Emulsion incorporating Eugenia dysenterica aqueous extract entrapped in chitosan microparticles as a novel topical treatment of cutaneous infections

The indiscriminate use of antibiotics has resulted in resistant strains of bacteria, especially of Staphylococcus aureus, which causes relevant skin diseases. With the objective to obtain a novel stable, safe and effective dermatological formulation for the treatment of these skin infections from a natural product, in this work we evaluated in vitro the activity of an aqueous extract of Eugenia dysenterica (EDA) to resistant strains of S. aureus and its cytotoxicity against skin cells. The extract was then entrapped into chitosan microparticles with further incorporation in a dermatologically acceptable formulation. The formulation had its stability evaluated and was tested to determine skin permeation of its biomarker, catechin, as well as its angiogenic activity. The EDA demonstrated effect against a series of S. aureus strains, particularly some resistant to current antibiotics. The extract also exhibited no significant cytotoxic effect on skin cells. Developed chitosan microparticles incorporated 70.1% of the catechin content from the EDA. The emulsion in which these microparticles were incorporated showed relative stability for 60 days at 6 °C. Also, this formulation increased catechin skin penetration and showed an angiogenic action. Therefore, it seems to be a promising alternative for topical treatment of skin infections caused by S. aureus.