Study of the Physicochemical Properties and Antimicrobial Activities of Nanoparticles Containing β-Cyclodextrin and Geranial

In general, β-cyclodextrin (β-CD) is widely used in various technologies of the food industries. The aims of this study were preparation, characterization and optimization of a novel nanosize formulation of β-CD NPs loaded with geraniol (GR). In the current study, the optimum conditions for maximum encapsulation efficiency and loading of geraniol were assessed using response surface methodology (RSM). Furthermore, in vitro antimicrobial activities against Staphylococcus aureus, Bacillus cereus, Salmonella entritidis, Escherichia coli, Candida albicans and Aspergillus niger were studied. The present study is the first study to investigate antimicrobial activity of the GR inclusion complexes in nanosize formulations. The GR complexes were assessed using scanning electron microscopy (SEM), infrared (IR) spectroscopy and differential scanning calorimetry (DSC). Furthermore, antimicrobial activity of the inclusion complexes (IC) against bacteria and fungi were assessed. Minimum inhibitory concentrations (MIC) and inhibition zones of the GR-β-CD inclusion complexes were calculated using agar/broth dilution and agar well-diffusion methods. Encapsulation efficiency (EE) and loading values of the optimized formulation included 87.25 and 10.45%, respectively, with a size distribution of 117 nm ±1 and appropriate particle size distribution (PDI). Moreover, SEM, IR and DSC verified fabrication of inclusion complexes between GR and β-CD. The inhibition zones of β-CD-GR complexes were recorded as the following order: Bacillus cereus > Staphylococcus aureus > Salmonella entritidis > Escherichia coli. The RSM helped prepare geraniol nanoinclusion complexes using β-cyclodextrin with optimum responses. The antimicrobial activity of GR highly enhanced after efficient complexation. This study provides appropriate information on use of inclusion complexes of GR.