Anti-Amnesic and Neuroprotective Effects of Ziziphus Jujuba Aqueous Extract on Scopolamine-Induced Cognitive Impairments in Rats

Abstract

Background: Alzheimer's disease is a neurological condition that affects more than 44 million people worldwide. The available treatments target the symptoms rather than underlying causes. Ziziphus jujuba (Rhamnaceae) is used in traditional Cameroonian medicine to treat many disorders including memory impairments. The study aimed to evaluate the anti-amnesic and neuroprotective effects of Z. jujuba aqueous extract on scopolamine-induced memory disorders in rats. Methods: Learning and memory impairments were induced in rats by scopolamine (1mg/kg, i.p.) for 15 days. Rats that developed cognitive impairments were divided as follows: two positive control groups received piracetam (200 mg/kg, p.o.) or tacrine (1 mg/kg, p.o.); three test groups received the extract (29, 57, and 114 mg/kg, p.o., respectively) daily for 15 days. At the end of treatments, memory impairments were assessed by Morris water maze and Y-maze tests. Thereafter, animals were sacrificed and some biochemical parameters (oxidative stress, inflammation, and apoptosis) were estimated in the hippocampus and prefrontal cortex.Results: Z. jujuba decreased the time to reach the platform and increased the time in the target quadrant. However, it failed to affect spontaneous alternation in the Y-maze. Furthermore, the extract reversed scopolamine-induced oxidative stress, inflammation, and apoptosis. This was confirmed with the prevention of neuronal loss in the hippocampus or prefrontal cortex. Conclusions: These findings suggest that Z. jujuba extract possesses ant-amnesic and neuroprotective effects. It seems that these effects are mediated in part by antioxidant, anti-inflammatory, and anti-apoptotic activities. This, therefore, justify its use to treat dementia and psychiatric disorders in Cameroon’s folk medicine.