Aniba canelilla (Kunth) Mez essential oil-loaded nanoemulsion: Improved stability of the main constituents and in vitro antichemotactic activity

Abstract

The essential oil extracted from Aniba canelilla (Kunth) Mez, an aromatic plant from the Amazon region, has 1-nitro-2-phenylethane and methyleugenol as major compounds and although presents historical evidence of treating topical disorders its incorporation in a formulation aiming topical administration was yet unexplored. In this sense, nanoemulsion containing essential oil of A. canelilla was produced by high pressure homogenization and characterized in terms of physicochemical parameters, morphology and thermo and photo (UVA and UVC) stabilities. In addition, in vitro antichemotactic activity was evaluated to the essential oil, isolated compounds and loaded nanoemulsion. The nanoemulsion showed nanometric droplet size with spherical shape, adequate size dispersion and negative charge. The nanoemulsion successfully protected the main compounds of A. canelilla essential oil from thermal degradation and volatilization, also protecting or delaying degradation against UVA and UVC light. The essential oil of A. canelilla, 1-nitro-2-phenylethane, methyleugenol and the nanoemulsion containing A. canelilla essential oil presented antichemotactic activity with reduction of polymorphonuclear neutrophils migration in the range of 24.1–100 %, suggesting an anti-inflammatory potential for these substances, mainly for the loaded nanoemulsion. These promising results revealed that the nanoemulsification of A. canelilla essential oil brought benefits as it maintained stability with an improvement of antichemotactic activity, suggesting it is an interesting strategy for topical delivery of 1-nitro-2-phenylethane and methyleugenol to treat inflamed skin.