Scientists across the U.S have discovered that peppermint oil and cinnamaldehyde can help in the treatment and curing of chronic wounds.
Photo Credit: FotoosVanRobin
The research led by Vincent M. Rotello of the University of Massachusetts, Amherst and others from other institutes, stated that self-assembling capsules containing peppermint oil and cinnamaldehyde can effectively kill the bacteria inside a biofilm that are resistant to even the strongest antibiotics.Chronic wounds do not cure in a synchronized set of phases and in a stipulated period of time, unlike most wounds do. They stay in the inflammatory stage for months and may never heal. They lack the balance between production and degradation of molecules, thereby the latter playing the most significant part.
By joining hands together, when bacteria produce biofilms by engulfing themselves in a shielding goo, they cause incessant infections and stay unaffected by antibiotics. Such biofilms often happen around internal devices like urinary catheters – something that a patient is given after any kind of surgery, and artificial joints.
Scientists said that cutting off the tissues or covering the devices with silver nitrate or other antibiotic agents can kill the bacteria and delay the biofilm formation, respectively – but all these are very expensive methods. Therefore, Rotello and his team opted for a cheaper and easily accessible way of using peppermint oil and cinnamaldehyde.
Rotello said that the terpene ingredients of peppermint oil and cinnamaldehyde – the element responsible for the flavor of cinnamon, help killing bacteria. But the only problem was that both of them were insoluble in water, thereby making it hard for them to go in direct contact with bacteria.
Rotello discovered that if droplets of peppermint oil and cinnamaldehyde were encapsulated in self-assembling silica nanoparticles in water then the amine group present in each nanoparticle would react with cinnamaldehyde to produce imine, thereby making the silica shell more hydrophobic.
A capsule of silica nanoparticles (gray) helps smuggle peppermint oil (green) and cinnamaldehyde (red) through bacterial biofilms. Cinnamaldehyde reacts with amines on the nanoparticles’ surfaces to make them more hydrophobic, stabilizing the capsule.
The research team found that these encapsulated silica nanoparticles easily infiltrated the biofilms of various bacteria, and caused an acidic atmosphere in them that in return broke the imines and unloaded the contents – peppermint oil and cinnamaldehyde.
Investigations showed that the capsules killed 99.99 percent of bacteria compared to the unencapsulated peppermint oil and cinnmaldehyde, which had only little effect.
The study also found that cinnamaldehyde present in the capsules encouraged the development of fibroblast cells, which are engaged in healing wounds.
Y.S Prakash who is an anesthesiologist and biomedical engineer at the Mayo Clinic in Rochester, Minnesota said, “What you need is something that will kill the biofilm but not the tissue beneath.”
Researchers are yet to find the exact mechanism by which the capsules work. However, Helen E. Blackwell of the University of Wisconsin, Madison, who is preparing ways to disturb the biofilms said that smuggling other therapeutic molecules with the oil droplets could also be a possibility.
Rotello and team is now expecting to test the capsules on mouse models.
The study has been published in the journal ACS Nano.