Antimicrobial activity of essential oils obtained from aromatic plants of Argentina

The aim of this work was to evaluate the antibacterial and antifungal activity of essential oils obtained from medicinal plants of the Argentine Republic. The antimicrobial activity of the essential oils of 14 plants collected from different zones was analyzed. The microorganisms used were Staphylococcus aureus, Staphylococcus epidermidis, Bacillus cereus, Micrococcus luteus, Enterococcus faecalis, Escherichia coli, Klebsiella sp., Proteus mirabilis, Pseudomonas aeruginosa, and the yeast Candida albicans. The disk diffusion method was performed to test antimicrobial activity. B. cereus and S. aureus were inhibited by most of the essential oils. Aloysia triphylla, Psila spartoides, and Anemia tomentosa were the most effective compounds against B. cereus, while A. triphylla and Baccharis flabellata were effective against S. aureus. None of the oils inhibited P. aeruginosa. B. flabellata and Pectis odorata were active only against Gram-positive bacteria. A. triphylla and P. spartoides inhibited all tested microorganism, and the remaining essential oils showed variable activity. The minimum inhibitory concentration ( MIC) of A. triphylla and P. spartoides essential oils were determined using the disk diffusion method. The lowest MICs were against S. aureus (1/16), B. cereus (1/16), S. epidermidis (1/8), and C. albicans (1.32) for A. triphylla. The lowest MICs were against S. aureus (1/32), B. cereus (1/32), P. mirabilis (1/32), and C. albicans (1/64) with P. spartoides. The results showed that B. cereus and S. aureus were the most sensitive microorganisms, and P. aeruginosa was the most resistant microorganism. This study may contribute to improve ethnobotanical knowledge and would help to discover substances with potential therapeutical uses, as food preservants or as food-borne pathogen inhibitors.