It is widely known that honey is antimicrobial. However, there are many different kinds of honey and the antimicrobial properties differ amongst them. Dr. Rizzo and I have been experimenting to determine the best honey to focus our research on. We sent out samples containing both raw honey and Manuka honey to LIU Post, where the antimicrobial factors of the samples are tested using the zone diameter of inhibition technique. When tested alone, the raw honey gave a value of 1.1 for the diameter, which is the minimum diameter needed to be considered antimicrobial. This showed us that raw honey itself was not as effective as Manuka honey, so we are now starting to focus on using different brands of Manuka Honey. In order to understand why there was such a difference in the effects of the pure honey samples, I conducted a literature search. The reason for the difference in antimicrobial effectiveness between these two honeys comes from their composition. Raw honey is a peroxide honey, while Manuka honey is non-peroxide. For peroxide honey, peroxide and polyphenols contribute most to the antimicrobial properties of the honey. For honey that is non-peroxide, the main antimicrobial component is methylglyoxal, with polyphenols also being important. Although it is present in all honeys, methylglyoxal is much more concentrated in Manuka honey, which has stronger antimicrobial properties than peroxides.
In addition to determining the most effective honey, we have also been experimenting to find the most effective essential oil to mix the honey with. It has been determined that cinnamon cassia is definitely the most effective among the oils. In the first set of samples I prepared and had tested, I mixed a 3:1:1 ratio of honey, oil, and aloe vera gel, respectively. This gave values of 3.5 and 2.2 when tested against the growth of S. aureus and E. Coli. I consulted Dr. Rizzo with these results and we decided to test the effect when we increased the concentration of the cinnamon cassia oil, and thus the aloe vera gel. In the next set of samples, I prepared a sample of a 3:2:2 ratio of manuka honey to cinnamon cassia oil to aloe, respectively. This gave values of 4 for S. aureus and 3.6 for E. Coli, both of which show a very high antimicrobial factor.
We are still working on testing the longevity of these surfaces. I made a large amount of one sample and sent a potion to LIU Post. I have some stored in the research lab, which we will be sending out in increments each month. This data will give us information on the integrity and antimicrobial efficacy of the material over time. We are also beginning to test the change in antimicrobial effects when different oils are mixed into one sample. In addition, the use of plant powders will also be implemented into the samples.