RESUMO
In this study, Rhizophora mangle L. mangrove plants and plant growth-promoting bacteria were evaluated for their ability to degrade polycyclic aromatic hydrocarbons in diesel oil-contaminated sediment. The diesel-contaminated soil was sown with plant growth-promoting bacteria in the R. mangle L. rhizosphere and monitored for 120 days in a greenhouse. The plant growth-promoting bacteria Pseudomonas aeruginosa and Bacillus sp. were analyzed for their ability to degrade eight priority polycyclic aromatic hydrocarbons, achieving a removal rate for naphthalene (80%), acenaphthene (> 60%), anthracene (> 50%), benzo(a)anthracene (> 60%), benzo(a)pyrene (> 50%) and dibenzo(a,h)anthracene (> 90%) in the treatments with and without plants. R. mangle L. demonstrated a removal rate above 50% for acenaphthene and fluoranthene. The bacterial strains promoted the development of the plant propagule in 55% of sediment contaminated with diesel. Scanning electron microscopy revealed the formation of biofilms by the strains in the roots of the plants in contact with the diesel. Thus, the interaction between Rhizophora mangle L. and the bacterial strains (Bacillus sp. and P. aeruginosa) demonstrated the potential of the strains to degrade diesel and bioremediate mangroves impacted by diesel oil.
RESUMO
A flora tem sido uma fonte valiosa de constituintes bioativos para manutenção da saúde humana. Tal fato tem reforçado a crescente investigação do potencial terapêutico das plantas medicinais. Neste contexto, o presente trabalho teve como objetivo avaliar o potencial antibacteriano dos extratos hidro-alcoólicos da casca, folha, e raiz de Avicennia schaueriana Stapf & Leechm. ex Moldenke, Verbenaceae. As partes vegetais foram coletadas no povoado pesqueiro de Siribinha, Bahia e os extratos vegetais foram preparados pelo método de maceração. Todos os testes de sensibilidade dos extratos vegetais foram avaliados por meio de testes não-paramétricos. O extrato da raiz de A. schaueriana apresentou uma atividade inibitória do crescimento superior aos extratos da folha e casca, com halos de inibição que variaram entre 7 a 18 mm de acordo com as concentrações e as cepas bacterianas testadas. Já a concentração inibitória mínima dos extratos hidro-alcoólicos de A. schaueriana apresentaram uma média de valores entre 0,62 a 10,00 mg/mL para as bactérias analisadas. Os resultados estatísticos confirmaram a diferença de sensibilidade dos microrganismos estudados frente aos extratos de A. schaueriana.
Natural products have been a valuable bioactives constituent source for maintenance of the health human being. Such fact has strengthened the increasing inquiry of the therapeutical potential of medicinal plants. This work had as objective evaluate the antibacterial potential from leaf, root and bark hydro-alcoholics extracts of Avicennia schaueriana Stapf & Leechm. ex Moldenke, Verbenaceae. The plant parts had been collected in the fishing town of Siribinha, Bahia and the plant extracts had been prepared by the method of maceration. All the tests of sensitivity of plant extracts had been evaluated by means of notparametric tests. The results of the test of diffusion in disk showed that the extract of the root of the A. schaueriana had been higher to extracts of the leaf and bark, with inhibition rings from growth varying of 7 to 18 mm; in accordance with the tested concentrations. Already the minimum inhibitory concentration of hydro-alcoholic extracts of A. schaueriana had presented an average of values between 0,62 to 10,00 mg/mL for the analyzed bacteria. The statistical results had confirmed the difference of sensitivity of the studied microorganisms front to extracts of the A. schaueriana.
