Triagem fitoquímica e avaliação da atividade antibacteriana de extratos das flores de Sambucus nigra L. (Caprifoliaceae)

Abstract

This study aimed to perform a phytochemical screening and to evaluate the antibacterial activity of the extracts of Sambucus nigra L. flowers. The aqueous (10%), ethanolic (5%) and ethyl acetate (5%) extracts were subjected to colorimetric tests for phytochemical screening and the antibacterial activity evaluation was performed by the disk-diffusion method in agar. The results showed that in the 6 and 12 mg concentrations the aqueous extract presented significant inhibition halos for Staphylococcus aureus, Pseudomonas aeruginosa and Streptococcus pyogenes, but when compared with the medicines used as a reference, the activity was not satisfactory and, besides, it indicated the absence of inhibition for all the tested strains with the concentration increase of 18 and 24mg. The phytochemical screening analysis showed the presence of flavonoids with intense color reaction in the aqueous and ethanol extracts, and of low intensity in the ethyl acetate sample. In the same extracts, the tests did not detect tannins, saponins, alkaloids and anthraquinones. It was concluded that the aqueous extract showed better inhibitory effect on the Staphylococcus aureus, Pseudomonas aeruginosa and Streptococcus pyogenes, but not enough to promote an effective inactivation when compared with the medicine tests.