Compound in Essential Oils Improves Wound Healing

Indiana University researchers have discovered that a chemical compound found in essential oils improves the healing process in mice when it is topically applied to a skin wound. The study was published Monday in PLOS ONE.

The chemical compound, beta-carophyllene, is found in lavender, rosemary, and ylang ylang, as well as various herbs and spices such as black pepper. Skin tissue that was treated with this compound showed increased cell growth and migration, which is critical to wound healing. Additionally, hair follicle stem cells in treated tissue exhibited increased gene expression. The scientists did not find any involvement of the olfactory system in the wound healing.

“This is the first finding at the chemical-compound level showing improved wound healing in addition to changes in gene expression in the skin," says first author Sachiko Koyama. “The way gene expression changed also suggests not only improved wound healing but also the possibility of less scar formation and a more full recovery. It’s an example that essential oils work; however, it’s not through our sense of smell.”

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 knew that beta-caryophyllene activates not only olfactory receptors but also cannabinoid receptor 2 (CB2), which has an anti-inflammatory impact. “In the wound healing process, there are several stages, starting from the inflammatory phase, followed by the cell proliferation stage and the remodeling stage,” she explains. “I thought maybe wound healing would be accelerated if inflammation was suppressed, stimulating an earlier switch from the inflammatory stage to the next stage.”

Suppressing inflammation did accelerate the wound-healing process, 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 doesn’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. “It’s not very precise to use the essential oils themselves because there are differences,” she says. “Even if you say you used lavender, when the lavender was harvested, where it was harvested, how it was stored—all of this makes a difference in the chemical composition.”