Aims:
Determination of essential oils components of two Algerian medicinal plants, Origanum glandulosum Desf(oregano) and Artemisia herba alba (white mugwort) and study of their antimicrobial activity against multi resistant strains of bacteria isolated from urinate and expectorations of infected patients , Escherichia coli, Klebsiella pneumoniae Pseudomonas aeruginosa, Staphylococcus aureus
Methods and results:
Essential oils (E.O) obtained by hydrodistillation were investigated by gas chromatography/mass spectrometry (GCMS). The main components were carvacrol(39%),thymol (21%) and δ terpinene (18.4%) in the extract of oregano and camphor (25.9%), cis-verbenol (18.5%) and α-thujone (16.1%) in white mugwort extract. Antimicrobial activity of both essential oils extracts was examined against four multiresistant bacteria strains, Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, and Staphylococcus aureus . Minimal Inhibitory Quantities (MIQ) of volatile phases were calculated. The volatile phase of oregano revealed an antibacterial activity on E. coli, K. pneumoniae and S. aureus (MIQ 20 µl), while the volatile phase of white mugwort was active only against S. aureus (MIQ 80µl). Minimal Inhibitory Concentrations (MIC) of Oregano E.O. 3.2 µl ml-1 and 4 µl ml-1 were recorded towards K. pneumoniae and E. coli respectivly ;and above 4 µl ml-1 for S .aureus . Mugwort E.O MIC towards S. aureus was higher than 8µl ml-1.
Conclusion:
Oregano essential oil was the most powerful against the whole strains tested in particularly against S. aureus, with a strongest activity towards P. aeruginosa., the essential oils of white mugwort inhibited only the growth of S. aureus.
Significance and impact of the study:
Due to the increasing microbial resistance of pathogenic microorganisms against antibiotics, and then the limitation of the use of antibiotics usage, natural substances like essential oils are interesting sources for looking for novel antimicrobial compounds.
