Plante présente dans de nombreux pays méditerranéens, l'Origan (genre Origanum) a été classé par Ietswaart en 74 espèces, sous-espèces, variétés ou hybrides. La composition chimique des huiles essentielles (HE) d'une trentaine d'espèces a été étudiée dans ce travail. Le matériel végétal a été fourni par le CNPMAI de Milly-la-Forêt qui a réalisé des cultures à partir de semis de graines collectées dans les pays d'origine. Les plants ainsi obtenus ont été récoltés, séchés, et les HE ont été extraites par hydrodistillation selon le procédé décrit par la Pharmacopée Européenne 5ème éd. L'analyse des 457 échantillons d'HE a été effectuée au moyen des techniques de CPG, soit couplée à la spectrométrie de masse pour l'identification des composés, soit couplée à un détecteur à ionisation de flamme pour leur quantification. L'analyse des résultats montre que les phénols sont présents dans la quasi-totalité des espèces étudiées, le carvacrol est le plus représenté puisque les HE de 22 espèces en renferment plus de 40 %, tandis que le thymol atteint des teneurs de plus de 40 % dans les HE de 8 espèces. Les monoterpènes oxygénés sont présents à plus de 50 % dans 7 espèces, les plus importants étant le linalol, l'α-terpinéol, le trans-hydrate de sabinène et le terpinène- 4-ol. Une seule espèce fournit une HE renfermant une quantité importante d'hydrocarbures monoterpéniques. Ce travail a permis d'une part d'indiquer des compositions d'HE non encore étudiées à ce jour et d'autre part de mettre en évidence des spécificités intra et inter espèces. En effet, lorsque le nombre d'échantillons d'HE analysés était suffisant, une étude statistique par ACP et test de Student a permis de montrer la présence de plusieurs chémotypes au sein d'une même espèce. L'origine géographique serait une variable importante puisque les HE de certaines espèces natives d'isolats géographiques (Ile de Chypre) possèdent généralement une composition unique contrairement à celles originaires du continent où la présence de 2 ou 3 chémotypes a parfois été montrée. Ce travail a aussi permis d'établir que O. dubium et O. majorana var. tenuifolium, initialement confondus, sont en fait 2 espèces botaniquement distinctes. La composition de leurs HE confirme cette différenciation : la première présente 2 chémotypes (1 à thymol et 1 à carvacrol), alors que l'HE de la seconde se compose principalement d'α-terpinéol, de trans-hydrate de sabinène et de terpinène-4-ol. Il n'a par contre pas été possible d'établir de manière formelle une relation chimiotaxonomique entre la composition chimique des HE d'Origan et la classification proposée par Ietswaart.

<p>During the breeding season Zebra finch, Taeniopygia guttata, females develops a brood patch on the ventral surface which facilitates heat exchange between the incubating bird and the egg. The brood patch has to be sensitive to changes in temperature, so that the eggs can be kept at an optimal temperature for embryo development. If the egg temperature drops it has to be re-warmed. Mild cooling of the brood patch has been shown to cause cold induced vasodilation, but the responsible mechanism for this is not known. In this study we investigated if known thermoreceptors, TRPV3 and TRPV4, could be involved in the alteration of blood flow. To activate TRPV3 and TRPV4 two agonists, carvacrol and 4α-PDD respectively, were applied on the brood patch. Changes in skin temperature and vascularity were then examined. The results obtained did not reveal any changes in the vascularity. Temperature changes in the skin that could be caused by an alteration in blood flow did not significantly change either. Still, a role of these channels in the brood patch cannot be excluded.</p>

Essential oils (EOs) or their isolated components, such as eugenol and carvacrol, have strong antimicrobial activities against both Gram-positive and Gram-negative bacteria and are generally recognized as safe by the FDA. However their hydrophobic properties limit their dispersion and stabilization in aqueous food systems. This requires higher concentrations, which in turn negatively affect the quality of foods. The objective here was to determine the effect of the natural emulsifier lecithin on the antimicrobial activity of eugenol and carvacrol and possible food applications. Escherichia coli K12 and E. coli O157:H7 strains ‘Cider’ and ATCC 43889 were used. Homogenized eugenol and carvacrol, with and without lecithin, were screened for antimicrobial activity. The stability of the samples measured by particle size and zeta potential was not affected by different concentrations of lecithin. For all strains, the antimicrobial activity of carvacrol and eugenol was enhanced significantly (P<0.05) by low concentration of lecithin. The D-value (time at a specific concentration of antimicrobial necessary to cause a 90% reduction in viable cells) for E. coli K12 exposed to 0.047% v/v eugenol or 0.015 % v/v carvacrol was reduced from 13.3 to 6.3 min and 17.4 to 9.7 min, respectively, with the addition of 0.0025% lecithin (w/v). Similarly 0.0025% w/v lecithin in the presence of 0.058% v/v eugenol or 0.0188% v/v carvacrol, caused the D-value to decrease from 4.0 to 1.2 min and 10.2 to 6.9 min, respectively, for E. coli strain ‘Cider’ and from 6.2 min to 3.6 min and 9.9 to 5.4 min, respectively, for E. coli ATCC 43889. Higher lecithin concentrations (> 0.005% w/v) increased D-values compared to lower concentrations. Similar results were found in vegetable juice. The results showed that a small amount of lecithin can enhance the antimicrobial activities of essential oils. Addition of lecithin had no effect on oil-water emulsion droplet particle size and the stability of the samples was not affected by different concentration of lecithin. We believe that lecithin enhances the antimicrobial activity of eugenol and carvacrol droplets by improving the ionic interactions between the positively charged lecithin-containing essential oil components and negatively charged bacterial cells.

During the breeding season Zebra finch, Taeniopygia guttata, females develops a brood patch on the ventral surface which facilitates heat exchange between the incubating bird and the egg. The brood patch has to be sensitive to changes in temperature, so that the eggs can be kept at an optimal temperature for embryo development. If the egg temperature drops it has to be re-warmed. Mild cooling of the brood patch has been shown to cause cold induced vasodilation, but the responsible mechanism for this is not known. In this study we investigated if known thermoreceptors, TRPV3 and TRPV4, could be involved in the alteration of blood flow. To activate TRPV3 and TRPV4 two agonists, carvacrol and 4α-PDD respectively, were applied on the brood patch. Changes in skin temperature and vascularity were then examined. The results obtained did not reveal any changes in the vascularity. Temperature changes in the skin that could be caused by an alteration in blood flow did not significantly change either. Still, a role of these channels in the brood patch cannot be excluded.

Access to abstract permanently restricted to Ball State community only / Access to thesis permanently restricted to Ball State community only / Department of Biology

With increasing world population, the demand for fish is growing thus there is a need to identify products with potential to increase the efficiency of fish production. Phytogenics are among the products being investigated as potential naturally derived growth promoters. The aim of this study was to identify phytogenic compounds and doses with growth-promoting effects in Nile tilapia and investigate relevant pathways underlying their growth promotion effects. The phytogenic compounds limonene, carvacrol and thymol, major constituents of essential oils from the plants citrus, oregano and thyme, respectively, were evaluated. Six Trials (Trials I, II, III, IV, V and VI) were carried out using diets supplemented with varying concentrations of the phytogenic compounds. In Trials I, II and III (Chapter 3), the effects of either limonene (Trial I), carvacrol (Trial II) or thymol (Trial III) on growth performance of Nile tilapia were investigated (objective 1) and performance parameters including final fish weight, daily growth coefficient, growth rate per metabolic body weight, percentage (%) weight gain, % survival, feed intake, feed conversion ratio and protein efficiency ratio were evaluated. Results from Trials I, II and III indicated that dietary supplementation of 400 and 500 ppm limonene and 750 ppm thymol had growth-promoting effects in Nile tilapia but the somatic growth was not associated with enhanced feed intake and feed utilisation efficiency. Trials IV and V (Chapter 4) investigated growth and nutritional physiology pathways in Nile tilapia regulated by individual phytogenic compounds (objective 2). This was accomplished by analysing the effects of limonene (Trial IV) and thymol (Trial V) supplemented diets on the expression of key genes participating in selected pathways of somatotropic axis-mediated growth, appetite regulation, nutrient digestion, absorption and transport, lipid metabolism, and antioxidant enzyme defence system. Limonene was supplemented in the diet at 0, 200, 400 and 600 ppm while thymol was supplemented at 0, 250 and 500 ppm. Trials IV and V found that growth-promoting effects of limonene (400 and 600 ppm) in Nile tilapia involved up-regulation of key genes within pathways including somatotropic axis-mediated growth, nutrient digestion, absorption and transport, lipid metabolism and antioxidant enzyme defence system. Dietary thymol at 250 and 500 ppm did not significantly enhance growth of Nile tilapia nor regulate the nutritional physiology pathways listed above. In Trial VI (Chapter 5), the effects of combined phytogenic compounds (limonene and thymol) on growth and nutritional physiology of Nile tilapia was tested (objective 3) to establish if the compounds had synergistic or additive effects on the growth of the fish as well as complementary effects on the selected nutritional physiology pathways. A candidate gene approach was also used for the selected pathways. Results from Trial VI showed that a diet supplemented with a combination of limonene (400 ppm) and thymol (500 ppm) has neither synergistic nor additive effects on the growth performance of Nile tilapia, with limonene mainly influencing the attained somatic growth. The analysed candidate genes involved in the pathways of nutrient digestion, absorption and transport, lipid metabolism, antioxidant enzymes and somatotropic axis growth also showed no synergistic or additive effects of a dietary combination of limonene and thymol in Nile tilapia. Overall, results from the study suggest approaches for developing functional diets for Nile tilapia using limonene and thymol growth promoters.

Submitted by ROBERTO PAULO CORREIA DE ARAÚJO (ppgorgsistem@ufba.br) on 2016-10-18T14:55:15Z No. of bitstreams: 1 Milena Ramos Reis.pdf: 2152638 bytes, checksum: 876fac844a4f4a8b22cb82e9cdeb5f3b (MD5) / Made available in DSpace on 2016-10-18T14:55:15Z (GMT). No. of bitstreams: 1 Milena Ramos Reis.pdf: 2152638 bytes, checksum: 876fac844a4f4a8b22cb82e9cdeb5f3b (MD5) / O carvacrol, um monoterpeno fenólico encontrado nos óleos essenciais de diversas plantas do gênero Origanum, já demonstrou causar hipotensão e vasodilatação em diferentes leitos vasculares de ratos normotensos, porém, seu efeito em ratos hipertensos ainda não foi elucidado. O objetivo deste estudo foi investigar os efeitos cardiovasculares do carvacrol em ratos espontaneamente hipertensos (SHR) e comparar com normotensos Wistar, utilizando ensaios farmacológicos in vitro (estudos funcionais e celulares) e in vivo. Nos ensaios funcionais in vitro, anéis de artéria mesentérica superior isolada de animais hipertensos e normotensos foram précontraídos com FEN (1μM) e o efeito de carvacrol (10-8-10-3M) foi observado. Em SHR, este monoterpeno induziu vasodilatação dependente de concentração (pD2=5,13 ± 0,05; Emáx=115,14 ± 5,46%; N=8) e, após a remoção do endotélio funcional, a potência da droga foi alterada significantemente (pD2=4,91 ± 0,05 N=9; p<0,01), sugerindo que a resposta vasodilatadora induzida por carvacrol, provavelmente, envolve uma via dependente e outra independente do endotélio vascular, porém, esta última parece ser a majoritária e, por isso, os ensaios seguintes foram realizados na ausência do endotélio vascular. Interessantemente, quando comparada com animais normotensos, a potência farmacológica de carvacrol foi reduzida significantemente (pD2=4,91 ± 0,05; N=9; p<0,05). Em anéis de ratos hipertensos, carvacrol reduziu o influxo de Ca2+ por canais Cav tipo-L, SOC e ROC, estes resultados foram semelhantes aos obtidos em ratos normotensos. Em ratos hipertensos, mas não em normotensos, a potência farmacológica do carvacrol em anéis pré-contraídos com FEN e na presença de diferentes inibidores de canais TRP (íon Gd3+, 10-5M; 2-APB, 10-6M ou 10-5M; BCTC, 2μM; 9-fenantrol, 10-5M; ou HC03003-1, 10-5M), foi reduzida em relação ao controle na ausência destes bloqueadores, sugerindo que os canais sensíveis à estes bloqueadores (TRPC1-7, TRPM2, M4 e TRPM8, TRPV1 e TRPA1), provavelmente, estão participando dos efeitos vasculares mediados por carvacrol e podem estar envolvidos no processo hipertensivo. Em estudos de patch-clamp em células de artéria mesentérica dispersas de ratos hipertensos, carvacrol (300μM) reduziu as correntes de entrada de Ba2+ por Cav tipo-L e este efeito foi semelhante em ratos normotensos. Além disso, em células de ratos hipertensos, o Mg2+ (2,5mM), bloqueador do TRPM6 e TRPM7, reduziu as densidades de ITRPM de entrada e saída, assim como carvacrol (100μM e 300μM), na ausência ou presença do 2-APB (100μM), bloqueador de TRPM7. A presença do 2-APB provocou inibição adicional nas densidades de ITRPM pelo carvacrol (100μM, mas não 300μM). Altas concentrações intracelulares de Mg2+ reduziram the magnitude of ITRPM7. Foi evidenciado que a ITRPM no controle é menor em ratos hipertensos que em normotensos. Estes dados obtidos e os relatados na literatura são sugestivos para provável inibição de ITRPM7 por carvacrol em células mesentéricas nativas. O efeito anti-hipertensivo do carvacrol foi avaliado por administração via orogástrica (50mg/kg/dia) durante 20 dias foi capaz de reduzir a pressão arterial média dos animais SHR tratados, no 20º dia do tratamento. O tratamento subcrônico com carvacrol não alterou os pesos cardíaco e corpóreo, nem a reatividade vascular. Em conclusão, esses dados sugerem que carvacrol possui atividade anti-hipertensiva em animais SHR, que pode ser devido ao seu efeito vasodilatador em anéis de artéria mesentérica superior isolada, provavelmente, por inibição do influxo de Ca2+ por Cav tipo-L, ROC, SOC e/ou canais TRPC1, 3 ou 6, além da inibição de correntes tipo-TRPM7 em miócitos mesentéricos.

Espécies reativas de oxigênio (ERO) são produzidas através da respiração aeróbica e durante processos inflamatórios. Além disso, agressões externas como radiações, poluição, estresse, alcoolismo e tabagismo aumentam a sua produção. Altos níveis de ERO podem ocasionar dano oxidativo à lipídios, proteínas e DNA, comprometendo a função normal da célula, podendo estar envolvidos na patogênese e agravamento de diversas doenças. Há evidências que sugerem que antioxidantes naturais presentes em alimentos conferem benefícios adicionais à saúde, atuando como anticarcinogênicos, antiinflamatórios ou agentes antimutagênicos. O orégano (Oreganum sp) é uma especiaria mediterrânea usada como condimento na alimentação e pela medicina popular para diversos tipos de moléstias. O óleo possui forte ação antimicrobiana, devido ao elevado conteúdo de monoterpenos, sendo os principais o carvacrol, o timol e o para-cimeno. O carvacrol (5-isopropil-2metilfenol) é um fenol monoterpênico, com sabor picante e odor característico e tem sido amplamente usado na indústria de alimentos como aditivo seguro para aumentar a vida útil dos alimentos, como aromatizante em produtos assados, doces, bebidas e gomas de mascar, e/ou agente antimicrobiano com atividades contra bactérias, fungos e leveduras. Estudos têm relatado efeito antidepressivo e ansiolítico do carvacrol em camundongos, assim como proteção contra a radiação UVB diminuindo a peroxidação lipídica, estresse oxidativo e danos no DNA em células linfocitárias humanas e atividade antioxidante em diferentes sistemas de lipídios. Nós avaliamos a viabilidade celular e parâmetros de citotoxicidade do carvacrol em células de neuroblastoma humano SH-SY5Y. Este parece modificar levemente a morfologia das células, sem modificar significativamente a biomassa celular, parecendo ser tóxico na concentração de 100 μg/mL. Nas demais concentrações (1 a 50 μg/mL) não houve citotoxicidade. No ensaio de DCFH-DA o carvacrol reduziu a produção de ERO intracelular e diminui significativamente a produção de radicais peroxil no ensaio TRAP. Esses dados reforçam a ideia do carvacrol ser um potencial antioxidante, sendo necessários mais estudos para avaliar o mecanismo de ação deste composto. / Reactive oxygen species (ROS) are produced through aerobic respiration and during inflammation. Besides, external aggressions such as radiation, pollution, stress, alcoholism and smoking increase their production. Elevated levels of ROS can cause oxidative damage to lipids, proteins and DNA, compromising the normal cell function, and may be involved in the pathogenesis and progression of several diseases. There is suggesting that natural antioxidants found in foods provide additional health benefits, acting as anticarcinogenic, anti-inflammatory agents or antimutagenic. Oregano (Oreganum sp) is a Mediterranean spice used in food as a condiment and in popular medicine to treat several types of diseases. The essential oil has strong antimicrobial activity, due to the high content of monoterpenes, the main ones being carvacrol, thymol and para-cymene. Carvacrol (5-isopropyl-2metilfenol) is a phenol monoterpene with spicy taste and odor and has been widely used in food industry as additive to preserve foods, as flavoring agent in baked goods, candy, drinks and chewing gums, and/or antimicrobial agent with activity against bacteria, fungi and yeasts. Studies have reported antidepressant and anxiolytic effects of carvacrol in mice, as well as protection against UVB radiation, decreased lipid peroxidation, oxidative stress and DNA damage in human lymphocyte cells, and antioxidant activity in different lipid systems. We evaluated cell viability and cytotoxicity parameters of carvacrol in human neuroblastoma cells SH-SY5Y. Carvacrol induced morphology changes in cells without significant modification of the cellular biomass content and it was toxic at the concentration of 100 μg/mL. In other concentrations (1-50 μg/mL) it showed no cytotoxicity. In DCFH-DA assay carvacrol reduced the intracellular ROS production and significantly decreased the production of peroxyl radicals in the TRAP assay. These data reinforce the idea of carvacrol as a potential antioxidant and more research is needed to evaluate the mechanism of action of this compound.

Espécies reativas de oxigênio (ERO) são produzidas através da respiração aeróbica e durante processos inflamatórios. Além disso, agressões externas como radiações, poluição, estresse, alcoolismo e tabagismo aumentam a sua produção. Altos níveis de ERO podem ocasionar dano oxidativo à lipídios, proteínas e DNA, comprometendo a função normal da célula, podendo estar envolvidos na patogênese e agravamento de diversas doenças. Há evidências que sugerem que antioxidantes naturais presentes em alimentos conferem benefícios adicionais à saúde, atuando como anticarcinogênicos, antiinflamatórios ou agentes antimutagênicos. O orégano (Oreganum sp) é uma especiaria mediterrânea usada como condimento na alimentação e pela medicina popular para diversos tipos de moléstias. O óleo possui forte ação antimicrobiana, devido ao elevado conteúdo de monoterpenos, sendo os principais o carvacrol, o timol e o para-cimeno. O carvacrol (5-isopropil-2metilfenol) é um fenol monoterpênico, com sabor picante e odor característico e tem sido amplamente usado na indústria de alimentos como aditivo seguro para aumentar a vida útil dos alimentos, como aromatizante em produtos assados, doces, bebidas e gomas de mascar, e/ou agente antimicrobiano com atividades contra bactérias, fungos e leveduras. Estudos têm relatado efeito antidepressivo e ansiolítico do carvacrol em camundongos, assim como proteção contra a radiação UVB diminuindo a peroxidação lipídica, estresse oxidativo e danos no DNA em células linfocitárias humanas e atividade antioxidante em diferentes sistemas de lipídios. Nós avaliamos a viabilidade celular e parâmetros de citotoxicidade do carvacrol em células de neuroblastoma humano SH-SY5Y. Este parece modificar levemente a morfologia das células, sem modificar significativamente a biomassa celular, parecendo ser tóxico na concentração de 100 μg/mL. Nas demais concentrações (1 a 50 μg/mL) não houve citotoxicidade. No ensaio de DCFH-DA o carvacrol reduziu a produção de ERO intracelular e diminui significativamente a produção de radicais peroxil no ensaio TRAP. Esses dados reforçam a ideia do carvacrol ser um potencial antioxidante, sendo necessários mais estudos para avaliar o mecanismo de ação deste composto. / Reactive oxygen species (ROS) are produced through aerobic respiration and during inflammation. Besides, external aggressions such as radiation, pollution, stress, alcoholism and smoking increase their production. Elevated levels of ROS can cause oxidative damage to lipids, proteins and DNA, compromising the normal cell function, and may be involved in the pathogenesis and progression of several diseases. There is suggesting that natural antioxidants found in foods provide additional health benefits, acting as anticarcinogenic, anti-inflammatory agents or antimutagenic. Oregano (Oreganum sp) is a Mediterranean spice used in food as a condiment and in popular medicine to treat several types of diseases. The essential oil has strong antimicrobial activity, due to the high content of monoterpenes, the main ones being carvacrol, thymol and para-cymene. Carvacrol (5-isopropyl-2metilfenol) is a phenol monoterpene with spicy taste and odor and has been widely used in food industry as additive to preserve foods, as flavoring agent in baked goods, candy, drinks and chewing gums, and/or antimicrobial agent with activity against bacteria, fungi and yeasts. Studies have reported antidepressant and anxiolytic effects of carvacrol in mice, as well as protection against UVB radiation, decreased lipid peroxidation, oxidative stress and DNA damage in human lymphocyte cells, and antioxidant activity in different lipid systems. We evaluated cell viability and cytotoxicity parameters of carvacrol in human neuroblastoma cells SH-SY5Y. Carvacrol induced morphology changes in cells without significant modification of the cellular biomass content and it was toxic at the concentration of 100 μg/mL. In other concentrations (1-50 μg/mL) it showed no cytotoxicity. In DCFH-DA assay carvacrol reduced the intracellular ROS production and significantly decreased the production of peroxyl radicals in the TRAP assay. These data reinforce the idea of carvacrol as a potential antioxidant and more research is needed to evaluate the mechanism of action of this compound.

Espécies reativas de oxigênio (ERO) são produzidas através da respiração aeróbica e durante processos inflamatórios. Além disso, agressões externas como radiações, poluição, estresse, alcoolismo e tabagismo aumentam a sua produção. Altos níveis de ERO podem ocasionar dano oxidativo à lipídios, proteínas e DNA, comprometendo a função normal da célula, podendo estar envolvidos na patogênese e agravamento de diversas doenças. Há evidências que sugerem que antioxidantes naturais presentes em alimentos conferem benefícios adicionais à saúde, atuando como anticarcinogênicos, antiinflamatórios ou agentes antimutagênicos. O orégano (Oreganum sp) é uma especiaria mediterrânea usada como condimento na alimentação e pela medicina popular para diversos tipos de moléstias. O óleo possui forte ação antimicrobiana, devido ao elevado conteúdo de monoterpenos, sendo os principais o carvacrol, o timol e o para-cimeno. O carvacrol (5-isopropil-2metilfenol) é um fenol monoterpênico, com sabor picante e odor característico e tem sido amplamente usado na indústria de alimentos como aditivo seguro para aumentar a vida útil dos alimentos, como aromatizante em produtos assados, doces, bebidas e gomas de mascar, e/ou agente antimicrobiano com atividades contra bactérias, fungos e leveduras. Estudos têm relatado efeito antidepressivo e ansiolítico do carvacrol em camundongos, assim como proteção contra a radiação UVB diminuindo a peroxidação lipídica, estresse oxidativo e danos no DNA em células linfocitárias humanas e atividade antioxidante em diferentes sistemas de lipídios. Nós avaliamos a viabilidade celular e parâmetros de citotoxicidade do carvacrol em células de neuroblastoma humano SH-SY5Y. Este parece modificar levemente a morfologia das células, sem modificar significativamente a biomassa celular, parecendo ser tóxico na concentração de 100 μg/mL. Nas demais concentrações (1 a 50 μg/mL) não houve citotoxicidade. No ensaio de DCFH-DA o carvacrol reduziu a produção de ERO intracelular e diminui significativamente a produção de radicais peroxil no ensaio TRAP. Esses dados reforçam a ideia do carvacrol ser um potencial antioxidante, sendo necessários mais estudos para avaliar o mecanismo de ação deste composto. / Reactive oxygen species (ROS) are produced through aerobic respiration and during inflammation. Besides, external aggressions such as radiation, pollution, stress, alcoholism and smoking increase their production. Elevated levels of ROS can cause oxidative damage to lipids, proteins and DNA, compromising the normal cell function, and may be involved in the pathogenesis and progression of several diseases. There is suggesting that natural antioxidants found in foods provide additional health benefits, acting as anticarcinogenic, anti-inflammatory agents or antimutagenic. Oregano (Oreganum sp) is a Mediterranean spice used in food as a condiment and in popular medicine to treat several types of diseases. The essential oil has strong antimicrobial activity, due to the high content of monoterpenes, the main ones being carvacrol, thymol and para-cymene. Carvacrol (5-isopropyl-2metilfenol) is a phenol monoterpene with spicy taste and odor and has been widely used in food industry as additive to preserve foods, as flavoring agent in baked goods, candy, drinks and chewing gums, and/or antimicrobial agent with activity against bacteria, fungi and yeasts. Studies have reported antidepressant and anxiolytic effects of carvacrol in mice, as well as protection against UVB radiation, decreased lipid peroxidation, oxidative stress and DNA damage in human lymphocyte cells, and antioxidant activity in different lipid systems. We evaluated cell viability and cytotoxicity parameters of carvacrol in human neuroblastoma cells SH-SY5Y. Carvacrol induced morphology changes in cells without significant modification of the cellular biomass content and it was toxic at the concentration of 100 μg/mL. In other concentrations (1-50 μg/mL) it showed no cytotoxicity. In DCFH-DA assay carvacrol reduced the intracellular ROS production and significantly decreased the production of peroxyl radicals in the TRAP assay. These data reinforce the idea of carvacrol as a potential antioxidant and more research is needed to evaluate the mechanism of action of this compound.