Author(s): PROCOPIO, F. R.; BREXÓ, R.P.; VITOLANO, L. E. S.; MARTINS, M. E. da M.; ASTOLFO, M. E. de A.; BOGUSZ JUNIOR, S.; FERREIRA, M. D.

Summary: Abstract Essential oils (EOs) are volatile compounds that may have antimicrobial and antioxidant properties. Despite their potential application, low water solubility and chemical instability are limiting factors. Nanoencapsulation processes can overcome this problem, protecting against external factors and promoting a moderate release. Therefore, the objective of the present study was to encapsulate Cymbopogon citratus (CC) and Origanum vulgare (OV) essential oils in ?-cyclodextrin (?CD) complexes. Diferent ratios (w/w) between ?CD and EOs (96:4, 92:8, 90:10, 88:12) were tested, seeking greater entrapment efciency. The particles were characterized by yield, entrapment efciency, size distribution, morphology, crystallinity, infrared spectroscopy, and thermal behavior. Furthermore, the thermal (70 °C) and photochemical (UV) stability of the free and encapsulated EO was evaluated for 48 h. The results showed that the ?CD-CC 90:10 and ?CD-OV 90:10 formulations presented greater entrapment efciency. Crystalline structures of varying sizes (200 to 800 nm), trapezoidal shape, and tendency to aggregation were obtained. Changes in the ?CD crystalline organization and the suppression of characteristic free oil absorption bands suggest the EO entrapment. Regarding stability results, ?CD-CC remained constant when CC showed losses of 20% (photodegradation) and 60% (thermal degradation) after 48 h of stress exposure. Free OV showed slight variations in absorbance over time, while ?CD-OV remained constant over 24 h (thermal degradation) and maintained 60% of oil over 48 h of photo exposure. Furthermore, OV and CC demonstrate color change over time, while ?CD-OV and ?CD-CC remained constant. The results demonstrate that nanoencapsulation can be an interesting tool for protecting EOs.

Publication year: 2025

Types of publication: Journal article

Unit: Embrapa Instrumentation

Keywords: Bioactivity, Inclusion complexes, · Thermal analysis