In vitro and in silico evaluation of the schistosomicidal activity of eugenol derivatives using biochemical, molecular, and morphological tools

Background Eugenol shows both antibacterial and antiparasitic activities, suggesting that it might be evaluated as an option for the treatment of praziquantel-resistant schistosome. Methods The in vitro activities of three eugenol derivatives (FB1, FB4 and FB9) on adult worms from Schistosoma mansoni were examined by fluorescence and scanning electron microscopy to analyze effects on the excretory system and integument damage, respectively. Biochemical tests with verapamil (a calcium channel antagonist) and ouabain (a Na+/K+-ATPase pump inhibitor) were used to characterize eugenol derivative interactions with calcium channels and the Na+/K+-ATPase, while in silico analysis identified potential Na+/K+-ATPase binding sites. Results The compounds showed effective doses (ED50) of 0.324 mM (FB1), 0.167 mM (FB4), and 0.340 mM (FB9). In addition, FB4 (0.322 mM), which showed the lowest ED50, ED90 and ED100 (p < 0.05), caused the most damage to the excretory system and integument, according to both fluorescence and scanning electron microscopy analysis. The death of adult worms was delayed by ouabain treatment plus FB1 (192 versus 72 hours) and FB9 (192 versus 168 hours), but the response to FB4 was the same in the presence or absence of ouabain. Besides, no changes were noted when all of the eugenol derivatives were combined with verapamil. Moreover, FB1 and FB9 inhibited Na+/K+-ATPase activity according to in silico analysis but FB4 did not show a time-dependent relationship and may act on targets other than the parasite Na+/K+-ATPase. Conclusion Eugenol derivatives, mainly FB4 when compared to FB1 and FB9, seem to act more effectively on the integument of adult S. mansoni worms.(AU)

Efeito Cardiodepressor do Acetato de Eugenil em Coração de Roedor / Cardiodepressive Effect of Eugenyl Acetate in Rodent Heart

Resumo No presente trabalho investigou-se o efeito inotrópico do acetato de eugenil (AE), bem como sua ação sobre a corrente de Ca2+ do tipo L (ICa,L). Os experimentos de contratilidade foram realizados em átrio esquerdo isolado de cobaia exposto às concentrações crescentes da droga (1 a 5.000μM). O AE reduziu a força de contração atrial (IC50=558±24,06μM) de modo dependente de concentração. O efeito do AE sobre a ICa,L também foi avaliado em cardiomiócitos ventriculares isolados de camundongos, utilizando-se a técnica de "patch-clamp". O AE apresentou um efeito inibitório (IC50=1.337±221μM) sobre os canais de Ca2+ sensíveis à voltagem (CaV1.2). Em conclusão, o AE apesenta efeito cardiodepressor que se deve, pelo menos em parte, à diminuição da entrada de Ca2+ nos cardiomiócitos.

Effect of methyl eugenol on nasal mucosal aquaporin 5 in rats with allergic rhinitis / 北京大学学报(医学版)

OBJECTIVE@#To observe the effect of methyl eugenol on the expression of aquaporin (AQP) 5 in nasal mucosa of rats with allergic rhinitis and to explore its significance.@*METHODS@#In the study, 128 Wistar rats were randomly divided into normal control group, AR model control group, budesonide positive control group, 80 mg/kg group, 40 mg/kg group, 20 mg/kg group and 10 mg/kg group, and ovalbumin (OVA) was used to establish the model of allergic rhinitis. After successful modeling, castor oil, budesonide and corresponding doses of methyl eugenol were given respectively. After 1, 2 and 4 weeks of administration, the distribution of AQP5 in nasal mucosa was observed by immunohistochemistry. The expression of AQP5 in nasal mucosa of each group was compared by Western blotting. The expression of AQP5 mRNA was compared with real-time PCR.@*RESULTS@#AQP5 was mainly located in the glandular epithelium and ductal epithelial cell membrane and cytoplasm. The expression of AQP5 and AQP5 mRNA in nasal mucosa of the rats in the model control group was lower than that in the normal control group (P<0.05). AQP5 and AQP5 mRNA in nasal mucosa of the rats in each treatment group were higher than those in the model control group in varying degrees. The expression of AQP5 in the budesonide group was not significantly different from that in the normal control group 1, 2 and 4 weeks after drug intervention (P>0.05), but there was significant difference between the budesonide group and the model control group (P<0.05). The expression of AQP5 mRNA in the budesonide group was significantly different from that in the normal control group and the model control group (P<0.05).After 2 weeks of intervention, the expression of AQP5 in each dose group of methyleugenol was not significantly different from that in the budesonide group (P>0.05). After 1 week of intervention, there was no significant difference in AQP5 mRNA between the 20 mg/kg group and the normal control group (P>0.05), but there was significant difference between the 20 mg/kg group and the model control group (P<0.05).@*CONCLUSION@#Methyl eugenol may increase the degree of edema of the nasal mucosa by reducing the expression of AQP5 and reduce the secretion of glands, thus alleviating the symptoms of allergic rhinitis, sneezing and runny nose.

Relaxant effects of Peperomia hispidula (Sw.) A. Dietr. on isolated rat tracheal rings / Efecto relajante de Peperomia hispidula (Sw.) A. Dietr. sobre anillos aislados de tráquea de rata

Peperomia hispidula (Sw.) A. Dietr. is used in Mexican traditional medicine for treating respiratory illnesses such as asthma. The latter disorder results from an excessive and inappropriate constriction of airway smooth muscle. The aim of the present study was to evaluate the relaxant activity of P. hispidula on isolated rat tracheal rings contracted with carbachol. The methyleugenol was identified as the main active constituent in the dichloromethane extract. To explore the possible mechanism of action, concentration-response curves were constructed in the presence and absence of propranolol (3 µM), indomethacin (10 µM), glibenclamide (1 µM), and L-NAME (300 µM), finding that neither reduced methyleugenol-induced smooth muscle relaxation. In conclusion, P. hispidula herein displayed relaxant activity on rat tracheal rings. The effect of methyleugenol, was probably not related to the activation of ß2-adrenoceptors, prostaglandins, K+ATP channels or nitric oxide.

Peperomia hispidula (Sw.) A. Dietr. es utilizada en la medicina tradicional mexicana para tratar enfermedades respiratorias como el asma. Este último trastorno es el resultado de una contracción excesiva e inapropiada del músculo liso de las vías respiratorias. El objetivo del presente estudio fue evaluar la actividad relajante de P. hispidula sobre anillos aislados de tráquea de rata contraídos con carbacol. El metileugenol fue identificado como el principal constituyente activo en el extracto de diclorometano. Para explorar el posible mecanismo de acción, se construyeron curvas concentración-respuesta en presencia y ausencia de propranolol (3 µM), indometacina (10 µM), glibenclamida (1 µM), y L-NAME (300 µM), encontrando que ninguno redujo la relajación del músculo liso inducida por metileugenol. En conclusión, P. hispidula muestra actividad relajante en anillos de tráquea de rata. El efecto de metileugenol, al parecer no está implicado con la activación de los receptores ß2-adrenérgicos, prostaglandinas, canales de K+ATP u óxido nítrico.

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.

Actividad acaricida del aceite esencial de la corteza de Croton malambo H. Karst, metil-eugenol y metil-isoeugenol contra Dermatophagoides farinae Hughes, 1961 / Acaricide activity of essential oil of Croton malambo H. Karst, methyl-eugenol and methyl-isoeugenol against Dermatophagoides farinae Hughes, 1961

Dermotophagoides farinae lives in the indoor environment of houses, where it is source of allergens; therefore its control is a priority in preventing respiratory allergies. The aim of this study was to evaluate the acaricidal activity of essential oil of Croton malambo H. Karst bark and their components methyl-eugenol and methyl-isoeugenol against Dermatophagoides farinae. The essential oil was obtained through hydro-distillation assisted by microwave radiation and analyzed by GC-MS. Acaricidal activity was assessed by dose- response bioassay, at different times, using benzyl benzoate as a positive control. The relative amount of methyl-eugenol and methyl- isoeugenol in the essential oil was 68.4 percent and 4.9 percent, respectively. The acaricidal activity was: essential oil > methyl-eugenol > benzyl benzoate > methyl-isoeugenol. The acaricidal properties of essential oil of Croton malambo bark and methyl-eugenol against Dermatophagoides farinae were established...

Dermatophagoides farinae habita en el interior de las casas, donde es fuente importante de alérgenos, por tanto su control es una prioridad en la prevención de alergias respiratoria. El objetivo de este estudio fue evaluar la actividad acaricida del aceite esencial de la corteza de Croton malambo H. Karst y sus componentes metil-eugenol y metil-isoeugenol contra Dermatophagoides farinae. El aceite esencial se obtuvo por hidrodestilación asistida por radiación de microondas y se analizó por CG-EM. La actividad acaricida se evaluó mediante bioensayo de dosis-respuesta a diferentes tiempos, usando benzoato de bencilo como control. La cantidad relativa de metil-eugenol y metil-isoeugenol en el aceite fue 68.4 por ciento y 4.9 por ciento, respectivamente. La actividad acaricida fue: aceite esencial > metil-eugenol > benzoato de bencilo > metil-isoeugenol. Se establecieron las propiedades acaricidas del aceite esencial de la corteza de Croton malambo y metil-eugenol contra Dermatophagoides farinae...

Application of Taguchi design and Response Surface Methodology for improving conversion of isoeugenol into vanillin by resting cells of Psychrobacter sp. CSW4

For all industrial processes, modelling, optimisation and control are the keys to enhance productivity and ensure product quality. In the current study, the optimization of process parameters for improving the conversion of isoeugenol to vanillin by Psychrobacter sp. CSW4 was investigated by means of Taguchi approach and Box-Behnken statistical design under resting cell conditions. Taguchi design was employed for screening the significant variables in the bioconversion medium. Sequentially, Box-Behnken design experiments under Response Surface Methodology [RSM] was used for further optimization. Four factors [isoeugenol, NaCl, biomass and tween 80 initial concentrations], which have significant effects on vanillin yield, were selected from ten variables by Taguchi experimental design. With the regression coefficient analysis in the Box-Behnken design, a relationship between vanillin production and four significant variables was obtained, and the optimum levels of the four variables were as follows: initial isoeugenol concentration 6.5 g/L, initial tween 80 concentration 0.89 g/L, initial NaCl concentration 113.2 g/L and initial biomass concentration 6.27 g/L. Under these optimized conditions, the maximum predicted concentration of vanillin was 2.25 g/L. These optimized values of the factors were validated in a triplicate shaking flask study and an average of 2.19 g/L for vanillin, which corresponded to a molar yield 36.3%, after a 24 h bioconversion was obtained. The present work is the first one reporting the application of Taguchi design and Response surface methodology for optimizing bioconversion of isoeugenol into vanillin under resting cell conditions

Inhibition of Aspergillus flavus colonization and aflatoxin (AfB1) in peanut by methyleugenol.

Methyleugenol is naturally occurring substance in oils and fruits and in various foods as flavoring agent. Effect of this methyleugenol in inhibiting A. flavus colonization and aflatoxin production on peanut pods and kernels has been studied. Spray of methyleugenol (0.5%) on peanut pods and kernels checked the colonization of A. flavus and aflatoxin synthesis. This chemical can be used as both prophylactic or post infection spray on peanut pods before storage. It is the first report on the inhibition of A. flavus by methyleugenol on peanut.

Efeitos de Eugenol e derivados sobre Biomphalaria glabrata / Effects of Eugenol and derivatives on Biomphalaria glabrata

Biomphalaria glabrata e suas desovas foram expostas durante 6 e 24 horas a concentraçäo de 1, 10, 100 e 1000 ppm de eugenol, O-metileugenol, O-benzileugenol e desidrodieugenol. O O-benzileugenol foi parcialmente tóxico para adultos e desovas a 10 ppm. Os outros produtos mostraram atividade ovicida e moluscicida em concentraçöes de 100 e 1000 ppm. Estes produtos causaram reduçäo significativa (p<0,05) da freqüência cardíaca dos moluscos após 6 e 24 horas de exposiçäo até 24 horas após este período. Além do efeito anestésico, ocorreu extroversäo do complexo peniano em dois exemplares expostos a 100 ppm do O-metileugenol. Sobre camundongos infectados experimentalmente com Schistosoma mansoni e tratados com eugenol, O-metileugenol nas doses orais de 150mg/Kg durante cinco dias, näo foram observados efeitos esquistossomicida ou anestésico

Quaternary ammonium salt derivatives of allylphenols with peripheral analgesic effect

Ammonium salt derivatives of natural allylphenols were synthesized with the purpose of obtaining potential peripheral analgesics. These drugs, by virtue of their physicochemical properties, would not be able to cross the blood brain barrier. Their inability to enter into the central nervous system (CNS) should prevent several adverse effects observed with classical opiate analgesics (Ferreira et al., 1984). Eugenol (1) O-methyleugenol (5) and safrole (9) were submitted to nitration, reduction and permethylation, leading to the ammonium salts 4, 8 and 12. Another strategy applied to eugenol (1), consisting in its conversion to a glycidic ether (13), opening the epoxide ring with secondary amines and methylation, led to the ammonium salts 16 and 17. All these ammonium salts showed significant peripheral analgesic action, in modified version of the Randall-Sellito test (Ferreira et al. 1978), at non-lethal doses. The ammonium salt 8 showed an activity comparable to that of methylnalorphinium, the prototype of an ideal peripheral analgesic (Ferreira et al., 1984).

Associaçäo do metileugenol a ketamina e diazepan para anestesia de curta duraçäo em animais de laboratório / Contribution of drugs association in short anesthesia to laboratory animals

O metileugenol (C11H14O2), peso molecular de 178 gramas, é um princípio ativo encontrado na fraçäo oleosa volátil de várias plantas como, por exemplo, na Cariophillus aromaticus L., conhecida como craveiro-da-india. Os efeitos anestésico, analgésico, anticonvulsivante e miorrelaxante säo conhecidos, segundo a literatura . O objetivo do nosso estudo foi avaliar a influência da Ketamina e do diazepan sobre a duraçäo do sono (DS) e o tempo de início da deambulaçäo após a droga (ID) em coelhos e cäes anestesiados com metileugenol. Coelhos e cäes adultos foram injetados previamente com ketamina (2 mg/Kg ev) e diazepan (0,8 mg/Kg ev), respectivamente, seguido de administraçäo de metil rugenol (5mg/Kg ev). Os resultados mostraram uma ampliaçäo significativa da duraçäo da anestesia com metileugenol pela associaçäo com ambas as drogas empregadas, embora houvesse uma maior vantagem para o diazepan nas duas especies animais, em relaçäo aos grupos controle, respectivamente

Circadian variation of methyleugenol anesthesia in albino rats

In Wistar rats synchronized to a 12-h light/12-h dark cycle (lights on from 08:00 to 20:h), the ip injection of methyleugenol (200 mg/Kg) at 08:00, 12:00 and 16:00 h significantly increased the sleeping time (time between loss and recovery of righting reflex) when compared to animals anesthetized at 20:00, 24:00 and 04:00h. These data provide another example of the importance of circadian rhythms in biological systems and their practical relevance to pharmacology