Bactericidal and antioxidant effects of essential oils from Satureja montana L., Myristica fragrans H. and Cymbopogon flexuosus

The extraction and characterization of the essential oils (EO) from Satureja montana L., Myristica fragrans H. and Cymbopogon flexuosus and the determination of their antibacterial and antioxidant activities were achieved. The EO were identified by gas chromatography/mass spectrometry and quantified by gas chromatography using a flame ionization detector. The antibacterial potential against Escherichia coli and Staphylococcus aureus was evaluated by cell susceptibility assays and by scanning electron microscopy. The antioxidant activity was evaluated by the 2,2-diphenyl-1-picrylhydrazyl assay, by beta-carotene bleaching and by determining the reducing power. Borneol (36 center dot 18%), gamma-terpineol (12 center dot 66%) and carvacrol (11 center dot 07%) were the principal components in the EO from S. montana, and sabinene (49 center dot 23%) and alpha-pinene (13 center dot 81%) were found in the EO from M. fragrans. Geranial (59 center dot 66%) and neral (38 center dot 98%) isomers were the only major components in the EO from C. flexuosus. The EO from S. montana was effective against E. coli, with minimum inhibitory and bactericidal concentrations (MIC and MBC) of 6 center dot 25 mu l ml(-1), whereas bactericidal potential against both was observed for the EO from M. fragrans; MIC = 6 center dot 25 mu l ml(-1) for S. aureus and MBC = 12 center dot 5 mu l ml(-1) for E. coli. A significant protective role on lipid substrates in the beta-carotene bleaching assay was seen for the EO from S. montana and M. fragrans. Overall, such EO can be promising agents against pathogenic bacteria and for protecting biomolecules during oxidative stress.