Effect of Melaleuca alternifolia oil on cytotoxicity and neuropeptide y gene expression

Background and Aims: This study aims to investigate the effect of tea tree oil (TTO), which is an oil produced by steam distillation of the Melaleuca alternifolia (Maiden & Betche) Cheel plant terminal branches and leaves, on changes in neuropeptide Y (NPY) gene expression in SH-SY5Y neuroblastoma cells. Methods: The first stage of this study investigates the cytotoxic/proliferative effects of TTO solutions prepared at different concentrations on the SH-SY5Y cell line using the tetrazolium reduction (MTT) assay. The next stage analyzes the effects of the determined TTO concentrations on NPY gene expression using the real-time polymerase chain reaction (qPCR) method. Results: TTO concentrations prepared at a ratio of 1:32, 1:64, and 1:28 (v/v) showed statistically significant effects on cells in the cytotoxicity test and were used in the gene expression analysis. The highest significant gene expression change was seen in the cells in which the TTO solution had been applied at a ratio of 1:64 for 24 hours. NPY gene expression in these cells was determined to have increased 2.24 times compared to control cells. Conclusion: Upon evaluating the results from the MTT assay and gene expression analysis, the solutions of the cells prepared at different TTO ratios were determined to have caused changes in gene expression. Future studies will be able to reveal all affected molecular pathways by increasing research involving TTO.