Preparation and characterization of chitosan nanoparticles loaded with Syzygum aromaticum essential oil and evaluation of their antileishmanial potential

Rym Essid¹, Ameni Ayed¹, Ghofran Atrous¹, Nadia Feris¹, Olfa Tabbene¹

¹ Laboratory of Bioactive Substances, Biotechnology Center in Borj-Cedria Technopole, BP 901, 2050 Hammam-Lif, Tunisia

Background: Essential oils have gained their importance in aromatic, cosmetic and therapeutic field as antimicrobial agents. However, their biological properties are limited due to their volatility, toxic nature, instability and ease of decomposition under environment or processing conditions. Thus, their encapsulation in matrices is an important tool for their stabilization. The present study aimed to develop, evaluate and characterize several encapsulating methods of S. aromaticum essential oil in order to improve their physicochemical characteristics and enhance their antileishmanial activity.

Materials/Methods:In this work the essential oil of S. aromaticum was encapsulated in the nanoparticles of alginate "HE/AL", chitosan "HE/CS" and in the alginate-chitosan complex "HE/AL/CS". The antileishmanial activity of S. aromaticum EO nanoparticles was investigated using standard micro-dilution assay and its cytotoxic potential was evaluated against macrophage cell lines RAW 264.7. Formed nanoparticles were characterized by ultraviolet-visible spectrophotometer, Fourier-transform infrared spectroscopy (FTIR) and dynamic light scattering.

Results: S. aromaticum EO/AL/CS-NPS exhibited a regular distribution with size range of 849.8 nm. The encapsulation efficiency of this system was more than 83.48%. This nanoencapsulation improved antileishmanial activity (from 15.66 µg/mL to 6.33 µg/mL) and showed a significant decrease of the cytotoxicity against macrophage cells Raw264.7 (four fold) (SI>1). Moreover, the loading of S. aromaticum EO into the complex chitosan/alginate was demonstrated by FTIR spectroscopy by the formation of new bands corresponding to the C-H band at 2922 cm^–1. Specific bands of EO on position 1452 and 1402 cm^–1 were observed in the formed nanoparticles. In addition, the specific band of CS and alginate at 2122 cm^–1 and 1033 cm^–1, respectively was observed in the formed nanopaticles with a shift in the position 2100 cm^-1 and 1030 cm^-1, respectively.

Conclusion: This study revealed that S. aromaticumEO nanoencapsulation into chitosan and alginate constitutes a potential delivery system with promising antileishmanial alternative.It stabilizes the physicochemical properties of EO using a very simple ionotropic pre-gelation technique with strong electrostatic interactions and enhances its biological activity.

Keywords: Syzygium aromaticum essential oil, nanoencapsulation, chitosan, alginate, antileishmanial activity