Potencial antioxidante dos extratos fenólicos da semente de quinoa (Chenopodium quinoa Willd) e avaliação dos efeitos sobre o déficit de memória induzido por escopolamina

Abstract

Quinoa (Chenopodium quinoa Willd) is a pseudocereal in which shows a high amount of bioactive compounds (CB). The quinoa cooking improves the taste and palatability, however, it provokes a reduction in the levels of CB and consequently of the antioxidant potential. In this context, the production of these extracts comes as an alternative to improve the use of BC, whereas its antioxidant action is associated to the combat of diseases and health benefits. Thus, the objective of this study is to evaluated by the antioxidant potential of ethanolic extracts of white (WQ) and red (RQ) seeds and analyzed the extracts with the greatest antioxidant potential, on the memory deficit induced by scopolamine (SPC) in mice in the object recognition task. Four ethanolic extracts were obtained with WQ and RQ, both of Peruvian origin, they were purchased in the local market and the extractions, using hexane and ethanol as solvent, were performed by soxhlet at 60 °C (S), and under shaking at room temperature (SRT). In the extracts was made the quantification of total phenolic compounds (CFT) by the Folin-Ciocalteu colorimetric method, being expressed as gallic acid equivalent (EAG) and the total flavonoids, expressed as quercetin equivalent (EQ). And then, the evaluation of the antioxidant potential was determined by the DPPH method expressed as Trolox equivalent. Next, the evaluation of the antioxidant potential was determined by the DPPH method and by ABTS both techniques expressed by Trolox equivalent. The extract of RQ-S, presented higher content of CFT and flavonoids (26.07 ± 0.70 mg EAG.g-1 and 93,80 ± 0,43 mg EQ.g- 1, respectively), as well as greater antioxidant potential measured by DPPH (18.48 ± 0.80 μmol Trolox.g-1), and was not significant enough for ABTS. Swiss mice were randomly divided into two groups receiving RQ-S (100 mg/kg) or saline (10 mL/kg) by oral gavage once daily for 7 days. On day 8 each group was again randomly divided into two groups receiving either SCP (1 mg/kg) or saline (10 mL/kg) by single intraperitoneal administration, 30 min before the training session on the object recognition task. The animals were submitted test session on the object recognition task 24 h later. After behavioral test, the hippocampus and cerebral cortex were removed for the determination of oxidative stress indicators (superoxide dismutase, catalase and TBARS) and acetylcholinesterase (AChE) activity. SCP administration induced a memory deficit, altered AChE activity and oxidative stress indicators in the hippocampus and the cerebral cortex. Oral administration of RQ-S (100 mg/kg during 7 days) prevented memory deficit, the changes of AChE activity and oxidative stress indicators induced by SCP. These results provide evidence that quinoa extract is an alternative treatment for SCP-induced memory deficits, and suggest the involvement of oxidative stress and cholinergic system.