ANTIMICROBIAL ACTIVITY AND POTENTIAL SECONDARY SIGNAL TRANSDUCTION MECHANISMS OF ELECAMPANE (Inula helenium L.) ROOT EXTRACT

Elecampane (Inula helenium L.) is a perennial plant mostly known for its high content of sesquiterpene lactones and volatile oils. These compounds can be extracted by hydrodistillation from its root. According to ethnomedicine literature they possess a strong disinfectant activity. Antibiotic resistant epidermal infections are deleterious health problems, which can lead to bloodstream infections, toxin-mediated diseases or rheumatic heart disease, etc. However elecampane root extract is capable of exerting a significant antimicrobial effect against them.

The aim of this study was to determine the antimicrobial activity of elecampane root extract. The antimicrobial activity was tested against 6 species of fungi (Candida albicans, Candida glabrata, Candida cruzei, Candida parapsilosis, Saccharomyces cerevisiae, Aspergilus niger) and 7 species of bacteria (Staphylococcus aureus, Methicillin-resistant Staphylococcus aureus (MRSA), Streptococcus pyogenes, Bacillus subtilis, Escherichia coli, E. coli D31, Pseudomonas aeruginosa). Also relevant secondary signal transduction mechanisms of action were researched upon by utilizing literature data.

The examined material was extracted by hydrodistillation from elecampane root using a Clevenger type apparatus. The antimicrobial testing was conducted using the two fold tube dilution method. For literature based study of mechanisms the research was performed in National Center for Biotechnology Information (NCBI) as well as Web of Science database.

The results showed that the extracted mixture of sesquiterpene lactones and essential oil exhibited considerable inhibitory effects against all tested fungi and bacteria. The Minimum Inhibitory Concentration (MIC) values ranged between 25 and >100 μg/mL. Elecampane extract's regulating effect on Mitogen-activated protein kinase (MAPK) cascade, Matrix-metalloproteinase (MMP)s, Nuclear Factor-kappaB (NF-κB) and Tumor necrosis factor (TNF) underpins it's antimicrobial properties against C. albicans, MRSA, TBC, S. pyogenes and P. aeruginosa strains.

The antimicrobial effects of the experimental material was confirmed. Based upon the results of the study the researchers concluded that elecampane in combinations with antibiotics and/or other drugs could increase the efficacy of existing antimicrobial therapies. Eleocampane extract could be also a usefull tool against antibiotic resistant microba and/or multi-infections.