Antibacterial Networks Based on Isosorbide and Linalool by Photoinitiated Process

In this study, we used photo-induced thiol-ene reactions to design bio-based cross-linked networks from diallyl derivative isosorbide, a crude monoterpene as linalool and a trithiol. The aim of this study is to prepare new antibacterial UV-cured networks by using a thiol-ene formulation with covalent immobilization of monoterpenes as antibacterial agents and without any organic solvent thanks to the solvent-like properties of linalool. The challenge was to demonstrate the advantage of using linalool as a chemical platform molecule and, at the same time, as an antibacterial agent. The incorporation of linear linalool to the rigid isosorbide moiety generates flexible networks. Different networks were prepared by varying the mass ratio of linalool (from 0 to 100% w/w) mixed into the coating and then characterized. Their antibacterial activities were investigated in vitro against two pathogenic bacteria strains: Escherichia coli and Staphylococcus aureus. The results have shown a promising antiadherence for S. aureus without any diffusion of linalool that will allow potential applications of terpenes coatings for antibacterial adhesion

Atividade antimicrobiana de óleos essenciais em bactérias patogênicas de origem alimentar Antimicrobial activity of essential oils against sessile and planktonic pathogens of food source

Objetivou-se identificar e quantificar os constituintes e avaliar a atividade antimicrobiana dos óleos essenciais de Mentha piperita, Cymbopogon citratus, Ocimum basilicum e Origanum majorana contra cepas de Escherichia coli enteropatogênica, Salmonella enterica Enteritidis, Listeria monocytogenes e Enterobacter sakazaki. A obtenção dos óleos essenciais foi realizada a partir de folhas secas, empregando-se a técnica de hidrodestilação e utilizando-se a aparelho de Clevenger modificado. A atividade antibacteriana dos óleos essenciais foi determinada pelo método de difusão em ágar. Observou-se que os óleos essenciais inibiram o crescimento bacteriano, mas a efetividade foi variada. Entre os óleos essenciais testados, M. piperita apresentou maior atividade antibacteriana para E. coli, (8.106 UA mL-1) quando comparada as demais bactérias, atividade moderada para Salmonella enterica Enteritidis e Enterobacter sakazakii (1.706 e 3.200 UA mL-1 respectivamente) e baixa atividade para Listeria monocytogenes (106,67 UA mL-1). Já óleo essencial de Cymbopogon citratus apresentou maior atividade antimicrobiana frente a E. coli (9.386 UA mL-1) e atividade moderada frente a Enterobacter sakazakii, Salmonella enterica Enteritidis e Listeria monocytogenes (2.773 UA mL-1 para ambas). Ocimum basilicum apresentou maior atividade antibacteriana frente E. coli e Enterobacter sakazakii (6.826 e 8.106 UA mL-1 respectivamente), moderada atividade frente a Salmonella enterica Enteritidis (1.600 UA mL-1) e não apresentou atividade frente a Listeria monocytogenes.Origanum majorana também foi testado neste estudo e apresentou maior atividade antimicrobiana frente E. coli (5.973 UA mL-1), atividade moderada para Salmonella enterica Enteritidis e Enterobacter sakazakii (1.706 e 2.346 UA mL-1 , respectivamente) e não apresentou atividade para Listeria monocytogenes.<br>ABSTRACT 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 (106,67 UA mL-1). 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