Daniellia oliveri (DO) is a traditional medicinal plant used for the treatment of diseases such as inflammation, schizophrenia, and epilepsy in Nigeria, Kenya, Congo, and Cameroon. This study was carried out to evaluate the potential neuroprotection effect of the aqueous root bark extract of Daniellia oliveri against diazepam-induced amnesia in mice. Thirty-six adult male mice were distributed into six groups: the three test groups received Daniellia oliveri root bark extract (100, 200, and 300 mg/kg), the normal control group received distilled water (10 ml/kg), a positive control group received piracetam (150 mg/kg), and the negative control received diazepam (2.5 mg/kg). Learning and memory were evaluated using the radial arm maze and the T-maze. Biomarkers of oxidative stress were also quantified in mice brains. Statistical analyses were performed using two-way ANOVA followed by Tukey’s post hoc test. Daniellia oliveri root bark aqueous extract decreased the number of working memory errors and number of reference memory errors in amnesic mice evaluated in the radial arm maze. Also, an increase in glutathione activity and a decrease in malondialdehyde levels were noted in the hippocampi homogenate of the extract-treated mice as compared to the diazepam-demented but untreated group. Moreover, pretreatment with Daniellia oliveri aqueous root bark extract reversed the decrease in hippocampal cell density observed in the nontreated diazepam group. Taken together, these results suggest that the aqueous extract of DO leaves possesses antioxidant potential and might provide an opportunity for the management of neurological abnormalities in amnesic conditions.

Guiera senegalensis JF Gmel. (Combretaceae) (GS) is a plant used in traditional medicine in West Africa for the treatment of several diseases, such as epilepsy and depression. However, its potential benefits in improving scopolamine (Sco)-induced memory impairment and brain oxidative stress in zebrafish have been investigated. In the present study, zebrafish (Danio rerio) were treated with GS (1, 4, and 8 μg/L) for 19 days as well as Sco (100 µM) 30 min before behavioral tests. Behavioral performance was assessed by the Y-maze test and novel object recognition test (NOR), whereas anxiety response was evaluated in the novel tank diving test (NTT). Subsequently, high-performance liquid chromatography (HPLC) was used to evaluate the GS chemical composition. Sco promoted oxidative stress and acetylcholinesterase (AChE) activity. Moreover, both oxidative stress parameters and AChE activity were ameliorated by GS treatment. Accordingly, the present findings further provided the potential use of GS as a natural, alternative treatment against cognitive disorders associated to Alzheimer’s disease (AD).

The present study was conducted to investigate protective effects of the aqueous extract of V. subterranea seeds landrace on amnesia induced by scopolamine in mice. V. subterranea aqueous extract (100, 200 and 400 mg/kg BW) was administered by gavage for nine consecutive days and memory impairment was induced by repeated intraperitoneal injection of scopolamine (1.5 mg/kg). The Y-maze (YM), Morris water maze (MWM), novel object recognition paradigm (NOR) and the T maze (TM) were used to assess learning, memory and retention. Superoxide dismutase (SOD), Catalase (CAT), Malondialdehyde (MDA) levels and Acetylcholine esterase activity was also evaluated in the mice hippocampi homogenates. V. subterranea aqueous extract (400 mg/kg) significantly increased the percentage of spontaneous alternation in the YM task and decreased escape latency in the MWM. Moreover, this dose brought about a significantly improvement in the time spent in the preferred TM arm and discrimination index in the NOR tasks despite repeated scopolamine injection. Additionally, low acetylcholine esterase levels, reduced lipid peroxidation (malondialdehyde) but increased antioxidant enzymes (catalase and superoxide dismutase) activity was observed in hippocampi homogenate of mice pre-treated with the extract. A protective action against hippocampal cell damage was also evident. This finding suggests that the aqueous extract of V. subterranea seed landrace may improve learning and memory.