ANÁLISE DA ATIVIDADE ANTIBACTERIANA E TOXICIDADE DE Drimys brasiliensis

Abstract

This study evaluates the antibacterial activity and toxicity of crude extracts, fractions and pure compounds of Drimys brasiliensis. The antibacterial activity of five extracts, twelve fractions and five isolated compounds were tested against six Gram-positive and six Gram-negative bacteria, and Helicobacter pylori. The methodology applied was agar dilution. The potential toxicity of the extracts was evaluated using the brine shrimp Artemia salina. Antibacterial activity tests showed some promising results: dichloromethane bark extract with minimum inhibitory concentration (MIC) for Bacillus cereus of 62.5 μg/mL; fraction G2 (7-13) with MIC for Staphylococcus aureus of 62.5 μg/mL; and p-methoxy-cinnamoyl-polygodial compound for Bacillus cereus with MIC of 31.25 μg/mL. There was no activity against the Gram-negative bacteria. For Helicobacter pylori, the dichloromethane bark extract showed MIC of 1000 μg/mL. The fractions with best results were E (32-49) and G2 (7-13), with a MIC of 500 μg/mL. Of the isolated compounds, polygodial was the one that showed the best activity, with MIC of 250 μg/mL. The dihloromethane bark extracts were active, with MICs for Ureaplasma urealyticum, Mycoplasma hominis and Mycoplasma arginini of 125, 500 and 500 μg/mL, respectively. Of the fractions, G2 showed a MIC 15.62 μg/mL for U. urealyticum and 125 μg/mL for the mycoplasma species. The assays with Artemia salina showed toxicity only for the dichloromethane bark extract, with a 50% lethal dose (LD50) of 27.51 μg/mL. The results showed the antibacterial activity of Drimys brasiliensis, with a risk of toxicity. Further studies are needed to assess the genotoxicity, and isolate other compounds that can contribute to the antimicrobial action of the plant material analyzed