Antimicrobial activity of some Mongolian plants

The main goal of our study was to evaluate the antimicrobial activity of 70 plant samples of 69 species belonging to 55 genera, and 26 families collected from Mongolia in August 2010-2011. A disk diffusion assay was performed to evaluate the antimicrobial activity of compounds qualitatively. In our study, there were 32 plant samples with anti-Staphylococcus aureus activity, 8 samples with anti-Escherichia coli activity, but there was no plant with anti-Candida albicans activity. The average value of inhibition zone of S. aureus was 16.06±5.14 mm, with very strong inhibition zones (24-28 mm) n=3 (Rosa acicularis Lindl., Saussurea amara (L.) DC., Pyrola incarnata (DC.) Freyn.); strong inhibition zones (18-22 mm), n=8 (Sedum aizoon L., Veronica incana L., Lappula intermedia (Ldb.) M. Pop., Phlomis tuberosea L., Dracocephalium foetidium Bunge., Rumex acetosa L., Iris lactea Pall., Schizonepeta multifida (L.) Briq.); moderate inhibition zones (12-16 mm), n=14 (Vaccinum vitisidea L., Hedysarum inundatum Turcz., Sanguisorba officinalis L., Thalichtrum foetidium L., T. simplex L., T. minus L., Galium verum L., Plantago major L., Thymus gobicus Tschern., Rheum undulatum L., Stellera chamaejasme L., Dasiphora fruticosa (L.) Rydb., Leonurus sibiricus L., Potentilla bifurca L.); weak inhibition zones (10-11 mm), n=7 (Campanula glomerata L., Geum aleppicum Jacq., Potentilla anserina L., Polygonum aviculare L., Galatella dahurica DC., Artemisia frigida Willd., Chamaenerion angustifolium (L.) Scop.). The average value of inhibition zone of E. coli was 12.75±2.38 mm and 8 plant samples (Saussurea amara (L.) DC., Geum aleppicum Jacq., Rosa acicularis Lindl., Chamaenerion angustifolium (L.) Scop., Allium mongolicum Rgl., Veronica incana L., Thymus gobicus Tschern., Potentilla bifurca L.) were with anti-Escherichia coli activities. This result showed that many species of plant samples have a strong antibacterial activity, which means that these plants must be the natural compound source and should be further explored for the isolation and characterization of bioactive molecules.