Chemical profiling and biological assessment of trunk bark essential oil from Eucalyptus camaldulensis: In vitro study coupled with chemoinformatics calculations

The aim of this study was to identify the chemical composition of the essential oil of Eucalyptus camaldulensis trunk bark (ECEO) and to investigate its in vitro antioxidant, anti-5-lipoxygenase, anti-acetylcholinesterase, antibutyrylcholinesterase and anti-alpha-amylase activities. The chemical composition of the essential oil extracted from trunk bark of E. camaldulensis was analyzed by GC-FID and GC/MS, twenty-one compounds were identified accounting for 96.3% of total oil. The phytochemical profile of this essential oil was distinguished by the dominance of oxygenated monoterpenes (58.4%) with Delta 8,9-dehydro-4-hydroxythymoldimethyl ether (31.4%), thymohydroquinone methyl ether (21.9%), and modephen-8-beta-ol (12.9%) as major compounds. Additionally, the ECEO was examined for its antioxidant activity using three in vitro tests (DPPH, ABTS center dot+ radicals and H2O2 assays). ECEO showed the highest effect in the hydrogen peroxide assay (IC50= 33.55 +/- 2.10 mu g/mL). Additionally, ECEO exhibited significant anti-alpha-amylase and anti-acetylcholinesterase activities (IC50= 10.02 +/- 1.88 and 5.88 +/- 0.81 mu g/mL, respectively). In silico analysis was in agreement with the in vitro studies in which most potent components of ECEO showed strong interactions into the binding sites of the enzymes (PDBs: 4EY6 (acetyl cholinesterase), and 7TAA (alpha-amylase)) and good ADMET properties. Our results might be due to the synergistic effect of constituents present in this essential oil or acting separately. The obtained results pave the way for the promising applications the essential oil obtained from E. camaldulensis trunk bark in food and the pharmaceutical fields.