食源性多酚对α-淀粉酶作用大米淀粉活性的影响

Inhibitory Effect of Food Derived Polyphenols on Activity ofα-Amylase with Rice Starch

为探究不同种类多酚在以大米淀粉为底物对淀粉酶的抑制特性,通过建立抑制动力学体系探究阿魏酸、没食子酸、芦丁3种食源性多酚对α-淀粉酶活性的抑制类型和抑制效果,并绘制相应曲线图。结果表明,随着食源性多酚浓度的增加,食源性多酚对α-淀粉酶的抑制效果越强,且其抑制效果按照芦丁、没食子酸、阿魏酸的顺序依次减弱,其半抑制质量浓度IC_(50)分别为6.53、11.87、15.38 mg/mL。通过对Lineweaver-Burk双倒数曲线等图形进行分析可以判断阿魏酸、芦丁对α-淀粉酶的抑制类型为竞争性和非竞争性混合抑制,没食子酸对α-淀粉酶的抑制类型为非竞争性和反竞争性混合抑制,根据曲线图分析并求得3种食源性多酚的抑制常数K_(ic)与K_(iu)。食源性多酚能够有效抑制淀粉酶酶解。

In order to explore the inhibition characteristics of different kinds of polyphenols on amylase with rice starch as substrate,the reaction conditions of reaction temperature 37℃and reaction time 3 min were set.The type and effects of ferulic acid,gallic acid and rutin onα-amylase were studied by the enzymatic kinetics method,and corresponding curve were drawn to further determine the relevant constants and obtain the inhibition equation.The results of inhibition experiment indicated that the higher the concentration of foodborne polyphenols added,the stronger the inhibition effect onα-amylase.The inhibitory effect of rutin,gallic acid and ferulic acid decreased in turn and the values of semi-inhibitory concentration IC_(50) of them were 6.53,11.87,15.38 mg/mL,respectively.The analysis of Lineweaver Burk double reciprocal curve and other graphs indicated that the inhibition types of ferulic acid and rutin onα-amylase were competitive and noncompetitive mixed inhibition,and the type of inhibitory effects of ferulic acid and rutin againstα-amylase was competitive-non-competitive mixed-type inhibition,while the inhibition type of gallic acid againstα-amylase was non-competitive-uncompetitive mixed inhibition.Through the analysis of Dixon curves and Cornish Bowden curves,the values of inhibition constants K_(ic) and K_(iu) of ferulic acid were 17.66 mg/mL and 27.86 mg/mL,while gallic acid ones were 21.72 mg/mL and 18.12 mg/mL and rutin ones were 7.83 mg/mL and 33.43 mg/mL.These results indicated that food derived polyphenols could effectively inhibit the enzymatic hydrolysis ofα-amylase.