Encapsulation of essential oils using cinnamic acid grafted chitosan nanogel: Preparation, characterization and antifungal activity

Chemical modifications in the chitosan structure may result in obtaining a new material with improved chemical properties, such as an ability to encapsulate lipophilic compounds. This study aimed to synthesize cinnamic acid grafted chitosan nanogel to encapsulate the essential oils of Syzygium aromalicum and Cinnamomum ssp., in order to develop a material to be applied in the control of dermatophylosis caused by the fungus Microspoium cants. The cinnamic acid graft in chitosan was verified by the Attenuated Total Reflectance Fourier Transform Infrared Spectroscopy (ATR-FTIR), Solid State Nuclear Magnetic Resonance of the C-13 Nucleus (C-13 SSNMR) and Thermal analysis coupled to mass spectrometry (TG-MS) techniques. The nanogel obtained showed affinity for the essential oils of S. aromaticum and Cinnamomum, with encapsulation efficiencies equal to 74% and 89%, respectively. When in an aqueous medium the nanogel with the encapsulated essential oils was able to form stable nanopartides with average sizes of 176.0 +/- 54.3 nm and 263.0 +/- 81.4 nm. The cinnamic acid grafted chitosan nanogel showed antifungal activity in vitro against M. cants, inhibiting up to 53.96% of its mycelial growth. Complete inhibition of mycelial growth was achieved by the nanogel with encapsulated essential oils. The results found in this work demonstrated the development of a material with potential application in the control of dermatophytosis caused by the fungus M. canis. (C) 2020 Elsevier B.V. All rights reserved.