Essential Oils as Antibiotics: Research Updates
French researchers at the Antibiology Laboratory, CHU Hospital Nord, Saint-Etienne, have just published data on the antibacterial action of several essential oils against a variety of microbe strains. The purpose of the study was to evaluate the potential of essential oils in treatment of nosocomial infections -- those that tend to occurr in hospitals that are secondary to the patient's original ailment or condition.
Published in the 'Letters of Applied Microbiology', the study concluded the strongest antibacterial oils are those from cinnamon bark and oregano. These have always been considered the most broad-spectrum antibactierial essential oils, with the lowest MIC, or 'minimum inhibitory concentration' required to eradictate the bacterial strain being tested. Aromatherapists sometimes consider using these oils 'the shotgun approach', being a little strong for most people to use without very strict guidelines or naturopathic support.
The best choices for antibacterial use of essential oils is the targeted use of the most appropriate oil for the bacteria involved. Dr. Kurt Schnaubelt in Advanced Aromatherapy offers an excellent chart of the effects of a great many essential oils on certain bacteria. Also of interest is the use of broad spectrum antibacterial blends (such as Purify). While their are no data yet to support their use, they are more than likely the better route for fortifying the immune system to defend against bacterial invaders. The addition of oils like Eucalyptus and Rosemary, while NOT strong antibiotics when tested in the laboratory, are very important as they HAVE been shown to directly enhance the workings of immune system cells.
Study: Comparison of bacteriostatic and bactericidal activity of 13 essential oils against strains with varying sensitivity to antibiotics.
Mayaud L, Carricajo A, Zhiri A, Aubert G.Antibiology Laboratory, CHU Hospital Nord, Saint-Etienne, France.
AIMS: To compare the bacteriostatic and bactericidal activity of 13 chemotyped essential oils (EO) on 65 bacteria with varying sensitivity to antibiotics. METHODS AND RESULTS: Fifty-five bacterial strains were tested with two methods used for evaluation of antimicrobial activity (CLSI recommendations): the agar dilution method and the time-killing curve method. EO containing aldehydes (Cinnamomum verum bark and Cymbopogon citratus), phenols (Origanum compactum, Trachyspermum ammi, Thymus satureioides, Eugenia caryophyllus and Cinnamomum verum leaf) showed the highest antimicrobial activity with minimum inhibitory concentration (MIC) <2%> or = 10% (v/v). Against P. aeruginosa, only C. verum bark and O. compactum presented MIC < or =2% (v/v). Cinnamomum verum bark, O. compactum, T. satureioides, C. verum leaf and M. alternifolia were bactericidal against Staphylococcus aureus and Escherichia coli at concentrations ranging from to 0.31% to 10% (v/v) after 1 h of contact. Cinnamomum verum bark and O. compactum were bactericidal against P. aeruginosa within 5 min at concentrations <2% (v/v). CONCLUSIONS: Cinnamomum verum bark had the highest antimicrobial activity, particularly against resistant strains. Significance AND IMPACT OF THE STUDY: Bacteriostatic and bactericidal activity of EO on nosocomial antibiotic-resistant strains.