Lippia origanoides Kunth. essential oil loaded in nanogel based on the chitosan and ρ-coumaric acid: Encapsulation efficiency and antioxidant activity

Abstract

The encapsulation of essential oils using natural polymers has been shown as a promising alternative, resulting in their active compounds protection and increased the dispersion in aqueous environment, thus enhancing their functional ability. Thus, in order to enable the Lippia origanoides Kunth. essential oil antioxidant applicability, this work aimed to develop a nanogel resulting from the ρ-coumaric acid binding to the chitosan structure. The obtained results by FT-IR and 13C NMR showed the formation of binding between chitosan and ρ-coumaric acid. The obtained nanogel presented encapsulation efficiency of 42 ± 2% and chitosan of 37 ± 1%. DLS studies showed that nanogel particles in aqueous environment had an average size of 521.9 ± 140.0 nm and 794.6 ± 209.5 nm containing essential oil encapsulated. The nanogel containing encapsulated essential oil had antioxidant capacity of 31.49 ± 0.82% and 53.48 mg of nanogel/mg of DPPH in activities based on the neutralization of the DPPH radical. In relation to the ability to neutralize the ABTS radical, the activity of nanogel containing essential oil was 444.8 mg of trolox/g of nanogel. The results showed that by means of the chemical modification of chitosan with ρ-coumaric acid it was possible to obtain a material capable of improving the applicability of the essential oil of L. origanoides as antioxidant.