Nanoemulsion encapsulation improves the stability and antibacterial efficacy of orange (Citrus x sinensis) peel essential oil

Abstract Antimicrobial resistance, especially in Pseudomonas aeruginosa, presents a serious global health threat. Natural products like essential oils have shown promising antibacterial properties due to their multi-component systems, which are less prone to developing resistance. However, their instability and volatility limit their broader use. This study focuses on stabilizing essential oils by encapsulating them in emulsions. Essential oil from Citrus × sinensis peels was extracted through steam distillation and analyzed using gas chromatography–mass spectrometry (GC–MS), identifying 29 compounds, with limonene as the primary component. Emulsions were formulated with various surfactant-oil ratios using Tween 80 as the surfactant and water as the dispersed phase. The mean droplet sizes (186.40 nm, 78.20 nm, and 73.97 nm) and polydispersity indices (1.0, 1.0, and 0.8) of emulsions labelled SN 7, 8, and 9 respectively were determined using dynamic light scattering, with SN 8 and SN 9 as nanoemulsion. The 9:1 surfactant-oil emulsion displayed better physical stability and a lower minimum inhibitory concentration (0.02 mg/mL) compared to the essential oil alone (0.04 mg/mL). All emulsions demonstrated bacteriostatic properties, with the 9:1 formulation showing the highest potential as an effective antibacterial agent. This highlights the potential for using stabilized essential oils for possible therapeutic applications.