Browsing by Author "Nafis, Ahmed"
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- A comparative study of the in vitro antimicrobial and synergistic effect of essential oils from Laurus nobilis L. and Prunus armeniaca L. from Morocco with antimicrobial drugs: new approach for health promoting productsPublication . Nafis, Ahmed; Kasrati, Ayoub; Jamali, Chaima Alaoui; Custódio, Luísa; Vitalini, Sara; Iriti, Marcello; Hassani, LahcenLaurus nobilis L. (laurel, Lauraceae) and Prunus armeniaca L. (apricot, Rosaceae) are important industrial crops and display significant biological properties, including antimicrobial activity. In this work, essential oils (EOs) prepared from the leaves of both species from Morocco were evaluated for the first time for possible synergistic in vitro antibacterial and antifungal effects with some conventional antimicrobial drugs, namely fluconazole, ciprofloxacin and vancomycin. Samples were further evaluated for chemical composition by gas chromatography-mass spectrometry (GC-MS). The main volatile compounds detected in L. nobilis were eucalyptol (40.85%), α-terpinyl acetate (12.64%) and methyl eugenol (8.72%), while P. armeniaca was dominated essentially by (Z)-phytol (27.18%), pentacosane (15.11%), nonacosane (8.76%) and benzaldehyde (7.25%). Regarding antimicrobial activity, both EOs inhibited significantly all the microorganisms tested. The EO from L. nobilis had the highest activity, with minimal inhibitory concentrations (MICs) ranging from 1.39 to 22.2 mg/mL for bacteria and between 2.77 and 5.55 mg/mL for yeasts. Conversely, the combination of the studied EOs with ciprofloxacin, vancomycin and fluconazol resulted in a noteworthy decrease in their individual MICs. In fact, of the 32 interactions tested, 23 (71.87%) demonstrated total synergism and 9 (28.12%) a partial synergistic interaction. The EO from L. nobilis exhibited the highest synergistic effect with all the antibiotics used, with fractional inhibitory concentration (FIC) index values in the range of 0.266 to 0.75 for bacteria, and between 0.258 and 0.266 for yeast. The synergistic interaction between the studied EOs and standard antibiotics may constitute promising anti-infective agents useful for treating diseases induced by antibiotic-resistant pathogens.
- In vitro antimicrobial and synergistic effect of essential oil from the red macroalgae Centroceras clavulatum (C. Agardh) Montagne with conventional antibioticsPublication . Custódio, Luísa; Nafis, Ahmed; El Khalloufi, Fatima; Aknaf, Asmae; Oudra, Brahim; Marraiki, Najat; Al-Rashed, Sarah; Elgorban, AbdallahM; Syed, Asad; Hassani, LahcenObjective: To study the chemical profile, antimicrobial properties, and synergistic effect with known antibiotics of essential oil extracted from the marine red macroalgae Centroceras clavulatum (C. Agardh) Montagne, collected in Morocco. Methods: The chemical composition of the oil was analyzed by gas chromatography-mass spectrometry. The oil was evaluated for antibacterial (Pseudomonas aeruginosa, Escherichia coli, Bacillus subtilis, Micrococcus luteus, Staphylococcus aureus, and Klebsiella pneumoniae), and antifungal activity (Candida albicans, Candida glabrata, Candida krusei, and Candida parapsilosis), by the disc diffusion method. The minimum inhibitory and minimum microbicidal concentrations of the oil were determined, as well as the synergistic effects of its application combined with the antibiotics ciprofloxacin and fluconazole, by the checkerboard method. Results: Thirty molecules were identified in the essential oil, comprising 96.27% of the total oil composition. Monoterpenes such as carvacrol (36.06%) were the most abundant compounds, followed by caryophyllene (14.67%), endo-borneol (9.04%), pyroterebic acid (3.23%) and caryophyllene oxide (3.13%). The oil exhibited a moderate antimicrobial activity with inhibition zone diameters ranging from 9.0 to 15.0 mm. The minimum inhibitory concentration values varied between 0.9 and 14.7 mg/mL, and Bacillus subtilis and Escherichia coli were the more sensitive bacteria with 0.9 and 1.9 mg/mL, respectively. The minimummicrobicidal concentration values ranged from 0.4 to 14.7 mg/mL. A significant synergic action was observed when the oil was applied in combination with ciprofloxacin and fluconazole, with fractional inhibitory concentration index values ranging from 0.31 to 0.50. Synergy was found in 80% of the combinations and a 2 to 16-fold reduction of antibiotics MIC was observed. Conclusions: Our findings suggest that the essential oil of Centroceras clavulatum should be further appraised for its potential use in the management of multi-drug resistant microorganisms, with the purpose to restore the activity of standard antimicrobial drugs.
- New insight into the chemical composition, antimicrobial and synergistic effects of the Moroccan endemic Thymus atlanticus (Ball) roussine essential oil in combination with conventional antibioticsPublication . Nafis, Ahmed; Iriti, Marcello; Ouchari, Lahcen; El Otmani, Fatima; Marraiki, Najat; Elgorban, Abdallah M.; Syed, Asad; Mezrioui, Noureddine; Hassani, Lahcen; Custódio, LuísaThis study reported the volatile profile, the antimicrobial activity and the synergistic potential of essential oil (EO) from the Moroccan endemic Thymus atlanticus (Ball) Roussine, in combination with the antibiotics ciprofloxacin and fluconazole for the first time, to the best of our knowledge. The EO chemical composition was determined by gas chromatography coupled to mass spectrometry (GC-MS) analysis and the antimicrobial activity assessed by the disc diffusion method against three Gram positive (Bacillus subtilis, Micrococcus luteus, Staphylococcus aureus) and three Gram-negative bacteria (Pseudomonas aeruginosa, Escherichia coli and one clinical isolate, Klebsiella pneumonia). The antifungal activity was evaluated in four pathogenic yeasts (Candida albicans, C. glabrata, C. krusei and C. parapsilosis). The minimum inhibition concentration (MIC) and the synergistic effect with ciprofloxacin and fluconazole were determined by the two-fold dilution technique and checkerboard test, respectively. Twenty-one constituents were identified by GC-MS in the EO, including carvacrol (21.62%) and borneol (21.13%) as the major components. The EO exhibited a significant antimicrobial activity with inhibition zones ranging from 0.7 mm to 22 mm for P. aeruginosa and B. subtilis, respectively, and MIC values varying from 0.56 mg/mL to 4.47 mg/mL. The fractional inhibitory concentration index (FICI) values ranged from 0.25 to 0.50 for bacteria and from 0.25 to 0.28 for yeasts. The maximum synergistic effect was observed for K. pneumonia with a 256-fold gain of antibiotic MIC. Our results have suggested that EO from T. atlanticus may be used alone or in association with antibiotics as a new potential alternative to prevent and control the emergence of resistant microbial strains both in the medical field and in the food industry.