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Abstract
This study was carried out to assess the chemical composition, antioxidant and antimicrobial activities of Eucalyptus citriodora essential oil growing in Algeria. The chemical composition of the oil was analyzed by GC and GC/MS and revealed the presence of 22 compounds which accounted for 97.13 % of the oil. The main compounds was Citronellal (69.77 %) followed by Citronellol (10.63 %) and Isopulegol (4.66 %). Antioxidant activity was evaluated by using 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay. The free radical scavenging activity of the oil was found to be inferior (IC50 values = 0.896 mg/ml) as compared to butylatedhydreoxytoluene (BHT), (IC50 value = 0.041 mg/ml). The antimicrobial activity of Eucalyptus citriodora essential oil against twelve bacteria and two yeasts was determined via both the disc diffusion method and the Disc volatilization method. Higher antimicrobial activity was observed in the liquid phase. The minimum inhibitory concentration (MIC) was found to vary from 0.6 to 20 μl/ml for bacteria while for yeasts it was equal to 1.25 μl/ml. The most sensitive strains were the Gram positive bacteria Staphylococcus epidermidis and the two yeasts while the most resistant bacterium was Pseudonomas aeruginosa. This is the first report on the antioxidant and antimicrobial properties of the essential oil of Eucalyptus citriodora growing in Algeria.
Keywords: Antimicrobial activity; Antioxidant activity; Chemical composition; Essential oil; Eucalyptus citriodora Hook.
1. Introduction
Aromatic plants, such as those from Myrtaceae family are known for their wide spread use both traditionally and commercially to increase the shelf-life and safety of foods. They have demonstrated several therapeutic properties, mainly antioxidant, antimicrobial and anti-inflammatory. This usefulness of plants is due to their complex mixture of compounds including aldehyde, and phenolic compounds [1]. In particular, the antimicrobial properties of plant essential oils and their constituents have been widely demonstrated [2]. Eucalyptus, a native from Australia, belongs to Myrtaceae family and includes about 800-900 species and subspecies [3, 4]. Today, Eucalyptus may be found almost everywhere in the world since it is grown in many countries [5] including tropical, subtropical and even sub-temperature countries [6]. Aromatic plants and their essential oils have been used since antiquity in flavor, fragrance, embalmment, preservation of foods, antimicrobial remedies, medecine, perfumery, and pharmaceutical industries [7, 8]. Eucalyptus has been largely studied as...