Protective effects of isofraxidin against scopolamine-induced cognitive and memory impairments in mice involve modulation of the BDNF-CREB-ERK signaling pathway

Neuroprotective potential of isofraxidin: Alleviating parkinsonian symptoms, inflammation and microglial activation

Background

Parkinson's disease (PD) is one of the most common neurodegenerative disorders. Previous research has confirmed that isofraxidin can reduce macrophage expression and inhibit peripheral inflammation. However, its effects on the central nervous system remain underexplored.

Objective

This study aims to determine whether isofraxidin offers protective effects against PD.

Methods

To assess the effects of isofraxidin, motor performance changes in LPS-induced PD mice were evaluated using rotarod, pole-climbing, and beam-walking tests. Striatal damage was examined through [18F]fluorodeoxyglucose ([18F]FDG) positron emission tomography (PET) imaging, and dopaminergic neurotoxicity was assessed using tyrosine hydroxylase (TH) staining. Microglial accumulation and activation were monitored with Iba-1 staining, while LPS-induced inflammation was examined via TNF-α and IL-1β staining.

Results

Isofraxidin pre-treatment significantly improved LPS-induced motor dysfunction, as evidenced by better performance in the rotarod, pole-climbing, and beam-walking tests. [18F]FDG PET imaging showed that isofraxidin restored glucose uptake in the striatum, countering LPS-induced damage. Furthermore, Iba-1 staining revealed that isofraxidin markedly inhibited LPS-induced microglial activation and accumulation. TNF-α and IL-1β staining indicated a reduction in inflammation with isofraxidin treatment. Additionally, TH staining supported the neuroprotective role of isofraxidin on dopaminergic neurons.

Conclusions

Isofraxidin exhibits notable neuroprotective properties by mitigating LPS-induced parkinsonian behaviors, microglial activation, inflammation, and dopaminergic neuron damage. These results highlight isofraxidin's potential as a therapeutic intervention for PD.

Dexmedetomidine Improves Learning Functions in Male Rats Modeling Cognitive Impairment by Modulating the BDNF/TrkB/CREB Signaling Pathway

Dexmedetomidine (DEX) is a selective alpha-2 adrenergic receptor agonist with sedative and anxiolytic properties. Increasing evidence reports that DEX has a neuroprotective effect. In this study, we investigated the potential effects of DEX on learning and memory functions in rats with experimental cognitive impairment. In the study, 21 adult male rats were used. The rats were divided into three groups, namely control, Scopolamine (SCOP) and SCOP + DEX. Cognitive impairment was induced with 1 mg/kg SCOP daily for 21 days. DEX was administered at a dose of 10 µg/kg between days 14 and 21 of the experiment. Following the injections, a spatial memory test was performed with a Morris Water Maze (MWM). At the end of the experiment, the hippocampus was dissected. The brain-derived neurotrophic factor (BDNF), acetylcholine (ACh) and acetylcholinesterase (AChE) levels were determined by ELISA. The tropomyosin receptor kinase B (TrkB) and Cyclic AMP-Response Element-Binding Protein (CREB) levels were measured by immunohistochemistry. DEX treatment improved the learning performance of rats compared to SCOP for 5 days. However, it did not significantly change memory performance. DEX increased the BDNF and ACh levels in the hippocampus while decreasing the AChE levels. Similarly, DEX treatment significantly increased CREB phosphorylation. No significant difference was observed between the TrkB receptor levels of the groups. This study demonstrated that the role of DEX in reducing SCOP-induced cognitive impairment is partially mediated by the increase in BDNF/TrkB/CREB signaling pathway activity.

Optimization and Chemical Characterization of Extracts Obtained from Ferula persica var. latisecta Aerial Parts and Roots and Their Neuroprotective Evaluation

BACKGROUND/OBJECTIVES

The genus Ferula has been traditionally used for the treatment of various illnesses, but the potential of Ferula persica var. latisecta against different Alzheimer's disease (AD) hallmarks has never been achieved.

METHODS

In this work, a pressurized liquid extraction (PLE) method was optimized to extract F. persica L. aerial parts and roots. Four different solvents (water, ethanol, ethyl acetate (EtAc), and cyclopentyl methyl ether (CPME)) were first tested, and the extraction yield, total phenolic content, reactive oxygen species scavenging capacity, and acetylcholinesterase (AChE) inhibition activity were evaluated.

RESULTS

The results indicated that EtAc and CPME were the best solvents to be used, with the results obtained from the aerial parts being better than those obtained from the root samples. Thereafter, the PLE method was further optimized by combining these solvents in different percentages (100% EtAc, 100% CPME, and 50:50% (v/v) EtAc:CPME) and temperatures (50, 115, and 180 °C). Response surface methodology was then applied to analyze the data, and two optimum extraction conditions were obtained: EtAc:CPME (79:21%) at 180 °C for the aerial parts and 100% CPME at 180 °C for the roots. At these conditions, the total flavonoid content (TFC) and the inhibitory capacities against butyrylcholinesterase (BChE) and lipoxygenase (LOX) enzymes were also evaluated, indicating that the aerial part extracts had higher TFC and LOX inhibitory capacity than the root extracts but lower activity against BChE. The comprehensive LC/GC-MS chemical characterization allowed for the tentative identification of 222 compounds belonging to 66 chemical subclasses, the abundancies of which widely varied depending on the matrix and the extraction conditions used.

CONCLUSIONS

The results obtained together with the application of advanced statistical analysis and molecular docking simulations suggested several sesquiterpenoids, such as selina-3,7(11)-diene, guaiol acetate, α-cyperone, and farnesyl acetate, as the molecules responsible of the in vitro results observed, with good neuroprotective potential against AD.

DAPK1 mediates cognitive dysfunction and neuronal apoptosis in PSD rats through the ERK/CREB/BDNF signaling pathway

Post-stroke depression (PSD) is one of the most common mental sequelae after a stroke and can damage the brain. Although PSD has garnered increasing attention in recent years, the precise mechanism remains unclear. Studies have indicated that the expression of DAPK1 is elevated in various neurodegenerative conditions, including depression, ischemic stroke, and Alzheimer's disease. However, the specific molecular mechanism of DAPK1-mediated cognitive dysfunction and neuronal apoptosis in PSD rats is unclear. In this study, we established a rat model of PSD, and then assessed depression-like behaviors and cognitive dysfunction in rats using behavioral tests. In addition, we detected neuronal apoptosis and analyzed the expression of DAPK1 protein and proteins related to the ERK/CREB/BDNF signaling pathway. The findings revealed that MCAO combined with CUMS can induce more severe depression-like behaviors and cognitive dysfunction in rats, while overexpression of DAPK1 may hinder the downstream ERK/CREB/BDNF signaling pathways, resulting in neuronal loss and exacerbation of brain tissue damage. In this study, we will focus on DAPK1 and explore its role in PSD.

The coumarin component isofraxidin targets the G-protein-coupled receptor S1PR1 to modulate IL-17 signaling and alleviate ulcerative colitis

OBJECTIVE

The increasing global prevalence of ulcerative colitis (UC) underscores the imperative to explore novel therapeutic approaches. Traditional Chinese medicine has historically shown potential in addressing this ailment. The current study aimed to elucidate the functional attributes and underlying mechanisms of isofraxidin, a coumarin derivative from Acanthopanax, in the context of UC.

METHODS

A murine model of dextran sodium sulfate (DSS)-induced UC was established, and we conducted a comprehensive assessment of the influence of isofraxidin on UC symptomatology, colonic histopathological manifestations, the inflammatory response, and apoptosis. The potential receptor of isofraxidin was initially identified through the Target database and molecular docking analysis. Subsequent in vivo and in vitro experiments were conducted to determine the effects of isofraxidin on the identified receptor and associated signaling pathways. Transfection was used to examine the receptor's role in the regulatory mechanism of isofraxidin.

RESULTS

Isofraxidin reduced UC symptoms and colonic histopathological impairments. Furthermore, isofraxidin ameliorated the DSS-induced inflammatory response and apoptosis in tissues. S1PR1 was identified as a target of isofraxidin and effectively suppressed activation of the IL-17 signaling pathway. Intriguingly, cellular experiments indicated that overexpression of S1PR1 counteracted the protective effect of isofraxidin.

DISCUSSION

In summary, our investigation revealed that isofraxidin could modulate S1PR1 and regulate the IL-17 signaling pathway, thus ameliorating DSS-induced UC. These findings establish a robust foundation for considering isofraxidin as a prospective therapeutic intervention to treat UC.

Protective effect of a hydromethanolic extract from Fraxinus excelsior L. bark against a rat model of aluminum chloride-induced Alzheimer's disease: Relevance to its anti-inflammatory and antioxidant effects

ETHNOPHARMACOLOGICAL RELEVANCE

Fraxinus excelsior L. (FE), commonly known as the ash, belongs to the Oleaceae family and has shown several pharmacological and biological properties, such as antioxidant, immunomodulatory, neuroprotective, and anti-inflammatory effects. It has also attracted the most attention toward neuroinflammation. Moreover, FE bark and leaves have been used to treat neurological disorders, aging, neuropathic pain, urinary complaints, and articular pain in traditional and ethnomedicine. Alzheimer's disease (AD) is a multifactorial neurodegenerative disorder resulting from the involvement of amyloid-beta, metal-induced oxidative stress, and neuroinflammation.

AIM OF THE STUDY

The objective of the current study was to assess the neuroprotective effects of hydromethanolic extract from FE bark in an AlCl3-induced rat model of AD.

MATERIALS AND METHODS

The maceration process was utilized to prepare the hydromethanolic extract of FE bark, and characterized by LC-MS/MS. To assess the anti-AD effects of the FE extract, rats were categorized into five different groups, AlCl3; normal control; FE-treated groups at 50, 100, and 200 mg/kg. Passive avoidance learning test, Y-maze, open field, and elevated plus maze behavioral tests were evaluated on days 7 and 14 to analyze the cognitive impairments. Zymography analysis, biochemical tests, and histopathological changes were also followed in different groups.

RESULTS

LC-MS/MS analysis indicated the presence of coumarins, including isofraxidin7-O-diglucoside in the methanolic extract of FE as a new isofraxidin derivative in this genus. FE significantly improved memory and cognitive function, maintained weight, prevented neuronal damages, and preserved the hippocampus's histological features, as demonstrated by behavioral tests and histopathological analysis. FE increased anti-inflammatory MMP-2 activity, whereas it decreased that of inflammatory MMP-9. Moreover, FE increased plasma antioxidant capacity by enhancing CAT and GSH while decreasing nitrite levels in the serum of treated groups. In comparison between the treated groups, the rats that received high doses of the FE extract (200 mg/kg) showed the highest therapeutic effect.

CONCLUSION

FE rich in coumarins could be an effective anti-AD adjunct agent, passing through antioxidant and anti-inflammatory pathways. These results encourage further studies for the development of this extract as a promising agent in preventing, managing, or treating AD and related diseases.

Betanin mitigates scopolamine-induced cognitive impairment by restoring cholinergic function, boosting brain antioxidative status, and increasing BDNF level in the zebrafish model

Betalains obtained from Beta vulgaris (family Caryophyllales) are regularly consumed as part of the regular diet with medicinal benefits due to antioxidant and anti-inflammatory properties. The objective of this article was to evaluate betanin's neuroprotective properties in a scopolamine-induced zebrafish paradigm. Betanin (BET) (50, 100, and 200 mg/L), and donepezil (10 mg/L) were delivered to zebrafish in a treatment tank once a day for 8 days, while memory impairment was produced by scopolamine (100 µM), which was given 60 min before behavioral assessments. The treatment dosages were determined based on acute toxicity studies. The existence of betacyanin and betaxanthins of BET was tested using liquid chromatography-mass spectrometry (LC-MS). The Y-maze task was used to examine the novelty and spatial memory, while the novel tank diving test was used to assess anxiety-like behavior (NTT). The activities of acetylcholinesterase (AChE) and the oxidative stress sensitivity in zebrafish brains were examined. Also, brain-derived neurotrophic factor (BDNF) level is quantified by an ELISA kit. Scopolamine-induced rises in AChE activity, memory loss, anxiety, and brain oxidant capacity were all reduced by BET. These results suggest that BET (50 and 100 mg/L) has a therapeutic ability to treat brain oxidative stress and cognitive deficits in amnesic zebrafish.