Perfil químico e atividade biológica dos óleos essenciais de Begonia reniformis Dryander (Begoniaceae)

Abstract

There are about 1500 species of Begonia distributed throughout the world, with about 215 found in Brazil, occurring the Northeast, Southeast and South states and in the Federal District. The species of Begonia are ornamental plants with economic valor. For our knowledge, there are no chemical and biological studies with essential oils of Begonia species, and this was the first study on the chemical composition and antimicrobial activity for Begonia reniformis. The essential oils were extracted from the leaves and stems of B. reniformis using a modified Clevenger apparatus. The obtained oil showed a yield of 0.03% and 0.01% for leaves and stems, respectively. 21 compounds were identified in the leaves oil, which is 84.8% of total and 17 in the stems oil, which is 97.2% of total. The major compounds identified were the sesquiterpenes β-vestipirene and silphiperfol-4,7(14)-diene for the leaf oil and the sesquiterpenes cubenol, junenol, δ-amorfene e cis-cadin-1(6),4-diene for the stem oil. Only two sesquiterpenes were identified in both oils. The essential oil of the leaves was tested against bacteria and fungi. The metronidazole was uses as positive controller for antibacterial activity in a Mueller Hinton liquid medium on dichloromethane. It were used the Gram-positive bacteria Staphylococcus aureus (02) and Bacillus subtilis (86) and gram-negative Escherichia coli (224) and Pseudomonas aeruginosa (416) for evaluation of activity oil. The results showed that for S. aureus and for E. coli the minimum inhibitory concentration (MIC) for the leaves oil was higher than 2500 μg / mL and for B. subtilis and P. aeruginosa the MIC was 625 μg / mL. The oil showed not activity against the fungi Candida albicans (1007) and Candida utilis (1009), in the concentration of 2500 μg. /mL.