Planta Med 2019; 85(18): 1571
DOI: 10.1055/s-0039-3400401
Main Congress Poster
Poster Session 2
© Georg Thieme Verlag KG Stuttgart · New York

Impact of herbal substances on efflux pumps in bacterial and human cells

J Solnier
1   Institute of Pharmaceutical Sciences, Department of Pharmacognosy, University of Graz,, Universitätsplatz 4, A-8010 Graz, Austria
,
S Bhakta
2   Department of Biological Sciences, Institute of Structural and Molecular Biology, Birkbeck, University of London,, Malet Street, London, WC1E 7HX, UK
,
F Bucar
1   Institute of Pharmaceutical Sciences, Department of Pharmacognosy, University of Graz,, Universitätsplatz 4, A-8010 Graz, Austria
› Author Affiliations
Further Information

Publication History

Publication Date:
20 December 2019 (online)

 

The rapid global expansion of multidrug (MDR) and extensively drug-resistant (XDR) bacteria reflects the urgent need of a novel course in antibiotic therapy to tackle infectious diseases such as tuberculosis [1]. Considering the rising numbers of multidrug resistance especially in mycobacteria including the Mycobacterium tuberculosis complex, they are one of the critical global health concerns [2]. Efflux pumps (EP) present one of the key strategies of bacteria to protect themselves against antimicrobials [3]. We investigated specific isolated flavonoids from Scutellaria species for their antimicrobial activity against the non-pathogenic surrogate models for Mycobacterium tuberculosis, i. e. Mycobacterium smegmatis mc2 155, Mycobacterium aurum ATCC 23366 and Mycobacterium bovis BCG ATCC 35734. The MICs of the plant compounds against the studied strains were determined using microbroth dilution and SPOTi- assays [5].

Prior to efflux assays, all compounds tested at sub inhibitory concentrations, were evaluated for their synergistic effects with ethidium bromide (EtBr) and rifampicin against M. smegmatis strain. M. smegmatis and M. aurum were further assessed for accumulation of EtBr in the presence and absence of the plant compounds as putative efflux pump inhibitors (EPIs) including the reference inhibitors verapamil (VP) and chlorpromazine (CPZ) by detecting efflux activity through a fluorometric method. Based on the results obtained from our experiments, skullcapflavone II exerts potent antimycobacterial activity against M. aurum (MIC = 7.8 mg / L) and M. bovis BCG (MIC = 31.25 mg / L) and considerably increases the susceptibility of M. smegmatis to ethidium bromide (MF = 128) and rifampicin (MF = 4).

 

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