Evaluation of Cedrus atlantica Essential Oil: Chemical Composition, Anticancer Activity and Molecular Docking Studies

Due to their high content of bioactive compounds with anticancer properties, essential oils (EO) are increasingly viewed as valuable therapeutic strategies in oncology. The aim of this study was to evaluate the chemical composition and anticancer activity of <i>Cedrus atlantica</i> EO (CAEO) and its PEG-400 and Tween 20 formulations. The gas-chromatography (GC) analysis revealed a sesquiterpene-rich profile, with β-himachalene (39.32%) as the major constituent, followed by α-Himachalene (16.76%) and γ-Himachalene (12.92%). The cytotoxicity studies, performed using Alamar Blue assay on normal HaCaT human keratinocytes and A375 human melanoma and HT-29 colorectal carcinoma cell lines, revealed that CAEO displayed minimal toxicity on HaCaT cells, while significantly reducing A735 and HT-29 cell viability, at any of the concentrations tested. The PEG- and Tween-based formulations of CAEO exhibited the same effect on cell viability as the simple water dispersion of CAEO. The immunofluorescence-based examination of cellular morphology suggested that CAEO induces apoptosis in both cancer cell lines: A375 and HT-29; this apoptosis-related mechanism was further supported by the caspase-3/7 assay, which revealed a significant increase in caspase-3/7 activity after CAEO treatment. To further investigate the underlying mechanism, the JC-1 staining and high-resolution respirometry assays demonstrated that CAEO induces mitochondrial membrane depolarization and reduced mitochondrial active respiration (OXPHOS). Molecular docking further indicated that isoledene and β-himachalene exhibit the highest predicted affinity for PI3Kγ, suggesting a potential involvement of PI3K-related signaling in the pro-apoptotic activity of CAEO. Together, these results suggest that CAEO induces apoptosis through a mitochondria-mediated mechanism.