Incorporation of Eugenia dysenterica extract in microemulsions preserves stability, antioxidant effect and provides enhanced cutaneous permeation

• Published in: Journal of molecular liquids 2018-09, Vol.265, p.408-415
• Main Authors: Ferreira-Nunes, Ricardo, Silva, Sandra Márcia Mazutti da, Souza, Paulo Eduardo Narcizo de, Magalhães, Pérola de Oliveira, Cunha-Filho, Marcílio, Gratieri, Taís, Gelfuso, Guilherme Martins
• Format: Article
• Language: English
• Subjects: Cagaita; Electronic paramagnetic resonance spectroscopy; Eugenia dysenterica; Free radicals; Hen's egg test chorioallantoic membrane; Stability
• ISSN: 0167-7322; 1873-3166
• DOI: 10.1016/j.molliq.2018.06.023

The aim of this paper was to develop stable, non-irritant topical formulations for the incorporation of aqueous extract from Eugenia dysenterica leaves, which could improve cutaneous permeation without compromising its antioxidant activity. For this, O/W and W/O microemulsions were obtained. Droplet sizes varied from 175 nm to 208 nm for the O/W formulations and from 27 nm to 35 nm for the W/O microemulsions, with PDI values below 0.2. Nanoformulations implemented a significant improvement in the stability of catechin over 90 days compared to simple solutions of the actives, especially the W/O microemulsions, which remained a catechin content of 96.1% and 96.6% (for the formulations containing the extract or the isolated catechin, respectively) when the formulations were stored at 6 °C, while the respective controls remained only 66.7% and 94.4% of catechin at the same storage conditions. All nanoformulations were capable of significantly increasing the penetration of catechin into skin, with emphasis on the O/W microemulsions, which proved to significantly increase the penetration of catechin to the deeper layers of the skin, compared to controls. The antioxidant activity of the active substances was maintained with the formulation in microemulsions, and the formulations containing the extracts presented superior activity to those containing the isolated catechin. All microemulsions presented low irritability potential. In conclusion, the microemulsions containing the aqueous extract of E. dysenterica leaves seem to be promising systems for topical application, which enables their use in dermatological treatments that require antioxidant action. [Display omitted] •Microemulsions improved stability of catechin isolated or in the extract.•Formulations were capable of increasing the penetration of catechin into the skin.•Microemulsions presented low irritability potential for topical administration.•The antioxidant activity of the active substances was maintained in microemulsions.•The systems seem to be promising for topical application as antioxidants.