Chemical composition, free radical scavenging capacity and molecular docking evaluation of essential oils from leaves, roots, and flowers of <i>Ambrosia polystachya</i> DC. growing in Tunisia

The essential oils (EOs) isolated from fresh leaves, roots, and flowers of <i>Ambrosia polystachya</i> DC. growing in Tunisia were analysed by GC/MS. Twenty-four compounds were identified in the leaf EO, with β-caryophyllene (27.7%), germacrene D (27.1%), and borneol (11.4%) as the main compounds. In the root EO, nineteen compounds were identified, among which <i>iso</i>pimara-7,15-dien-3-one (23.3%), modephene (15.5%), and α-isocomene (13.6%) were detected with the highest relative abundances. The flower EO consisted of twenty-seven compounds, the main ones being β-caryophyllene (26.5%), caryophyllene oxide (14.8%), and germacrene D (14.0%). All EOs were rich in sesquiterpene hydrocarbons and oxygenated sesquiterpenes, but with differences between the percentages of the compounds among the different studied organs. The obtained EOs also possessed good free radical scavenging activity assessed by the DPPH test. Furthermore, an <i>in-silico</i> evaluation against Human catalase (pdb:1DGH) of the major phytoconstituents using molecular docking analysis suggests their potential for antioxidant applications.