Atividade antimicrobiana de óleos essenciais em bactérias patogênicas de origem alimentar

Abstract

Palavras-chave: monoterpenos, patógenos de origem alimentar, propriedades antibacterianasABSTRACT: Antimicrobial activity of essential oils against sessile and planktonic pathogens of food source. The objective of this work was to identify and quantify the constituents, and to evaluate the antimicrobial activity of the essential oils from Mentha piperita, Cymbopogon citratus, Ocimum basilicum and Origanum majorana, against enteropathogenic Escherichia coli, Salmonella enterica Enteritidis, Listeria monocytogenes and Enterobacter sakazakii. The essential oils were obtained from dried leaves by using the hydrodistillation technique and the modified Clevenger apparatus, and their bacterial activity was determined by using the agar diffusion technique. The essential oils inhibited bacterial growth, but their effectiveness was varied. Among the essential oils tested, that from M. piperita showed a greater antimicrobial activity against E. coli (8.106 UA mL -1 ), moderate activity for S. enterica Enteritidis and E. sakazakii (1.706 e 3.200 UA mL -1 respectively) and low activity for L. monocytogenes (106, ). However, the essential oil from C. citratus presented a greater antimicrobial activity against E. coli (9.386 UA mL -1 ) and a moderate activity against E. sakazakii, S. enterica Enteritidis and L. monocytogenes (2.773 UA mL -1 for both). The essential oil from O. basilicum showed a greater antimicrobial activity against E. coli and E. sakazakii (6.826 e 8.106 UA mL -1 respectively), moderate activity against S. enterica Enteritidis (1.600 UA mL -1 ), and was inactive against L, monocytogenes. Origanum majorana, which was also tested in our work, showed a greater antibacterial activity against E. coli, (5.973 UA mL -1 ) moderate activity against S. enterica Enteritidis and E. sakazakii (1.706 e 2.346 UA mL -1 , respectively), and was inactive against L. monocytogenes.

Characterization of the Biological Potential of the Essential Oils from Five Species of Medicinal Plants

“…The minimum inhibitory concentrations (MICs) of the essential oils tested against Gram-negative and Gram-positive bacteria are described in Table 2 Valeriano et al [24], analyzing the antibacterial activity of the essential oil from M. piperita against the same bacterial strains evaluated in this study, observed that this species had a higher activity against E. coli and a low activity against L. monocytogenes. According to the authors, menthol, neoisomenthol, menthone, methyl acetate and iso-menthone were the principal components, whereas in the present work, similar activities against both E. coli and L. monocytogenes were observed for the essential oil from this species, and the principal constituents found were carvone and limonene.…”

“…Studies report that menthol is active against various micro-organisms, including P. aeruginosa [24]. Subsequently, work performed by Valeriano et al…”

Antimicrobial Activity of the Essential Oil from <i>Hyptis carpinifolia</i> Benth

“…Gram-negative bacteria can be attributed to the presence of an outer membrane in its structure that might hinder the penetration and action of essential oil constituents [2]. Among the Gram-positive bacteria, L. monocytogenes was more resistant than S. aureus, whereas Gram-negative E. coli were more susceptible to the action of the essential oil, and the other bacteria were only inhibited at the highest concentration assessed.…”

“…Among these microorganisms are the bacteria Salmonella ssp, Listeria monocytogenes and Escherichia coli, which are responsible for a large number of cases of diseases and mortality [2].…”

<b>Essential oil from <i>Chenopodium ambrosioides</i> L.: secretory structures, antibacterial and antioxidant activities

“…In most cases, Gramnegative bacteria are less sensitive that Grampositive bacteria, because cell wall of Gram-negative is rich in polysaccharides, with inhibits the penetration of antimicrobial substances (Burt, 2004). According to Valeriano, Piccoli, Cardoso, and Alves (2012), the moderate antibacterial activity determined by the agar diffusion method can be attributed to the low affinity between less polar components of the essential oil and the polar substrate (agar). Moreover, although the essential oils present difficulty in diffusing uniformly throughout the culture medium, its volatility contributes to the formation of inhibition zones, making this technique a valid method for the determination of antimicrobial activity (Lambert, Skandamis, Coote, & Nychas, 2001;Inouye, Uchida, Maruyama, Yamaguchi, & Abe, 2006).…”