Development of a Lemon-peppermint Essential Oil Nanoemulsion Blend: Effects on Bacillus spp. Inhibition, A549 Lung Cancer Cell Viability, Cell Cycle Progression, and Genotoxicity.

The increasing resistance to treatments and limited effectiveness of singular medications against cancer and foodborne bacteria highlight the need for therapeutic synergy using multiple natural components. This study aimed to develop a blend nanoemulsion (NE) combining two plant essential oils, lemon (LEO) and peppermint (PEO), for anticancer and antibacterial testing. The chemical composition of PEO and LEO was analyzed by GC-MS, identifying D-limonene (77.89%) and menthol (56.63%) as their primary constituents. The NEs were prepared with droplet sizes of 57.2 (LEO), 104.2 (PEO), and 44.3 nm (blend), confirmed by FTIR. Cellular viability, DNA damage, and cell cycle progression in A549 lung cancer cells were assessed, showing a 50% reduction in viability after treatment with LEO (1.7 mg/mL), PEO (4.9 mg/mL), and the blend (2.5 mg/mL). Blend NE induced apoptosis and halted the S-phase of the cell cycle. Antibacterial activity was evaluated against Bacillus cereus, Bacillus subtilis, and Pseudomonas aeruginosa. Regarding MIC, blend NE (20 mg/mL) was more effective than LEO-NE (40 mg/mL) and PEO-NE (80 mg/mL) against B. subtilis. TEM analysis confirmed bacterial lysis, supporting the blend NE's superior antimicrobial effects. This synergy holds promise for enhanced cancer treatment and antibacterial applications.