiro-inositol as a reference substance.The major components of the ethanol extract were flavonoids,with a total content of 74.0%,in which the relative content of rutin was 86.5% and those of quercetin and isoquercetin were at trace levels according to colorimetric and HPLC determinations.However,after high-pressure hydrolysis,the content of total flavonoids in the ethanol extract increased to 76.2%,of which rutin,quercetin and isoquercetin represented 60.6%,25.2% and 13.5%,respectively.The major components of the water extract were 43.6% D-chiro-inositol and 2.9% inositol.All the three tested samples had inhibition effect on α-glucosidase in the following decreasing order：the hydrolysate of the ethanol extract 〉the ethanol extract〉 the water extract.Their IC50 values were 0.0085,0.0578 g/L and 17.3551 g/L,respectively.Therefore,highpressure hydrolysis could increase the inhibition effect of buckwheat bran ethanol extract on α-glucosidase activity （the IC50 of the hydrolysate was approximately one quarter of that of acarbose;the smaller IC50,the stronger inhibition effect）.In addition,the water extract did not inhibit the activity of the enzyme at low concentrations,but had inhibition effect at high concentrations.