Cláudia Alexandra de Andrade

Determinação do conteúdo fenólico e avaliação da atividade antioxidante de Acacia podalyriifolia A. Cunn. ex G. Don, Leguminosae-mimosoideae

Acacia species are usually used as treatment for several diseases. Chemotaxonomic studies have related the Acacia genus as a source of phenolic compounds, which present several biological properties. This work emphasizes the antioxidant activity of Acacia podalyriifolia. This plant is natural from Australia and vastly cultivated in the South of Brazil as ornamental feature. The plant material (flowers) was shadow-dried and submitted to the extraction with ethanol, followed by partition with hexane, dichloromethane and ethyl acetate. The phytochemical screening performed in the ethanol crude extract and in its fractions showed the presence of phenolic compounds and flavonoids. Determination of the phenolic content was performed with the Folin Ciocalteau reagent. It was found out that the ethyl acetate fraction (FAE) was the one that displayed the biggest concentration (338,5 mg of gallic acid/g of FAE). In the evaluation of the radical scavenging activity, using the free radical DPPH, the ethyl acetate fraction showed the highest antioxidant activity (IC50 = 3,22 µg/mL from FAE).

Antioxidant and antibacterial activity of extracts, fractions and isolated substances from the flowers of Acacia podalyriifolia A. Cunn. ex G. Don

Os extratos e fracoes de Acacia podalyriifolia foram analisados previamente para a atividade antibacteriana atraves da difusao em disco e as propriedades antioxidantes foram verificadas pela determinacao da capacidade removedora do radical livre DPPH e pela mensuracao do conteudo de fenolicos totais (Metodo de Folin). O presente estudo descreve as atividades antibacteriana (determinacao da concentracao inibitoria minima) e antioxidante (especies reativas do acido tiobarbiturico - teste TBARS) para o extrato etanolico e as fracoes diclorometano e acetato de etila e para duas flavanonas (naringenina e 5-β-D-glicosil-naringenina) isoladas das flores de Acacia podalyriifolia A. Cunn. ex G. Don. As flavanonas naringenina e 5-β-D-glicosil-naringenina ainda nao haviam sido obtidas desta especie. A atividade antibacteriana mais efetiva foi observada com a fracao acetato de etila (CIM=0,25 mg/mL contra Staphylococcus aureus ATCC 6538; CIM=0,125 mg/mL, contra Staphylococcus epidermidis ATCC 12229; CIM=0,5 mg/mL contra Streptococcus pyogenes ATCC 19615, Klebsiella pneumoniae ATCC 13883 e Proteus mirabilis ATCC 43071). As amostras avaliadas demonstraram atividade pelo teste TBARS, especialmente o extrato etanolico (1000 ppm), que foi o mais ativo (29,43% ± 0.65), seguido pela fracao acetato de etila (1000 ppm, 24,84% ± 1,28), ambos demonstrando atividade mais elevada que a apresentada pelo acido ascorbico (1000 ppm, 21,73% ± 1,77), ainda que menor que a do BHT (1000 ppm, 35,15% ± 3,42), ambas substâncias de referencia. Naringenina e 5-β-D-glicosil-naringenina demonstraram acao antioxidante, porem somente a naringenina inibiu o crescimento de bacterias gram-positivas e gram-negativas.

Avaliação da atividade antibacteriana e triagem fitoquímica das flores de Acacia podalyriifolia A. Cunn. ex G. Don Leguminosae-Mimosoideae

The antibacterial activity of the flowers of Acacia podalyriifolia A. Cunn. (Leguminosae) was evaluated through the gel diffusion method. The bacteria tested were: Staphylococcus aureus (ATCC 6538), Staphylococcus epidermidis (ATCC 1228), Escherichia coli (ATCC 11229) and Pseudomonas aeruginosa (ATCC 27853). The culture media was agar Mueller-Hinton. Paper discs (6 mm in diameter) with 1000, 500, 250 e 125 mg of the tested extracts (crude ethanolic and its fractions; Ethyl Acetate and Dichloromethane) were used. The results indicated action against the gram-positive tested strains in different levels. The Ethyl Acetate extract showed a higher activity. Phenols and flavonoids were detected in the flowers of A. podalyriifolia through phytochemical screening.