Ziziphus jujuba (Rhamnaceae) Alleviates Working Memory Impairment and Restores Neurochemical Alterations in the Prefrontal Cortex of D-Galactose-Treated Rats

Investigation of the Cognitive Activity Between the Leaf Extracts of Eclipta alba and Ziziphus jujuba in Diabetic Animal Models

Diabetes mellitus (DM), a prevalent metabolic disorder, is associated with widespread damage to bodily systems, notably causing significant dysfunction within the peripheral and central nervous systems (CNS). The primary objective of this study is to explore the extent of DM's impact on cognitive and behavioral functions and to evaluate the therapeutic potential of ethanol leaf extracts from Ziziphus jujuba (ZJ) and Eclipta alba (EA) in mitigating these adverse effects. Utilizing an established animal model, we aimed to determine the effectiveness of these plant extracts in ameliorating the cognitive impairments commonly seen in diabetic states. In our experimental framework, we allocated Wistar rats (n=6 per group) into eight different groups, inducing DM through alloxan administration. The intervention groups were treated orally with either the standard antidiabetic drug glibenclamide or varying doses of ZJ and EA extracts over periods of seven and 21 days. Throughout the study, we carefully tracked fluctuations in blood glucose levels, noting considerable decreases, particularly following the 21-day treatment interval. Post-treatment, the rats' cognitive functions were assessed using the Morris water maze (MWM) test. This evaluation revealed significant cognitive enhancement in the diabetic rats administered with ZJ and EA extracts, with these groups displaying reduced latency in finding the submerged platform, indicative of improved learning and memory. These observations were statistically significant (p<0.01). The findings underscore the hypoglycemic effects of ZJ and EA extracts and suggest their viability as cognitive enhancers in the context of DM. The protective effects of these extracts against cognitive decline caused by DM are clear. They add important new information to the research on natural phytochemicals for managing chronic diseases. This study opens new avenues for the application of these substances in treating neurocognitive disorders associated with DM.

Chronic but not acute nicotine treatment ameliorates acute inflammation-induced working memory impairment by increasing CRTC1 and HCN2 in adult male mice

BACKGROUND

Systemic inflammation in which lipopolysaccharide (LPS) is released into circulation can cause cognitive dysfunction and we have previously shown that LPS impaired working memory (WM) which refers to the ability to guide incoming behavior by retrieving recently acquired information. However, the mechanism is not very clear, and currently, there is no approved strategy to improve inflammation-induced WM deficit. Notably, epidemiological studies have demonstrated a lower occurrence rate of inflammatory-related diseases in smoking patients, suggesting that inflammation-induced WM impairment may be improved by nicotine treatment. Here, our object is to investigate the effect and potential mechanisms of acute and chronic nicotine treatment on LPS-produced WM deficiency.

METHODS

Delayed alternation T-maze task (DAT) was applied for evaluating WM which includes both the short-term information storage and the ability to correct errors in adult male mice. Immunofluorescence staining and immunoblotting were used for assessing the levels and distribution of CREB-regulated transcription coactivator 1 (CRTC1) and hyperpolarization-activated cation channels 2 (HCN2) in the medial prefrontal cortex (mPFC) and hippocampus. Quantitative PCR and ELISA were employed for analyzing the mRNA and protein levels of TNF-α and IL-1β.

RESULTS

Our results revealed that administration of LPS (i.p.) at a dose of 0.5 mg/kg significantly produced WM impairment in the DAT task accompanied by an increase in IL-1β and TNF-α expression in the mPFC. Moreover, intra-mPFC infusion of IL-1Ra, an IL-1 antagonist, markedly alleviated LPS-induced WM deficiency. More important, chronic (2 weeks) but not acute nicotine (0.2 mg/kg, subcutaneous) treatment significantly alleviated LPS-induced WM deficiency by upregulating CRTC1 and HCN2. Of note, intra-mPFC infusion of HCN blocker ZD7288 produced significant WM deficiency.

CONCLUSIONS

In summary, in this study, we show that chronic nicotine treatment ameliorates acute inflammation-induced working memory deficiency by increasing CRTC1 and HCN2 in adult male mice.

Evaluation of the Impact of Alternanthera philoxeroides (Mart.) Griseb. Extract on Memory Impairment in D-Galactose-Induced Brain Aging in Mice through Its Effects on Antioxidant Enzymes, Neuroinflammation, and Telomere Shortening

Aging is a well-known factor that accelerates brain deterioration, resulting in impaired learning and memory functions. This current study evaluated the potential of an extract of Alternanthera philoxeroides (AP), an edible flavonoid-rich plant, to ameliorate D-galactose-induced brain aging in male mice. Chronic administration of D-galactose (150 mg/kg/day) in mice mimicked the characteristics of aging by accelerating senescence via downregulation of the following telomere-regulating factors: mouse telomerase reverse transcriptase (mTERT) and mouse telomeric repeat-binding factors 1 (mTRF1) and 2 (mTRF2). D-galactose also decreased the activities of the antioxidant enzymes catalase (CAT) and superoxide dismutase (SOD), while increasing expression of neuroinflammatory cytokines in the frontal cortex and hippocampus. Daily treatment of D-galactose-induced aging mice with AP at 250 and 500 mg/kg/day or vitamin E (100 mg/kg/day) significantly increased the activities of SOD and CAT, as well as expression of mTERT, mTRF1, and mTRF2, which are involved in telomere stabilization, but decreased the levels of proinflammatory cytokines IL-1β, IL-6, and TNF-α. In the behavioral portion of the study, AP improved aging-related cognitive deficits in short-term memory as shown by the Y-maze task and the novel object recognition test (NORT) and long-term memory as shown by the Morris water maze test (MWMT). The flavones kaempferol-O-glucoside (1), quercetin (2), alternanthin B (3), demethyltorosaflavone D (4), and chrysoeriol-7-O-rhamnoside (5), which could be responsible for the observed effects of AP in the D-galactose-induced aging mice, were identified by HPLC analysis.

A Literature Review of the Pharmacological Effects of Jujube

Jujube is a plant native to China that could be used in medicine and food. Its dried fruit is a superior herb commonly used in traditional Chinese medicine formulations for its calming effect and for nourishing the blood and strengthening the spleen and stomach. Jujube contains numerous active components including polysaccharides, phenols, and triterpene acids, which show a diverse array of pharmacological activities such as neuroprotection and the prevention and treatment of cardiovascular diseases. In this paper, the research status of jujube over the past two decades has been statistically evaluated. Meanwhile, by tracking the latest research advances, the pharmacological efficacy and molecular mechanisms of jujube are exhaustively expounded to provide specific and systematic references for further research on the pharmacological effects of jujube and its application in the food and pharmaceutical industries.

Attention-deficit/hyperactivity disorder and inflammation: natural product-derived treatments-a review of the last ten years

OBJECTIVE

Attention-deficit hyperactivity disorder (ADHD) is a psychiatric disorder characterized by symptoms of inattention, hyperactivity, and impulsivity. Stimulant medication is the main pharmacological treatment for ADHD. However, the traditional pharmacological treatments may have significant side effects; therefore, non-pharmacological approaches are needed. Thus, there has been growing interest in alternative herbal treatments. The aim of this review was to comprehensively assess the current evidence for plant-based treatment of ADHD in human and animal models, as well as their ability to modulate the inflammatory process.

METHODS

This study was an integrative review of the current evidence for the plant-based treatment of ADHD. The research involved using literature available on PubMed and Scopus databases.

FINDINGS

Spontaneously hypersensitive rats treated with baicalin exhibited significant reductions in locomotion, increased spatial learning skills, and increased levels of dopamine in the striatum. Supplementation with Sansonite improved memory and attention capacity. In human studies, Ginkgo biloba significantly improved the symptoms of inattention and reduced memory impairment. In studies conducted using Korean Red ginseng, Klamath, and Crocus sativus L., the patients showed significant improvements in symptoms of inattention and hyperactivity/impulsivity. Furthermore, we demonstrated that the identified plants modulate the inflammatory process through pro-inflammatory and anti-inflammatory cytokines, nitric oxide, Th cells, Toll-like receptor 4, and mitogen-activated protein kinases.

CONCLUSION

All the studies included in this review focused on plants with demonstrated potential against inflammatory processes, positioning them as promising candidates for ADHD treatment, due to their potential to attenuate or even prevent neuroinflammatory mechanisms.

Aspirin ameliorates the neurotoxicity of benzo[a]pyrene in mice and HT22 cells: Possible role of miRNA-mRNA network

Benzo[a]pyrene (B[a]P) is neurotoxic, however, the mechanism and potential prevention are yet not clear. This study explored the miRNA-mRNA network in the B[a]P-induced neurotoxicity in mice and HT22 cells and the intervention of aspirin (ASP). HT22 cells were treated for 48 h with DMSO, B[a]P (20 μM), or both B[a]P (20 μM) and ASP (4 μM). Following B[a]P treatment, compared to the DMSO controls, HT22 cells showed injured cell morphology, reduced cell viability and neurotrophic factor concentrations, and increased LDH leakage, Aβ_1-42, and inflammatory factor concentrations, which were improved by ASP. RNA sequencing and qPCR verified the significant differences of miRNA and mRNA profiles following B[a]P treatment, which were rescued by ASP. Bioinformatics analysis suggested the miRNA-mRNA network could be involved in the neurotoxicity of B[a]P and the intervention of ASP. The neurotoxicity and neuroinflammation were induced in mice's brains by B[a]P, and the target miRNA and mRNA were proved to be consistent with in vitro, which were ameliorated by ASP. The findings demonstrate a possible role of miRNA-mRNA network in the B[a]P-induced neurotoxicity. If this is confirmed by additional experiments, it will provide a promising pathway of intervention against B[a]P, using ASP or other agents with fewer toxic effects.

Neuroprotective Effects of a Multi-Herbal Extract on Axonal and Synaptic Disruption in Vitro and Cognitive Impairment in Vivo

Background

Alzheimer's disease (AD) is a multifactorial disorder characterized by cognitive decline. Current available therapeutics for AD have limited clinical benefit. Therefore, preventive therapies for interrupting the development of AD are critically needed. Molecules targeting multifunction to interact with various pathlogical components have been considered to improve the therapeutic efficiency of AD. In particular, herbal medicines with multiplicity of actions produce cognitive benefits on AD. Bugu-M is a multi-herbal extract composed of Ganoderma lucidum (Antler form), Nelumbo nucifera Gaertn., Ziziphus jujuba Mill., and Dimocarpus longan, with the ability of its various components to confer resilience to cognitive deficits.

Objective

To evaluate the potential of Bugu-M on amyloid-β (Aβ) toxicity and its in vitro mechanisms and on in vivo cognitive function.

Methods

We illustrated the effect of Bugu-M on Aβ_25-35-evoked toxicity as well as its possible mechanisms to diminish the pathogenesis of AD in rat cortical neurons. For cognitive function studies, 2-month-old female 3×Tg-AD mice were administered 400 mg/kg Bugu-M for 30 days. Behavioral tests were performed to assess the efficacy of Bugu-M on cognitive impairment.

Results

In primary cortical neuronal cultures, Bugu-M mitigated Aβ-evoked toxicity by reducing cytoskeletal aberrations and axonal disruption, restoring presynaptic and postsynaptic protein expression, suppressing mitochondrial damage and apoptotic signaling, and reserving neurogenic and neurotrophic factors. Importantly, 30-day administration of Bugu-M effectively prevented development of cognitive impairment in 3-month-old female 3×Tg-AD mice.

Conclusion

Bugu-M might be beneficial in delaying the progression of AD, and thus warrants consideration for its preventive potential for AD.

Effects of Ziziphus Jujuba Extract Alone and Combined with Boswellia Serrata Extract on Monosodium Iodoacetate Model of Osteoarthritis in Mice

Background

As a chronic joint condition, osteoarthritis (OA) is a common problem among older people. Pain, aching, stiffness, swelling, decreased flexibility, reduced function, and disability are the symptoms of arthritis.

Objectives

In this study, we tested the extracts of Ziziphus jujuba (ZJE) and Boswellia serrata (BSE) to reduce OA symptoms as an alternative treatment.

Methods

NMRI mice were administered an intra-articular injection of monosodium iodoacetate (MIA; 1 mg/10 mL) in the left knee joint cavity for the induction of OA. Hydroalcoholic extracts of ZJE (250 and 500 mg/kg), BSE (100 and 200 mg/kg), and combined ZJE and BSE were orally administered daily for 21 days. Following behavioral tests, plasma samples were collected to detect inflammatory factors. To screen for general toxicity, acute oral toxicity was evaluated.

Results

Oral administration of all the hydroalcoholic extracts significantly increased the locomotor activity, pixel values of the foot-print area, paw withdrawal threshold, the latency of the withdrawal response to heat stimulation, and decreased the difference between pixel values of hind limbs compared to the vehicle group. Also, the elevated levels of IL-1β, IL-6, and TNF-α were reduced. As tested in this study, ZJE and BSE were practically nontoxic and had a high degree of safety.

Conclusions

This study demonstrated that the oral administration of ZJE and BSE slows the progression of OA through anti-nociceptive and anti-inflammatory properties. Oral co-administration of ZJE and BSE extracts can be used as herbal medicine to inhibit OA progression.

An aqueous macerate of Ziziphus jujuba reduces long-term spatial memory impairment in D-galactose treated rats: role of anti-inflammatory pathways

Pharmacological treatments against Alzheimer disease provide only symptomatic relief and are associated with numerous side effects. Previous studies showed that a concoction of Ziziphus jujuba leaves possesses anti-amnesic effects in scopolamine-treated rats. More recently, an aqueous macerate of Z. jujuba leaves has been shown to reduce short-term memory impairment in D-galactose-treated rats. However, no study on the effect of an aqueous macerate of Z. jujuba on long-term memory impairment was performed. Therefore, this study evaluates the effect of an aqueous macerate of Z. jujuba on long-term spatial memory impairment in D-galactose-treated rats. Long-term spatial memory impairment was induced in rats by administering D-galactose (350 mg/kg/day, s.c.), once dailyfor 21 days. On the 22nd day, the integrity of this memory was assessed using the Morris water maze task. Rats that developed memory impairment were treated with tacrine (10 mg/kg, p.o.), or aspirin (20 mg/kg, p.o.), or extract (41.5, 83, and 166 mg/kg, p.o.), once daily, for 14 days. At the end of the treatment, memory impairment was once more assessed using the same paradigm. Animals were then euthanized, and some pro-inflammatory cytokine markers were analyzed in the hippocampus or blood. The extract at all doses significantly reduced the latency to attain the platforming of the water maze test. The extract (83 mg/kg) also increased the time spent in the target quadrant during the retention phase. The extract markedly reduced the concentration of pro-inflammatory cytokine markers in the hippocampus and blood. Together, these results suggest that this aqueous extract Z. jujuba reduces long-term spatial memory impairment. This effect may be mediated in part by its anti-inflammatory activity.

Therapeutic and palliative role of a Unani herbal decoction in COVID-19 and similar respiratory viral illnesses: Phytochemical & pharmacological perspective

ETHNOPHARMACOLOGICAL RELEVANCE

Outbreaks of respiratory viral infections like Severe Acute Respiratory Syndrome, Middle-East Respiratory Syndrome, and Coronavirus Disease-2019 have been a regular occurrence in the past 100 years. A significant proportion of the morbidity and mortality in influenza is attributed to the co-morbidities and complications induced by the disease, involving the vital organs and physiological functions. In this context, traditional medicines offer effective protective, palliative, and therapeutic benefits, as observed in several studies on various types of influenza, including COVID-19. The Unani herbal decoction comprising of 'Unnāb (Ziziphus jujuba Mill. fruit), Sapistān (Cordia dichotoma G. Forst. fruit), and Behīdāna (Cydonia oblonga Mill. seed) was originally prescribed by Hakim Ajmal Khan (1868-1927 AD) for various respiratory ailments as a bronchodilator, anti-inflammatory, and for clearing the respiratory tract. During COVID-19, the decoction was prescribed by the Ministry of Ayurveda, Yoga, Unani, Siddha, and Homeopathy (AYUSH), Government of India, for mild patients in home isolation, and also as a self-care drink for healthy people. Preliminary studies are of the view that the decoction could reduce COVID-19 incidence and prevent severe disease in the population where it was administered.

AIMS OF THE STUDY

We intend to review the pharmacological activity of the Unani decoction ingredients, i.e., Z. jujuba, C. dichotoma, and C. oblonga, in context with respiratory viral infections and their co-morbidities, to develop an understanding of its action mechanism.

METHODOLOGY

We reviewed Unani classical textbooks for information on the therapeutic activity of the decoction ingredients. Scientific studies published in English from the year 2000 onwards on leading scientific websites (PubMed, MEDLINE, Scopus, and Springer) were searched for information regarding the efficacy of the drugs in influenza and its common complications. Non-English language articles, or those published prior to 2000, and those which included plant parts other than those traditionally included in the decoction were excluded.

OBSERVATIONS

A wide range of therapeutic and palliative effects have been observed in the three herbs included in the Unani decoction, including anti-viral, anti-bacterial, immuno-modulatory, anti-inflammatory, hepato-, and nephroprotective, anti-atherosclerotic, anti-tussive, broncho-dilatory, and regulation of gut microbiota. Together, these effects can help to mitigate and prevent most of the complications caused as a result of respiratory viral infections.

CONCLUSION

The combined effects of ingredients in this Unani herbal decoction can potentially help to mitigate most of the pathological changes and complications caused by influenza viruses. With further clinical research, the decoction may be potentially utilized as a prophylactic and therapeutic against viral influenza.

Aqueous extract of Parkia biglobosa (Jacq.) R. Br. (Fabaceae) exerts antiepileptogenic, anti-amnesic, and anxiolytic-like effects in mice via mechanisms involving antioxidant and anti-inflammatory pathways

Parkia biglobosa (Jacq.) R. Br. (Fabaceae) is a widely distributed tree, used in traditional medicine to treat amebiasis, hookworm infection, ascariasis, asthma, sterility, dental pain, headaches, cardiac disorders, and epilepsy. To date, no study on the effect of an aqueous extract of P. biglobosa on epileptogenesis and associated neuropsychiatric disorders has been undertaken. Therefore, this study aimed to investigate antiepileptogenic-, antiamnesic-, and anxiolytic-like effects of an aqueous extract of P. biglobosa using pentylenetetrazole (PTZ)-induced kindling in mice. Animals were divided into six groups of eight mice each. Thus, a PTZ group received distilled water (10 ml/kg, per os), a positive control group received sodium valproate (300 mg/kg, p.o.), and three test groups received the aqueous extract of P. biglobosa (80, 160, and 320 mg/kg, p.o.).In addition, a control group of eight mice receiving distilled water (10 ml/kg, p.o.) was formed. The treatments were administered to mice, 60 min before administration of PTZ (20 mg/kg, i.p.). These co-administrations were performed once daily, for 22 days. The number and duration of seizures (stages 1, 2, 3, and 4 of seizures) exhibited by each mouse were assessed for 30 min during the treatment period. Twenty-four hours following the last administration of the treatments and PTZ, novel object recognition and T-maze tests were performed to assess working memory impairment in mice, while the open field test was performed to assess anxiety-like behavior. After these tests, the animals were sacrificed, and the hippocampi were collected for biochemical and histological analysis. During the period of PTZ-kindling, the extract at all doses completely (p < 0.001) protected all mice against stages 3 and 4 of seizures when compared to sodium valproate, a standard antiepileptic drug. The extract also significantly (p < 0.001) attenuated working memory impairment and anxiety-like behavior. In post-mortem brain analyses, the extract significantly (p < 0.001) increased γ-aminobutyric acid (GABA) level and reduced oxidative stress and inflammation. Histological analysis showed that the aqueous extract attenuated neuronal degeneration/necrosis in the hippocampus. These results suggest that the extract is endowed with antiepileptogenic-, anti-amnesic-, and anxiolytic-like effects. These effects seem to be mediated in part by GABAergic, antioxidant, and anti-inflammatory mechanisms. These results suggest the merit of further studies to isolate the bioactive molecules responsible for these potentially therapeutically relevant effects of the extract.

The Potential Neuroprotective Effect of Cyperus esculentus L. Extract in Scopolamine-Induced Cognitive Impairment in Rats: Extensive Biological and Metabolomics Approaches

The aim of the present study is to investigate the phytochemical composition of tiger nut (TN) (Cyperus esculentus L.) and its neuroprotective potential in scopolamine (Scop)-induced cognitive impairment in rats. The UHPLC-ESI-QTOF-MS analysis enabled the putative annotation of 88 metabolites, such as saccharides, amino acids, organic acids, fatty acids, phenolic compounds and flavonoids. Treatment with TN extract restored Scop-induced learning and memory impairments. In parallel, TN extract succeeded in lowering amyloid beta, β-secretase protein expression and acetylcholine esterase (AChE) activity in the hippocampus of rats. TN extract decreased malondialdehyde levels, restored antioxidant levels and reduced proinflammatory cytokines as well as the Bax/Bcl2 ratio. Histopathological analysis demonstrated marked neuroprotection in TN-treated groups. In conclusion, the present study reveals that TN extract attenuates Scop-induced memory impairments by diminishing amyloid beta aggregates, as well as its anti-inflammatory, antioxidant, anti-apoptotic and anti-AChE activities.

Dichrocephala integrifolia Aqueous Extract Antagonises Chronic and Binges Ethanol Feeding-Induced Memory Dysfunctions: Insights into Antioxidant and Anti-Inflammatory Mechanisms

Ethanol consumption is widely accepted despite its addictive properties and its mind-altering effects. This study aimed to assess the effects of Dichrocephala integrifolia against, memory impairment, on a mouse model of chronic and binges ethanol feeding. Mice were divided, into groups of 8 animals each, and received distilled water, Dichrocephala integrifolia aqueous extract (25; 50; 100; or 200 mg/kg) or memantine (200 mg/kg) once a day, while fe, with Lieber-DeCarli control (sham group only) or Lieber-DeCarli ethanol diet ad libitum for 28 days. The Y maze and the novel object recognition (NOR) tests were used to evaluate spatial short-term and recognition memory, respectively. Malondialdehyde, nitric oxide, glutathione levels, and proinflammatory cytokines (Il-1β, TNF-α, and Il-6) were evaluated in brain homogenates following behavioral assessments. The results showed that chronic ethanol administration in mice was associated with a significant (p < 0.001) reduction in the spontaneous alternation percentage and the discrimination index, in the Y maze and the NOR tests, respectively. It significantly (p < 0.01) increased oxidative stress and inflammation markers levels in the brain. Dichrocephala integrifolia (100 and 200 mg/kg) as well as memantine (200 mg/kg) significantly (p < 0.001) increased the percentage of spontaneous alternation and the discrimination index, in the Y maze and NOR tests, respectively. Dichrocephala integrifolia (100 and 200 mg/kg) likewise memantine (200 mg/kg) significantly (p < 0.01) alleviated ethanol-induced increase, in the brain malondialdehyde level, nitric oxide, Il-1β, TNF-α, and Il-6. From these findings, it can be concluded that Dichrocephala integrifolia counteracted memory impairment, oxidative stress, and neuroinflammation induced by chronic ethanol consumption in mice.

Aspirin ameliorates the cognition impairment in mice following benzo[a]pyrene treatment via down-regulating BDNF IV methylation

Benzo[a]pyrene (B[a]P) is neurotoxic, however, the mechanisms remain unclear and there is no effective prevention. Available evidence suggests a role of DNA methylation in B[a]P-induced neurotoxicity. This study investigated the brain-derived neurotrophic factor (BDNF) IV methylation in the development of and aspirin intervention against B[a]P's neurotoxicity in mice and HT22 cells. Mice were intraperitoneally treated with solvent or B[a]P (0.5, 2, and 10 mg/kg b.w.) for 60 days. An intervention group was treated simultaneously with B[a]P (10 mg/kg, i.p.) and aspirin (10 mg/kg, daily water-drinking). The treated mice showed a dose-dependent cognitive and behavioral impairment, and cerebral cell apoptosis, which were alleviated by aspirin co-treatment. Following B[a]P treatment, DNA methyltransferase (DNMTs) and BDNF IV hypermethylation were increased in the cerebral cortex of mice compared to controls, while significant decreases were found in BDNF IV and BDNF mRNA, and BDNF protein levels. Aspirin co-treatment rescued DNMTs activation and BDNF IV hypermethylation, and mitigated the recession in BDNF mRNA and protein induced by B[a]P treatment. Similar results were shown in HT22 cells. These findings reveal a critical role of BDNF IV methylation in the neurotoxicity of B[a]P, and demonstrate a promising prevention of aspirin against B[a]P-induced cognitive impairment via inhibiting BDNF IV hypermethylation.

Antiamnesic and Neuroprotective Effects of an Aqueous Extract of Ziziphus jujuba Mill. (Rhamnaceae) on Scopolamine-Induced Cognitive Impairments in Rats

Background

Alzheimer's disease is a neurological condition that affects about 44 million people worldwide. The available treatments target symptoms rather than the underlying causes. Ziziphus jujuba (Rhamnaceae) is widely used in traditional Cameroonian medicine to treat diabetes, pain, infections, and dementia. Previous studies reported that Z. jujuba aqueous macerate improves working memory impairment, but no study on the antiamnesic effect of a concoction of Z. jujuba in rats has been performed. Therefore, this study aimed to assess the antiamnesic and neuroprotective effects of an aqueous extract of Z. jujuba on scopolamine-induced cognitive impairments in rats.

Methods

Learning and memory impairments were induced in rats by administering scopolamine (1 mg/kg, i.p.) to 58 rats for 15 days. Rats that developed learning and memory impairments in Morris water maze and Y-maze paradigms were divided into 7 groups (8 rats each) and treated daily for 15 days as follows: the normal control group received distilled water (10 ml/kg, p.o.), the negative control group received distilled water (10 ml/kg, p.o.), positive control groups either received donepezil (1.2 mg/kg, p.o.) or tacrine (10 mg/kg, p.o.), and the three test groups were given the extract (29, 57, and 114 mg/kg, p.o.). At the end of treatments, learning and memory impairments were determined using the same paradigms. Animals were then euthanized, and biochemical parameters of oxidative stress, inflammation, and apoptosis were analyzed in the hippocampus and prefrontal cortex.

Results

On the 4th day of the acquisition phase in the Morris water maze, Z. jujuba (29 and 114 mg/kg) reduced (p < 0.001) the latency to reach the platform, while in the retention phase, Z. jujuba (57 and 114 mg/kg) decreased (p < 0.001) the time to reach the platform and increased the time in the target quadrant (p < 0.05) compared to control. Surprisingly, the extract failed to affect spontaneous alternations in the Y-maze. Furthermore, the extract (29, 57, and 114 mg/kg) reversed (p < 0.001) scopolamine-induced oxidative stress, inflammation, and apoptosis. This was supported by the reduction of neuronal alterations in the hippocampus and prefrontal cortex.

Conclusions

Compared to donepezil, a standard drug against Alzheimer's disease, these findings suggest that Z. jujuba extract possesses antiamnesic and neuroprotective effects, and these effects are mediated in part through antioxidant, anti-inflammatory, and antiapoptotic activities. These findings help to explain its use in treating psychiatric disorders in Cameroon's folk medicine.