Cytotoxic and Apoptotic Effects of Leptospermum petersonii-Derived 6-Methyltectochrysin in A375 Melanoma Cells

Background/Objective: Melanoma is the most aggressive form of skin cancer and most common among fair-skinned people, and about 80% of fatalities are from skin lesions. The rise in deaths from melanoma worldwide has been related to a lack of access to healthcare, mostly in low-income nations. Melanoma therapy using current treatments, such as cisplatin, has been beneficial. However, it has been linked to irreversible DNA damage, whereas most current treatments are either ineffective or have intolerable side effects. This study investigated the cytotoxic effects of Leptospermum petersonii extracts on A375 melanoma cells and aimed to identify at least one putative bioactive compound. L. petersonii is a well-established medicinal plant for its antimicrobial activities, and its leaves are reported to contain essential oils that suppress fungus development. However, no previous research on the effects of this herb on cancer has been reported. Methods: The sequential extraction was conducted by soaking the leaves in hexane, ethyl acetate, and methanol. The chemical 6-methyltectochrysin was effectively isolated from L. petersonii and showed cytotoxicity against melanoma cancer cells. Caspase Glo 3/7 and Annexin V-FITC–PI apoptotic tests were performed following 6-methyltectochrysin administration. Results: The findings showed cytotoxicity and possible apoptosis induction in A375 cells, and further examination using relative expression analysis revealed an increase in the pro-apoptotic Bax and a decrease in the anti-apoptotic Bcl-2 gene. Conclusions: Further research is needed to identify molecular pathways and targets of the compound 6-methyltectochrysin in melanoma cancer cells.