Antibacterial Activities of Selected Cameroonian Plants and Their Synergistic Effects with Antibiotics against Bacteria Expressing MDR Phenotypes.

Stephen T Lacmata,Jean P Dzoyem,Jules R Kuiate,Gerald Ngo Teke,Victor Kuete,Jean-Marie Pages,Simplice B Tankeo

doi:10.1155/2012/623723

Abstract

The present work was designed to assess the antibacterial properties of the methanol extracts of some Cameroonian medicinal plants and the effect of their associations with currently used antibiotics on multidrug resistant (MDR) Gram-negative bacteria overexpressing active efflux pumps. The antibacterial activities of twelve methanol extracts of medicinal plants were evaluated using broth microdilution. The results of this test showed that three extracts Garcinia lucida with the minimal inhibitory concentrations (MIC) varying from 128 to 512 μg/mL, Garcinia kola (MIC of 256 to 1024 μg/mL), and Picralima nitida (MIC of 128 to 1024 μg/mL) were active on all the twenty-nine studied bacteria including MDR phenotypes. The association of phenylalanine arginine β-naphthylamide (PAβN or efflux pumps inhibitor) to different extracts did not modify their activities. At the concentration of MIC/2 and MIC/5, the extracts of P. nitida and G. kola improved the antibacterial activities of some commonly used antibiotics suggesting their synergistic effects with the tested antibiotics. The results of this study suggest that the tested plant extracts and mostly those from P. nitida, G. lucida and G. kola could be used alone or in association with common antibiotics in the fight of bacterial infections involving MDR strains.

Highlights

Bacterial infections are responsible for 90% of infections found in health care services
Extracts were tested for their antibacterial activities alone and in combination with phenylalanine arginine β-naphthylamide (PAβN) on a panel of Gram-negative bacteria by the microdilution method
Flavonoids, phenols, saponins, anthocyanins, anthraquinones, sterols, tannins, and triterpenes have been found active on pathogenic microorganisms [44, 45]

Summary

Introduction

Bacterial infections are responsible for 90% of infections found in health care services. The emergence of MDR bacterial strains appears as the major cause of treatment failure [1]. Among the known mechanisms of resistances, active efflux via resistance-nodulation-cell division (RND) pumps is one of the most occurring system in Gram-negative bacterial strains [2]. Efflux pumps are transport proteins involved in the extrusion of toxic substrates (including virtually all classes of clinically relevant antibiotics). The present work was designed to investigate the antibacterial potential against MDR bacteria expressing active efflux though RND pumps. Medicinal plants of Cameroon used in this study include the fruits of Citrus medica L. (Rutaceae), the bulbs of Allium sativum L. Medicinal plants of Cameroon used in this study include the fruits of Citrus medica L. (Rutaceae), the bulbs of Allium sativum L. (Liliaceae) and Allium cepa

Methods

Results

Conclusion