Estudo químico e biológico de Eugenia florida (Myrtaceae)

Abstract

The use of medicinal plants in Brazil is facilitated by the great plant biodiversity of the country's biomes. The Cerrado has a range of medicinal plants that can be scientifically explored. The genus Eugenia sp. presents some species that are little studied scientifically, so the work was developed with the aim of promoting the chemical and biological study of the dry crude extract and the ethyl acetate fraction of the Eugenia florida species. The collected leaves were subjected to drying in an oven with circulation and air renewal, followed by a rough division by spraying in a knife mill and subsequent particle size standardization. The preparation of the dry extract and the ethyl acetate fraction was carried out using the exhaustive method of simple percolation and liquid-liquid partition. Part of the extractive solution was concentrated in a rotary evaporator followed by a drying process using a Spray Dryer with the addition of colloidal silicon dioxide drying aid to obtain the dry extract. The results obtained through the analysis by profile in mass spectrometry allowed the verification of the presence of phenolic acids, flavonoids and, a fact that corroborates with data present in the literature for the genus Eugenia sp. Among the compounds identified in the extracts, the following stand out: piscidic acid, delphinidin-O-hexose, myricetin-Opentose, p-coumaric acid-O-hexose, naringenin, kaempferol-O-deoxyhexose-Ohexose,betulinic acid heteroside, quercetin-O-hexose-O-galloylexose-Ogaloidesoxyhexose and tetrameric catechin. The in vivo test was conducted with the model of Galleria mellonella larvae, the results obtained demonstrated absence of toxicity, allowing to proceed with the biological tests. In order to evaluate the potential of antimicrobial activity, the MIC (minimum inhibitory concentration) method was performed. The microbiological assay evaluated activity against standard strains of two bacterial strains (Escherichia coli ATCC 25922 and Staphylococcus aureus ATCC 6538) and a fungal strain (Candida albicans ATCC 10231). Against the S. aureus strain, the inhibition occurred in the range between 250 and 500 µg/mL for the ethanolic extract, which is considered moderate antimicrobial activity, for the ethyl acetate fraction, the result presented for the inhibition was between 500 and 1000 µg/mL for fraction demonstrating mildly active antimicrobial activity. For the MIC referring to the ethyl acetate fraction against the strains of E. coli and C. albicans, it did not show expressive results, however for the ethanolic extract the results obtained were significant and presented in the range of 500 to 1000 µg/mL demonstrating Slightly active antimicrobial activity. Thus, there are indications that the correlation between the compounds identified in the present work and the results found in the CIM tests is due to the potential for antimicrobial action attributed to flavonoids.