Toxicity and larvicidal activity on Aedes aegypti of citronella essential oil submitted to enzymatic esterification / Toxicidade e atividade larvicida sobre Aedes aegypti de óleo essencial de citronella submetido à esterificação enzimática

Abstract The essential oil of citronella (Cymbopogon winterianus) has several biological activities, among them the insect repellent action. Some studies showed that cinnamic acid esters can be applied as natural pesticides, insecticides and fungicides. In this context, the objective of the present work was to evaluate the production of esters from citronella essential oil with cinnamic acid via enzymatic esterification. Besides, the essential oil toxicity before and after esterification against Artemia salina and larvicidal action on Aedes aegypti was investigated. Esters were produced using cinnamic acid as the acylating agent and citronella essential oil (3:1) in heptane and 15 wt% NS 88011 enzyme as biocatalysts, at 70 °C and 150 rpm. Conversion rates of citronellyl and geranyl cinnamates were 58.7 and 69.0% for NS 88011, respectively. For the toxicity to Artemia salina LC50 results of 5.29 μg mL-1 were obtained for the essential oil and 4.36 μg mL-1 for the esterified oils obtained with NS 88011. In the insecticidal activity against Aedes aegypti larvae, was obtained LC50 of 111.84 μg mL-1 for the essential oil of citronella and 86.30 μg mL-1 for the esterified oils obtained with the enzyme NS 88011, indicating high toxicity of the esters. The results demonstrated that the evaluated samples present potential of application as bioinsecticide.

Resumo O óleo essencial de citronela (Cymbopogon winterianus) possui diversas atividades biológicas, entre elas a ação repelente a insetos. Alguns estudos mostraram que os ésteres do ácido cinâmico podem ser aplicados como pesticidas naturais, inseticidas e fungicidas. Nesse contexto, o objetivo do presente trabalho foi avaliar a produção de ésteres a partir do óleo essencial de citronela com ácido cinâmico via esterificação enzimática. Além disso, foi investigada a toxicidade do óleo essencial antes e após a esterificação contra Artemia salina e a ação larvicida sobre Aedes aegypti. Os ésteres foram produzidos utilizando ácido cinâmico como agente acilante e óleo essencial de citronela (3: 1) em heptano e 15% em peso da enzima NS 88011 como biocatalisadores, a 70 ° C e 150 rpm. As taxas de conversão de cinamatos de citronelil e geranil foram 58,7 e 69,0% para NS 88011, respectivamente. Para a toxicidade sobre Artemia salina foram obtidos CL50 de 5,29 μg mL-1 para o óleo essencial e 4,36 μg mL-1 para os óleos esterificados com NS 88011. Na atividade inseticida contra larvas de Aedes aegypti, obteve-se CL50 de 111,84 μg mL-1 para o óleo essencial de citronela e 86,30 μg mL-1 para os óleos esterificados com a enzima NS 88011, indicando alta toxicidade dos ésteres. Os resultados demonstraram que as amostras avaliadas apresentam potencial de aplicação como bioinseticida.

Chemical composition and phytotoxicity of essential oils of Croton doctoris S. Moore (Euphorbiaceae) / Composição química e fitotoxicidade dos óleos essenciais de Croton doctoris S. Moore (Euphorbiaceae)

Essential oils from the stems and leaves of Croton doctoris were analyzed by gas chromatography and mass spectrometry, resulting in 22 identified compounds. The effects of these essential oils on the germination, root and shoot growth, total chlorophyll content, potential root respiration, peroxidase activity, catalase, superoxide dismutase, and mitotic index in lettuce and onion were determined. Antioxidant, antimicrobial, and cytotoxic activity were also investigated. The results revealed that the stem oil consisted of 15 compounds, of which caryophyllene oxide (24.5%) and E-caryophyllene (13.3%) were the major constituents. The leaf oil contained E-caryophyllene (39.6%) and α-humulene (13.2%) as major compounds. The oils inhibited the germination and growth of lettuce and onion seedlings and reduced chlorophyll content, root respiration, and cell division. They also caused oxidative stress, indicated by the increased activity of the evaluated antioxidant enzymes. These abnormal physiological processes contributed to the inhibition of plant growth. The most pronounced phytotoxic effects were observed in the stem oil. The cytotoxicity tests indicated that leaf oil was more active than stem oil, resulting from the presence of biologically active sesquiterpenes that inhibit the growth of cancer cells.

Os óleos essenciais do caule e da folha de Croton doctoris foram analisados por cromatografia gasosa (GC) e espectrometria de massa (GC-MS) resultando em 22 compostos identificados. Os efeitos dos óleos essenciais na germinação, crescimento de raízes e parte aérea, teor total de clorofila, respiração radicular, atividade de peroxidase, catalase e superóxido de dimetase e índice mitótico foram determinados em alface e cebola. Atividade antioxidante, antimicrobiana e citotóxica também foram investigadas. Os resultados revelaram que o óleo do caule é constituído por 15 compostos, dos quais os principais são o óxido de cariofileno (24,5%) e E-cariofileno (13,3%). O óleo foliar apresentou E-cariofileno (39,6%) seguido de α-humuleno (13,2%) como compostos majoritários. Os óleos inibiram a germinação e o crescimento das plântulas de alface e cebola e reduziram o conteúdo de clorofila, a respiração radicular e a divisão celular. Eles também causaram estresse oxidativo, indicado pelo aumento da atividade das enzimas antioxidantes avaliadas. Esses processos fisiológicos anormais contribuem para a inibição do crescimento das plantas. Os efeitos fitotóxicos mais pronunciados foram observados no óleo do caule. Nos testes de citotoxicidade observou-se que o óleo das folhas foi mais ativo, resultante da presença de sesquiterpenos biologicamente ativos que atuam inibindo o crescimento das células cancerígenas.

Ação inseticida in vitro do óleo essencial de Lippia gracilisSchauer sobre Damalinia Bovicola ovis (Schrank, 1781) / In vitro action of Lippia gracilis Schauer essential oil on Damalinia Bovicola ovis (Schrank, 1781)

O objetivo deste trabalho é avaliar a eficácia inseticida in vitro do óleo essencial de Lippia gracilis sobre Bovicolaovis. Os espécimes (n = 900) de B.ovis foram coletados de ovinos naturalmente infestados, distribuídos aleatoriamente em grupos, e submetidos aos diferentes tratamentos: (G1) 1.000 a 15,6 mg/ml óleo essencial de Lippia gracilis; (G2) Tween 80 a 3% (controle negativo), e: (G3) Amitraz 1,25 g/mL (controle positivo). Realizou-se 4 réplicas (25 piolhos por réplica) para cada tratamento. A viabilidade dos piolhos foi avaliada nos tempos de 1, 3, 6, 24, 48 e 72 h. Os dados foram expressos em eficácia média ± desvio padrão (SPSS versão 23.0) e diferenças estatísticas dos grupos experimentais foram obtidas por Kruskal-Wallis e Friedman. Para obtenção da CI50e CI90 foi realizada Regressão de Probit, com nível de significância de p< 0,05. O óleo essencial de L. gracilis nas concentrações de 100 a 62,5 mg/mL apresentaram eficácia de 100%, 1 h pós-exposição. Os valores de CI50 e CI90 foram 18,1 mg/mL e 44,9 mg/mL, respectivamente. Dessa forma, concluímos que o óleo essencial de L. gracilis apresentou eficácia sobre B.ovis in vitro.

The objective of this work is to evaluate the in vitro insecticidal efficacy of the essential oil of Lippia gracilis against Bovicolaovis. The specimens (n = 900) of B.ovis were collected from naturally infested sheep, randomly distributed in groups, and subjected to different treatments: (G1) 1,000 to 15.6 mg/ml essential oil of Lippia gracilis; (G2) 3% Tween 80 (negative control), and: (G3) Amitraz 1.25 g/mL (positive control). 4 replicates (25 lice per replica) were performed for each treatment. Louse viability was assessed at 1, 3, 6, 24, 48 and 72 h. The data were expressed as mean efficacy ± standard deviation (SPSS version 23.0) and statistical differences in the experimental groups were obtained by Kruskal-Wallis and Friedman. Probit regression was performed to obtain the IC50 and CI90, with a significance level of p <0.05. The essential oil of L. gracilis at concentrations of 100 to 62.5 mg/mL showed 100% efficacy, 1 h post-exposure. The IC50 and CI90 values were 18.1 mg/mL and 44.9 mg/mL, respectively. Thus, we conclude that L. gracilis essential oil is effective on B. ovis.

Effect of hot or warm property on skin toxicity of essential oil as penetration enhancer and its mechanism / 中国中药杂志

To compare the effect of hot or warm property of Chinese medicine(CM) on the skin toxicity of essential oils(EOs) as penetration enhancer in vitro and in vivo, and explore the mechanism. EOs were extracted from WIM of Bichengqie(Litseae Fructus), Dingxiang(Flos Syzygii Aromatici), Huajiao(Pericarpium Zanthoxyli Bungeani), and Xiaohuixiang(Fructus Foeniculi) with warm property, and Ganjiang(Rhizoma Zingiberis), Gaoliangjiang(Rhizoma Alpiniae Officinari), Hujiao(Fructus Piperis), and Wuzhuyu(Fructus Evodiae Rutaecarpae) with hot property, respectively. Then the in vitro toxicity was evaluated by human keratinocyte cytotoxicity. In vivo skin irritation potency was also evaluated through pathological observation after topical administration. The components, especially those located in stratum corneum, were analyzed by GC-MS. The main components, namely monoterpenes and sesquiterpenes, of EOs extracted from CM with hot property,were detected for the interaction with keratino-lipid ceramide 3 by molecular simulation technology; and the interaction energy value was calculated based on the optimal conformation. It was found that the skin cell toxicity of EOs from CM with hot property was significantly higher than that of EOs from CM with warm property. However, there was no significant difference between them by in vivo skin irritation evaluation. Whether from CM with hot property or warm property, EOs showed a significant reduced toxicity compared with azone. Sesquiterpenes(33.56%±19.38%) were found to be one of the main components in EOs from CM with hot property, while almost no sesquiterpenes was found in EOs from CM with warm property. After topical administration of EOs from CM with hot property, sesquiterpenes were demonstrated to be prone to locate in stratum corneum. The results of molecular simulation also revealed that the interaction between sesquiterpenes and ceramide 3 was significantly stronger than that of monoterpenes(P<0.01). In conclusion, the location of sesquiterpenes in stratum corneum resulted in the significant difference between in vitro skin cell toxicity and in vivo skin irritation potency. The EOs from CM with hot property shall be taken into account for further development of potent penetration enhancer.

Fumigant toxicity of some essential oils against Red Flour Beetles, Tribolium castaneum (Herbst) and its safety to mammals / Toxidade fumigante de alguns óleos essenciais contra besouros de farinha vermelha, Tribolium castaneum (Herbst) e sua segurança para mamíferos

Abstract Fumigant activities for three essential oils; Garlic oil (Allium sativum L); Chili pepper (Capsicum annuum L.) and Nigella (Nigella sativa L.) were assessed at different concentrations against the adult and 20-days old larval stages of Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae) in the laboratory. The accumulative mortality was observed at different exposure periods (3, 5 and 7 days). The residual effect of garlic oil that was the effective oil, on the treated wheat grains was evaluated with respect to histological changes in the liver, kidney, and stomach of rat fed on this treated wheat. The results showed that the mortality rates of treated stages increased with increasing the time of fumigation treatment. Moreover the highest essential oils toxicity at the Median lethal concentration (LC50) values for exposure periods (3, 5 and 7 days) to fumigation were (126, 53, and 47 mg/L air) for adult stage and were (79, 62, and 41 mg/L air) for larval stage, respectively in the case of Garlic oil treatment. While, the lowest essential oils effective was Nigella oil at the Median lethal concentration (LC50) values for exposure periods (3, 5 and 7 days) to fumigation were (3594, 629, and 335 mg/L air) for adult stage and were (1040, 416, and 227 mg/L air) for larval stage, respectively. The toxicity effect of various essential oils against adults and larvae of T. castaneum at the LC50at 7 days fumigation could be arranged in descending order as follows: Garlic oil, Chili pepper oil, and Nigella oil. The histological changes showed that the organs slightly affected at the fumigation for 3 days. It may be concluded that the garlic essential oil is the good effective fumigant to control T. castaneum in the stored products and it recommended that the fumigation period does not exceed 3 days. The garlic essential oil has the potential for applications in IPM programs for stored-grain pests because of its high volatility and fumigant activity and its safety.

Resumo Atividades fumigantes de três óleos essenciais - óleo de alho (Allium sativum L.); pimenta-malagueta (Capsicum annuum L.) e Nigella (Nigella sativa L.) - foram avaliadas em diferentes concentrações contra adultos e larvas de Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae) com 20 dias de idade em laboratório. A mortalidade acumulada foi observada em diferentes períodos de exposição (3, 5 e 7 dias). O efeito residual do óleo de alho, ou seja, o óleo eficaz, nos grãos de trigo tratados foi avaliado em relação às alterações histológicas no fígado, rim e estômago de ratos alimentados com esse trigo tratado. Os resultados mostraram que as taxas de mortalidade dos estágios tratados cresceram com o aumento do tempo de exposição ao tratamento de fumigação. A maior toxidade dos óleos essenciais nos valores de Concentração Letal Média (CL50) para os períodos de exposição (3, 5 e 7 dias) à fumigação foi (126, 53 e 47 mg/L ar) para a fase adulta e (79, 62 e 41 mg/L ar) para a fase de larva, respectivamente no caso do tratamento com o óleo de alho, enquanto que o óleo essencial menos eficaze foi o óleo de Nigella, com valores de CL50 para os períodos de exposição (3, 5 e 7 dias) à fumigação (3594, 629 e 335 mg/L ar) para a fase adulta, e (1040, 416 e 227 mg/L ar) para a fase de larva, respectivamente. O efeito da toxidade de vários óleos essenciais contra adultos e larvas de T. castaneum em LC50 aos sete dias de fumigação pôde ser organizado em ordem decrescente, como segue: óleo de alho, óleo de pimenta e óleo de Nigella. As alterações histológicas mostraram que os órgãos foram levemente afetados na fumigação por três dias. Pode-se concluir que o óleo essencial de alho é um bom fumigante efetivo no controle de T. castaneum nos produtos armazenados, e recomendou-se que o período de fumigação não ultrapassasse três dias. O óleo essencial de alho tem potencial para aplicações em programas de Integrated Pests Management (IPM) para pragas de grãos armazenados, devido à sua alta volatilidade, atividade fumigante e respectiva segurança.

Essential oils from Citrus x aurantium and Citrus x latifolia (Rutaceae) have anesthetic activity and are effective in reducing ion loss in silver catfish ( Rhamdia quelen )

This study investigated the anesthetic effect of the essential oils (EOs) from the peel of Citrus x aurantium (EOCA) and Citrus x latifolia (EOCL) on silver catfish Rhamdia quelen. Fish were exposed to different concentrations of EOCA and EOCL to determine time of anesthesia induction and recovery. Induction of anesthesia was observed in all fish exposed to 400, 600 or 800 µL L−1 EOCA and 300, 400 or 500 µL L−1 EOCL. Another group of fish were exposed for 8 h to 50, 100, or 200 µL L−1 of either EOs. Overall, fish exposed to ethanol and both EOs presented higher ventilatory frequencies (VF) than the control group throughout the 8 h of exposure. Net ion (Na+, K+ and Cl−) effluxes and ammonia excretion were significantly lower in fish exposed to 50, 100 or 200 µL L−1 of either EOs compared to control fish. Mortality was 37% in fish exposed to 200 µL L−1 of either EOs after 8 h. These findings suggest that EOCA and EOCL are useful anesthetics and sedatives for Rhamdia quelen, but their usefulness as alternatives to reduce stress in fish transportation at the lower concentrations tested (50-100 µL L−1) deserves further study.(AU)

O efeito anestésico dos óleos essenciais (OEs) da casca de Citrus x aurantium (OECA) e Citrus x latifolia (OECL) em jundiá Rhamdia quelen foi investigado. Os peixes foram expostos a diferentes concentrações de OECA e OECL para determinar o tempo de indução e recuperação da anestesia. Todos peixes expostos a 400, 600 ou 800 µL L−1 OECA e 300, 400 ou 500 µL L−1 OECL foram anestesiados. Outro grupo de peixes foi exposto aos OEs durante 8 h a 50, 100 ou 200 µL L−1. Peixes expostos ao etanol e aos OEs apresentaram VF maior que o grupo controle durante as 8 h de exposição. Os efluxos líquidos de Na+, K+, Cl− e a excreção de amônia foram significativamente menores nos peixes expostos a 50, 100 ou 200 µL L−1 dos OEs em comparação com o grupo controle. A mortalidade foi de 37% nos peixes expostos a 200 µL L−1 de ambos os OEs após 8 h. Os resultados sugerem que OECA e OECL são anestésicos e sedativos úteis para o jundiá, mas sua utilidade como alternativa para reduzir o estresse no transporte de peixes nas concentrações mais baixas testadas (50-100 µL L−1) necessita de estudos adicionais.(AU)

Comparative toxicity of essential oil and blends of selected terpenes of Ocotea species from Pernambuco, Brazil, against Tetranychus urticae Koch

ABSTRACT Essential oils from the leaves of two species of the genus Ocotea that occur in the Atlantic Forest in the state of Pernambuco, Brazil, were analyzed using gas chromatography-mass spectrometry. The acaricidal activity of these oils as well as 11 selected components and blends were evaluated in fumigation and residual contact tests against the two-spotted spider mite (Tetranychus urticae). Sixty-seven constituents were identified, totaling 97.3 ± 0.3% and 97.8 ± 0.5% of the oils from O. duckei and O. glomerata, respectively. Sesquiterpene was the dominant class. The compounds β-caryophyllene (18.6 ± 0.1%) and aromadendrene (17.3 ± 0.6%) were the main constituents of the oils from O. duckei and O. glomerata, respectively. Acaricidal action varied depending on the method employed, species and chemical nature of the selected constituents. The mites were susceptible to the oils and chemical constituents using the fumigation method. The O. duckei oil was respectively 2.5-fold and 1.5-fold more toxic than the O. glomerata oil using the fumigation and residual contact methods. Among the selected constituents, β-caryophyllene was the most toxic, independently of the method employed. The individual toxicity of the selected compounds and their blends as well as the role of these constituents in the overall toxicity of the essential oils are also discussed.

Toxicity of clove essential oil and its ester eugenyl acetate against Artemia salina / Toxicidade do óleo essencial de cravo e seu éster acetato de eugenila contra Artemia salina

Abstract The production of compounds via enzymatic esterification has great scientific and technological interest due to the several inconveniences related to acid catalysis, mainly by these systems do not fit to the concept of “green chemistry”. Besides, natural products as clove oil present compounds with excellent biological potential. Bioactives compounds are often toxic at high doses. The evaluation of lethality in a less complex animal organism can be used to a monitoring simple and rapid, helping the identification of compounds with potential insecticide activity against larvae of insect vector of diseases. In this sense, the toxicity against Artemia salina of clove essential oil and its derivative eugenyl acetate obtained by enzymatic esterification using Novozym 435 as biocatalyst was evaluated. The conversion of eugenyl acetate synthesis was 95.6%. The results about the evaluation of toxicity against the microcrustacean Artemia salina demonstrated that both oil (LC50= 0.5993 µg.mL–1) and ester (LC50= 0.1178 µg.mL–1) presented high toxic potential, being the eugenyl acetate almost 5 times more toxic than clove essential oil. The results reported here shows the potential of employing clove oil and eugenyl acetate in insecticide formulations.

Resumo A produção de compostos via esterificação enzimática possui grande interesse científico e tecnológico devido às inúmeras inconveniências relacionadas com a catálise ácida, principalmente por estes sitemas não se adequarem ao atual termo “tecnologias limpas”. Além disso, produtos naturais como o óleo de cravo, apresentam compostos com excelentes potenciais biológicos. Compostos bioativos são quase sempre tóxicos em altas doses. A avaliação da letalidade em um organismo animal menos complexo pode ser usada para um monitoramento simples e rápido, servindo também para a identificação de compostos com potencial atividade inseticida contra larvas de insetos vetores de doenças. Neste sentido, foi determinada a toxicidade frente a Artemia salina do óleo essencial de cravo e do seu derivado acetato de eugenila obtido por esterificação enzimática com lipase Novozym 435. A conversão da reação de síntese de acetato de eugenila foi de 95,6%. Os resultados referentes à avaliação da toxicidade frente ao microcrustáceo Artemia salina demonstraram que tanto o óleo (LC50= 0,5993 µg.mL–1) quanto o éster (LC50= 0,1178 µg.mL–1) apresentam elevado potencial toxicológico, sendo que o éster apresenta aproximadamente 5 vezes mais toxicidade em relação ao óleo. Estes resultados demonstram o potencial emprego do óleo de cravo e de acetato de eugenila em formulações de inseticidas.

Efeito fungitóxico de óleos essenciais sobre Phakopsora euvitis, agente causal da ferrugem da videira / Fungitoxic effect of essential oils on Phakopsora euvitis, causal agent of grape rust

O conhecimento sobre os efeitos indesejáveis do uso de fungicidas convencionais, associado à preocupação de órgãos reguladores e consumidores quanto à qualidade dos alimentos, tem estimulado a busca por novas alternativas para o controle de doenças de plantas. O objetivo deste trabalho foi avaliar, em laboratório e em campo, a atividade antifúngica de 16 óleos essenciais sobre Phakopsora euvitis , agente causal da ferrugem da videira. Foram utilizados os óleos essenciais de orégano, menta piperita, pimenta preta, nim, eucalipto globulus , citronela, canela, manjerona, alecrim, manjericão, camomila azul, cânfora branca, cravo, gengibre, tomilho branco e melaleuca. No laboratório foram realizados dois experimentos: no primeiro, foi avaliada a germinação de esporos, em meio ágar-água acrescido do óleo essencial, nas concentrações de 0,0, 0,1, 0,5, 1, 2 e 4% (v/v), e sobre este foi depositada a suspensão de esporos. No segundo experimento, aplicaram-se os óleos essenciais em folhas destacadas de videira, seguindo-se a inoculação dos esporos de P. euvitis , avaliando-se a germinação dos esporos. A partir dos dados obtidos foram calculadas as percentagens de inibições da germinação de esporos e a dose letal (DL90). Em plantas de videira no campo foi realizada uma aplicação dos óleos essenciais, na concentração de 1%, e avaliada a severidade da ferrugem, após 15 e 30 dias. As DL90 dos óleos essenciais variaram entre 0,39% (nim) e 3,9% (orégano). Os óleos essenciais mais eficientes sobre P. euvitis , em condições in vitro , foram os de camomila azul, citronela, eucalipto globulus , gengibre, nim e tomilho branco. Na aplicação realizada em campo todos os óleos essenciais reduziram significativamente a severidade da ferrugem, destacando-se os óleos essenciais de canela, citronela, nim e tomilho branco. Aspectos relacionados à fitotoxicidade necessitam ser elucidados. Os óleos essenciais avaliados apresentam potencial para serem utilizados no manejo da ferrugem da videira, contudo estudos complementares fazem-se necessários.(AU)

Knowledge about undesirable effects of conventional fungicides, and concern from consumers and Regulatory Agencies about food quality have encouraged the research on new alternatives for controlling plant diseases. The objective of this study was to evaluate the antifungal activity of 16 essential oils on Phakopsora euvitis , causal agent of grape rust in vitro and under field conditions. The essential oils tested were oregano, peppermint, black pepper, neem, eucalyptus globulus , citronella, cinnamon, marjoram, rosemary, basil, blue chamomile, white camphor, clove, ginger, tea tree and white thyme. In vitro , two experiments were carried: (i) evaluation of spores germination in water agar media amended with essential oil at 0 (control), 0.1, 0.5, 1, 2 and 4% (v/v). (ii) Evaluation of spores germination on detached leaves of vine previously treated with a solution of essential oils at 0, 0.1, 0.5, 1, 2 and 4%. The percentage of inhibition in the spores germination and LD90 values were calculated. Under field conditions, essential oils 1% (v/v) were sprayed on vine plants, and rust severity was evaluated twice, 15 and 30 days post application. In in vitro tests, the LD90 values ranged from 0.39 (neem) to 3.9% (oregano). The most efficient essential oils on Phakpsora euvitis were blue chamomile, citronella, eucalyptus globulus , ginger, neem and white thyme. Under field conditions, all essential oils reduced rust severity and among them, those from cinnamon, citronella, neem and white thyme showed the highest level of rust control. Our results show that the essential oils tested are effective for the management of grape rust. However, further studies on the phytotoxicity of these compounds are still required.(AU)

In vitro inhibition of the bovine viral diarrhoea virus by the essential oil of Ocimum basilicum (basil) and monoterpenes

The bovine viral diarrhoea virus (BVDV) is suggested as a model for antiviral studies of the hepatitis C virus (HCV). The antiviral activity of the essential oil of Ocimum basilicum and the monoterpenes camphor, thymol and 1,8-cineole against BVDV was investigated. The cytotoxicities of the compounds were measured by the MTT (3-(4.5-dimethylthiazol-2-yl)-2.5-diphenyltetrazolium bromide) test, and the antiviral activities were tested by the plaque reduction assay. The oil or compounds were added to the assay in three different time points: a) pre-treatment of the virus (virucidal assay); b) pre-treatment of the cells; or c) post-treatment of the cells (after virus inoculation). The percentage of plaques inhibition for each compound was determined based on the number of plaques in the viral control. The results were expressed by CC50 (50% cytotoxic concentration), IC50 (inhibitory concentration for 50% of plaques) and SI (selectivity index = CC50/IC50). Camphor (CC50 = 4420.12 µgmL-1) and 1,8-cineole (CC50 = 2996.10 µgmL-1) showed the lowest cytotoxicities and the best antiviral activities (camphor SI = 13.88 and 1,8-cineol SI = 9.05) in the virucidal assay. The higher activities achieved by the monoterpenes in the virucidal assay suggest that these compounds act directly on the viral particle.

Toxicidade de óleos essenciais de eucalipto e citronela sobre Sitophilus zeamais Motschulsky (Coleoptera: curculionidae) / Toxicity of essential oils of eucalyptus and citronella on Sitophilus zeamais Motschulsky (Coleoptera: curculionidae)

As análises realizadas por cromatografia gasosa acoplada à espectrometria de massas CG/EM apresentou o citronelal como o principal fitoconstituinte dos óleos essenciais de Corymbia citriodora Hill & Johnson, e Cymbopogon nardus (L.), com 61,78 e 36,53%, respectivamente. A toxicidade dos óleos essenciais e do citronelal foi verificada para Sitophilus zeamais por meio das estimativas das curvas de concentrações resposta e tempos de exposição letais para 50 e 95% dos insetos (CL50, CL95, TL50 e TL95). A toxicidade do citronelal foi maior para S. zeamais, com CL50 e CL95 de 0,340 e 0,820µL/cm2 e TL50 e TL95 de 11,89 e 59,50h, respectivamente. A repelência de S. zeamais foi maior para os óleos essenciais de C. nardus e C. citriodora nas concentrações de 0,660; 0,881; 1,101 e 1,321µL/cm2 com 86,6 a 98,8%. O número de insetos emergidos dos grãos pulverizados com os óleos essenciais foi maior para o citronelal nas concentrações de 0,330; 0,440; 0,550, e 0,660µL/cm2 . A redução da massa de grãos foi menor para aqueles grãos tratados com C. citriodora e C. nardus. Óleos essenciais de C. citriodora e C. nardus podem proteger produtos armazenados pelo dano causado por S. zeamais.

Analysis of GC / MS showed citronellal as the main phytochemicals of the essential oils of Corymbia citriodora and Cymbopogon nardus, with 61.78% and 36.53%, respectively. The toxicity of essential oils and citronellal was verified for maize weevils, through the estimates of the concentration response curves and lethal exposure times, for 50% and 95% of the adults insect (LC50, LC95, LT50 and TL95). The toxicity of citronellal was higher for Sitophilus zeamais, with LC50 and LC95 of 0.340 at 0.820 µL/cm2, TL50 and TL95 of 11.89 and 59.50h, respectively. The repellency of S. zeamais was higher for the essential oils of C. nardus and C. citriodora, at concentrations of 1.321, 1.101, 0.881 and 0.660 µL/cm2, ranging from 86.6 to 98.8%. The number of insects emerged from grain sprayed with essential oils was lower for the citronellal, at concentrations of 0.330, 0.440, 0.550, and 0.660 µL/cm2. The reduction in grain weight was lower for those grains, treated with C. citriodora and C. nardus. Essential oils of E. citriodora and C. nardus can protect stored products from damage caused by S. zeamais.

Toxicity of the essential oil of the cytral chemotype of Lippia alba (Mill.) N. E. Brown

The essential oil (EO) of Lippiaalba (Mill.) N. E. Brown (Verbenaceae) has been traditionally used to treat several diseases. In this study, the acute toxic effects of the citral chemotype of L. alba EO were evaluated in mice. Animals were treated via intraperitoneal receiving the L. alba essential oil at doses between 50 and 2500 mg/kg, and the control group received sesame oil (vehicle). The EO induced dose-dependent neurotoxic effects at doses greater than 1000 mg/kg, including decreased locomotion, motor skills and muscle strength, hypotonia, dyspnea, kyphosis and convulsions. The EO was lethal at a dose of 2500 mg/kg. Animals receiving 1000 mg/kg were euthanized at the end of the treatment period and their blood and livers were collected for analysis. Mice exposed to L. alba EOpresented significantly greater plasma alanine aminotransferase (ALT) activities than the control group. Liver histological changes included mild inflammation, in particular, an increase in nuclear size. Compared to vehicle control group, changes in expressionfor selected genes were significant for FABP5, a fatty acid transport related gene. In summary, the intraperitoneal administration of L. alba EO (citral chemotype) causes neurological damage in mice at doses equal or greater than 1500 mg/kg, whereas at 1000 mg/kg, it generates mild liver damage. Therefore, the systemic use of this EO raises concerns about its safety.

El aceite esencial (AE) de Lippia alba(Mill.) NE Brown (Verbenaceae) ha sido utilizado tradicionalmente para tratar varias enfermedades. En este estudio, los efectos tóxicos agudos del AE de Lippia alba quimiotipo citral fueron evaluados en ratones. Los animales fueron tratados por vía intraperitonealrecibiendo el AE en dosis entre 50 y 2500 mg/kg de peso, y el grupo control aceite de sésamo (vehículo). Dosis superiores a 1000 mg/kg del AE mostraron efectos neurotóxicos incluyendo disminución de la locomoción e hipotonía, disnea, cifosis y convulsiones. El AE fue letal a la dosis de 2500 mg/kg. Veinticuatro horas después de que los animales fueron tratados con 1000 mg/kg del AE se les realizó eutanasia y su sangre e hígado fueron recolectados para análisis. Los ratones expuestos al AE de L. alba, presentaron actividad alanina aminotransferasa (ALT) en plasma significativamente mayor que el grupo control. Dentro de los cambios histológicos hepáticos se incluyen inflamación leve, en particular, un aumento del tamaño nuclear. En comparación con el grupo control, la expresión de genes seleccionados tuvo diferencias significativas para FABP5, un gen relacionado con el transporte de ácidos grasos. En conclusión, la administración intraperitoneal del AE de L. alba (quimiotipo citral) causa dañosneurológicos en ratones a una dosis igual o superior a 1500 mg/kg, mientras que a 1000 mg/kg, genera daño hepático leve. Por lo tanto, el uso sistémico de este AE plantea preocupaciones en cuanto a su seguridad.

Antibacterial activity, chemical composition, and cytotoxicity of leaf's essential oil from Brazilian pepper tree (Schinus terebinthifolius, Raddi)

The antibacterial potential of leaf's essential oil (EO) from Brazilian pepper tree (Schinus terebinthifolius Raddi) against staphylococcal isolates from dogs with otitis externa was evaluated. The minimum inhibitory concentration of EO ranged from 78.1 to 1,250 fg/mL. The oil was analyzed by GC and GC/MS and cytotoxicity tests were carried out with laboratory animals.

Cytotoxic effects of essential oils and extracts of some mentha species on vero, Hela and Hep2 cell lines

Mentha species are widely used in traditional medicine mostly as anti-flatulence. Nowadays, their usage as flavor and preservative in food, cosmetic and pharmaceutical industries has been developed. Moreover, cytotoxic effects of some Mentha species have been reported. In this study, cytotoxic properties of Mentha piperita, M. spicata, M. aquatica, M. crispa, M. pulegium and M. longifolia have been investigated. Different concentrations of essential oils and total extracts of six Mentha species were tested by MTT assay against Vero, Hep2 and Hela cell lines. The results showed that all samples were toxic against Vero, Hela and Hep2 cell lines [IC[50] 28.1-166.2 micro g/ml]. All examined Mentha species extracts and essential oils have cytotoxic effects but some of them could be considered as potent toxic agents

Bases farmacológicas e toxicológicas potenciais do óleo essencial de Mentha spp / Potential pharmacological and toxicological basis of the essential oil from Mentha spp

During the past few years, interest in the potential clinical and pharmacological basis of the efficacy and safety of herbal medicines has increased greatly, due to widespread domestic self-medication with these agents. Some authors have analyzed the use of Mentha ssp. in the pharmacological industry. The essential oil from Mentha spp. is used to treat discomfort of the gastrointestinal tract, irritable bowel syndrome, myalgia and neuralgia, as well as oral mucosal inflammation, and also as an expectorant, an antimicrobial and an ingredient in many analgesic creams. The essential oil also contains chemical compounds that are associated with side effects such as nausea, vomiting, allergic reactions, flushing and headaches. Therefore, the purpose of the present review was to examine the literature on the efficacy and safety of the possible clinical and pharmacological uses of the essential oil from Mentha spp. in human beings.

Nas últimas décadas, houve um aumento crescente no interesse sobre as bases clínicas e farmacológicas potenciais em relação à eficácia e a segurança das drogas produzidas de plantas medicinais, devido à automedicação destes agentes. Diversos autores avaliaram o óleo essencial de Mentha spp., devido a sua larga utilização na indústria farmacológica. O óleo essencial de Mentha spp. componente de muitos analgésicos e com atividade antimicrobiana, é usado para tratamentos nos desconfortos gastrintestinais e dutos biliares superiores, Síndrome de Bowel, expectorante, mialgia e neuralgia, bem como na inflamação oral da mucosa. No entanto, esse óleo contém compostos químicos que apresentam efeitos colaterais tais como náusea, vômito, reações alérgicas e dores de cabeça. O objetivo desta revisão atual foi avaliar dados da literatura específica sobre a possível utilização, eficácia e segurança clínica e farmacológica do óleo essencial de Mentha spp. em seres humanos.

The effect of essential oils of sweet fennel and pignut on mortality and learning in africanized honeybees (Apis mellifera L.) (Hymenoptera: Apidae)

It was recently discovered that exposure to small concentrations of the essential oils of sweet fennel (Foeniculum vulgare Mill) or pignut [Hyptis suaveolens (L.) Poit] can be used to control aphids. What is not known is whether these oils also influence honeybee behavior. Experiments using both harnessed and free-flying foragers at concentrations used to control aphids showed that bees readily associated the odors with a reward, discriminated between them, and were not repelled. Honeybees, however, would not consume the oils when mixed with sucrose to create an unconditioned stimulus. An experiment in which harnessed bees consumed various concentrations showed that concentrations greater than 50 percent were detrimental. The experiments reported here provide further evidence supporting the use of conditioning techniques to evaluate the use of essential oils on honey bee behavior.

Recentemente foi descoberto que pequenas concentrações de óleos essenciais de erva-doce (Foeniculum vulgare Mill) ou alfazema [Hyptis suaveolens (L.) Poit] podem ser usadas para controlar pulgões. O que não se sabe é se esses óleos também podem influenciar o comportamento de abelhas melíferas. Experimentos utilizando abelhas encapsuladas ou livres, em diferentes concentrações usadas para controlar pulgões, mostraram que as abelhas rapidamente associaram o odor a um estímulo aprendendo a discriminá-lo, e não foram repelidas pelo mesmo. No entanto, as abelhas melíferas não consumiriam os óleos quando misturados à sacarose para criar um estímulo incondicional. Em um experimento, em que abelhas encapsuladas foram submetidas a várias concentrações dos óleos essenciais, concentrações maiores que 50 por cento foram prejudiciais às abelhas. Os experimentos relatados aqui reforçam a validade do uso de técnicas de condicionamento para avaliar a ação de óleos essenciais no comportamento das abelhas melíferas.

Phytotoxicity of volatile oil from Eucalyptus citriodora against some weedy species.

A study was undertaken to explore the phytotoxicity of volatile essential oil from Eucalyptus citriodora Hook. against some weeds viz. Bidens pilosa, Amaranthus viridis, Rumex nepalensis, and Leucaena leucocephala in order to assess its herbicidal activity. Dose-response studies conducted under laboratory conditions revealed that eucalypt oils (in concentration ranging from 0.0012 to 0.06%) greatly suppress the germination and seedling height of test weeds. At 0.06% eucalypt oil concentration, none of the seed of test weeds germinated. Among the weed species tested, A. viridis was found to be the most sensitive and its germination was completed inhibited even at 0.03%. Not only the germination and seedling growth, even the chlorophyll content and respiratory activity in leaves of emerged seedlings were severely affected. In A. viridis chlorophyll content and respiratory activity were reduced by over 51% and 71%, respectively, even at a very low concentration of 0.06%. These results indicated an adverse effect of eucalypt oils on the photosynthetic and energy metabolism of the test weeds. A strong negative correlation was observed between the observed effect and the concentration of eucalypt oil. Based on the study, it can be concluded that oil from E. citriodora possess strong inhibitory potential against weeds that could be exploited for weed management.

Estudo da embriotoxicidade da beta-ionona em ratos / Study of the embryotoxic of beta-ionona in the rat

Beta-ionona (4-[2,6,6-trimethyl-1-cyclohexen-1-1yl]-3-buten-2-one; CAS 79-77-6) é um sesquiterpeno degradado (C13) encontrado nos óleos essenciais de uma variedade de plantas, entre os quais o óleo de violeta. Este composto tem sido usado na indústria, como intermediário na síntese de fragrâncias, vitamina A e como aditivo alimentar, sobretudo na indústria de vinhos. O objetivo deste estudo foi avaliar o potencial embriotóxico da beta-ionona que, em estudos anteriores, mostrou claros indícios de induzir embrioletalidade em ratos. Ratas Wistar foram tratadas por entubação gástrica com beta-ionona (125, 250, 500 e 1000 mg/kg de peso corporal/dia) ou apenas com veículo (óleo de milho), entre os dias 6 e 15 de gravidez. No dia 21, as fêmeas foram sacrificadas por inalação de CO2 e submetidas à cesárea. O útero gravídico foi pesado com todo seu conteúdo. (...) Neste nível de dose, a beta-ionona também afetou adversamente o desenvolvimento embrionário, causando embrioletalidade, evidenciada pelo aumento de perdas peri-implantação e pelo discreto aumento na proporção de reabsorções por implantações. Ainda em relação ao efeito embrioletal da beta-ionona observado neste estudo, pode-se dizer que as fêmeas foram mais suscetíveis do que os machos. No presente estudo, não foram encontrados indícios de retardo do crescimento intra-uterino induzido pelo exposição in utero à beta-ionona, nem aumento na incidência de alterações estruturais de vísceras ou esqueléticas em nenhum dos níveis de dose estudados. Os dados deste estudo indicaram que a beta-ionona não é teratogênica em ratos, uma vez que não houve aumento na freqüência de malformações viscerais e/ou esqueléticas em conseqüência à exposição in utero a este composto.

Aceites esenciales con actividad citotóxica como indicador de propiedades insecticidas / Essential oils activity citotoxic as indicador of properties insecticides

El presente estudio trata sobre la extracción y evaluación de la toxicidad general contra Artemia salina de aceites esenciales de especies vegetales aromáticas. Los aceites fueron obtenidos mediante destilación por arrastre de vapor de agua de diferentes órganos: partes áreas (hojas y tallos) y dermis de cítricos (cáscara). Como indicador de toxicidad se ha calculado la Dosis Letal Media (DL-50) de los aceites contra el camarón salino, considerando que la evaluación biológica contra A. salina, es también utilizada como una prueba preliminar orientada al descubrimiento de nuevos insecticidas y dado que todos los aceites en estudio han presentado valores de Dl-50 menores a 100ppm, podriamos indicar que los aceites estudiados son potenciales insecticidas naturales y considerando sus índices de toxicidad presentaron el siguiente orden: Ruda graveolen (Ruda, Dl-50=2.7ppm), aceite de Wakataya saiko (Wakataya, Dl-50=3.9ppm), cariophyllus aromáticus (Clavo, Dl-50=33.9ppm), Juniperus communis (Pino, Dl-50=38.5ppm), Piper sp. (Matico, Dl-50=41.3ppm) y Eucaliptus globulus (Eucalipto, Dl-50=85.6ppm)

Absence of genotoxic activity of beta-myrcene in the in vivo cytogenetic bone marrow assay

beta-Myrcene (MYR, 7-methyl-3-methylene-1,6 octadiene) is a peripheral analgesic substance and one of the major constituents of lemongrass oil (Cymbopogon citratus, Stapf), a plant widely used in Brazilian folk medicine. In the present study the genotoxicity of MYR was evaluated in vivo using the rat bone marrow cytogenetic assay. Male and female Wistar rats weighing 250 g (223 to 286 g) and 178 g (168 to 186 g), respectively, were used. Two or four rats of either sex were treated orally with MYR (0.1, 0.5 and 1.0 g/kg po), corn oil (negative control) and cyclophosphamide 30 mg/kg ip (positive control). Animals were sacrificed and bone marrow cells were harvested 24 and 48 h after MYR administration. The mitotic index and the frequency of chromosome aberrations were evaluated. Fifty metaphase cells were examined per animal. A dose related increase in mitotic index was observed 24-h after MYR administration. No evidence of MYR-induced clastogenicity was observed under the experimental conditions of this in vivo assay. The present results and previous negative findings of in vitro mutagenicity tests strongly indicate that MYR is not a genotoxic substance