Wound healing activity of Sweetgum oil (Liquidambar orientalis L. balsam): Characterization of its mechanism of action on HaCaT human keratinocyte cells and possible responsible active constituents

The wound healing activity of sweetgum oil being a product of Liquidambar orientali s endemically grown in Turkey was tested in cell culture and its mechanism of action was first investigated in this study. By using extracts of sweetgum oil belonging to two different local producers in Muğla, experiments were conducted with human derived HaCaT keratinocyte cells lines. For the investigation of possible active constituents of sweetgum oil samples, IT-TOF/MS spectroscopic analyses were applied. Titrated Centella asiatica extract, a standard wound healing drug, was used as a positive control to compare the efficacy of sweetgum oil. Initially, MTT assay was applied to determine the non-toxic concentration of sweetgum oil and a possible proliferative activity in HaCaT keratinocyte cells. Real-time cell analysis system for proliferation and cell migration detection; scratch test and real-time polymerase chain reaction (RT-PCR) to check collagen type-1 alpha-1 mRNA expression. In MTT assay, non-toxic concentrations were determined as 0.1, 0.01 and 0.001 µg/mL. According to the real-time cell analysis system results, a significant increase in cell proliferation and migration was observed at 0.001 µg/mL concentrations. In scratch assay, it was observed that the distance on both sides of the wound was significantly closed at 0.001 µg/mL concentrations. Effects on HaCaT cells were time-dependent in nature. According to the Real-Time PCR result, no increase in collagen type-1 alpha-1 mRNA expression was observed. From these findings, it was concluded that sweetgum oil is effective in wound healing, and phenylpropyl cinnamate seems to be the main active ingredient for this effect.