Characterization of the phenolic composition and antimicrobial activities of Turkish medicinal plants

In this paper, antibacterial and antimycobacterial activity of five Labiatae plant methanol extracts, commonly used for treating cold, stomachache, and sore throat, Salvia fruticosa Mill., Salvia tomentosa Mill., Sideritis albiflora Hub.-Mor. (endemic), Sideritis leptoclada O. Schwarz & P. H. Davis, (endemic), and Origanum onites L., were investigated, and their phenolic compounds were determined by HPLC. Antibacterial activity was analyzed against Staphylococcus aureus, Staphylococcus epidermidis, Enterococcus faecalis, Bacillus cereus, Escherichia coli, Salmonella typhimurium, Enterobacter aerogenes, and Klebsiella pneumoniae. Antimycobacterial activity was assayed against Mycobacterium tuberculosis. The best antibacterial activity (MIC 640 mu g/mL) was shown against S. typhimurium and E. aerogenes by S. fruticosa; E. coli, and S. typhimurium, E. aerogenes by S. tomentosa; S. typhimurium, and E. aerogenes by S. leptoclada and S. typhimurium, E. aerogenes and S. epidermidis by O. onites, respectively. The best antimycobacterial activity (MIC 196 mu g/mL) was shown by S. tomentosa. S. fruticosa (MIC 392 mu g/mL) and O. onites (MIC 784 mu g/mL) showed moderate activity against M. tuberculosis. S. albiflora, with low level rosmarinic acid and carvacrol content, showed inhibition against bacteria except K. pneumoniae, B. cereus and M. tuberculosis. The correlation between in vitro activity and ethnobotanical usage was evaluated.