蒲公英水提多酚的脲酶抑制作用及机理

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，IC₅₀）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。

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

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. IC₅₀ 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.