Screening and unveiling antibacterial mechanism of dandelion phenolic extracts against Staphylococcus aureus by inhibiting intracellular Na⁺–K⁺ ATPase based on molecular docking and molecular dynamics simulation

Abstract

Staphylococcus aureus is one of the most frequently food-contaminated incidence of healthcare-associated Gram-positive bacteria. The antibacterial function and mechanism of phenolic compounds from dandelion are still unclear. Herein, this work aims to screen one of dandelion phenolic extracts with the strongest antibacterial function from its organ such as flower, stem, leaf and root, and to reveal its antibacterial mechanism. The results indicated dandelion flower phenolic extract (DFPE) containing the highest content of caffeic acid, followed by luteolin and luteolin-7-O-glucoside. They, especially caffeic acid and luteolin-7-O-glucoside, played a key role in making the bacterial cellular-membrane ruptured against the bacteria. The leakage of the intracellular substances (adenosine triphosphate and Na⁺–K⁺ ATPase) was further confirmed. Conventional hydrogen bond, pi-anion, pi-alkyl were involved in the interaction between caffeic acid or luteolin-7-O-glucoside and Na⁺–K⁺ ATPase. Additionally, the dynamic equilibrium of the liganded ATPase complex were achieved after 105 ns, and the lower values from the radius of gyration and solvent accessible surface area in the complex demonstrated the highly tight and compact structure of the liganded protein. The highest free binding energy (ΔG_bind = −47.80 kJ/mol) between Na⁺–K⁺ ATPase and luteolin-7-O-glycloside was observed. Overall, DFPE can be used as an effective anti-bacterial agent due to the contribution of its bioactive ingredients such as caffeic acid and luteolin-7-O-glucoside for membrane-breaking.

Communicated by Ramaswamy H. Sarma

Keywords:

• Dandelion flower
• phenolic compounds
• anti-bacterial agent
• membrane leakage
• CLSM and SEM
• molecular simulation

Author contributions

Xuefeng Xu & Xiang Wang: Conceptualization, Investigation. Pujun Xie: Conceptualization, Data curation, Investigation, Formal analysis, Visualization, Validation, Writing-review & editing, Funding acquisition.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the National Natural Science Foundation of China under Grant No. 32271820, and Natural Science Foundation of Jiangsu Province under Grant No. BK20181124.