Antibacterial Activity of the IraqiRheum ribes. Root

The antibacterial activity of the ethanol, aqueous, and organic extracts from the root of Rheum ribes. Linn (Polygonaceae) was examined. Four anthraquinone aglycone components, chrysopahnol, physcion, aloe emodin, and emodin, were isolated from the biologically active extract and identified by spectroscopic analysis. Emodin is recorded for the first time in this species. The MIC values of the biologically active extracts, aloe emodin, and emodin, were 500, 125, 250, and 63 µg/mL against Staphylococcus aureus., respectively. The extracts and compounds did not inhibit Pseudomonas aeruginosa. and Escherichia coli. at the highest concentration tested, 4000 and 250 µg/mL, respectively.