In vitro wound healing potential of cyclohexane extract of Onosma dichroantha Boiss. based on bioassay-guided fractionation.

Onosma dichroantha Boiss. is a biennial herb used in traditional medicine in Iran for healing wounds and burns. Our previous study demonstrated that cyclohexane extract of O. dichroantha Boiss. enhanced wound healing in vitro. The aim of the present study was to identify the active fractions and compounds responsible for this effect through bio-guided fractionation followed by three in vitro tests for anti-inflammation, proliferation, and migration (scratch test). Fractionation of the CE extract yielded six fractions (Fr. A to Fr. F). Fr. F showed the most remarkable wound healing activity in three assays. Fr. F was further fractionated into five subfractions (FF-SUB1 to FF-SUB5). FF-SUB1 and FF-SUB2 were selected for further purification based on their wound healing activity. The major components, F. F1 to F. F5, were isolated from these two subfractions and identified as acetylshikonin, deoxyshikonin, β, β-dimethylacrylshikonin, β-hydroxyisovalerylshikonin, and trans-anethole of the active subfractions. Bioassay-guided fractionation revealed that naphthoquinone derivatives, as an active component, are responsible for the wound healing properties of the fractions and subfractions of cyclohexane extract of O. dichroantha roots. The findings indicate that these fractions and subsections, as well as purified compounds, have a high potential for further investigation as an effective therapeutic agent in wound healing using in vivo models.