中文摘要：

采用石油醚、乙酸乙酯与正丁醇萃取获得不同极性的苦荞提取物，采用超高效液相色谱-串联四极杆飞行时间质谱法分析提取物的成分。结果表明苦荞提取物中含有大量的黄酮类物质，主要包括芦丁、槲皮素、异槲皮素及其糖苷等，还含有羟基苯甲酸等酚酸类物质。再以抑制率、抑制类型、荧光猝灭效应实验分析提取物对α-淀粉酶的抑制作用。结果表明，苦荞提取物对α-淀粉酶的抑制作用表现为乙酸乙酯相提取物、正丁醇相提取物与粗提物的结果类似，都有较为显著的抑制作用，而石油醚相提取物则没有明显且规律的抑制效果，可推断出苦荞提取物中各成分共同发挥了对α-淀粉酶活性的抑制作用，且抑制类型为非竞争性抑制。通过荧光猝灭实验得知抑制的机理为苦荞提取物中的成分与α-淀粉酶结合，从而使α-淀粉酶的荧光特性发生静态猝灭。

英文摘要：

The purpose of this study was to investigate the chemical composition andα-amylase inhibitory activity of the crude ethanol extract of tartary buckwheat and its fractions obtained by successive extraction with organic solvents of different polarities including petroleum ether,ethyl acetate and N-butyl alcohol.An ultra performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry(UPLC-Q-TOF-MS)method in the negative ion mode was established to analyze the major constitutions in the extracts.Results showed that the majority of the extracts were the flavonoids rutin,quercetin,quercetin-3-rutinoglucoglucoside,isoquercetin and kaempferol-3-O-rutinoside as well as some phenols such as hydroxybenzoic acid.The inhibition rate againstα-amylase and the inhibition type were determined and fluorescence quenching experiments were used to study theα-amylase inhibitory activity of the extracts.Results revealed that the crude extract,and the ethyl acetate-soluble and N-butyl alcohol-soluble fractions all significantly inhibitedα-amylase activity whereas the petroleum ether-soluble fraction could not.Therefore,it can be inferred that the inhibition ofα-amylase by tartary buckwheat extracts likely resulted from the combined action of different fractions in a noncompetitive manner,as indicated by the kinetic analysis.Fluorescence quenching experiments revealed that the fluorescence ofα-amylase was statically quenched as it formed a complex with the extracts of tartary buckwheat.