An In vitro Investigation of Cytotoxic Potential of Platanus orientalis Leaves on Lung Cancer Cell Line

Platanus orientalis is a medicinal plant with numerous biological activities, including wound healing, anti-inflammatory, antioxidant, and anti-proliferative activities. This study aimed to evaluate the anticancer effect of Platanus orientalis leaf ethanol extract (PO-EE) against A549 human lung cancer cells and determine the possible mechanism of the extract-induced apoptosis. PO-EE was obtained by Soxhlet extraction in 80% ethanol at 45oC for 16 hours. Phytochemical constituents of PO-EE were determined using gas chromatography-mass spectrometry (GC-MS). Cytotoxicity of PO-EE was evaluated using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay, followed by high-content screening for apoptosis detection. Apoptotic mechanism was investigated by evaluating caspases 8 and 9 activities, as well as BAX and Bcl-2 genes expression. GC-MS analysis revealed fatty acids as the major components of PO-EE. Anti-cancer activity screening results showed that PO-EE significantly inhibited the proliferation of A549 cells in a concentration-dependent manner, with an IC50 of 65.22 µg/mL. High-content screening confirmed the cytotoxic effects of PO-EE, showing increased nuclear condensation, membrane permeability, loss of mitochondrial membrane potential, and cytochrome c release in treated cells. PO-EE induced caspases 8 and 9 activation in A549 cells, indicating the involvement of both extrinsic and intrinsic apoptotic mechanisms. Molecular analysis revealed a 2.85-fold upregulation of the pro-apoptotic BAX gene expression and 0.11-fold downregulation of Bcl-2 gene upon PO-EE treatment. These findings suggest that PO-EE exhibits potent anticancer activity against A549 cells by triggering apoptosis through mitochondrial dysfunction and caspase cascade activation. The findings therefore highlight the therapeutic potential of P. orientalis leaf extract, especially for lung cancer treatment.