Phenolic Extracts of Zizyphus lotus L. (Rhamnaceae) and Ruta chalepensis L. (Rutaceae) as Alternatives to Antibiotics and their Antimicrobial Effects on Clinical Multidrug-Resistant Pathogens

Authors : Nour El Houda Bekkar, Meddah Boumediene, Yavuz Selim Cakmak, Bahadır Keskin, Pascal Sonnet

Pages : 163-183

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Publication Date : 2022-12-29

Article Type : Research

Abstract :Objective: The phytochemical composition and the antibacterial and antifungal properties of Zizyphus lotus L. (ZL) leaves and Ruta chalepensis L. (RC) aerial parts harvested from Oran in northwest Algeria were assessed against multidrug-resistant (MDR) clinical pathogens. Materials and Methods: The phenolic compounds identification in the hydromethanolic (MeOH.E) and the aqueous extracts (Aq. E) was done by HPLC-DAD analysis, while the phenolic, flavonoid and tannin contents were determined using quantitative methods. The antibacterial and antifungal activities were also determined. The synergistic effect between both plants was elucidated using the checkerboard dilution test. Results: An important phenolic content was determined with higher concentrations in Z. lotus leaves extracts than R. chalepensis. The HPLC-DAD analysis allowed us to identify benzoic acid as the major phenolic compound in Z. lotus extracts, while catechin, quercetin and epicatechin were the major compounds identified in R. chalepensis. Important antimicrobial activity was observed against all the clinical pathogen strains. The most potent effect was estimated against MDR Salmonella enterica sp. arizonae with 20±0.1mm of growth inhibition zone diameter using RCMeOH.E, while a diameter of 35.03±0.06 mm was measured using ZLMeOH.E. Also, important anti-Candida activity was estimated. No synergistic interaction against the different microbial strains was determined by applying the combinations of both plants\' extracts, with a fractional inhibitory concentration index superior to 4 (FICindex >4). Conclusion: Z. lotus and R. chalepensis can be exploited in the medical field as a potential source of antimicrobial components.
Keywords : Antibiotic alternatives, antimicrobial activity, multidrug-resistant pathogens, phenolic compounds, R. chalepensis, Z. lotus