An inclusion complex of eugenol into β-cyclodextrin: Preparation, and physicochemical and antifungal characterization

The inclusion of eugenol (EG) into beta-cyclodextrin (BCD), its structural characterization and antifungal activity, and mode of action for control of Peronophythora litchii in postharvest fresh litchi fruits is described. Nuclear magnetic resonance spectra revealed chemical shifts in H-3 and H-5 protons of beta CD, indicating EG inclusion into the lipophilic cavity of beta CD. In vitro assays showed beta CD-EG significantly inhibited P. litchii colony growth in a concentration- and time-dependent manner (MIC100 = 0.2 g). In vivo assays showed beta CD-EG significantly (p < 0.05) reduced the decay index of treated fresh litchi fruits. After exposure to beta CD-EG, the surface of P. litchii hyphae and/or sporangiophores became wrinkled, with folds and breakage observed by scanning electron microscopy. Damage to hyphal and/or sporangiophore cell walls and membrane structures post-treatment with beta CD-EG was confirmed by transmission electron microscopy. Therefore, beta CD-EG shows great potential as a controlled-release agent against P. litchii. (C) 2015 Elsevier Ltd. All rights reserved.