Determination of the Antibacterial and Antioxidant Activity of Crude Extract of Bruceaantidysenterica Leaves

Abstract

Bruceaantidysenterica (abalo in Amharic) is a medicinal plant widely used in traditional medicine for treatment of several diseases and ailments. This study aimed to investigate the classes of the phytochemical constituents of the leaves of Bruceaantidysenterica extracted with the solvents of petroleum ether, ethyl acetate, and methanol. The crud extract evaluated their antioxidant and antimicrobial activities. Qualitative phytochemical screening of the leaves of this plant indicated the presence of alkaloids, flavonoids, phenols, quinones, steroids, terpenoids, saponins, tannins and cumaroins. Quantitative analysis of the leaves of Bruceaantidysenterica revealed that the total phenolic content, expressed as gallic acid equivalent, ranged from 28.5 to 120.06 mg/g of dry weight of extracts. Likewise, the total flavonoid content of the extract, expressed as quercetin equivalent, varied from 26.05 to 83.663 mg/g of dry weight of extracts. All extracts showed antioxidant and antimicrobial activity. As seen from ferric reducing antioxidant power (FRAP) assay, methanol and ethyl acetate extracts of the leaves of Bruceaantidysenterica showed the highest total reducing power while petroleum ether extract exhibited the lowest total reducing power. Furthermore, all the extracts were tested against two gram positive bacteria (Staphylococcus aureus, Streptococcus pyogene) and two gram negative bacteria (Escherichia coli, k. pneumonia) bacteria by Kirby-Bauer standard disc diffusion method. Antibacterial effects of leaves extracts of bruceaantidysenterica showed different degrees of inhibition against both Gram positive and Gram negative bacteria. The methanol and ethyl acetate extracts showed higher antibacterial activity than petroleum ether extracts.