Chemical composition, antimicrobial activity and synergistic potential of essential oil from endemic Lavandula maroccana (Mill.)

• Published in: South African journal of botany Vol. 125; pp. 202 - 206
• Main Authors: Soulaimani, B., Nafis, A., Kasrati, A., Rochdi, A., Mezrioui, N.-E., Abbad, A., Hassani, L.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.09.2019
• Subjects: Antimicrobial activity; Chemical composition; Essential oil; Lavandula maroccana Murb; Synergistic potential; Antimicrobial activity; Essential oil; Chemical composition; Lavandula maroccana Murb; Synergistic potential
• ISSN: 0254-6299; 1727-9321
• DOI: 10.1016/j.sajb.2019.07.030

The aims of the present study were to evaluate for the first time the chemical composition and in vitro antimicrobial potential of essential oil (EO) obtained from endemic Lavandula maroccana (Murb.) singly or in combination with some conventional antimicrobials (ciprofloxacin, vancomycin, fluconazol, and amphotericin B) against a panel of pathogenic microorganisms. The gas chromatography/mass spectrometry (GC/MS) analysis of EO led to the identification of 20 components, representing 98.8% of the total oil. The main constituent was the phenolic monoterpene carvacrol (78.2%), followed by 2-Methoxy-4-vinylphenol (2.5%), and Spathulenol (2.2%). The results of the antimicrobial assays demonstrated that L. maroccana EO displayed moderate activity, with minimal inhibitory concentration (MIC) values of 4.604 mg/mL for yeasts and ranged from 2.302 to 18.416 mg/mL for bacteria. According to FIC index values, the combination between L. maroccana EO and conventional antimicrobials elicited very promising synergistic effects against all tested strains. In fact, at sub-inhibitory concentrations L. maroccana EO contributed to the decrease of fluconazol and amphotericin B MICs of Candida strains by 64- to 128-fold and by 2- to 4-fold, respectively. Regarding bacterial strains, L. maroccana EO has reduced the ciprofloxacin and vancomycin MICs by 4- to 33-fold and by 2- to 4-fold, respectively. From these results, it can be concluded that L. maroccana EO can be considered as a promising source of natural antimicrobials, and constitute a potential candidate to be used in combination antibiotic therapy in order to reduce the overuse of antibiotics, and to combat some human infectious diseases. •Composition and synergistic antimicrobial potential of L. maroccana EO have been investigated.•Lavandula maroccana EO was characterized by the dominance of carvacrol.•Lavandula maroccana EO showed moderate antimicrobial activity.•Lavandula maroccana EO combined with antimicrobials showed promising synergistic effects.•The studied EO contributed to the decrease of antimicrobial MICs by 2- to 128-fold.