Chemical compound in essential oils may improve wound healing

A chemical compound found in essential oils improves the healing process in mice when it is topically applied to a skin wound, which could lead to improved treatments for skin injuries in humans, according to a new study by researchers at Indiana University and published in the journal PLOS One.

In the study, researchers led by Sachiko Koyama, PhD, found that skin tissue treated with beta-carophyllene, which is found in lavender, rosemary and ylang ylang, as well as various herbs and spices such as black pepper, showed increased cell growth and cell migration critical to wound healing. The researchers led by also observed increased gene expression of hair follicle stem cells in the treated tissue. The scientists did not find any involvement of the olfactory system in the wound healing.

Essential oils are natural, concentrated oils extracted from plants. Their use by humans dates back to ancient Egypt, but the scented oils have experienced a resurgence in popularity in the U.S. over the past few years, with many people using them for aromatherapy.

Koyama, whose original field of study is pheromones, said she wasn't interested in essential oils at first. The project started when she saw several students studying the wound healing process in mice in the Medical Sciences Program at the IU School of Medicine-Bloomington. Having previously worked in the IU College of Arts and Sciences' Department of Psychological and Brain Sciences, where scientists are working with cannabinoid receptors, Koyama knew that beta-caryophyllene activates not only olfactory receptors but also cannabinoid receptor 2 (CB2), which has anti-inflammatory impact when it is activated.

This accelerated the wound healing process, she said, but the resulting change in gene expression indicates that the improved healing is not merely achieved through activation of the CB2 receptor.

Although the study's results are promising, Koyama said she wouldn't recommend that people start treating their injuries with just any essential oils, as her research applies to a very specific chemical compound with known purity, diluted in a specific concentration.

Koyama said further research is required to figure out how beta-carophyllene might be used to develop new treatments for skin wounds in humans. She said she hopes to better understand the mechanisms that accelerate the healing process and to find a combination of chemical compounds that could be used together to accelerate drug delivery and chemical stability, which is important for avoiding or suppressing allergic responses caused by oxidation of the chemical compounds.

"There are many things to test before we can start using it clinically, but our results are very promising and exciting,” said Koyama in a statement. “Someday…we may be able to develop a drug and drug delivery methods using the chemical compounds found in essential oils."