Antimicrobial properties and analytical profile of traditional Eruca sativa seed oil: Comparison with various aerial and root plant extracts

The present study investigates the antimicrobial activity of various solvent extracts of Eruca sativa (aerial and root) and seed oil against-antibiotic resistant Gram-negative (Escherichia coli, Pseudomoms aeruginosa and Shigella flexneri) and Gram-positive (Staphylococcus aureus and Bacillus subtilis) bacteria. Among the various preparations, seed oil was the most active, exhibiting a maximum zone inhibition of 97% for Gram-positive bacteria and of 74-97% for Gram-negative bacteria. The MIC of the seed oil was found to be 65-75 and 60-70 mu g/ml for Gram-negative and Gram-positive bacteria, respectively. Analytical investigation on main volatile and non-volatile components was performed on seed oil. Among the formers allyl isothiocyanate (40 mu g/g). 3-butenyl isothiocyanate (260 mu g/g), 4-methylsulfinybutyl isothiocyanate (sulforaphane 743 mu g/g), 2-phenylethyl isothiocyanate (159 mu g/g) and bis(isothiocyanatobutyl)disulphide (similar to 5000 mu g/g) were determined by head space/SPME/GC-MS analysis. Free fatty acids were 1.6% w/w of the oil and overall 25 fatty acids were identified. Erucic and oleic acids were the main fatty acids both in the free (7.8 and 2.1 mg/ml) and esterified forms (50.6% w/w and 14.9% w/w of total fatty acids). Unsaponifiable fraction was 1.8% w/w. Seed oil of E. sativa has promising pharmacological efficacies and ensures the presence of bio-active components responsible for the observed beneficial effects. Our findings support its use in traditional medicine as antimicrobial bioagent and highlight the potential of this food plant for its possible clinical use. (C) 2009 Elsevier Ltd. All rights reserved.