蒲公英水提多酚的脲酶抑制作用及机理

Inhibitory Effect and Mechanism of Urease by Water-extracted Polyphenols in Dandelion

蒲公英水提多酚具有很高的抑制脲酶活性的潜力,本文以蒲公英全草粉为材料,采用液质联用法(High Performance Liquid Chromatography-Mass Spectrometry,HPLC-MS)、苯酚-次氯酸盐比色法、Lineweaver-Burk双倒数作图法、荧光分析法和分子对接筛选蒲公英中抑制脲酶活性的主要水提多酚,并分析其抑制效果和作用机制。结果表明,蒲公英水提多酚主要成分是菊苣酸和咖啡酸,含量分别为10.62%和7.39%,结合能量为-5.65和-3.60 kcal/mol,对脲酶的抑制率之和占蒲公英水提总多酚抑制率的75.76%,是抑制脲酶活性的主要成分;半数抑制浓度(the half maximum inhibitory concentration,IC_(50))分别为0.34±0.07和3.04±0.68 mmol/L,抑制效果呈浓度依赖性和低浓度高效性;两者与脲酶的作用位点相同,抑制类型均为以氢键和范德华力为主的非竞争性抑制类型,且荧光猝灭机制为静态猝灭。本研究为阐明蒲公英中抑制脲酶的主要多酚及作用机理,促进多酚类脲酶抑制剂的开发提供了理论依据。

Water-extracted polyphenols in dandelion have been reported to possess a high potential for inhibit urease.Dandelion powder with whole grass was used to screen the main water-extracted polyphenols in dandelion with inhibiting urease,and study the inhibitory effects and mechanisms by HPLC-MS,Berthelot Method,Lineweaver-Burk method,fluorescence analysis and molecular docking in this paper.The results showed that main components of water-extracted polyphenols in dandelion were cichoric acid and caffeic acid,the contents were 10.62% and 7.39%,binding energies were-5.65 and-3.60 kcal/mol,and the sum of their inhibitory rates to urease accounted for 75.76% of the total water-extracted polyphenols in dandelion,indicating they are the major components to inhibit urease.IC_(50) were 0.34±0.07 and 3.04±0.68 mmol/L,respectively.The inhibitory effects were both concentration-dependent and highly effective at low concentrations.They had the same action site against urease,the inhibition types were non-competitive inhibition type dominated by hydrogen bond and van der Waals force,and the fluorescence quenching mechanism is static quenching.This study would provide a theoretical basis for elucidating the main polyphenols of dandelion and their mechanism against urease,and promoting the development of polyphenol as urease inhibitors.