Composição química e atividades antimicrobiana e antioxidante do óleo essencial de Myrcia sylvatica (G.Mey.) DC. (Myrtaceae)

Abstract

Myrcia sylvatica (Myrtaceae) popularly known as ginja, vassourinha, or pedra ume caá, is a shrubby species with common occurrence in mostly of savannas at Santarém, Pará. For its use to be quite diverse in the region, and still be a species with few studies on the biological activity, the aim of this study was to evaluate the chemical composition and the antimicrobial and antioxidant activities from the essential oil of Myrcia sylvatica (OEMS) on the basis of fresh and /or dry biomass. OEMS from fresh and dried leaves analyzes were performed by gas chromatography coupled to mass spectrometry (CG/EM), and performed the antimicrobial activity of the same samples front of strains of Gram-positive bacteria, Gram-negative bacteria and yeasts. To evaluate the antioxidant capacity, OEMS of fresh leaves was used, employing the methods: DPPH, ABTS, FRAP and β-carotene. The OEMS of fresh and dried leaves presented as major compounds 1-epi-cubenol, ar-curcumene, cadalene, β-selinene, β-calacorene, cis-calamenene, ar-tumerol, muskatone, δ-cadinene, and cubenol. And when evaluated the antimicrobial activity of the two samples, there was significant inhibition, compared to standard, only for Gram-positive bacterium. The OEMS when tested their antioxidant capacity was able to reduce the DPPH radical, with inhibition ranging from 8,6 to 52,0%, and IC50 = 1,94 ± 0,12 mg/ml in 60 minutes of reaction, and capturing the radical cation ABTS with TEAC value of 32,85 ± 0,86 μM of Trolox/g of OEMS sample. The FRAP method, showed a value of z = 193,47 ± 2,63 μM of ferrous sulfate / g of OEMS in 45 minutes of reaction. In β-carotene/linoleic acid system the essential oil inhibited 26,1% of the β-carotene oxidation at 120 min of reaction. The essential oil of M. sylvatica in its chemical composition has a higher percentage of cyclic sesquiterpenes. The same has antimicrobial activity against Gram-positive bacteria independent from the processing of samples (fresh or dried leaves) and antioxidant capacity, while being low when compared to standards. According to the research conducted widens the knowledge about the species, highlighting the use of OEMs to develop new drugs with antimicrobial and antioxidant properties.