In silico and in vitro evaluation of efflux pumps inhibition of α,β-amyrin

Abstract

The use of the bacterial efflux pump mechanism to reduce the concentrations of antibiotics in the intracellular to the extracellular region is one of the main mechanisms by which bacteria acquire resistance to antibiotics. The present study aims to evaluate the antibacterial activity of the α,β-amyrin mixture isolated from Protium heptaphyllum against the multidrug-resistant strains of Escherichia coli 06 and Staphylococcus aureus 10, and to verify the inhibition of the efflux resistance mechanisms against the strains of S. aureus 1199B and K2068, carrying the NorA and MepA efflux pumps, respectively. The α,β-amyrin did not show clinically relevant direct bacterial activity. However, the α,β-amyrin when associated with the gentamicin antibiotic presented synergistic effect against the multidrug-resistant bacterial strain of S. aureus 10. In strains with efflux pumps, α,β-amyrin was able to inhibit the action of the efflux protein NorA against Ethidium Bromide. However, this inhibitory effect was not observed in the MepA efflux pump. In addition, when evaluating the effect of standard efflux pump inhibitors, clorptomazine and CCCP, α,β-amyrin showed a decrease in MIC, demonstrating the presence of the efflux mechanism through synergism. Docking studies indicate that α, β-amyrin have a higher affinity energy to MepA, and NorA than ciprofloxacin and norfloxacin. Also, α, β-amyrin bind to the same region of the binding site as these antibiotics. It was concluded that the α, β-amyrin has the potential to increase antibacterial activity with the association of antibiotics, together with the ability to be a strong candidate for an efflux pump inhibitor.

Communicated by Ramaswamy H. Sarma

Keywords:

• α
• β-amyrin mixture
• antibacterial activity
• efflux pump
• molecular docking

Acknowledgements

The authors thanks to the Centro Nacional de Processamento de Alto Desempenho (CENAPAD-UFC) of the UFC for the computational resources.

Availability of supporting data

All the theoretical data from this work were obtained using the Molecular Docking methodology. All the data generated and discussed during this work are included in this published article and in the supplementary information file.

Consent for publication

Not applicable.

Disclosure statement

No potential conflict of interest was reported by the authors.

Ethics approval and consent to participate

This research does not involve the use of human or animal material.

Credit author statement

Raíssa C. Oliveira: Investigation; Formal analysis; Writing – review and editing. Paulo Nogueira Bandeira: Co-supervision; Conceptualization: Telma Leda G. Lemos: Project administration; Conceptualization. Hélcio Silva dos Santos: Project administration; Formal analysis; Writing – review and editing. Jackelyne R. Scherf: Methodology; Data curation. Janaína E. Rocha: Methodology; Data curation. Raimundo L.S. Pereira: Methodology; Data curation. Thiago S. Freitas: Methodology; Data curation. Priscila R. Freitas: Methodology; Data curation. Francisco N. Pereira- Junior: Methodology; Data curation. Márcia M. Marinho: Software; Validation. Emanuelle M. Marinho: Formal analysis; Writing – review and editing. Emmanuel S. Marinho: Software; Formal analysis; Writing – review and editing. Carlos E.S. Nogueira: Formal analysis; Writing – review and editing. Henrique D.M. Coutinho: Project administration; Resources; Funding. Alexandre M.R. Teixeira: Supervision; Formal analysis, Writing – review and editing. All authors have read and agreed to the published version of the manuscript.

Correction Statement

This article has been republished with minor changes. These changes do not impact the academic content of the article.

Additional information

Funding

This study was supported by the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior – CAPES (Finance code 001 for R.C. Oliveira), by the Fundação Cearense de Apoio ao Desenvolvimento Científico e Tecnológico – FUNCAP. (Grants#: N° BP2-0107-00026.01.00/15 for H.S. Santos, and N° BP4-00172-00065.01.01/20 for C.E.S. Nogueira), and by the Conselho Nacional de Desenvolvimento Científico e Tecnológico – CNPq (Grants#: N° 305719/2018-1 for A.M.R. Teixeira, N° 426995/2018-0).