this study tested 15 different essential oils and how they affected both the formation of biofilms and the degradation of already formed biofilms. the oils were tested against lysteria, which is one of the most potent foodborne pathogens in the world. Infection by this agent can cause death in up to 30% of cases.
the oils tested were Rosemary, peppermint, tea tree,garlic, aloe vera, licorice, St. John's wort, clove, thyme, cranberry, green tea, buchu, rooibus, echinacea.
They determined that just about all of the essential oils inhibited the formation of biofilms. However! Inhibiting the formation of biofilms is totally different than degrading biofilms that have already been formed. The latter is much much more difficult. many different compounds inhibit biofilms from forming in the first place. However, only a few actually break up biofilms that have already established themselves.
In this case, of the 15 essential oils that inhibited the formation of biofilms, only three of them actually degraded biofilms that had already been formed.
Those three essential oils are - Rosemary, peppermint, and tea tree. the study gives the scientific name for these three oils. in my previous entry I posted a study comparing the results of using eucalyptus and peppermint against bio films. In that study the two oils both proved to be highly effective against biofilms, with eucalyptus being slightly more effective.
Combining the results of those two studies brings us to the conclusion that both eucalyptus and peppermint oils are the most effective essential oils against biofilms according to the research available so far.
much more data on this study is given at the link if you are interested in reading more
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Abstract
- Top of page
- Abstract
- Introduction
- Materials and methods
- Results
- Discussion
- Conclusions
- References
Aims: The antibiofilm activity of extracts obtained from selected herbs, spices, beverages and commercially important medicinal plants was investigated on Listeria monocytogenes.
Methods and Results: The growth and development of the biofilm was assessed using the crystal violet (CV) assay. The respiratory activity was assessed using the 2, 3-bis [2-methyloxy-4-nitro-5-sulfophenyl]-2H-tetrazolium-5-carboxanilide (XTT) reduction assay. The majority of extracts tested prevented cell adhesion to the polyvinyl chloride (PVC) surface. Seven of the 15 extracts reduced biofilm adhesion of both the clinical and the type strains by at least 50%. In contrast, inhibition of a preformed biofilm was more difficult to achieve, with only three extracts (Rosmarinus officinalis, Mentha piperita and Melaleuca alternifolia) inhibiting the growth of both strains by at least 50%.
Conclusions: Although most extracts were able to reduce initial cell attachment, inhibition of growth in a preformed biofilm was more difficult to achieve.
Significance and Impact of the Study: The ability to reduce biofilm biomass as shown by several plant extracts warrants further investigation to explore the use of natural products in antibiofilm adhesion.
http://onlinelibrary.wiley.com/doi/10.1111/j.1472-765X.2009.02747.x/full
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