Volatile-Driven Antioxidant Activity of Pomelo Peel Essential Oil: Bridging Chemical Composition and Cellular Redox...

Pomelo (Citrus maxima) peel essential oil is a volatile-terpenoid-rich plant extract that may exhibit antioxidant-associated effects in biological systems. However, the relationship among its chemical composition, conventional antioxidant capacity, and cellular effects under oxidative stress remains insufficiently defined. This study integrated gas chromatography-mass spectrometry (GC-MS) profiling with chemical antioxidant assays and an SH-SY5Y cell-based oxidative-stress model. Under the selected analytical and data-processing conditions, limonene was the only compound confidently identified and integrated by GC-MS. In chemical assays, pomelo peel essential oil showed moderate DPPH radical-scavenging and ferric-reducing activities compared with the hydrophilic reference antioxidants Trolox and ascorbic acid. Cellular effects were evaluated separately in SH-SY5Y cells exposed to H₂O₂-induced oxidative stress. Pomelo peel essential oil was tested at 25, 50, and 100 μg/mL using cotreatment and pretreatment protocols. In the cotreatment model, cells were exposed simultaneously to the essential oil and H₂O₂, whereas in the pretreatment model, cells were incubated with the essential oil before H₂O₂ challenge. Pomelo peel essential oil attenuated intracellular ROS accumulation and lipid peroxidation and improved cell viability, with clearer effects at 50 and 100 μg/mL. Pretreatment generally produced stronger cytoprotective effects than cotreatment. These findings indicate that conventional chemical antioxidant assays alone may not fully predict cellular antioxidant-associated effects, particularly for lipophilic essential oils. Pomelo peel essential oil therefore showed cytoprotective activity in an SH-SY5Y oxidative-stress model, although the contributing constituents and underlying molecular mechanisms require further investigation.