Antimicrobial and Antibiotic-Resistance Reversal Activity of Some Medicinal Plants from Cameroon against Selected Resistant and Non-Resistant Uropathogenic Bacteria

Abstract

Background and Aim: Antibiotics’ resistance is the leading cause of complications in the treatment of urinary tract infections. This study aimed to screen the antimicrobial potential of 8 plants from Cameroon against multi-resistant uropathogenic (MRU) bacteria and to investigate their antibioresistance reversal properties. Method: Bioactive compounds were extracted from leaves of Leucanthemum vulgare, Cymbopogon citratus, Moringa oleifera and Vernonia amygdalina; barks of Cinchona officinalis and Enantia chlorantha barks and seeds of Garcinia lucida and leaves and seeds of Azadirachta indica using water and ethanol as solvents. The extracts were tested against Escherichia coli ATCC 25922, Staphylococcus aureus ATCC 6538 and Candida albicans 10231 using the well diffusion and the broth microdilution methods. The antibiotic-resistance reversal activity was assessed against selected MRU bacteria. The phytochemical composition and the elemental composition of the most active extracts were assessed respectively using HPLC-MS/MS and X-ray fluorescence (XRF) spectrometry. Results: Among the most active plants, in decreasing order of antimicrobial activity we found ethanolic (EE) and aqueous extracts (AE) of E. chloranta bark (ECB), EE of L. vulgare leaves and G. lucida seeds. The best synergies between common antibiotics and extracts were found with EE-ECB which well-modulated kanamycin nitrofurantoin and ampicillin. All the compounds identified in EE-ECB were alkaloids and the major constituents were palmatine (51.63%), columbamine+7,8-dihydro-8-hydroxypalmatine (19.21%), jatrorrhizine (11.02%) and pseudocolumbamine (6.33%). Among the minerals found in EE-ECB (S, Si, Cl, K, Ca, Mn, Fe, Zn and Br), Br, Fe and Cl were the most abundant with mean fluorescence intensities of 4.6529, 3.4854 and 2.5942 cps/uA respectively. Conclusions: The ethanol extract of the bark of E. chlorantha has remarkable, broad-spectrum antimicrobial and contains several palmatine derivatives.

Keywords

• medicinal plants
• antimicrobial
• synergy test
• antibiotics
• multiresistant
• uropathogenic bacteria