RESUMO

Ortho-eugenol is a synthetic derivative from eugenol, the major compound of clove essential oil, which has demonstrated antidepressant and antinociceptive effects in pioneering studies. Additionally, its effects appear to be dependent on the noradrenergic and dopaminergic systems. Depression and anxiety disorders are known to share a great overlap in their pathophysiology, and many drugs are effective in the treatment of both diseases. Furthermore, high levels of anxiety are related to working memory deficits and increased oxidative stress. Thus, in this study we investigated the effects of acute treatment of ortho-eugenol, at 50, 75 and 100 mg/kg, on anxiety, working memory and oxidative stress in male Swiss mice. Our results show that the 100 mg/kg dose increased the number of head-dips and reduced the latency in the hole-board test. The 50 mg/kg dose reduced malondialdehyde levels in the prefrontal cortex and the number of Y-maze entries compared to the MK-801-induced hyperlocomotion group. All doses reduced nitrite levels in the hippocampus. It was also possible to assess a statistical correlation between the reduction of oxidative stress and hyperlocomotion after the administration of ortho-eugenol. However, acute treatment was not able to prevent working memory deficits. Therefore, the present study shows that ortho-eugenol has an anxiolytic and antioxidant effect, and was able to prevent substance-induced hyperlocomotion. Our results contribute to the elucidation of the pharmacological profile of ortho-eugenol, as well as to direct further studies that seek to investigate its possible clinical applications.

Assuntos

RESUMO

Due to the complex nature of pain and the participation of physical, cognitive, psychological and behavioral aspects, pain management has several approaches. The use of medicinal plants in developing countries is quite expressive. Seeking new options for the treatment of emerging or debilitating diseases. Therefore, the present study seeks to elucidate the effects of the monoterpene, citronellal, differentiating its activity by isomers (R)-(+) and (S)-(-) citronellal. The study used several methods to evaluate the effects of citronellal isomers on motor coordination, nociceptive response, and the involvement of opioid, glutamatergic, and transient receptor pathways. The methods included rota-rod, hot-plate, and formalin tests, as well as the use of specific inhibitors and agonists. Data were analyzed using inferential statistics with a 95% confidence level. Both isomers did not significantly affect the motor coordination of the studied animals. The isomer (S)-(-) citronellal showed better results in relation to its structural counterpart, managing to have an antinociceptive effect in the formalin and hot plate tests with a lower concentration (100 mg/kg) and presenting fewer side effects, however, the this study was not able to elucidate the mechanism of action of this isomer despite having activity in studies with substances that act on specific targets such as glutamate and capsaicin, its activity was not reversed with the use of antagonists for pathways related to nociception. While the (R)-(+) citronellal isomer, despite showing total activity only at a concentration of 150 mg/kg, was able to determine its mechanism of action related to the opioid pathway by reversing its activity by the antagonist naloxone, being this is a pathway already correlated with nociception control treatments, however, it is also related to some unwanted side effects. In this way, new studies are sought to elucidate the mechanism related to the isomer (S)-(-) citronellal and a possibility of use in other areas related to the treatment of pain or inflammation.

Assuntos

RESUMO

Due to the complex nature of pain and the participation of physical, cognitive, psychological and behavioral aspects, pain management has several approaches. The use of medicinal plants in developing countries is quite expressive. Seeking new options for the treatment of emerging or debilitating diseases. Therefore, the present study seeks to elucidate the effects of the monoterpene, citronellal, differentiating its activity by isomers (R)-(+) and (S)-(-) citronellal. The study used several methods to evaluate the effects of citronellal isomers on motor coordination, nociceptive response, and the involvement of opioid, glutamatergic, and transient receptor pathways. The methods included rota-rod, hot-plate, and formalin tests, as well as the use of specific inhibitors and agonists. Data were analyzed using inferential statistics with a 95% confidence level. Both isomers did not significantly affect the motor coordination of the studied animals. The isomer (S)-(-) citronellal showed better results in relation to its structural counterpart, managing to have an antinociceptive effect in the formalin and hot plate tests with a lower concentration (100 mg/kg) and presenting fewer side effects, however, the this study was not able to elucidate the mechanism of action of this isomer despite having activity in studies with substances that act on specific targets such as glutamate and capsaicin, its activity was not reversed with the use of antagonists for pathways related to nociception. While the (R)-(+) citronellal isomer, despite showing total activity only at a concentration of 150 mg/kg, was able to determine its mechanism of action related to the opioid pathway by reversing its activity by the antagonist naloxone, being this is a pathway already correlated with nociception control treatments, however, it is also related to some unwanted side effects. In this way, new studies are sought to elucidate the mechanism related to the isomer (S)-(-) citronellal and a possibility of use in other areas related to the treatment of pain or inflammation.

Devido à natureza complexa da dor e a sua participação de aspectos físicos, cognitivos, psicológicos e comportamentais, o manejo da dor possui diversas abordagens. O uso de plantas medicinais em países em desenvolvimento é bastante expressivo. Buscando novas opções para o tratamento de denças emergentes ou debilitantes. Portanto, o presente estudo busca elucidar os efeitos do monoterpeno, citronelal, diferenciando sua atividade pelos isômeros (R)-(+) e (S)-(-) citronelal. O estudo utilizou diversos métodos para avaliar os efeitos dos isômeros de citronelal na coordenação motora, resposta nociceptiva e o envolvimento de vias opioides, glutamatérgicas e de receptores transitórios. Os métodos incluíram testes de rota-rod, placa quente e formalina, além do uso de inibidores e agonistas específicos. Os dados foram analisados estatisticamente com um intervalo de confiança de 95%. Ambos os isomeros não afetaram significativamente a coordenação motora dos animais em estudo. O isômero (S)-(-) citronelal apresentou melhores resultados em relação ao seu homólogo estrutural, conseguindo ter um efeito antinociceptivo nos testes de formalina e placa quente com menor concentração (100 mg/kg) e apresentando menos efeitos colaterais, entretanto, o presente estudo não foi capaz de elucidar o mecanismo de ação deste isomero apesar de ter atividadade em estudos com substancias que agem em alvos específicos como glutamato e capsaicina, sua atividade não foi revertida com a utilização de antagonistas para as vias relacionadas à nocicepção. Enquanto o isômero (R)-(+) citronelal, apesar de apresentar de apresentar total atividade somente na concentração de 150 mg/kg, foi capaz de determinar seu mecanismo de ação relacionado à via opióide pela reversão da sua atividade pelo antagonista naloxona, sendo esta uma via já correlacionada com os tratamentos de controle da a nocicepção, no entanto, também está relacionada a alguns efeitos colaterais indesejados. Desta forma busca-se novos estudos para elucidação do mecanismo relacionados ao isomero (S)-(-) citronellal e uma possibilidade de utilização em outras areas relacionadas ao tratamento da dor ou inflamação.

Assuntos

RESUMO

Ortho-eugenol is a synthetic derivative from eugenol, the major compound of clove essential oil, which has demonstrated antidepressant and antinociceptive effects in pioneering studies. Additionally, its effects appear to be dependent on the noradrenergic and dopaminergic systems. Depression and anxiety disorders are known to share a great overlap in their pathophysiology, and many drugs are effective in the treatment of both diseases. Furthermore, high levels of anxiety are related to working memory deficits and increased oxidative stress. Thus, in this study we investigated the effects of acute treatment of ortho-eugenol, at 50, 75 and 100 mg/kg, on anxiety, working memory and oxidative stress in male Swiss mice. Our results show that the 100 mg/kg dose increased the number of head-dips and reduced the latency in the hole-board test. The 50 mg/kg dose reduced malondialdehyde levels in the prefrontal cortex and the number of Y-maze entries compared to the MK-801-induced hyperlocomotion group. All doses reduced nitrite levels in the hippocampus. It was also possible to assess a statistical correlation between the reduction of oxidative stress and hyperlocomotion after the administration of ortho-eugenol. However, acute treatment was not able to prevent working memory deficits. Therefore, the present study shows that ortho-eugenol has an anxiolytic and antioxidant effect, and was able to prevent substance-induced hyperlocomotion. Our results contribute to the elucidation of the pharmacological profile of ortho-eugenol, as well as to direct further studies that seek to investigate its possible clinical applications.

Ortho-eugenol é um derivado sintético do eugenol, composto principal do óleo essencial de cravo, que demonstrou efeitos antidepressivos e antinociceptivos em estudos pioneiros. Além disso, seus efeitos parecem ser dependentes dos sistemas noradrenérgico e dopaminérgico. Sabe-se que os transtornos de depressão e ansiedade compartilham uma grande sobreposição em sua fisiopatologia, e muitas drogas são eficazes no tratamento de ambas as doenças. Além disso, altos níveis de ansiedade estão relacionados a déficits de memória de trabalho e aumento do estresse oxidativo. Assim, o presente estudo investigou os efeitos do tratamento agudo de orto-eugenol, nas doses de 50, 75 e 100 mg/kg, na ansiedade, memória de trabalho e estresse oxidativo em camundongos Swiss machos. Nossos resultados mostram que a dose de 100 mg/kg aumentou o número de mergulhos e reduziu a latência no teste da placa perfurada. A dose de 50 mg/kg reduziu os níveis de malondialdeído no córtex pré-frontal e o número de entradas no labirinto em Y em comparação com o grupo de hiperlocomoção induzida por MK-801. Todas as doses reduziram os níveis de nitrito no hipocampo. Também foi possível avaliar uma correlação estatística entre a redução do estresse oxidativo e a hiperlocomoção após a administração do orto-eugenol. No entanto, o tratamento agudo não foi capaz de prevenir os déficits de memória de trabalho. Portanto, o presente estudo mostra que o orto-eugenol tem efeito ansiolítico e antioxidante, sendo capaz de prevenir a hiperlocomoção induzida pela substância. Nossos resultados contribuem para a elucidação do perfil farmacológico do orto-eugenol, bem como para direcionar novos estudos que busquem investigar suas possíveis aplicações clínicas.

Assuntos