Abstract:

To solve the problems of volatility and poor stability of Zanthoxylum bungeanum essential oil (ZBEO), ZBEO nanoliposomes (ZBEO-NL) were developed in this study using a thin-film hydration-high-pressure homogenization method with egg yolk lecithin and cholesterol as encapsulation materials, with the aim of improving stability and expanding application potential. The physicochemical properties of ZBEO-NL were systematically evaluated by encapsulation efficiency, dynamic light scattering, transmission electron microscopy, Fourier-transform infrared spectroscopy, X-ray diffraction, thermogravimetric analysis, and storage stability tests. The antibacterial activity was investigated using the agar diffusion method. The nanoliposomes exhibited an encapsulation efficiency of 88.7% ± 1.2%, a monodisperse unilamellar vesicle structure, and a hydrated particle size of 161.69 ± 2.4 nm (Zeta potential = -32.12 ± 0.8 mV), clearly superior to empty liposomes (158.80 ± 3.1 nm, Zeta potential = -27.08 ± 1.2 mV). Fourier-transform infrared spectroscopy and X-ray diffraction analysis revealed that amorphous complexes were formed through hydrogen bonding and hydrophobic interactions between phospholipid molecules and ZBEO, while thermogravimetric analysis confirmed that its thermal decomposition temperature was delayed to 435.6 ℃. Storage studies showed a minimal encapsulation efficiency reduction of 8.2% after 14 days at 4 ℃. Antibacterial tests showed that ZBEO-NL exhibited a significantly stronger inhibitory effect against Escherichia coli (inhibition zone diameter: 18.55 ± 0.33 mm) and Bacillus subtilis (14.37 ± 0.17 mm) compared to free ZBEO (16.25 ± 0.80 mm and 12.24 ± 0.10 mm, respectively), with statistical significance (P < 0.05). In this study, a highly stable ZBEO nanodelivery system was successfully constructed, and ZBEO-NL was developed based on a bionic phospholipid-cholesterol membrane structure, providing a theoretical basis and technical support for the industrial application of natural antibacterial agents.

Key words:

Zanthoxylum bungeanum essential oil, Nanoliposomes, Characterization, Stability; Antibacterial activity