Investigação da ação do tipo antidepressiva de fungos endofíticos do guaraná (Paullinia cupana) em camundongos

• Autor(a) principal: Leite, Mariana Garott Ignácio
• Data de Publicação: 2021
• Tipo de documento: Trabalho de conclusão de curso
• Idioma: por
• Título da fonte: Biblioteca Digital de Monografias da UFMT
• Texto Completo: http://bdm.ufmt.br/handle/1/2834
• topic: CNPQ::CIENCIAS EXATAS E DA TERRA::QUIMICA; Depressão; Extratos de fungos; Monoamonooxidase; Teste de suspensão de cauda; Teste do campo aberto; Teste do nado forçado; Depression; Fungal extracts; Monoamine oxidase; Tail suspension test; Open field test; Forced swim test

Paulinia cupana, popularly known as guarana, presents endophytic fungi in several parts of its constitution, which are sources of natural bioactive substances that have therapeutic use. The main objective of this work was to investigate whether endophytic fungi isolated from the roots and seeds of guarana affect the activity of cerebral monoamine oxidase in vitro and/or induce behavioral antidepressant-like actions in Swiss mice. Five fungi extracted from guarana seeds and roots (F. solani, G. zeae, G. acutata, M. terrestris, and P. asparagi) were tested. Monoamine oxidase is a mitochondrial enzyme responsible for the degradation of neurotransmitters and has two isoforms, MAO-A and MAO-B. Monoamine oxidase inhibitors handle decreasing the degradation of monoamines increasing the levels of monoamines released in the synaptic clefts, so rising the monoaminergic activity, owning the potential to produce an antidepressant-like action. Our results showed that, except for the G. zeae extract, being excluded from the study of isoforms, the other extracts were effective in reducing the total MAO activity at the concentration of 100 μg/mL, but with different degrees of inhibition. For the study of MAO-A and MAO-B isoforms, our results showed the endophytic fungi affect both isoforms but seem to inhibit mainly the subtype B at concentrations considered low (around of 100 μg/mL). The behavioral tests performed in this work, forced swim test (FST) and tail suspension test (TST) are widely used to assess antidepressant-like activity in rodents. Both tests are supported by the hypothesis that rodents, when subjected to a dead-end and aversive situation, alternates its behavior between periods of agitation and immobility in an attempt to escape the stressful event. Antidepressants tend to shorten the total duration of immobility and increase the time to the first episode of latency to immobility in the FST and TST. In this study, all extracts were administered to the mice at the dose of 300 mg/Kg by the intragastric (i.g.) route. Our results showed the M. terrestris extract reduced the total immobility time in both TST and FST and increased the time to the first latency episode in TST by 106%, but not in the FST. P. asparagi did not induce behavioral changes, whereas F. solani extract significantly reduced the total time of immobility and increased latency for the first episode of immobility in both tests. G. acutata reduced the total immobility time by 30% and increased latency by 96.1% in TST; in TNF, despite not changing latency for the first episode of immobility, it reduced total immobility time by 25.7%. Animals treated with extracts were also evaleted in the open filed test (OFT) in order to discard psychostimulant effect, which could influence the interpretation of data for TST and FST. Animals treated with G. acutata extract showed a significant increase in the number of crossings (32.3%) and the number of rearings (69.7%) indicating a psychostimulant-like effect. For the other fungi extracts evaluated there was no changes in locomotor and exploratory activity. Finally, although initial our results suggest extracts of endophytic fungi extracted from guarana are promising agents for further studies focusing on antidepressant treatments.