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.
In making my first samples, there were a few problems we ran into. We had previously determined that we needed to add aloe Vera gel in order to create a homogeneous mixture. Once we determined this, we needed to analyze the effect of its addition of the results of UV radiation and antimicrobial activity. The results showed that the higher the amount of aloe Vera gel, the more UV was able to penetrate the surface, which is not ideal. In order to reduce the effect of the aloe Vera gel, I experimented with adding lower concentrations. The concentration had to be high enough to still create a homogeneous mixture, but low enough to not effect the UV too extensively. It was found that for some samples, adding half of the amount of aloe still allowed the honey and oils to mix effectively, but for other samples, changing the amount of aloe did not allow for the separate layers to mix. We are still doing literature searches on the structure of the oils, honey, and aloe to further understand the interaction of the aloe with different oils and why lowering the concentration is allowed for some samples, but not others.
The surfaces we are creating are meant to have a longer shelf life and this aspect of our research had not been tested for this particular project. Dr. Rizzo and I devised a plan to test this. I made samples that were tested right away, but I kept part of these samples to be tested progressively throughout the semester. The UV radiation did not appear to change with the time the samples sat. However, we are still waiting for the antimicrobial results.
Dr. Rizzo and I are studying the use of Manuka Honey and Beeswax as a Natural Antibacterial Wound Dressing. We are creating a flexible wound dressing with these materials by infusing a variety of natural oils and powders. Our laboratory has previously demonstrated antimicrobial efficacy of a formulation utilizing other natural butters and oils against Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa. Our goal is to demonstrate that these novel materials will prevent skin infections and possibly serve to heal an already infected wound. Through this project, I will have the opportunity to present at a national conference for the American Chemical Society, where I will be able to discuss my research with many established scientists
My methods include measuring out certain volumes of essential oils and infusing them with various types of honey as well as beeswax. The types of honey include Manuka honey, Raw honey, and Raw unfiltered honey. The addition of aloe vera gel has proven to be necessary as well, due to the fact that the honey and oils do not mix together by themselves. The aloe allows all of the materials to combine into the same layer for testing. Once the sample is made, its resistance to ultraviolet radiation is tested as well as its antibacterial effect.