Antibacterial activity of aqueous and methanol extracts of Rumex alpinus and Rumex caucasicus

This study was designed to examine the in vitro antibacterial activities of Rumex alpinus L. and Rumex caucasicus L. (Polygonacea), both known as kivircik labada or evelik in Turkey, and used to treat constipation, diarrhea, and eczema. Aerial parts of Rumex alpinus and Rumex caucasicus, extracted with water and methanol, were screened for in vitro activity by using disk diffusion assays against 121 strains belonging to 52 bacterial species. The minimum inhibitory concentrations (MICs) of single compounds were determined by the microbroth dilution method. The aqueous extract of each species had no antibacterial effect against the test microorganisms, whereas the methanol extract of both species had an inhibitory effect on the growth of microorganisms. Rumex caucasicus was found to be more effective than Rumex alpinus on the tested microorganisms. This is the first report of the antibacterial potency of Rumex alpinus and Rumex caucasicus on a range of foodborne bacteria. The results provide evidence that Rumex alpinus and Rumex caucasicus might be potential sources of new antibacterial agents.