Open Access Research article

In Vitro antibacterial and antibiotic-potentiation activities of four edible plants against multidrug-resistant gram-negative species

Jaurès AK Noumedem12, Marius Mihasan2, Jules R Kuiate1*, Marius Stefan2, Dumitru Cojocaru2, Jean P Dzoyem1 and Victor Kuete1*

Author Affiliations

1 Department of Biochemistry, Faculty of Science, University of Dschang, Dschang, Cameroon

2 Department of Biochemistry and Molecular Biology, Faculty of Biology, University ALI Cuza, Iasi, Romania

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BMC Complementary and Alternative Medicine 2013, 13:190  doi:10.1186/1472-6882-13-190

Published: 25 July 2013



The present study was designed to investigate the antibacterial activities of the methanol extracts of four Cameroonian edible plants, locally used to treat microbial infections, and their synergistic effects with antibiotics against a panel of twenty nine Gram-negative bacteria including Multi-drug resistant (MDR) phenotypes expressing active efflux pumps.


The broth microdilution method was used to determine the minimum inhibitory concentrations (MICs) of the extracts [alone and in the presence of the efflux pumps inhibitor (EPI) Phenylalanine-Arginine β-Naphtylamide (PAβN)], and those of antibiotics in association with the two of the most active ones, Piper nigrum and Telfairia occidentalis. The preliminary phytochemical screening of the extracts was conducted according to the standard phytochemical methods.


Phytochemical analysis showed the presence of alkaloids and flavonoids in all studied extracts. Other chemical classes of secondary metabolites were selectively present in the extracts. The results of the MIC determination indicated that the crude extracts from P. nigrum and V. amygdalina were able to inhibit the growth of all the twenty nine studied bacteria within a concentration range of 32 to 1024 μg/mL. At a similar concentration range (32 to 1024 μg/mL) the extract from T. occidentalis inhibited the growth of 93.1% of the tested microorganisms. At MIC/2 and MIC/5, synergistic effects were noted between the extracts from P. nigrum and T. occidentalis and seven of the tested antibiotics on more than 70% of the tested bacteria.


The overall results of the present study provide information for the possible use of the studied edible plants extracts in the control of bacterial infections including MDR phenotypes.

Antibacterial activities; Edible plants; Gram-negative bacteria; Multidrug resistance; Efflux pumps