Origanum syriacum Induces Apoptosis in Lung Cancer Cells by Altering the Ratio of Bax/Bcl2.

Background: The lung cancer is the leading cause of death worldwide. Although methods such as surgery, chemotherapy, radiotherapy, and immunotherapy are used for treatment, these treatments are sometimes inadequate. In addition, the number of chemotherapeutic agents used is very limited, and it is very important to use new natural agents that can increase the effect of these methods used in treatment.

Objective: The present study was designed to determine the suppression of proliferation and induction of apoptosis activities and phenolic content of Origanum syriacum methanol extract (OsME) on lung cancer cells (A549).

Methods: For this purpose, the cell viability of A549 cells exposed to OsME was first determined. The morphological changes of the cell were observed by an inverted phase contrast microscope. Moreover, the percentage of apoptotic and necrotic cells was determined by FACS with AnnexinV/Propodium iodide staining. Additionally, proapoptotic Bax and antiapoptotic Bcl-2 mRNA levels were determined by Real-time PCR. Phenolic compounds of OsME were detected by LC-MS-MS.

Results: It was observed that the viability and proliferation of lung cancer cells decreased after the treatment of different concentrations of OsME. At a concentration of 200 mg/ml of OsME, most of the cell membrane structures were observed to disintegrate. Meanwhile, a 25 μg/ml concentration of OsME increased the Bax expression and percentage of late apoptotic cells. Vanillic acid and luteolin were identified as the main phenolic compounds of OsME.

Conclusion: OsME exhibited antiproliferation activity on A549 cells and induced apoptosis at low doses.