Multitarget Antioxidant and Anticancer Potential of <i>Euphorbia greenwayi</i> Essential Oil: Phytochemical Profiling and Molecular Insights

Abstract

The Euphorbia greenwayi essential oil (EGEO) was analyzed by GC-MS, and 17 components were identified, accounting for 99.70%, predominantly monoterpene (98.28%). The major components were limonene (26.46%), α-pinene (18.50%), 1,8-cineole (25.62%), β-pinene (6.52%), and γ-terpinene (4.36%). Antioxidant potential was evaluated using DPPH and ABTS radical scavenging assays. The EGEO exhibited dose-dependent activity, with respective IC₅₀ values of 417.7 and 448.8 mg/L, indicating moderate antioxidant capacity. Cytotoxic activity was assessed on THLE-2 (normal liver), MCF-7 (breast cancer), and HepG2 (liver cancer) cells. The EGEO exhibited negligible cytotoxicity toward THLE-2 cells (> 93% viability at 0.1-500 µg/mL), while showing pronounced cytotoxicity against MCF-7 cells (IC₅₀ = 166.65 µg/mL) and moderate activity against HepG2 cells (IC₅₀ = 328.03 µg/mL), highlighting selective antiproliferative effects. Molecular docking further substantiated the anticancer potential of EO constituents. Limonene demonstrated the strongest binding affinity against aurora kinase A (-10.586 kcal/mol) and the tumor suppressor PTEN (-6.397 kcal/mol), outperforming other tested monoterpenes. It established key interactions with hinge (Ala273), DFG motif residues in aurora A, and P-loop residues (Cys124, Arg130) in PTEN, positioning it as a dual-target lead compound. Sabinene also showed favorable binding to aurora A (-9.964 kcal/mol) but was less active toward PTEN. These findings suggested that EGEO possesses promising antioxidant and anticancer properties, with limonene emerging as a potential multitarget therapeutic agent for oxidative stress-related and proliferative disorders.