Evaluation of antimicrobial activity of the crude ethanol extract of Eugenia uniflora L. leaves

Abstract

Eugenia uniflora L. is a tree whose leaves are used in popular medicine as an antihypertensive, antimicrobial drug, in the treatment of bronchitis, influenza and as an antipyretic. This paper reports the antimicrobial activity of a crude ethanol extract of E. uniflora L. leaves. The crude extract was prepared from material collected in Goiânia, Goiás (Brazil), dried, pulverized and subjected to phytochemical screening. The antimicrobial activity was tested against spore-forming and non-sporing Gram-positive and Gram-negative bacteria as well as Candida albicans, using the well-diffusion test and the agar dilution method to determine the minimum inhibitory concentration (MIC). The phytochemical screening showed the presence of tannins, steroids, triterpenes, heterosides, anthraquinones, flavonoids and saponins. Antimicrobial activity testing showed that the crude E. uniflora L. leaf extract inhibited all the Gram-positive bacteria (MICs from 0.273 to 8.75 mg/mL), among which the spore-formers exhibited MICs from 1.094 to 2.187 mg/mL. The MIC for most Gram-negative bacteria varied from 4.375 to 17.5 mg/mL. C. albicans NTC 2010 (MIC of 0.547 mg/mL) inhibition was also noted. The antimicrobial activity found in this in vitro study of E. uniflora L. may justify its popular use as a medicine.