Thymol induces mitochondrial pathway-mediated apoptosis via ROS generation, macromolecular damage and SOD diminution
Devasahayam Jaya Balan1, Tamilselvam Rajavel1,2, Mamali Das1
1Department of Biotechnology, Alagappa University [Science Campus], Karaikudi, Tamil Nadu, 630 003, India.
Background:
Thymol is a monoterpene phenol found in thyme species plants. The present study was carried out to investigate the effect of thymol and its molecular mechanism on non-small lung cancer (A549) cells.
Methods:
The cytotoxic effect of thymol on A549 cells was assessed via MTT assay. ROS production, macromolecular damage, apoptosis were determined using DCF-DA, PI, AO/EtBr stains, respectively. ROS-dependent effect of thymol was confirmed using NAC. The expression of caspase-9, Bcl-2, Bax and cell cycle profile was analyzed via western blot and FACS, respectively.
Results:
The antiproliferative effect of thymol on A549 cells was found to be both dose and time dependent with IC50 values of 112 μg/ml (745 μM) at 24 h. Thymol treatment favored apoptotic cell death and caused G0/G1 cell cycle arrest. It mediated cellular and nuclear morphological changes, phosphatidylserine translocation, and mitochondrial membrane depolarization. Additionally, upregulation of Bax, downregulation of Bcl-2, and apoptotic fragmented DNA were also observed. Thymol induced ROS by reducing the SOD level which was confirmed via in vitro and in silico analysis. Furthermore, the levels of lipid peroxides and protein carbonyl content were elevated in thymol-treated groups. Notably, N-acetyl cysteine pretreatment reversed the efficacy of thymol on A549 cells. Moreover, thymol-treated human PBMC cells did not show any significant cytotoxicity.
Conclusion:
Overall, our results confirmed that thymol can act as a safe and potent therapeutic agent to treat NSCLC.
Insights
Thymol, a natural compound, effectively inhibits non-small cell lung cancer (NSCLC) by inducing apoptosis and cell cycle arrest. It shows potent anti-cancer effects with minimal toxicity to normal cells.
Area of Science:
- Natural product chemistry
- Molecular oncology
- Cell biology
Background:
- Thymol is a monoterpene phenol derived from thyme plants.
- Non-small cell lung cancer (NSCLC) is a major global health concern.
- Investigating natural compounds for NSCLC therapy is crucial.
Purpose of the Study:
- To evaluate the anti-cancer effects of thymol on A549 NSCLC cells.
- To elucidate the molecular mechanisms underlying thymol's action.
- To assess thymol's safety profile on normal human cells.
Main Methods:
- Cytotoxicity assessed using MTT assay.
- Apoptosis, cell cycle, ROS production, and DNA damage analyzed via flow cytometry and western blot.
- N-acetyl cysteine (NAC) used to confirm ROS-dependent effects.
Main Results:
- Thymol exhibited dose- and time-dependent antiproliferative activity against A549 cells (IC50 = 112 μg/ml at 24h).
- Thymol induced apoptosis, G0/G1 cell cycle arrest, and ROS generation, while downregulating Bcl-2 and upregulating Bax.
- Thymol demonstrated significant anti-cancer effects with no significant cytotoxicity observed in human peripheral blood mononuclear cells (PBMCs).
Conclusions:
- Thymol possesses potent anti-cancer properties against NSCLC.
- Thymol's mechanism involves ROS induction, apoptosis, and cell cycle arrest.
- Thymol represents a potential safe and effective therapeutic agent for NSCLC treatment.
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