Chemical Profiling and ROS-Dependent Antiproliferative Activity of Artemisia nilagirica (C.B.Clarke) Pamp. (Asteraceae) Essential Oil in Human Gastric Adenocarcinoma Cells.

Essential oils (EOs) are known for their rich chemical diversity and wide-ranging pharmacological properties. This study investigated the chemical profile and antiproliferative mechanism of Artemisia nilagirica (Asteraceae) essential oil (ANEO) against human gastric adenocarcinoma cells (AGS and KATO III). Hydrodistillation yielded 0.95% (v/w) ANEO, with camphor (22.59%), caryophyllene oxide (11.28%), and humulene epoxide II (10.52%) as major constituents. ANEO showed potent, dose-dependent cytotoxicity with IC50 values of 23.51 ± 0.39 µg/mL (AGS) and 17.36 ± 0.55 µg/mL (KATO III). Mechanistically, ANEO induced significant oxidative stress, causing intracellular reactive oxygen species (ROS) accumulation (up to 11,600 ± 580 units in AGS), glutathione depletion, and increased lipid peroxidation (Thiobarbituric acid reactive substances (TBARS) up to 4.00 ± 0.11 nmol/mg in AGS and 4.10 ± 0.31 nmol/mg in KATO III). This oxidative imbalance triggered mitochondrial-dependent apoptosis, evidenced by cytochrome c release (up to 10,600 ± 490 units in KATO III) and increased apoptotic protease-activating factor-1 (Apaf-1) expression, leading to effector caspases-3/7 activation. The findings demonstrate that ANEO exerts its anti-gastric cancer effect primarily via ROS-mediated oxidative stress, activating the intrinsic apoptotic pathway.