3种黄酮类化合物对α-淀粉酶的抑制机制

Inhibition Mechanism of Three Flavonoids on α-Amylase

黄酮类化合物可以通过抑制α-淀粉酶的活性来调节血糖水平,然而,黄酮类化合物对α-淀粉酶的抑制机制和二者构效关系的研究十分有限,特别是B环上的羟基化和C环上的糖基化对黄酮类化合物抑制α-淀粉酶的影响尚不清楚。为探究黄酮类化合物对α-淀粉酶的抑制机制和构效关系,分析了芦丁、槲皮素、山奈酚3种黄酮类化合物对α-淀粉酶的抑制类型、荧光淬灭特性、构象变化、结合力和结合位点。结果表明,山奈酚对α-淀粉酶的抑制能力最强,芦丁最弱。C环C3处的糖基化和B环C3’处的羟基化均削弱了黄酮类化合物对α-淀粉酶的抑制作用。淬灭亲和力被C环C3处的糖基增强,被B环C3’处的羟基削弱。3种黄酮类化合物主要通过氢键和疏水作用与α-淀粉酶自发结合,导致酶的结构和疏水微环境被改变,进而有效抑制α-淀粉酶的活性。研究旨在为富含黄酮类化合物的降血糖食品的开发和应用提供理论参考。

Flavonoids can regulate blood sugar levels by inhibiting the activity of α-amylase.However,there were very limited research on the inhibitory mechanism and structure-activity relationship of flavonoids onα-amylase.Especially,the effects of hydroxylation on the B ring and glycosylation on the C ring related to the inhibitory ability of flavonoids onα-amylase were still unclear.Therefore,in order to explore the inhibitory mechanism and structure-activity relationship of flavonoids onα-amylase,the types of inhibition,fluorescence quenching properties,conformational changes,binding force and binding sites of three flavonoids(rutin,quercetin and kaempferol)were investigated in this study.The results showed that kaempferol had the strongest ability to inhibitα-amylase and rutin had the weakest ability to inhibit α-amylase,respectively.The inhibitory effect of flavonoids was attenuated by glycosylation at C3 on the C ring and hydroxylation at C3'on the B ring.The quenching affinity was enhanced by a glycosyl group at C3 on the C ring and weakened by a hydroxyl group at C3'on the B ring.Hydrogen bonds and hydrophobic interactions caused the spontaneous binding between the flavonoids and α-amylase,which changed structure and hydrophobic microenvironment of α-amylase,and inhibited α-amylase activity effectively.The purpose of this study was to provide theoretical support for the development and application of hypoglycemic foods rich in flavonoids.