Neuroprotective effects of Onion (Allium cepa) Ethanolic Extract on Animal Model of Parkinson's Disease Induced by 6-hydroxydopamine: A Behavioral, Biochemical, and Histological Study

Objectives: Parkinson's disease (PD), a progressive neurodegenerative disorder. Oxidative stress plays an important role in PD pathophysiology. Onion has antioxidant properties. In an experimental study, we have evaluated the effects of onion ethanolic extract (OEE) on animal models of Parkinson disease (PD) in male rats. Methods: Studied groups were sham group, Parkinson's group (Parkinson rats without treatment), and three treatment groups including Parkinson rats that treated with OEE at 50, 100, and 200 mg/kg/day. Animal model of PD was induced by injection of 6-hydroxydopamine (6-OHDA) into the right substantia nigra. The administration of all the extracts were started 14 days before the surgery and continued daily for seven days after surgery. Learning and memory were evaluated by a Morris water maze. In addition, malondialdehyde (MDA) concentrations and histological parameters (density of neurons) were determined by thiobarbituric acid reactive substances (TBARS) and Nissl staining, respectively. Results: Our results showed that 6-OHDA led to cognitive dysfunction, increased MDA and neuronal damage compared sham group. However, the administration of OEE was improved cognitive dysfunction, decreased MDA and prevented neuronal damage in animal model of PD. Conclusion: The onion could be a new nutrition strategy and essential part of the food diet for preventing PD.