Tropical Journal of Pharmaceutical Research

Original Research Article | OPEN ACCESS

Antimicrobial Activity of Flavonoids against Extended-Spectrum β-Lactamase (ESβL)-Producing Klebsiella pneumoniae.

B Özçelik1¹ , Deliorman D Orhan², S Özgen¹, F Ergun²

¹Department of Pharmaceutical Microbiology, Faculty of Pharmacy, Gazi University, 06330, Ankara, Turkey,; ²Department of Pharmacognosy, Faculty of Pharmacy, Gazi University, 06330 Ankara, Turkey..

For correspondence:- B Özçelik1 Email: berrin@gazi.edu.tr

Received: 10 July 2008 Accepted: 22 August 2008 Published: 16 December 2008

Citation: Özçelik1 B, Orhan DD, Özgen S, Ergun F. Antimicrobial Activity of Flavonoids against Extended-Spectrum β-Lactamase (ESβL)-Producing Klebsiella pneumoniae.. Trop J Pharm Res 2008; 7(4):1151-1157 doi: 10.4314/tjpr.v7i4.8

© 2008 The authors.
This is an Open Access article that uses a funding model which does not charge readers or their institutions for access and distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0) and the Budapest Open Access Initiative (http://www.budapestopenaccessinitiative.org/read), which permit unrestricted use, distribution, and reproduction in any medium, provided the original work is properly credited..

Abstract

Purpose: In the present study, six flavonoids (5,7-dimethoxyflavanone-4’-O-β-D-glucopyranoside, 5,7-dimethoxyflavanone-4’-O-[2’’-O-(5’’’-O-trans-cinnamoyl)-β-D-apiofuranosyl]-β-D-glucopyranoside, naringenin-7-O-β-D-glucopyranoside, 5,7,3’-trihydroxy-flavanone-4’-O-β-D-glucopyranoside, rutin, and nicotiflorin) isolated from Galium fissurense, Viscum album ssp. album and Cirsium hypoleucum were screened against extended-spectrum β-lactamase producing multidrug-resistant (trimetoprime-sulphametoxazole, sulbactam-ampicillin, clavulonate-amoxicilin, ceftriaxon, cefepime, imipenem, ceftazidime, tobramicin, gentamicin, ofloxacin, ciprofloxacin) bacteria Klebsiella pneumoniae (ESβLs).

Methods: We performed susceptibility testing according to the Clinical and Laboratory Standards Institute (CLSI, formerly NCCLS) and used an inhibition endpoint for determination of the minimum inhibition concentrations (MICs).

Results: All the flavonoids showed in vitro antimicrobial activity against all the isolated strains of K. pneumoniae similar to the control antibacterial (ofloxacin) at the concentrations of 32 - 64 µg ml^-l; another control, ampicillin, had no activity. Since, ESβL-producing strains are known to be resistant to all b-lactam antibiotics, our results fall notably within the concentration range for antimicrobial activity.

Conclusion: To the best of our knowledge, this is the first report of the study of the activity of these flavonoids against (ESβL)-producing K. pneumoniae and may throw light to the low-toxicity of flavonoids, and their potentials for developing therapies for infections caused by ESβL-producing bacteria in the future. Further work is under investigation to identify their precise antibacterial mechanism.

Keywords: Antimicrobial activity, ES^6;Ls, Flavonoids, Klebsiella pneumoniae, Ofloxacin, Ampicillin.