Bioprospecção de atividade antioxidante e antimicrobiana da casca de Stryphnodendron adstringens (Mart.) Coville (Leguminosae-Mimosoidae)

ABSTRACT O presente estudo teve por objetivo avaliar a classe de metabólitos secundários responsável pela atividade antioxidante e antimicrobiana de extratos da casca de Stryphnodendron adstringens (Mart.) Coville (Leguminosae-Mimosoidae), planta amplamente utilizada medicinalmente pela população. Foram obtidos extratos da casca utilizando etanol 50%, etanol 70%, acetona:água (7:3, v/v) e clorofórmio. A bioprospecção da atividade antioxidante foi realizada por meio de cromatografia em camada delgada revelada com 2,2-difenil-1-picrilhidrazila (DPPH) e a capacidade de seqüestro de radicais livres utilizando DPPH foi quantificada por espectrofotometria. A bioprospecção da atividade antibacteriana foi realizada por meio de difusão em ágar e bioautografia. A cromatografia revelada com DPPH revelou atividade antioxidante na região onde foram identificadas as manchas referentes aos derivados de taninos e o extrato clorofórmico foi o que apresentou menor capacidade de seqüestro de radicais livres. A atividade antimicrobiana foi comprovada para os extratos polares pela formação de halos de inibição de crescimento bacteriano e a bioautografia revelou atividade na região onde foram identificadas as manchas de derivados tânicos. Assim, foi determinado que extratos da casca de S. adstringens apresentaram atividades antioxidante e antimicrobiana devido aos metabólitos secundários derivados da classe de taninos, que são os principais constituintes desta droga vegetal, de acordo com a literatura. Palavras-chave: Stryphnodendron adstringens; atividade antioxidante; atividade antimicrobiana; taninos.

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