Antioxidant and antimicrobial properties of randomly methylated β cyclodextrin – captured essential oils

Free essential oils and their active components have a low physiochemical stability and low aqueous solubility which limit their applications as food preservatives and in packaging industry. The aim of this study was to characterize the physicochemical properties, antioxidant activities and antimicrobial activity of randomly methylated β cyclodextrin (RAMEB) encapsulated thyme oil, lemon balm oil, lavender oil, peppermint oil and their active components that include thymol, citral, linalool, menthol and borneol. Inclusion complex formation of essential oils (EOs) and RAMEB were evaluated by several methods. Antioxidant capacities of RAMEB-EOs/components were reported to be more stable than free EOs/components (P < 0.05). Rapid SYBR green I/propidium iodide live/dead microbial cellular discrimination assay for Schizosaccharomyces pombe, Escherichia coli and Staphylococcus aureus showed similar results when compared with flow cytometry analysis (P < 0.01) suggesting that our novel microplate fluorescence method could be applied for the fast live/dead microbial discrimination in antimicrobial assays.