Investigation into the Antimicrobial Activities of Tincture Prepared from Twenty Six Plants Growing in Macedonia

Antibiotic resistance has become a global concern. In recent years there has been increasing incidence of multiple resistances in human pathogenic microorganisms, largely due to the indiscriminate use of commercial antimicrobial drugs commonly employed in the treatment of infectious diseases. This has forced scientists to search for new antimicrobial substances from various sources like medicinal plants. The study was designed to determine the antimicrobial properties of a tincture prepared from 26 plants growing in Macedonia. The antimicrobial potential of the tincture was evaluated using the micro-broth dilution method using 96-well microtiter plates, which enabled determination of the minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) or minimal fungicidal concentration (MFC). The tincture was subjected to serial dilutions in descending concentrations starting from a concentration of 50% and finishing with a concentration of 0.39%. Thirteen reference bacterial strains and eight fungal strains were used. Generally, the tincture was found to be active, with MIC ranging from 0.39 to 25%, and with MBC and MFC ranging from 0.78 to 50%. However, of the tested fungi, Fusarium sp. and A. niger ATCC 1052 were found to be the most resistant of the examined microorganisms, the most resistant appeared to be P. aeruginosa ATCC 9027 and S. enteridis FNS-BCC 98. The present study suggests that the tincture from these plants is a potential source of natural antibacterial and antifungal agents. After this screening experiment, further work should be performed to describe the antimicrobial activities in more detail.