Optimization and Characterization of Lippia citriodora Essential Oil Loaded Niosomes: A Novel Plant-based Food Nano Preservative

The Lippia citriodora essential oil (LCEO) loaded nano-niosomes were prepared by thin-film hydration method utilizing different molar ratios of surfactants (Span 60/Tween 60) and stabilizers (cholesterol/vitamin D3) as well as different amounts of essential oil. The chemical composition of LCEO was evaluated with Gas chromatography mass spectrometry. alpha- curcumene (28.84%) and limonene (23.72%) were two major components of LCEO. The encapsulation efficiency, zeta potential, vesicle size, and PDI of niosome samples were investigated. All variables significantly affected the physicochemical properties of niosomes (P < 0.05). Based on the results, different ratios of Span 60/Tween 60 significantly affected the particle size, Zeta potential and PDI (P < 0.05). Besides, it was found that the amount of LCEO and cholesterol/vitamin D3 ratios had significant effects on the all investigated parameters. The niosome containing Span 60, cholesterol, and 5.5 mg/ml LCEO was chosen as the optimal formulation. The niosomes prepared by this formulation had high encapsulation efficiency (>85%) and a nanometric size of < 200 nm. Differential scanning calorimetry and Fourier transform infrared spectroscopy analyses confirmed the successful incorporation of LCEO into the niosome. The results of scanning electron microscopy indicated that the niosomes had good size distribution, quasi-spherical form, and smooth surface. According to the results of evaluating the antimicrobial activity of LCEO, using the well diffusion method, the antimicrobial effect of niosome incorporated LCEO was more than that of free LCEO. It was also found that the sensitivity of Staphylococcus aureus to the encapsulated LCEO was more than that of Escherichia coli. DPPH scavenging method was used to characterize the antioxidant activity of the essential oil, showing that niosome containing LCEO has good antioxidant activity. It could be concluded that these new colloidal systems have an interesting potential for application in food industry as a novel plant-based food nano preservative to deliver poorly-soluble bioactive compounds.