IC50 values from DPPH and ABTS assays (mean±SEM).

For many years, essential oils (EOs) have gained attention as natural alternatives to synthetic antimicrobials and antioxidants, although their cytotoxicity remains a major concern for topical use. Leaf EOs from vetiver (Chrysopogon zizanioides), lemongrass (Cymbopogon citratus), and bud EO from clove (Syzygium aromaticum) were tested for their antimicrobial, antioxidant, and cytotoxic activities. Disk diffusion, minimum inhibitory concentration (MIC), and minimum inhibitory concentration (MBC) testing were performed to assess antimicrobial activity against the common skin bacterial pathogens: Methicillin-sensitive Staphylococcus aureus (MSSA), Methicillin-resistant Staphylococcus aureus (MRSA), Staphylococcus epidermidis, and Pseudomonas aeruginosa. Clove bud oil exhibited the lowest MIC value of 0.98 μg/mL, whereas vetiver and lemongrass were less effective. In addition, clove bud oil showed the highest antioxidant activity (IC₅₀ value: 3.8 μg/mL for DPPH and 11.3 μg/mL for ABTS). Cytotoxicity on HaCaT cell line showed IC₅₀ for clove, lemongrass and vetiver of 122.14, 123.77 μg/mL and 312.55 μg/mL respectively. The oils of clove bud and vetiver both have antimicrobial activity well below their respective cytotoxic concentrations, indicating a broad margin of safety. However, lemongrass oil required higher concentrations, approaching or exceeding its IC₅₀, particularly against S. epidermidis. These results support the potential of clove bud and vetiver oils for safe topical antimicrobial applications, with caution advised for lemongrass.