Anticancer, Antimicrobial, and Cytotoxic Potential of Melaleuca alternifolia Essential Oil: An In Vitro Evaluation

Abstract

The present study evaluated the anticancer, antioxidant, cytotoxic, and antimicrobial potential of Melaleuca alternifolia essential oil using in vitro models and GC–MS profiling. Its cytotoxic effects against HEK293 cells and antibacterial activity against selected pathogens were also assessed for potential therapeutic significance. Fresh leaves of M. alternifolia were collected, authenticated, shade-dried, and subjected to hydrodistillation using a Clevenger-type apparatus. The obtained essential oil was dried over anhydrous sodium sulfate and stored. GC–MS was employed for chemical profiling. Antioxidant activity was evaluated using the FRAP radical-scavenging assay, with ascorbic acid as the standard. Cytotoxic activity was determined by MTT assay using HEK293 cells, with doxorubicin as the reference drug. Antimicrobial activity against Escherichia coli and Staphylococcus aureus was evaluated by agar well diffusion. IC₅₀ values were calculated using GraphPad Prism.GC–MS analysis identified several volatile bioactive constituents, including terpenoids, fatty acid derivatives, and alcohols. The essential oil exhibited concentration-dependent antioxidant activity. MTT analysis demonstrated concentration-dependent reductions in HEK293 cell viability, with an IC₅₀ of 68.69 ± 0.05 µg/mL, whereas doxorubicin showed an IC₅₀ of 48.62 ± 0.04 µg/mL. Microscopic examination revealed cell shrinkage, rounding, reduced cell density, and altered morphology. The essential oil also demonstrated antibacterial activity against E. coli and S. aureus. M. alternifolia essential oil exhibits promising antioxidant, cytotoxic, and antimicrobial properties, supporting its potential as a natural source of bioactive compounds. Further mechanistic and in vivo studies are warranted to establish its therapeutic efficacy and safety.