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

Abstract

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 μg/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 μg/mL) was shown by S. tomentosa. S. fruticosa (MIC 392 μg/mL) and O. onites (MIC 784 μg/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.

Keywords::

• Antibacterial
• antimycobacterial
• methanol extract
• Salvia
• Sideritis
• Origanum

Declaration of interest: The authors are grateful to the Scientific and Technological Research Council of Turkey (TUBITAK). This research was supported by a grant from TUBITAK, TBAG (Research grant no.104T336).