A Study on the Composition, Antimicrobial and Antioxidant Activities of the Leaf Essential Oil of Apium leptophylum (Pers.) Benth. Growing in Ethiopia
AbstractIn Ethiopian traditional medicine the leaves of Apium leptophyllum (Pers.) Benth. are used for the treatment of a disease condition locally known as “Mitch”, which is characterized mainly by inflammation, sweat and
loss of appetite. Steam distillation of the leaves of A. leptophyllum afforded a colourless essential oil with a yield of 0.24% (v/w). Gas chromatography-mass spectrometry (GC/MS) analysis revealed the presence of twenty components comprising 98.64% of the total peak area of which more than 80% of the oil was represented by only five major components. These were identified as thymoquinol dimethyl ether (46.00%), γ-terpinene (12.63%), isothymol methyl ether (12.57%), p-cymene (10.29%) and thymol methyl ether (6.80%). The in vitro antimicrobial activity of the oil as investigated by standard disc diffusion technique indicated that it was active against a broad spectrum of pathogens including Gram-positive and Gramnegative bacteria as well as some fungal strains. However, its activity was more prominent against the
Gram-negative bacteria E. coli, P. aeruginosa, S. dysenteriae and V. cholerae with an MIC value of 50 μg/ml. In addition, the oil demonstrated an excellent in vitro radical scavenging activity in 2,2-diphenyl-1- picrylhydrazyl (DPPH) assay with an IC50 value of 4.3 μl/ml. The traditional use of the plant for abating the symptoms of “Mitch” could be justified by its antimicrobial and radical scavenging activities which are probably related to the etiology of the disease condition.