Diosmin is neuroprotective in a rat model of scopolamine-induced cognitive impairment

Alleviative effect of scopolamine‑induced memory deficit via enhancing antioxidant and cholinergic function in rats by pinostrobin from Boesenbergia rotunda (L.)

Pinostrobin, a key bioactive compound found in the medicinal plant Boesenbergia rotunda (L.), has been noted for its beneficial biological properties including antioxidant, anti-inflammation, anti-cancer and anti-amnesia activities. In view of this, the present study purposed to evaluate the neuroprotective potential of pinostrobin in reversing scopolamine-induced cognitive impairment involving oxidative stress and cholinergic function in rats. A total of 30 male Wistar rats were randomly divided into five groups (n=6): Group 1 received vehicle as a control, group 2 received vehicle + scopolamine (3 mg/kg, i.p.), group 3 received pinostrobin (20 mg/kg, p.o.) + scopolamine, group 4 received pinostrobin (40 mg/kg, p.o.) + scopolamine and group 5 received donepezil (5 mg/kg, p.o.) + scopolamine. Treatments were administered orally to the rats for 14 days. During the final 7 days of treatment, a daily injection of scopolamine was administered. Scopolamine impaired learning and memory performance, as measured by the novel object recognition test and the Y-maze test. Additionally, oxidative stress marker levels, acetylcholinesterase (AChE) activity, choline acetyltransferase (ChAT) and glutamate receptor 1 (GluR1) expression were determined. Consequently, the findings demonstrated that the administration of pinostrobin (20 and 40 mg/kg) markedly improved cognitive function as indicated by an increase in recognition index and by spontaneous alternation behaviour. Pinostrobin also modulated the levels of oxidative stress by causing a decrease in malondialdehyde levels accompanied by increases in superoxide dismutase and glutathione activities. Similarly, pinostrobin markedly enhanced cholinergic function by decreasing AChE activity and promoting ChAT immunoreactivity in the hippocampus. Additionally, the reduction in GluR1 expression due to scopolamine was diminished by treatment with pinostrobin. The findings indicated that pinostrobin exhibited a significant restoration of scopolamine-induced memory impairment by regulating oxidative stress and cholinergic system function. Thus, pinostrobin could serve as a potential therapeutic agent for the management of neurodegenerative diseases such as Alzheimer's disease.

Diosmin ameliorates inflammation, apoptosis and activates PI3K/AKT pathway in Alzheimer's disease rats

Alzheimer's disease (AD), a prevalent cognitive disorder among the elderly, is frequently linked to the abnormal accumulation of myloid-β (Aβ), which is mainly as a result of neuronal death and inflammation. Diosmin, a flavonoid, is considered a potential drug for the treatment of AD. Our study aimed to uncover the molecular mechanism of diosmin in AD therapy. Here, rats were randomly divided into three groups: control, Aβ25-35, and Aβ25-35 + diosmin groups. AD model rats were induced by Aβ25-35 intraventricular injection, meanwhile 50 mg/kg diosmin was orally administered for 6-week intervention. Morris water maze test assessed learning and memory abilities. Hippocampal neuronal damage was determined by HE, Nissl, and TUNEL staining. These assays indicate that diosmin improves cognitive dysfunction and reduces hippocampal neuronal loss and apoptosis. Western blot showed that diosmin reduced Bax (1.21 ± 0.12) and cleaved caspase-3 (1.27 ± 0.12) expression, and increased Bcl-2 (0.70 ± 0.06), p-PI3K (0.71 ± 0.08), and p-AKT (0.96 ± 0.10) in the hippocampus. ELISA indicated diosmin reduces IL-1β, IL-6, and TNF-α levels, suggesting anti-inflammation effect. These results suggest that diosmin inhibits neuronal apoptosis and neuroinflammatory responses to improve cognitive dysfunction in AD rats, possibly related to upregulation of the PI3K/AKT pathway, providing a scientific basis for its use in AD treatment.

Ameliorative effect of vanillic acid against scopolamine-induced learning and memory impairment in rat via attenuation of oxidative stress and dysfunctional synaptic plasticity

Alzheimer's disease (AD) is characterized by cognitive impairment, loss of learning and memory, and abnormal behaviors. Scopolamine (SCOP) is a non-selective antagonist of muscarinic acetylcholine receptors that exhibits the behavioral and molecular hallmarks of AD. Vanillic acid (VA), a phenolic compound, is obtained from the roots of a traditional plant called Angelica sinensis, and has several pharmacologic effects, including antimicrobial, anti-inflammatory, anti-angiogenic, anti-metastatic, and antioxidant properties. Nevertheless, VA's neuroprotective potential associated with the memory has not been thoroughly investigated. Therefore, this study investigated whether VA treatment has an ameliorative effect on the learning and memory impairment induced by SCOP in rats. Behavioral experiments were utilized to assess the learning and memory performance associated with the hippocampus. Using western blotting analysis and assay kits, the neuronal damage, oxidative stress, and acetylcholinesterase activity responses of hippocampus were evaluated. Additionally, the measurement of long-term potentiation was used to determine the function of synaptic plasticity in organotypic hippocampal slice cultures. In addition, the synaptic vesicles' density and the length and width of the postsynaptic density were evaluated using electron microscopy. Consequently, the behavioral, biochemical, electrophysiological, and ultrastructural analyses revealed that VA treatment prevents learning and memory impairments caused by SCOP in rats. The study's findings suggest that VA has a neuroprotective effect on SCOP-induced learning and memory impairment linked to the hippocampal cholinergic system, oxidative damage, and synaptic plasticity. Therefore, VA may be a prospective therapeutic agent for treating AD.

Evaluation of the Effect of Loratadine versus Diosmin/Hesperidin Combination on Vinca Alkaloids-Induced Neuropathy: A Randomized Controlled Clinical Trial

Neurological injury is a crucial problem that interferes with the therapeutic use of vinca alkaloids as well as the quality of patient life. This study was conducted to assess the impact of using loratadine or diosmin/hesperidin on neuropathy induced by vinca alkaloids. Patients were randomized into one of three groups as follows: group 1 was the control group, group 2 received 450 mg diosmin and 50 mg hesperidin combination orally twice daily, and group 3 received loratadine 10 mg orally once daily. Subjective scores (numeric pain rating scale, douleur neuropathique 4, and functional assessment of cancer therapy/gynecologic oncology group-neurotoxicity (FACT/GOG-Ntx) scores), neuroinflammation biomarkers, adverse drug effects, quality of life, and response to chemotherapy were compared among the three groups. Both diosmin/hesperidin and loratadine improved the results of the neurotoxicity subscale in the FACT/GOG-Ntx score (p < 0.001, p < 0.01 respectively) and ameliorated the upsurge in neuroinflammation serum biomarkers. They also reduced the incidence and timing of paresthesia (p = 0.001 and p < 0.001, respectively) and dysuria occurrence (p = 0.042). Both loratadine and diosmin/hesperidin attenuated the intensity of acute neuropathy triggered by vinca alkaloids. Furthermore, they did not increase the frequency of adverse effects or interfere with the treatment response.

Neuroprotective effect of ranolazine improves behavioral discrepancies in a rat model of scopolamine-induced dementia

Background

Ranolazine (Rn), an antianginal agent, acts in the central nervous system and has been used as a potential treatment agent for pain and epileptic disorders. Alzheimer's disease (AD) is one of the most prevalent neurodegenerative diseases and the leading factor in dementia in the elderly.

Aim

We examined the impact of Rn on scopolamine (Sco)-induced dementia in rats.

Methods

Thirty-two albino male rats were divided into four groups: control, Rn, Sco, and Rn + Sco.

Results

A significant decrease in the escape latency in the Morris water maze test after pre-treatment with Rn explained better learning and memory in rats. Additionally, Rn significantly upregulated the activities of the antioxidant enzymes in the treated group compared to the Sco group but substantially reduced acetylcholinesterase activity levels in the hippocampus. Moreover, Rn dramatically reduced interleukin-1 β (IL-1β) and IL-6 and upregulated the gene expression of brain-derived neurotrophic factor (BDNF). Furthermore, in the Sco group, the hippocampal tissue's immunohistochemical reaction of Tau and glial factor activating protein (GFAP) was significantly increased in addition to the upregulation of the Caspase-3 gene expression, which was markedly improved by pre-treatment with Rn. The majority of pyramidal neurons had large vesicular nuclei with prominent nucleoli and appeared to be more or less normal, reflecting the all-beneficial effects of Rn when the hippocampal tissue was examined under a microscope.

Conclusion

Our findings indicated that Rn, through its antioxidative, anti-inflammatory, and anti-apoptotic effects, as well as the control of the expression of GFAP, BDNF, and Tau proteins, has a novel neuroprotective impact against scopolamine-induced dementia in rats.

Diosmin ameliorates LPS-induced depression-like behaviors in mice: Inhibition of inflammation and oxidative stress in the prefrontal cortex

Diosmin is a flavone glycoside with a confirmed therapeutic effectiveness on the chronic venous disorders. In this paper, the classical mouse depression model induced by LPS was established to explore the effect of Diosmin on depression. Firstly, we found that Diosmin could inhibit the inflammation and neuronal damage in the prefrontal cortex (PFC) of mice, and thus alleviating the LPS-induced depressive-like behaviors. Specifically, Diosmin treatment significantly suppressed the secretion of pro-inflammatory cytokines (TNF-α, IL-6 and IL-1β), reduced the activation of microglia, and inhibited the expression of NLRP3 inflammasome and its downstream effector caspase-1 in both PFC of mice and BV2 microglial cells exposed to LPS. Then, we demonstrated that pretreatment with Diosmin dramatically suppressed the LPS-induced oxidative stress in the PFC of mice, manifested in the decrease of reactive oxygen species and malondialdehyde while increase of catalase activity. Consistently, Diosmin also alleviated the oxidative stress in BV2 cells exposed to LPS. Finally, we confirmed that Diosmin effectively suppressed the activation of NF-κB signaling pathway in the PFC of LPS-treated mice. Further in vitro experiments also verified that Diosmin could prevent the p65 transposition to nucleus in LPS-treated BV2 cells, suggesting that the antidepressant effects of Diosmin are partially mediated by blocking of NF-κB signaling. Taken together, this study proposes the potential antidepressant effect of Diosmin, which provides useful support to the development of new therapies for depression.

Montelukast Ameliorates Scopolamine-induced Alzheimer's Disease: Role on Cholinergic Neurotransmission, Antioxidant Defence System, Neuroinflammation and Expression of BDNF

BACKGROUND

Alzheimer's disease (AD) is an overwhelming neurodegenerative disease with progressive loss of memory. AD is characterized by the deposition of the senile plaques mainly composed of β-amyloid (Aβ) fragment, BDNF decline, Cholinergic system overactivity and neuroinflammation. Montelukast (MTK), a leukotriene receptor antagonist, showed astounding neuroprotective effects in a variety of neurodegenerative disorders.

OBJECTIVE

This study aims to investigate the ameliorative effects of Montelukast in the scopolamineinduced Alzheimer's disease (AD) model in rats and evaluate its activity against neuroinflammation.

METHODS

Thirty rats were split into five groups: Control group (1 mL/kg normal saline, i.p.), Montelukast perse (10 mg/kg, i.p.), Disease group treated with Scopolamine (3 mg/kg, i.p.), Donepezil group (3 mg/kg, i.p.), Montelukast treatment group (10 mg/kg, i.p.) and behavioural and biochemical tests were carried out to assess the neuro protective effect.

RESULTS

Scopolamine treatment led to a significant reduction in learning and memory and an elevation in cholinesterase levels when compared with the control group (p < 0.01). Additionally, elevated oxidative stress and Amyloid-β levels were associated with enhanced neuroinflammation (p < 0.05, p < 0.01). Furthermore, the decline in neurotrophic factor BDNF is also observed when compared with the normal control group (p < 0.01). Montelukast pre-treatment significantly attenuated learning and memory impairment and cholinesterase levels. Besides, Montelukast and standard drug donepezil administration significantly suppressed the oxidative stress markers (p < 0.01), Amyloid-β levels, neuroinflammatory mediators (p < 0.05) and caused a significant increase in BDNF levels (p < 0.05).

CONCLUSION

Montelukast bestowed ameliorative effects in scopolamine-induced AD animal models as per the previous studies via attenuation of memory impairment, cholinesterase neurotransmission, oxidative stress, Amyloid-β levels, neuroinflammatory mediators and enhanced BDNF levels.

Endophytic fungi: a potential source for drugs against central nervous system disorders

Neuroprotection is one of the important protection methods against neuronal cells and tissue damage caused by neurodegenerative diseases such as Alzheimer's, Parkinson's, Huntington's, and multiple sclerosis. Various bioactive compounds produced by medicinal plants can potentially treat central nervous system (CNS) disorders. Apart from these resources, endophytes also produce diverse secondary metabolites capable of protecting the CNS. The bioactive compounds produced by endophytes play essential roles in enhancing the growth factors, antioxidant defence functions, diminishing neuroinflammatory, and apoptotic pathways. The efficacy of compounds produced by endophytic fungi was also evaluated by enzymes, cell lines, and in vivo models. Acetylcholine esterase (AChE) inhibition is frequently used to assess in vitro neuroprotective activity along with cytotoxicity-induced neuronal cell lines. Some of drugs, such as tacrine, donepezil, rivastigmine, galantamine, and other compounds, are generally used as reference standards. Furthermore, clinical trials are required to confirm the role of these natural compounds in neuroprotection efficacy and evaluate their safety profile. This review illustrates the production of various bioactive compounds produced by endophytic fungi and their role in preventing neurodegeneration.

Umbelliferone Ameliorates Memory Impairment and Enhances Hippocampal Synaptic Plasticity in Scopolamine-Induced Rat Model

Alzheimer's disease (AD) is a neurodegenerative disorder, characterized by memory loss and cognitive decline. Among the suggested pathogenic mechanisms of AD, the cholinergic hypothesis proposes that AD symptoms are a result of reduced synthesis of acetylcholine (ACh). A non-selective antagonist of the muscarinic ACh receptor, scopolamine (SCOP) induced cognitive impairment in rodents. Umbelliferone (UMB) is a Apiaceae-family-derived 7-hydeoxycoumarin known for its antioxidant, anti-tumor, anticancer, anti-inflammatory, antibacterial, antimicrobial, and antidiabetic properties. However, the effects of UMB on the electrophysiological and ultrastructure morphological aspects of learning and memory are still not well-established. Thus, we investigated the effect of UMB treatment on cognitive behaviors and used organotypic hippocampal slice cultures for long-term potentiation (LTP) and the hippocampal synaptic ultrastructure. A hippocampal tissue analysis revealed that UMB attenuated a SCOP-induced blockade of field excitatory post-synaptic potential (fEPSP) activity and ameliorated the impairment of LTP by the NMDA and AMPA receptor antagonists. UMB also enhanced the hippocampal synaptic vesicle density on the synaptic ultrastructure. Furthermore, behavioral tests on male SD rats (7-8 weeks old) using the Y-maze test, passive avoidance test (PA), and Morris water maze test (MWM) showed that UMB recovered learning and memory deficits by SCOP. These cognitive improvements were in association with the enhanced expression of BDNF, TrkB, and the pCREB/CREB ratio and the suppression of acetylcholinesterase activity. The current findings indicate that UMB may be an effective neuroprotective reagent applicable for improving learning and memory against AD.

Barbigerone prevents scopolamine-induced memory impairment in rats by inhibiting oxidative stress and acetylcholinesterase levels

The current study was designed for the evaluation of barbigerone on memory loss. In this experimental study, 24 Wistar rats (n = 6) were used. Control rats and scopolamine (SCOP)-treated control group rats were orally administered with 3 ml of 0.5% sodium carboxymethyl cellulose (vehicle), whereas barbigerone was (10 and 20 mg kg^-1) administered orally to the rats from the test group. During the 14-day treatment, control group rats were given 3 ml kg^-1 day^-1 saline, and all other groups were administered SCOP (1 mg kg^-1 day^-1, i.p.) 1 h after barbigerone p.o. treatment. The spontaneous alternation activities, learning capacities of a rat's memory were tested with Morris water maze and Y-maze. Reduced glutathione, malondialdehyde, acetylcholine esterase (AChE) and catalase (CAT) levels were measured in rat brain tissue as oxidative stress/antioxidant markers. Moreover, the levels of tumour necrosis factor, interleukin-6 (IL-6) and IL-1β were also estimated. Treatment with barbigerone in SCOP-administered rats dramatically reduced SCOP-induced neurobehavioural deficits, oxidative stress and neuroinflammatory markers, improved endogenous antioxidants, and restored AChE activity. By improving cholinergic function and reducing oxidative damage, barbigerone could mitigate the effects of SCOP-induced changes in the brain.

Diosmin-Loaded Nanoemulsion-Based Gel Formulation: Development, Optimization, Wound Healing and Anti-Inflammatory Studies

The wound-healing process is complex and prone to interruption or failure, which can result in the development of chronic wounds that never heal. This can be overcome by seeking prompt medical attention, which will reduce the likelihood of complications and speed up the healing of the cutaneous wound. It has been established that functionalized engineered biomaterials are a possible strategy for starting skin wound care. The purpose of the current study is to develop a diosmin (DSM)-loaded nanoemulsion (NE)-based gel formulation and to investigate its wound healing and anti-inflammatory activity on rats. The DSM-loaded NEs (F1-F17) were developed and optimized with the help of Box-Behnken Design Expert. The DSM-Nes were developed using lauroglycol 90 (LG90^®) as oil, Tween-80 as surfactant and transcutol-HP (THP) as co-surfactant. The optimized Nes showed globule size (41 ± 0.07 nm), polydispersity index (PDI) (0.073 ± 0.008) and percentage of entrapment efficiency (%EE) (87 ± 0.81%). This optimized DSM-loaded NEs (F1) was further evaluated and incorporated into 1% carbopol 940 gel. F1-loaded gel was then characterized for drug content, spreadability, in vitro release, wound healing, and anti-inflammatory studies. The developed gel of DSM was found to show significantly better (p < 0.05) wound-healing and anti-inflammatory activity.

Diosmin prophylaxis reduces gentamicin-induced kidney damage in rats

Gentamicin is an essential aminoglycoside antibiotic, but it is only used to treat severe bacterial infections due to its high nephrotoxicity in patients. We evaluated the preventive effects of diosmin (as a natural ingredient) on gentamicin-related kidney damage in rats. In this research, 28 male Wistar rats were divided into four groups: control, gentamicin (100 mg/kg (i.p.), daily for 1 week), gentamicin plus diosmin (50 mg/kg, p.o., daily for 2 weeks), and diosmin (50 mg/kg/day, p.o. for 2 weeks). After the final gavage, blood samples were collected for the determination of blood urea nitrogen (BUN) and creatinine. Kidneys are used for biochemical, inflammatory, and histological tests. The concentrations of creatinine, BUN, nitric oxide, malondialdehyde, tumor necrosis factor α (TNF-α), and interleukin 1 beta (IL-1β) were significantly increased. But, the level of glutathione and activities of catalase, glutathione peroxidase, and superoxide dismutase decreased during treatment with gentamicin. On the other hand, the concentrations of creatinine, BUN, nitric oxide, malondialdehyde, TNF-α, and IL-1β were significantly reduced, and the glutathione level, activities of catalase, and glutathione peroxidase were significantly increased via co-administration with diosmin. Diosmin had ameliorative impacts against gentamicin-related kidney injury due to its antioxidant and anti-inflammatory activities.

Diosmin and its glycocalyx restorative and anti-inflammatory effects on injured blood vessels

The endothelium, a crucial homeostatic organ, regulates vascular permeability and tone. Under physiological conditions, endothelial stimulation induces vasodilator endothelial nitric oxide (eNO) release and prevents adhesion molecule accessibility and leukocyte adhesion and migration into vessel walls. Endothelium dysfunction is a principal event in cardiovascular disorders, including atherosclerosis. Minimal attention is given to an important endothelial cell structure, the endothelial glycocalyx (GCX), a negatively charged heterogeneous polysaccharide that serves as a protective covering for endothelial cells and enables endothelial cells to transduce mechanical stimuli into various biological and chemical activities. Endothelial GCX shedding thus plays a role in endothelial dysfunction, for example by increasing vascular permeability and decreasing vessel tone. Consequently, there is increasing interest in developing therapies that focus on GCX repair to limit downstream endothelium dysfunction and prevent further downstream cardiovascular events. Here, we present diosmin (3',5,7-trihydroxy-4'-methoxyflavone-7-rhamnoglucoside), a flavone glycoside of diosmetin, which downregulates adhesive molecule expression, decreases inflammation and capillary permeability, and upregulates eNO expression. Due to these pleiotropic effects of diosmin on the vasculature, a possible unidentified mechanism of action is through GCX restoration. We hypothesize that diosmin positively affects GCX integrity along with GCX-related endothelial functions. Our hypothesis was tested in a partial ligation left carotid artery (LCA) mouse model, where the right carotid artery was the control for each mouse. Diosmin (50 mg/kg) was administered daily for 7 days, 72 h after ligation. Within the ligated mice LCAs, diosmin treatment elevated the activated eNO synthase level, inhibited inflammatory cell uptake, decreased vessel wall thickness, increased vessel diameter, and increased GCX coverage of the vessel wall. ELISA showed a decrease in hyaluronan concentration in plasma samples of diosmin-treated mice, signifying reduced GCX shedding. In summary, diosmin supported endothelial GCX integrity, to which we attribute diosmin's preservation of endothelial function as indicated by attenuated expression of inflammatory factors and restored vascular tone.

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.

Minocycline attenuates cholinergic dysfunction and neuro-inflammation-mediated cognitive impairment in scopolamine-induced Alzheimer's rat model

OBJECTIVE

Minocycline, a semisynthetic tetracycline-derived antibiotic, has various pharmacological effect such as anti-inflammatory, anti-oxidative stress, and anti-apoptotic effects. The current study investigated the involvement of neuro-inflammatory, oxidative stress, and cholinergic markers in neuroprotection by minocycline against scopolamine-induced brain damage.

METHODS

Minocycline was administered (oral, 10, 15, and 30 mg/kg, daily) to groups of amnesic rats for 21 days. Passive avoidance memory and spatial learning and memory were assessed. Following that, oxidative stress, cholinergic function, and neuro-inflammation markers were evaluated in the brain tissue.

RESULTS

According to our biochemical data, treatment of the scopolamine-injured rats with minocycline decreased the levels of malondialdehyde and acetylcholinesterase (AChE) as well as mRNA expression of AChE and neuro-inflammation markers (tumor necrosis factor-α, interleukin (IL)-1β, IL-6). It also increased the total thiol levels and superoxide dismutase activity as well as mRNA expression of cholinergic receptor M1 (ChRM1). Moreover, minocycline modified distance and latencies in Morris water maze, prolonged latency to enter the black zone and light time while decreasing time spent and frequency of entries to darkness.

CONCLUSION

Taken together, the data indicate that treatment with minocycline improved memory dysfunction mediated possibly through restoring AChE and ChRM1 levels, oxidant/antioxidant balance, as well as inhibiting inflammatory responses.

Resveratrol ameliorates learning and memory impairments induced by bilateral hippocampal injection of streptozotocin in mice

Resveratrol (RES) is a polyphenol with diverse beneficial pharmacological activities, and our previous results have demonstrated its neuroprotective potential. The purpose of this study was to investigate the therapeutic effect of RES in Alzheimer's disease (AD)-like behavioral dysfunction induced by streptozotocin (STZ) and explore it's potential mechanism of action. STZ was microinjected bilaterally into the dorsal hippocampus of C57BL/6J mice at a dose of 3 mg/kg, and RES was administered intragastrically at a dose of 25 mg/kg for 5 weeks. Neurobehavioral performance was observed, and serum concentrations of insulin and Nesfatin-1 were measured. Moreover, the protein expression of amyloid beta 1-42 (Aβ_1-42), Tau, phosphorylated Tau (p-Tau) (Ser396), synaptic ras GTPase activation protein (SynGAP), postsynaptic density protein 95 (PSD95), synapsin-1, synaptogomin-1, and key molecules of the Wnt/β-catenin signaling pathway in the hippocampus and prefrontal cortex (PFC) were assessed. Finally, pathological damage to hippocampal tissue was examined by Nissl and immunofluorescence staining. The results showed that compared with the controls, bilateral hippocampal microinjections of STZ induced task-specific learning and memory impairments, as indicated by the disadvantaged performances in the novel object recognition test (NOR) and Morris water maze (MWM), but not the contextual fear conditioning test (CFC). Treatment with RES could improve these behavioral disadvantages. The serum concentrations of insulin and Nesfatin-1 in the model group were remarkably higher than those of the control group. In addition, protein expression of Aβ_1-42, Tau, and p-Tau (Ser396) was increased but expression of SynGAP, PSD95, brain-derived neurotrophic factor (BDNF), and p-GSK-3β/GSK-3β were decreased in the hippocampus. Although the protein expression of BDNF and SynGAP was also markedly decreased in the PFC of the model mice, there was no significant difference among groups in the protein expression of PSD95, BDNF, synapsin-1, synaptogomin-1, and p-GSK-3β/GSK-3β. RES (25 mg/kg) reversed the enhanced insulin level, the abnormal protein expression of Aβ_1-42, Tau, and p-Tau (Ser396) in the hippocampus and PFC, and the hippocampal protein expression of SynGAP, PSD95 and BDNF. In addition, RES reversed the STZ-induced decrease in the number of Nissl bodies and the increase in fluorescence intensity of IBA1 in the hippocampal CA1 region. These findings indicate that RES could ameliorate STZ-induced AD-like neuropathological injuries, the mechanism of which could be partly related to its regulation of BDNF expression and synaptic plasticity-associated proteins in the hippocampus.

Potential of flavonoids as anti-Alzheimer's agents: bench to bedside

Developing therapies for neurodegenerative diseases are challenging because of the presence of blood-brain barrier and Alzheimer being one of the commonest and uprising neurodegenerative disorders possess the need for developing novel therapies. Alzheimer's is attributed to be the sixth leading cause of death in the USA and the number of cases is estimated to be increased from 58 million in 2021 to 88 million by 2050. Natural drugs have benefits of being cost-effective, widely available, fewer side effects, and immuno-booster can be useful in managing Alzheimer. Flavonoids can slow the neuronal degeneration as they have shown activity in central nervous system and are able to cross the blood-brain barrier. These can be easily extracted from fruits, vegetable, and plants. In Alzheimer disease, flavonoids scavenges the reactive oxygen species and reduces the production of amyloid beta protein. Agents from sub-classes of flavonoids such as flavanones, flavanols, flavones, flavonols, anthocyanins, and isoflavones having pharmacological action in treating Alzheimer disease are discussed in this review.

Mechanistic Insight into Diosmin-Induced Neuroprotection and Memory Improvement in Intracerebroventricular-Quinolinic Acid Rat Model: Resurrection of Mitochondrial Functions and Antioxidants

Neurodegeneration is the final event after a cascade of pathogenic mechanisms in several brain disorders that lead to cognitive and neurological loss. Quinolinic acid (QA) is an excitotoxin derived from the tryptophan metabolism pathway and is implicated in several ailments, such as Alzheimer's, Parkinson's, Huntington's, and psychosis disease. Diosmin (DSM) is a natural flavonoid possessing such properties that may halt the course of neurodegenerative progression. In past studies, free radical scavenging, along with properties, such as antihyperglycemic, anti-inflammatory, and vasoactive properties, of DSM were pragmatic. Hence, in the current experimentations, the neuroprotective activity of DSM was investigated in the QA rat prototype. QA was administered through the intracerebroventricular route (QA-ICV) in rats on day one, and DSM (50 and 100 mg/kg, intraperitoneal route) was given from day 1 to 21. Memory, gait, sensorimotor functions, and biomarkers of oxidative mutilation and mitochondrial functions were evaluated in the whole brain. Results showed significant deterioration of sensorimotor performance, gait, and working- and long-term memory in rats by QA-ICV. These behavioral anomalies were significantly attenuated by DSM (50 and 100 mg/kg) and donepezil (standard drug). QA-ICV-induced decrease in body mass (g), diet, and water ingestion were also attenuated by DSM or donepezil treatments. QA-ICV inhibited mitochondrial complex I and II activities that caused an increase in oxidative and nitrosative stress along with a reduction in endogenous antioxidants in the brain. DSM dose-dependently ameliorated mitochondrial functions and decreased oxidative stress in QA-ICV-treated rats. DSM can be a possible alternative in treating neurodegenerative disorders with underlying mitochondrial dysfunction pathology.

Chinese Herbal Extracts Exert Neuroprotective Effect in Alzheimer's Disease Mouse Through the Dopaminergic Synapse/Apoptosis Signaling Pathway

Background: Alzheimer's disease (AD) as an age-related, irreversible neurodegenerative disease, characterized by cognitive dysfunction, has become progressively serious with a global rise in life expectancy. As the failure of drug elaboration, considerable research effort has been devoted to developing therapeutic strategies for treating AD. TCM is gaining attention as a potential treatment for AD. Gastrodia elata Blume, Polygala tenuifolia Willd., Cistanche deserticola Ma, Rehmannia lutinosa (Gaertn.)DC., Acorus gramineus Aiton, and Curcuma longa L. (GPCRAC) are all well-known Chinese herbs with neuroprotective benefits and are widely used in traditional Chinese decoction for AD therapy. However, the efficacy and further mechanisms of GPCRAC extracts in AD experimental models are still unclear. The purpose of this study was to investigate the synergistic protective efficacy of GPCRAC extracts (composed of extracts from these six Chinese medicines), and the protein targets mediated by GPCRAC extracts in treating AD. Methods: Scopolamine-induced cognitive impairment mouse model was established to determine the neuroprotective effects of GPCRAC extracts in vivo, as shown by behavioral tests and cerebral cholinergic function assays. To identify the potential molecular mechanism of GPCRAC extracts against AD, label-free quantitative proteomics coupled with tandem mass spectrometry (LC-MS/MS) were performed. The integrated bioinformatics analysis was applied to screen the core differentially expressed proteins in vital canonical pathways. Critical altered proteins were validated by qPCR and Western blotting. Results: Administration of GPCRAC extracts significantly recovered scopolamine-induced cognitive impairment, as evidenced by the improved learning and memory ability, increased Ach content and ChAT activity, as well as decreased AchE activity in the hippocampus of mice. In total, 390 proteins with fold-change>1.2 or <0.83 and p < 0.05 were identified as significant differentially expressed proteins, of which 110 were significantly up-regulated and 25 were significantly down-regulated between control and model group. By mapping the significantly regulated proteins, we identified five hub proteins: PPP2CA, Gsk3β, PP3CC, PRKACA, and BCL-2 that were associated with dopaminergic synapse and apoptosis signaling pathway, respectively. Western blotting and QPCR demonstrate that the expression levels of these core proteins could be significantly improved by the administration of GPCRAC extracts. These pathways and some of the identified proteins are implicated in AD pathogenesis. Conclusion: Administration of GPCRAC extracts was effective on alleviating scopolamine-induced cognitive impairment, which might be through modulation of dopaminergic synapse and apoptosis signaling pathway. Consequently, our quantitative proteome data obtained from scopolamine-treated model mice successfully characterized AD-related biological alterations and proposed novel protein biomarkers for AD.

The potential neuroprotective effect of diosmin in rotenone-induced model of Parkinson's disease in rats

Most treatments for Parkinson's disease (PD) focus on improving the symptoms and the dopaminergic effects; nevertheless, they cannot delay the disease progression. Diosmin (DM), a naturally occurring flavone that is obtained from citrus fruits, has demonstrated anti-apoptotic, anti-inflammatory and antioxidative properties in many diseases. This study aimed to assess the neuroprotective effects of diosmin in rotenone-induced rat model of PD and investigate its potential underlying mechanisms. A preliminary dose-response study was conducted where rats were treated with DM (50,100 and 200 mg/kg, p.o.) concomitantly with rotenone (2 mg/kg, s.c.) for 4 weeks. Catalepsy, motor impairment, spontaneous locomotion, body weight, histological examination and tyrosine hydroxylase (TH) immunoreactivity were evaluated in both the midbrains and striata of rats. Treatment with DM (200 mg/kg) showed the most promising outcome therefore, it was selected for further evaluation of α-synuclein, Bax, Bcl2, nuclear factor kappa B (NF-кB), nuclear factor erythroid 2- related factor 2 (Nrf2), and heme oxygenase-1 (HO-1), in addition to biochemical analysis of tumor necrosis factor-α (TNF-α). Results showed that DM (200 mg/kg, p.o.) prevented rotenone-induced motor impairment, weight reduction and histological damage. Furthermore, it significantly inhibited rotenone-induced decrease in TH expression. These results were correlated with reduction in α-synuclein immunoreactivity, together with improvement of Bax/Bcl2 ratio compared to rotenone group. DM also attenuated rotenone-induced increase in NF-кB expression as well as TNF- α levels. Moreover, DM inhibited rotenone-induced upregulation of Nrf2/HO-1 pathway. Thus, the current study suggests that DM might be a promising candidate for managing the neuropathological course of PD.

Anti-Amnesic Effects of Epigallocatechin Gallate on Scopolamine-Induced Learning and Memory Dysfunction in Sprague-Dawley Rats

Epigallocatechin gallate (EGCG) is a major flavan-3-ol of green tea polyphenols that exhibits various beneficial health effects, including antioxidant, anti-bacterial, and anti-inflammatory properties. This study aimed to evaluate whether EGCG prevents scopolamine-induced learning and memory impairment in in vivo and ex vivo models. Male Sprague-Dawley (SD) rats were pre-treated with EGCG (5 mg/kg/day; intraperitoneal injection (i.p.)) for 10 days. Then, EGCG and scopolamine (1 mg/kg/day; i.p.) were applied 60 and 30 min before the behavioral tests, respectively, for another 9 days. EGCG alleviated the cognitive deficits in the Y-maze, passive avoidance, and Morris water maze tests. EGCG showed improved cholinergic functions by decreasing acetylcholinesterase activity in hippocampi dissected from the brain of the rats after the behavioral tests. EGCG also reduced oxidative stress, partly due to increased superoxide dismutase activity and decreased malondialdehyde level in the hippocampi of the rat brains after the behavioral tests. Furthermore, EGCG attenuated the scopolamine-induced blockade of long-term potentiation in organotypic hippocampal tissue of seven-day-old SD rats. Taken together, these results suggested that EGCG is a potential therapeutic agent for alleviating cognitive dysfunction.

Evaluation of analgesic, antiamnesic and antidiarrheal potentials of Medicago denticulata extract using animal model

The analgesic, antidiarrheal, and neuro-pharmacological potentials of Medicago denticulata leaves extract were screened in animal models. Potential analgesic response was noted (*P < 0.05, ^**P < 0.01, ^***P < 0.001) in formalin, acetic acid and heat-induced pain models in a dose-dependent manner. Maximum activity by means of writhing inhibition was documented for Medicago denticulata at 300 mg/kg that was found to be 71.79% (17.43 ± 1.31). In first phase, the Medicago denticulata at a dose of 150 and 300 mg/kg showed analgesic activity and reduced the pain by 54.18% (18.39 ± 1.67) and 62.90% (14.89 ± 1.56), respectively. In second phase, the Medicago denticulata at a dose of 150 and 300 mg/kg showed analgesic activity and reduced the pain by 69.48% (19.78 ± 1.44) and 70.89% (18.86 ± 1.58), respectively. In hot plate method, the Medicago denticulata at a dose of 150 and 300 mg/kg showed the maximum response of 61.16% (8.47 ± 1.23) and 67.39% (10.09 ± 1.04), respectively at 60 min. Scopolamine significantly reduces spontaneous alteration in Y-maze model for antiamnesic activity. Medicago denticulata significantly increased the discrimination index in a dose-dependent manner using novel object recognition test (NORT) model. Exploration time in sec for the novel object was increased significantly (P < 0.001) by donepezil decreased for familiar one with a discrimination index (DI) of 62.18%. Medicago denticulata significantly increased the discrimination index by 60.86% and 57.24% at 300 and 150 mg/kg b.w, respectively. The lowest DI of 53.80% at 75 mg/kg was observed in comparison to the amnesic group. The Medicago denticulata significant decreased the elevated levels of acetylcholinesterase (AChE) and malondialdehyde (MDA and enhancing level of acetylcholine (ACh), superoxide dismutase (SOD) and catalase (CAT) acting as an antioxidant agent. Medicago denticulata reduced the total number of diarrheal feces to lesser extent at dose-dependent manner. From the study results, it is suggested that the Medicago denticulata extract possess good analgesic and antiamnesic activity however the antidiarrheal effects of plant were negligible. In the current study, the traditional use of the plant as a source of medicine has been validated.

A new arylsulfanyl-benzo-2,1,3-thiadiazoles derivative produces an anti-amnesic effect in mice by modulating acetylcholinesterase activity

The aim of the present study was investigate the binding affinity of 5-((4-methoxyphenyl)thio)benzo[c][1,2,5]thiadiazole (MTDZ) with acetylcholinesterase (AChE). We also evaluated the effect of MTDZ against scopolamine (SCO)-induced amnesia in mice and we looked at the toxicological potential of this compound in mice. The binding affinity of MTDZ with AChE was investigated by molecular docking analyses. For an experimental model, male Swiss mice were treated daily with MTDZ (10 mg/kg, intragastrically (i.g.)) or canola oil (10 ml/kg, i.g.), and induced, 30 min later, with injection of SCO (0.4 mg/kg, intraperitoneally (i.p.)) or saline (0.9%, 5 ml/kg, i.p.) daily. From day 1 to day 10, mice were submitted to the behavioral tasks (Barnes maze, open-field, object recognition and location, Y-maze and step-down inhibitory avoidance tasks), 30 min after induction with SCO. On the tenth day, the animals were euthanized and blood was collected for the analysis of biochemical markers (creatinine, aspartate (AST), and alanine (ALT) aminotransferase). MTDZ interacts with residues of the AChE active site. SCO caused amnesia in mice by changing behavioral tasks. MTDZ treatment attenuated the behavioral changes caused by SCO. In ex vivo assay, MTDZ also protected against the alteration of AChE activity, reactive species (RS) levels, thiobarbituric acid reative species (TBARS) levels, catalase (CAT) activity in tissues, as well as in transaminase activities of plasma caused by SCO in mice. In conclusion, MTDZ presented anti-amnesic action through modulation of the cholinergic system and provided protection from kidney and liver damage caused by SCO.

Activating AhR alleviates cognitive deficits of Alzheimer's disease model mice by upregulating endogenous Aβ catabolic enzyme Neprilysin

Rationale: Neprilysin (NEP) is a major endogenous catabolic enzyme of amyloid β (Aβ). Previous studies have suggested that increasing NEP expression in animal models of Alzheimer's disease had an ameliorative effect. However, the underlying signaling pathway that regulates NEP expression remains unclear. The aryl hydrocarbon receptor (AhR) is a ligand-activated cytoplasmic receptor and transcription factor. Recent studies have shown that AhR plays essential roles in the central nervous system (CNS), but its physiological and pathological roles in regulating NEP are not entirely known.

Methods: Western blotting, immunofluorescence, quantitative RT-PCR and enzyme activity assay were used to verify the effects of AhR agonists on NEP in a cell model (N2a) and a mouse model (APP/PS1). Luciferase reporter assay and chromatin immunoprecipitation (ChIP) assay were conducted to investigate the roles of AhR in regulating NEP transcription. Object recognition test and the Morris water maze task were performed to assess the cognitive capacity of the mice.

Results: Activating AhR by the endogenous ligand L-Kynurenine (L-KN) or FICZ, or by the exogenous ligand diosmin or indole-3-carbinol (I3C) significantly increases NEP expression and enzyme activity in N2a cells and APP/PS1 mice. We also found that AhR is a direct transcription factor of NEP. Diosmin treatment effectively ameliorated the cognitive disorder and memory deficit of APP/PS1 transgenic mice. By knocking down AhR or using a small molecular inhibitor targeting AhR or NEP, we found that diosmin enhanced Aβ degradation through activated AhR and increased NEP expression.

Conclusions: These results indicate a novel pathway for regulating NEP expression in neurons and that AhR may be a potential therapeutic target for the treatment of Alzheimer's disease.

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.

Determination of Diosmin in Pharmaceutical Products with Chemically Modified Voltammetric Sensors

In this paper, the electrochemical behavior of two types of sensors based on modified screen-printed electrodes (one screen-printed electrode based on carbon (SPCE) and another screen-printed electrode modified with Prussian Blue (PB/SPCE)) was studied with the aim of sensitive detection of diosmin, an active pharmaceutical compound from the class of flavonoids. The scan electron microscopy technique was used for the morphological characterization of PB/SPCE. The preliminary analysis assessed the electrochemical behavior of SPCE and PB/SPCE in KCl solution and in a double solution of potassium ferrocyanide-potassium chloride. It was shown that the active area of PB/SPCE is superior to the one of SPCE, the greater sensitivity being related with the presence of the electroactive modifier. Similarly, in the case of diosmin detection, the PB/SPCE sensor detect more sensitivity the diosmin due to the electrocatalytic effect of PB. From the study of the influence of reaction rate on the sensor's electrochemical response, it was shown that the detection process is controlled by the adsorption process, the degree of surface coverage with electroactive molecules being higher in the case of PB/SPCE. From the PB/SPCE calibration curve, it wasdetermined that it has high sensitivity and low detection and quantification limit values (limit of detection 5.22 × 10^-8 M). The applicability of the PB/SPCE sensor was confirmed by sensitive analysis of diosmin in pharmaceutical products. The voltammetric method is suitable for the detection and quantification of diosmin in pharmaceutical products. The method is simple, accurate, and quick and can be used in routine analysis in the examination of the quality of pharmaceutical products and other types of samples.

Neuroprotective effects of quercetin produced by an endophytic fungus Nigrospora oryzae isolated from Tinospora cordifolia

AIMS

Alzheimer's disease is considered one of the most prevalent neurodegenerative disorders and dementia is the core symptom of this disease. This study was aimed to test the bioactive compounds produced by endophytic fungus for the inhibition of acetylcholinesterase (AChE) activity and to identify the compound responsible for this activity.

METHODS AND RESULTS

Endophytic fungi were isolated from the medicinal plant Tinospora cordifolia and screened for AChE inhibition and antioxidant activity. The extract of one of the isolates Nigrospora oryzae (GL15) showed maximum AChE inhibition as well as antioxidant activity. The compound responsible for AChE inhibition (fraction 3) was identified as quercetin based on UV, FTIR spectra, HPLC and ESI-MS analyses. Furthermore, the identification of quercetin in the extract of fraction 3 was confirmed by ¹ H NMR analysis. This extract showed anti-dementia-like activity in scopolamine (SCO) model. The minimal effective dose of the extract of fraction 3 modulated the SCO-provoked cognitive deficits such as impairments in spatial recognition memory and latency period in Y-maze test and passive avoidance test, respectively. The SCO-induced modulation in cholinergic pathway was ameliorated by the extract of N. oryzae in hippocampus, resulting in decrease in AChE activity and restoration of cytoarchitecture of hippocampus.

CONCLUSIONS

The bioactive compound quercetin produced by N. oryzae may cure the learning and memory shortfalls via AChE-mediated mechanism in experimental mice.

SIGNIFICANCE AND IMPACT OF THE STUDY

The endophytic fungus N. oryzae serves as a potential source for the bioactive compound quercetin, which plays an important role in the management of Alzheimer's disease.

Long-term administration of metformin ameliorates age-dependent oxidative stress and cognitive function in rats

BACKGROUND

Aging is an inevitable physiological process, associated with a decline in cognitive function. Recently, metformin, as the first-line treatment for type II diabetes, has been shown to increase the life expectancy of diabetic patients. Therefore, researchers are paying increasing attention to its anti-aging properties. Oxygen free radicals are responsible for oxidative stress, which is a prominent factor in age-associated diseases. This study aimed to evaluate the effects of long-term administration of metformin on age-dependent oxidative stress and cognitive function.

METHODS

In this experimental study, 32 normal (nondiabetic) male Wistar rats were randomly assigned into control and metformin groups (n = 16 per group). The metformin group received 100 mg/kg of metformin in drinking water daily for six months. The shuttle box test was used for the passive avoidance task in 24-month-old rats. For the biochemical assay, the total antioxidant capacity (TAC) and malondialdehyde (MDA) level were measured. Nissl and TUNEL staining were also used for histopathological assessments. Data were analyzed using independent t-test.

RESULTS

The present findings revealed that metformin significantly reduced the MDA level and increased the TAC in the hippocampus of the metformin group (p < 0.05). The survival of hippocampal CA1 neurons was significantly higher in the metformin group as compared to the control group, while the number of TUNEL-positive neurons decreased significantly (p < 0.05). On the other hand, metformin markedly improved the passive avoidance memory in the metformin group as compared to the control group (p < 0.05).

CONCLUSION

It can be concluded that long-term metformin intake, by modulating the oxidant/antioxidant mechanisms, prevents the loss of hippocampal neurons caused by age-dependent oxidative stress and improves memory.

Scrophularia buergeriana Extract (Brainon) Improves Scopolamine-Induced Neuronal Impairment and Cholinergic Dysfunction in Mice through CREB-BDNF Signaling Pathway

We evaluated the effectiveness of Scrophularia buergeriana extract (Brainon) on cognitive dysfunction and determined its underlying mechanisms in a scopolamine (SCO)-treated mouse model of memory impairment. Brainon treatment for 28 days ameliorated the symptoms of memory impairment as indicated by the results of both passive avoidance performance and the Morris water mazes. Brainon lowered acetylcholinesterase activity and raised acetylcholine levels in the hippocampus. The treatment elevated the protein levels of brain-derived neurotrophic factor (BDNF) and phosphorylated cAMP response element-binding (CREB). Additionally, the excessive generation of SCO-induced reactive oxygen species (ROS) and subsequent oxidative stress were suppressed by the enhancement of superoxide dismutase (SOD)-1 and SOD-2 proteins. mRNA levels of upregulated interleukin (IL)-1β, IL-6, and tumor necrosis factor (TNF)-α, as well as the apoptotic protein Bcl-2-associated X protein (Bax), cleaved caspase-9, and cleaved poly adenosine diphosphate-ribose polymerase (PARP) expression after SCO injection were downregulated by Brainon treatment. Collectively, these findings suggested that Brainon possesses anti-amnesic effects through the CREB-BDNF pathway. Moreover, it exerted antioxidant, anti-inflammatory, and anti-apoptotic effects in SCO-induced mice exhibiting cognitive impairment and memory loss.

Disposable Pencil Graphite Electrode for Diosmin Voltammetric Analysis

Diosmin (DIO) is a naturally occurring flavonoid with multiple beneficial effects on human health. The presence of different hydroxyl groups in diosmin structure enables its electrochemical investigation and quantification. This work presents, for the first time, diosmin voltammetric behavior and quantification on the cost-effective, disposable pencil graphite electrode (PGE). Diosmin oxidation on PGE involves two irreversible steps, generating products with reversible redox behaviors. All electrode processes are pH-dependent and predominantly adsorption-controlled. Differential pulse (DPV) and adsorptive stripping differential pulse (AdSDPV) voltammetric methods have been optimized for diosmin quantification o an H-type PGE, in 0.100 mol/L H₂SO₄. The linear ranges and limits of detection were for DPV 1.00 × 10^-6-1.00 × 10^-5 mol/L and 2.76 × 10^-7 mol/L DIO for DPV and 1.00 × 10^-7-2.50 × 10^-6 mol/L and 7.42 × 10^-8 mol/L DIO for AdSDPV, respectively. The DPV method was successfully applied for diosmin quantification in dietary supplement tablets. The percentage recovery was 99.87 ± 4.88%.

A mechanistic view on the neurotoxic effects of air pollution on central nervous system: risk for autism and neurodegenerative diseases

Many reports have shown a strong association between exposure to neurotoxic air pollutants like heavy metal and particulate matter (PM) as an active participant and neurological disorders. While the effects of these toxic pollutants on cardiopulmonary morbidity have principally been studied, growing evidence has shown that exposure to polluted air is associated with memory impairment, communication deficits, and anxiety/depression among all ages. So, these toxic pollutants in the environment increase the risk of neurodegenerative disease, ischemia, and autism spectrum disorders (ASD). The precise mechanisms in which air pollutants lead to communicative inability, social inability, and declined cognition have remained unknown. Various animal model studies show that amyloid precursor protein (APP), processing, oxidant/antioxidant balance, and inflammation pathways change following the exposure to constituents of polluted air. In the present review study, we collect the probable molecular mechanisms of deleterious CNS effects in response to various air pollutants.

Thymus vulgaris Essential Oil Protects Zebrafish against Cognitive Dysfunction by Regulating Cholinergic and Antioxidants Systems

Thymus vulgaris L. is an aromatic herb used for medicinal purposes such as antimicrobial, spasmolytic, antioxidant, anti-inflammatory, antinociceptive, antitumor, and may have beneficial effects in the treatment of Alzheimer’s disease. The present study aimed to investigate whether Thymus vulgaris L. essential oil enhances cognitive function via the action on cholinergic neurons using scopolamine (Sco)-induced zebrafish (Danio rerio) model of memory impairments. Thymus vulgaris L. essential oil (TEO, 25, 150, and 300 µL/L) was administered by immersion to zebrafish once daily for 13 days, whereas memory impairment was induced by Sco (100 μM), a muscarinic receptor antagonist, delivered 30 min before behavioral tests. Spatial memory was assessed using the Y-maze test and novel object recognition test (NOR). Anxiety and depression were measured in the novel tank diving test (NTT). Gas Chromatograph-Mass Spectrometry (GC-MS) analysis was used to study the phytochemical composition of TEO. Acetylcholinesterase (AChE) activity and oxidative stress response in the brain of zebrafish were determined. TEO ameliorated Sco-induced increasing of AChE activity, amnesia, anxiety, and reduced the brain antioxidant capacity. These results suggest that TEO may have preventive and/or therapeutic potentials in the management of memory deficits and brain oxidative stress in zebrafish with amnesia.

Effect of Glycyrrhizic Acid on Scopolamine-Induced Cognitive Impairment in Mice

Purpose

Cognitive impairment is one of the main symptoms of Alzheimer disease and other dementias. Glycyrrhiza uralensis is a natural product that has a protective effect against cognitive impairment. In this study, we investigated whether glycyrrhizic acid, among the main bioactive components of Glycyrrhiza uralensis, has a neuroprotective effect on scopolamine-induced cognitive impairment.

Methods

Twenty-week-old male Institute of Cancer Research mice were used in this study. The scopolamine-induced cognitive impairment mice model was used. Glycyrrhizic acid was orally administered to mice once daily for 21 days, while scopolamine (1 mg/kg) treatment was delivered 30 minutes before behavioral tests. Donepezil (2 mg/kg) was used as a positive drug control. To evaluate the effect of glycyrrhizic acid, the following assessments were performed on hippocampal tissue: Y-maze test, acetylcholinesterase activity, antioxidant enzymes’ activity (superoxide dismutase, catalase). Western blotting for phosphor-extracellular signal-regulated kinase, P38, and c-Jun NH2-terminal kinase was conducted.

Results

We found that glycyrrhizic acid administration significantly improved scopolamine-induced cognitive impairment in the Y-maze test. The acetylcholinesterase activity, superoxide dismutase, and catalase activity in the glycyrrhizic acid-treated group showed a significant reversal of cognitive impairment compared with the scopolamine-treated group.

Conclusions

Our results suggest that glycyrrhizic acid has a neuroprotective effect on cognitive function in scopolamine-induced cognitive impairment.

Role of phytochemicals as nutraceuticals for cognitive functions affected in ageing

Cognitive decline can occur with normal ageing and in age-related brain disorders, such as mild cognitive impairment and dementia, including Alzheimer's disease, with limited pharmacological therapies available. Other approaches to reduce cognitive decline are urgently needed, and so, the role of dietary interventions or nutraceuticals has received much attention in this respect. In this review, we examine the evidence for dietary plants and their chemical constituents as nutraceuticals, relevant to both cognitive decline in normal ageing and in dementia. Pharmacological (in vitro and in vivo), clinical and epidemiological evidence is assessed for both frequently consumed plants and their dietary forms, including tea, coffee, cocoa (chocolate), red wine, grapes, citrus and other fruits; in addition to plants used less frequently in certain diets and those that cross the blurred boundaries between foods, nutraceuticals and medicinal plants. For the latter, turmeric, saffron, sage, rosemary and lemon balm are examples of those discussed. LINKED ARTICLES: This article is part of a themed section on The Pharmacology of Nutraceuticals. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v177.6/issuetoc.

Metabolism and pharmacological activities of the natural health-benefiting compound diosmin

Diosmin is a famous natural flavonoid for treating chronic venous insufficiency and varicose veins.

Polyphenolic Profiling, Quantitative Assessment and Biological Activities of Tunisian Native Mentha rotundifolia (L.) Huds

Phenolic profiling of ten plant samples of Mentha rotundifolia (L.) Huds. collected from different bioclimatic areas of Tunisia, was for the first time carried out by using a fast ultra-high-performance liquid chromatography (UHPLC)-high resolution tandem mass spectrometry (HRMS/MS) method on a Q Exactive platform equipped with an electrospray ionization (ESI) source. An intraspecific, interpopulation variability was evidenced and a total of 17 polyphenolic metabolites were identified and quantified by using the UHPLC-HRESIMS/MS method, here validated for specificity, linearity, limit of detection, limit of quantitation, accuracy and precision. The quantitative method resulted sensitive at the nM level and reliable for rapid polyphenol quantification in vegetal matrices. The metabolomic study allowed us to identify a new compound, named salvianolic acid W, which was isolated and characterized mainly by NMR and MS analysis. A statistical correlation of the phenolic composition with antioxidant and anti-acetylcholinesterase activities was provided.