Phytochemical Investigation of Rumex Abyssinicus Root Barks and In Vitro Evaluation of Its Antibacterial Activities

Different parts of Rumex abyssinicus have been used as a traditional medicine by local community in Ethiopia. Root and root barks of this plant are used traditionally by people of Ilu Ababor (Ethiopia) to lower blood pressure, heal wound and treat stomach ache. This paper presents the isolation and characterization of compound from the root barks of Rumex abyssinicus and evaluation of its antibacterial activity. The powdered plant material was sequentially extracted using n-hexane, chloroform, acetone and methanol. The crude extracts and the isolated compound (RA-3) were evaluated against four bacterial strains: Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa and Salmonella thyphimurium as a potential antibacterial agent. Both the acetone and methanol crude extracts showed promising inhibitory effects against all the tested bacterial strains. The strongest inhibitory activity was observed for acetone extract against Staphylococcus aureus (21 mm) as compared to the standard Gentamicin (25 mm). The isolated compound showed inhibitory effect only on Staphylococcus aureus and Pseudomonas aeruginosa. The acetone extract was subjected to column chromatographic separation and resulted in the isolation of one pure compound (RA-3). The structure of this compound was characterized with the help of spectroscopic methods (IR and NMR). The isolated compound was characterized as Emodin based on spectroscopic data and in comparison with literature reports.