In vitro antimicrobial effect of curcumin

Curcumin is a major phenolic constituent of Curcuma longa L. The purpose of the present work was comparative analysis of the antimicrobial activity of curcumin using CLSI recommendations. In the study, there were tested six Gram(+) bacteria (Enterococcus faecalis, Staphylococcus aureus, MRSA, S. epidermidis, Streptococcus agalactiae, S. pyogenes), five Gram(-) (Acinetobacter lwoffii, Escherichia coli, Klebsiella oxytoca, Proteus mirabilis, Pseudomonas aeruginosa) and fungus Candida albicans. The minimal inhibitory concentrations (MICs) of curcumin were determined by the micro-dilution method. Curcumin was dissolved in 40% water solution of DMSO. Curcumin did not inhibit the growth of C. albicans, MRSA, S. agalactiae, and P. mirabilis (MICs >1000 μg/mL), while it demonstrated very strong effect on strains of S. epidermidis (MICs 15.6-31.25 μg/mL) and S. pyogenes (62.5-125 μg/mL). Curcumin sensitivity was also observed for A. lwoffii (125-250 μg/mL), P. aeruginosa (250-500 μg/mL) as well as E. coli and K. oxytoca (500-1000 μg/mL). Among S. aureus and E. faecalis strains, we found both resistant (MICs >1000 μg/mL) and sensitive (500 μg/mL) bacteria. Summarizing our study, curcumin belongs to the potent natural antibacterial agents of plant origin, but its activity varies greatly depending on the species and even the bacterial strain.