Wound Healing Activity of the Essential Oil of Bursera morelensis, in Mice

Abstract

Bursera morelensis is used in Mexican folk medicine to treat wounds on the skin. It is an endemic tree known as “aceitillo”, and the antibacterial and antifungal activity of its essential oil has been verified; it also acts as an anti-inflammatory. All of these reported biological activities make the essential oil of B. morelensis a candidate to accelerate the wound-healing process. The objective was to determine the wound-healing properties of B. morelensis’ essential oil on a murine model. The essential oil was obtained by hydro-distillation, and the chemical analysis was performed by gas chromatography-mass spectrometry (GC-MS). In the murine model, wound-healing efficacy (WHE) and wound contraction (WC) were evaluated. Cytotoxic activity was evaluated in vitro using peritoneal macrophages from BALB/c mice. The results showed that 18 terpenoid-type compounds were identified in the essential oil. The essential oil had remarkable WHE regardless of the dose and accelerated WC and was not cytotoxic. In vitro tests with fibroblasts showed that cell viability was dose-dependent; by adding 1 mg/mL of essential oil (EO) to the culture medium, cell viability decreased below 80%, while, at doses of 0.1 and 0.01 mg/mL, it remained around 90%; thus, EO did not intervene in fibroblast proliferation, but it did influence fibroblast migration when wound-like was done in monolayer cultures. The results of this study demonstrated that the essential oil was a pro-wound-healing agent because it had good healing effectiveness with scars with good tensile strength and accelerated repair. The probable mechanism of action of the EO of B. morelensis, during the healing process, is the promotion of the migration of fibroblasts to the site of the wound, making them active in the production of collagen and promoting the remodeling of this collagen.

Wound Healing Activity of α-Pinene and α-Phellandrene

“…Cell viability tests were performed in monolayer cultures of fibroblasts via live/dead staining, after 24 h of applying PIN and FEL at two concentrations (0.1 and 0.01 mg/mL). Neither concentration of each terpene affected the cell viability, since few red nuclei (dead cells) were observed (Figure 1), corroborating previous results corresponding to B. morelensis essential oil that contains these terpenes [17].…”

“…Neither concentration of each terpene affected the cell viability, since few red nuclei (dead cells) were observed (Figure 1), corroborating previous results corresponding to B. morelensis essential oil that contains these terpenes [17]. Once the cell viability of the fibroblast cultures was estimated, cell proliferation was evaluated by a PrestoBlue assay, where the absorbance is directly proportional to the cell proliferation.…”

“…Monoterpenes are C10, plastid derived terpenoids, often with appreciable volatility [20]. Among the terpenes that have been found in the EO of B. morelensis are α-pinene (PIN) and α-phellandrene (FEL) [15,17], particularly in our previous work…”

“…where it was shown that the EO of B. morelensis has healing activity and we found PIN in a concentration very close to 9% and FEL in a concentration very close to 1% [17] so, in this work, it was decided to test the healing activity of these terpenes at these concentrations. Both terpenes show anti-inflammatory activity [21][22][23].…”

“…Although there is growing interest in understanding the mechanisms underlying monoterpenes' pharmacological activity [28], little is known about the biological effects of PIN and FEL. Considering that these monoterpenes are important components of the EO of B. morelensis [17], this work aimed to determine their wound healing activity.…”