Plant volatiles from the Brazilian restinga with bactericidal activity against multiresistant bacteria

This study aimed to evaluate the bactericidal activity of Myrtaceae foliar volatile compounds against strains of Pseudomonas aeruginosa (PAO-1) and Burkholderia cenocepacia (ET-12). Although these bacteria are clinically important to human health, they, along with other bacteria (Escherichia coli, Staphylococcus aureus and Streptococcus agalactiae), also have a high profile of antimicrobial resistance associated with bovine mastitis. The chemical composition of volatiles found in Myrtaceae foliar volatiles was also characterized. To accomplish this, the essential oil was extracted from dry leaves of Eugenia astringens, Eugenia arenaria and Myrrhinum atropurpureum by hydrodistillation. Minimum inhibitory concentration (MIC) was determined by microdilution in broth. Essential oil from E. astringens leaf could inhibit growth the fives trains by the Agar diffusion method. MIC demonstrated a reduction in bacterial growth by 74% ± 2.8 (P. aeruginosa), 78.3% ±10.5 (B. cenocepacia), 87.1% ± 1.4 (E. coli), 99 % ±0.02 (S. aureus) and 99.9 ±0.01 (S. agalactiae). The terpene α-pinene was detected in all thre especies, especially M. atropurpureum and E. astringens. E. astringens showed a high contente of (E)-caryophyllene.