Antimicrobial Efficacy of Liposome-Encapsulated Citral and Its Effect on the Shelf Life of Shatangju Mandarin.

ABSTRACT: Liposome-encapsulated citral was prepared by means of a hot homogenization method. The microstructure, particle size, and zeta potential of the capsules were analyzed by transmission electron microscope and dynamic light scattering, respectively, in which the results showed a good dispersion stability of the citral-loaded liposome. In vitro tests showed that liposome-encapsulated citral significantly (P < 0.05) reduced the populations of Escherichia coli, Bacillus subtilis, Staphylococcus aureus, and Penicillium italicum more than free citral. In vivo tests conducted on fresh Shatangju mandarin showed that liposome-encapsulated citral-treated fruit exhibited a decay incidence of 56.67%, which is 42.04% lower than free citral-treated fruit (97.78%) after 26 days of storage at 25°C and 60 to 70% relative humidity. Additionally, fruit treated with citral-loaded liposome significantly reduced weight loss and viable yeast and mold during storage. In summary, liposome-encapsulated citral could be an effective antimicrobial agent to extend the shelf life of the Shatangju mandarin.

Preparation, characterization and in vitro release study of drug-loaded sodium carboxy-methylcellulose/chitosan composite sponge.

A sodium carboxy-methylcellulose (CMC)/chitosan (CS) composite sponge as drug carrier was prepared, and its structure and functions were investigated. Samples with different CMC/chitosan ratios and under different pH conditions were synthesized via a freeze-drying method. The microstructure of the dried sponges was analyzed by Scanning Electron Microscope (SEM). Molecule interactions between polymers were confirmed by Fourier transform infrared (FTIR) spectra and Thermal gravimetric analyze (TGA). The swelling degree, weight loss, in vitro drug release behavior and antibacterial property of the sponges were determined as well. The results showed that the CMC/chitosan ratio and the pH value significantly affected the appearance of the blending solution and the microstructure of the final product, and also affected the sponge's degradation behavior, drug-loading capacity and the antibacterial activity. Gentamicin (GEN) as a hydrophilic model drug was remarkably superior to the other two hydrophobic drugs, ibuprofen (IBU) and roxithromycin (ROX), with respect to in vitro releasing. Moreover, higher CMC content and lower pH value of the sponge were confirmed to lead a larger loading for GEN. The bacteriostatic experiment showed a strong antimicrobial ability of GEN-loaded sponges on inhibiting Escherichia coli.