Atividade antimicrobiana in vitro do extrato etanólico de Caesalpinia ferrea Mart. (Leguminosae)

Abstract

Conjunctivitis can compromise the integrity of the eye and produce significant tissue destruction. Knowledge of the causative agent and progression of the disease, including the establishment of an effective and consistent treatment will influence the prognosis and evolution of this disease. The usual treatment is antibiotic therapy, but long term use of topic antimicrobials can result in multidrug resistance of pathogenic bacteria and/or fungi. The aim of this study was to evaluate the "in vitro" antimicrobial activity of the raw ethanolic extract of Caesalpinia ferrea, and determine the minimum inhibitory concentration (MIC) against bacterial agents collected from dogs with conjunctivitis from our routine ophthalmology ambulatory services, and evaluate the sensitivity profile of these strains to ciprofloxacine, a commonly used antimicrobial in veterinary medical clinic, and the plant extract. Phytochemical tests confirmed the presence of bioactive compounds (flavonoids and hydrolysable tannins), that demonstrated significant antimicrobial activity against Gram-positive Staphylococcus sp. and Streptococcus sp. Antibiogram evaluation by disc diffusion method confirmed that all strains were sensitive to the C. ferrea extract, with inhibition zones ranging 8 to 24 mm when compared to standard antibiotic with zones with 0 to 35 mm. This demonstrated the viability of ethanol extract the C. ferrea as a natural antimicrobial agent and the possibility of its use as a therapeutic option for biological tests in vivo and as a complementary treatment for conjunctivitis in dogs.