Protective Effects of Baicalin on Aβ₁₋₄₂-Induced Learning and Memory Deficit, Oxidative Stress, and Apoptosis in Rat

Therapeutic Potential of Polyphenols in Cellular Reversal of Patho-Mechanisms of Alzheimer's Disease Using In Vitro and In Vivo Models: A Comprehensive Review

Alzheimer's disease (AD) is considered one of the most common neurological conditions associated with memory and cognitive impairment and mainly affects people aged 65 or above. Even with tremendous progress in modern neuroscience, a permanent remedy or cure for this crippling disease is still unattainable. Polyphenols are a group of naturally occurring potent compounds that can modulate the neurodegenerative processes typical of AD. The present comprehensive study has been conducted to find out the preclinical and clinical potential of polyphenols and elucidate their possible mechanisms in managing AD. Additionally, we have reviewed different clinical studies investigating polyphenols as single compounds or cotherapies, including those currently recruiting, completed, terminated, withdrawn, or suspended in AD treatment. Natural polyphenols were systematically screened and identified through electronic databases including Google Scholar, PubMed, and Scopus based on in vitro cell line studies and preclinical data demonstrating their potential for neuroprotection. A total of 63 significant polyphenols were identified. A multimechanistic pathway for polyphenol's mode of action has been proposed in the study. Out of 63, four potent polyphenols have been identified as promising potential candidates, based on their reported clinical efficacy. Polyphenols hold tremendous scope for the development of a future drug molecule as a phytopharmaceutical that may be incorporated as an adjuvant to the therapeutic regime. However, more high-quality studies with novel delivery methods and combinatorial approaches are required to overcome obstacles such as bioavailability and blood-brain barrier crossing to underscore the therapeutic potential of these compounds in AD management.

The Effect of Zeolite Zinc on Memory Performance and Hippocampal Cell Death in a Rat Model of Alzheimer's-like Disease Induced by Aβ1-42

Alzheimer's disease (AD) is one of the most common neurodegenerative disorders, characterized by the slow and progressive loss of brain structure and function, primarily affecting older individuals. Evidence has shown that disruption of zinc homeostasis in the brain contributes to synaptic dysfunction, as well as impairments in learning and memory. In this study, we evaluated the effect of zeolite zinc on memory performance and hippocampal cell death in a rat model of Alzheimer's disease (AD) induced by intracerebroventricular administration of Aβ1-42. We employed the Morris water maze, shuttle box, and open field tests to assess spatial memory, passive avoidance memory, and anxiety-like behavior, respectively. P-Tau and the amyloid precursor protein (APP) expression, along with hippocampal cell death, were also evaluated. Both Aβ1-42 and zeolite zinc were injected intracerebroventricularly. The results showed that zeolite zinc partially reversed Aβ1-42-induced impairments in memory performance and mitigated the effects of Aβ1-42 on locomotor activity, although it did not fully restore baseline levels. In addition, Aβ1-42 increased the expression of APP and P-Tau, as well as the number of dead cells, whereas zeolite zinc reduced these effects. In conclusion, our findings suggest that while zeolite zinc plays a role in modulating the pathophysiology of AD, its therapeutic effects only partially reverse the progression or symptoms of AD, indicating the need for further investigation into optimal dosing or combination therapies.

Mitigating neurodegenerative diseases: the protective influence of baicalin and baicalein through neuroinflammation regulation

Neurodegenerative diseases (NDDs) represent a category of serious illnesses characterized by the progressive deterioration of neuronal structure and function. The exploration of natural compounds as potential therapeutic agents has gained increasing attention in recent years owing to their wide range of pharmacological activities and minimal side effects. Baicalin (BAI) and baicalein (BE), polyphenolic flavonoids, derived from the root of Scutellaria baicalensis, evidently show potential in treating NDDs. This review provides an overview of the current understanding of the roles of BAI and BE in alleviating neuroinflammation, a pivotal pathological process implicated in various NDDs. Studies conducted prior to clinical trials have shown that BAI and BE exert protective effects on the nervous system in different animal models of NDDs. Furthermore, mechanistic studies indicate that BAI and BE exert anti-inflammatory effects by inhibiting pro-inflammatory cytokines, suppressing microglial activation, and regulating microglial phenotypes. These effects are mediated through the modulation of inflammatory signaling cascades, including Toll-like receptor 4 (TLR4), mitogen-activated protein kinase (MAPK), amp-activated protein kinase (AMPK), NOD-like receptor thermal protein domain-associated protein 3 (NLRP3) inflammasome, and nuclear factor erythroid 2-related factor 2 (Nrf2)/hemoglobin oxygenase-1 (HO-1). Overall, BAI and BE exhibit promising potential as natural compounds with anti-inflammatory properties and offer innovative therapeutic approaches for managing NDDs.

Nanoformulated fisetin ameliorates Alzheimer's disease via reducing proinflammatory cytokines and activating the NRF2/HO-1 pathway

Aim: The study aimed to evaluate the neuroprotective effect of a chitosan-coated fisetin nanoformulation in an experimental Alzheimer's disease (AD) model, focusing on improving fisetin's pharmacokinetics and exploring its impact on both brain and colon pathology.Materials & methods: AD was induced in mice by intracerebroventricular administration of Aβ1-42. Mice were treated with either fisetin or a fisetin nanoformulation (5 mg/kg/day, orally) for 21 days. Behavioural assessments were conducted to evaluate memory impairment, motor deficits, and depression-like behaviour. Oxidative stress markers and pro-inflammatory cytokines were measured in the cortex, hippocampus and colon. The changes in cortical and hippocampal AChE levels were also recorded. Histological studies were performed on the cortex, hippocampus (dentate gyrus), and proximal colon.Results: The fisetin nanoformulation significantly improved neurobehavioral outcomes, reducing memory impairment, motor deficits and depression-like symptoms induced by Aβ1-42. It also decreased oxidative and nitrosative stress, along with pro-inflammatory cytokine levels in the cortex, hippocampus and colon. Histological analyses revealed improved brain and colon tissue architecture after treatment with the nanoformulation.Conclusion: The chitosan-coated fisetin nanoformulation enhanced the neuroprotective effects of fisetin in an AD model, likely by improving its pharmacokinetic profile. The findings also suggest a potential link between colon health and Aβ-induced AD pathology, underscoring the therapeutic potential of fisetin nanoformulations in AD management.

Different amyloid β42 preparations induce different cell death pathways in the model of SH-SY5Y neuroblastoma cells

Amyloid β42 (Aβ42) plays a decisive role in the pathology of Alzheimer's disease. The Aβ42 peptide can aggregate into various supramolecular structures, with oligomers being the most toxic form. However, different Aβ species that cause different effects have been described. Many cell death pathways can be activated in connection with Aβ action, including apoptosis, necroptosis, pyroptosis, oxidative stress, ferroptosis, alterations in mitophagy, autophagy, and endo/lysosomal functions. In this study, we used a model of differentiated SH-SY5Y cells and applied two different Aβ42 preparations for 2 and 4 days. Although we found no difference in the shape and size of Aβ species prepared by two different methods (NaOH or NH4OH for Aβ solubilization), we observed strong differences in their effects. Treatment of cells with NaOH-Aβ42 mainly resulted in damage of mitochondrial function and increased production of reactive oxygen species, whereas application of NH4OH-Aβ42 induced necroptosis and first steps of apoptosis, but also caused an increase in protective Hsp27. Moreover, the two Aβ42 preparations differed in the mechanism of interaction with the cells, with the effect of NaOH-Aβ42 being dependent on monosialotetrahexosylganglioside (GM1) content, whereas the effect of NH4OH-Aβ42 was independent of GM1. This suggests that, although both preparations were similar in size, minor differences in secondary/tertiary structure are likely to strongly influence the resulting processes. Our work reveals, at least in part, one of the possible causes of the inconsistency in the data observed in different studies on Aβ-toxicity pathways.

Effect of baicalin and baicalin-bovine serum albumin nanoparticle against bendiocarb exposure in rats

Background

The aim of the study was to investigate the effect of baicalin and baicalin-bovine serum albumin nanoparticles against bendiocarb exposure in rats.

Methods

Eighty male Wistar Albino rats aged 4-6 weeks were used. Corn oil (vehicle) alone was administered to the control group. To other groups, BSA-nanoparticle equivalent to that binding baicalin at a dose of 20 mg/kg.bw, 20 mg/kg.bw baicalin, baicalin-BSA nanoparticle equivalent to that binding baicalin at a dose of 20 mg/kg.bw, 4 mg/kg.bw bendiocarb, combination of 4 mg/kg.bw bendiocarb and 20 mg/kg.bw baicalin, combination of 4 mg/kg.bw bendiocarb and BSA-nanoparticle equivalent to that binding baicalin at a dose of 20 mg/kg.bw and combination of 4 mg/kg.bw bendiocarb and baicalin-BSA nanoparticle equivalent to that binding baicalin at a dose of 20 mg/kg.bw was administered to animals by oral gavage with vehicle for 21 days, after which organs (liver, kidney, brain, testes, heart and lung) and blood samples were collected. Blood/tissue oxidative stress (MDA, NO, GSH, SOD, CAT, GSH-Px, GR, GST, G6PD), serum biochemical (glucose, triglyceride, cholesterol, BUN, creatinine, uric acid, total protein, albumin, LDH, AST, ALT, ALP and pseudocholinesterase) and liver and kidney apoptotic/anti-apoptotic (caspase 3, 9, p53, Bcl-2 and Bax) parameters were evaluated. Body weights/organ weights and plasma/liver bendiocarb analyses were obtained.

Conclusion

While bendiocarb administered alone caused oxidative stress/tissue damage, baicalin and baicalin-BSA nanoparticle showed a mitigating effect. However, this effect was more pronounced in the baicalin-BSA nanoparticle group. BSA-nanoparticle alone did not have a significant effect in reversing the adverse effect caused by bendiocarb.

Upregulation of Nrf2 signaling: A key molecular mechanism of Baicalin's neuroprotective action against diabetes-induced cognitive impairment

BACKGROUND AND AIM

Diabetes-associated cognitive impairment (DCI) is a prevalent complication of diabetes. However, there is a lack of viable strategies for preventing and treating DCI. This study aims to explore the efficacy of baicalin (Bai) in attenuating DCI and elucidating the underlying mechanisms.

EXPERIMENTAL PROCEDURE

GK rats fed a high-fat and high-glucose diet were utilized to investigate the therapeutic potential of Bai. Cognitive function was assessed using the Morris water maze and novel object recognition tests. To gain insight into the molecular mechanisms underlying Bai's neuro-protective effects, co-cultured BV2/HT22 cells were established under high-glucose (HG) stimulation. The modes of action of Bai were subsequently confirmed in vivo using the DCI model in db/db mice.

KEY RESULTS

Bai restored cognitive and spatial memory and attenuated neuron loss, along with reducing expressions of Aβ and phosphorylated Tau protein in diabetic GK rats. At the cellular level, Bai exhibited potent antioxidant and anti-inflammatory effects against HG stimulation. These effects were associated with the upregulation of Nrf2 and supressed Keap1 levels. Consistent with these in vitro findings, similar mechanisms were observed in db/db mice. The significant neuroprotective effects of Bai were abolished when co-administered with ATRA, a Nrf2 blocker, in db/db mice, confirming that KEAP1-Nrf2 signaling pathway was responsible for the observed effect.

CONCLUSIONS AND IMPLICATIONS

Bai demonstrates a great therapeutic potential for attenuating DCI. The antioxidant defense and anti-inflammatory actions of Bai were mediated through the KEAP1-Nrf2 axis. These findings advance our understanding of potential treatment approaches for DCI, a common complication associated with diabetes.

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.

Research Progress on Natural Plant Molecules in Regulating the Blood-Brain Barrier in Alzheimer's Disease

Alzheimer's disease (AD) is a prevalent neurodegenerative disorder. With the aging population and the continuous development of risk factors associated with AD, it will impose a significant burden on individuals, families, and society. Currently, commonly used therapeutic drugs such as Cholinesterase inhibitors, N-methyl-D-aspartate antagonists, and multiple AD pathology removal drugs have been shown to have beneficial effects on certain pathological conditions of AD. However, their clinical efficacy is minimal and they are associated with certain adverse reactions. Furthermore, the underlying pathological mechanism of AD remains unclear, posing a challenge for drug development. In contrast, natural plant molecules, widely available, offer multiple targeting pathways and demonstrate inherent advantages in modifying the typical pathologic features of AD by influencing the blood-brain barrier (BBB). We provide a comprehensive review of recent in vivo and in vitro studies on natural plant molecules that impact the BBB in the treatment of AD. Additionally, we analyze their specific mechanisms to offer novel insights for the development of safe and effective targeted drugs as well as guidance for experimental research and the clinical application of drugs for the prevention and treatment of AD.

Antiplatelet drugs: Potential therapeutic options for the management of neurodegenerative diseases

The blood platelet plays an important role but often remains under-recognized in several vascular complications and associated diseases. Surprisingly, platelet hyperactivity and hyperaggregability have often been considered the critical risk factors for developing vascular dysfunctions in several neurodegenerative diseases (NDDs) like Alzheimer's disease, Parkinson's disease, Huntington's disease, and multiple sclerosis. In addition, platelet structural and functional impairments promote prothrombotic and proinflammatory environment that can aggravate the progression of several NDDs. These findings provide the rationale for using antiplatelet agents not only to prevent morbidity but also to reduce mortality caused by NDDs. Therefore, we thoroughly review the evidence supporting the potential pleiotropic effects of several novel classes of synthetic antiplatelet drugs, that is, cyclooxygenase inhibitors, adenosine diphosphate receptor antagonists, protease-activated receptor blockers, and glycoprotein IIb/IIIa receptor inhibitors in NDDs. Apart from this, the review also emphasizes the recent developments of selected natural antiplatelet phytochemicals belonging to key classes of plant-based bioactive compounds, including polyphenols, alkaloids, terpenoids, and flavonoids as potential therapeutic candidates in NDDs. We believe that the broad analysis of contemporary strategies and specific approaches for plausible therapeutic treatment for NDDs presented in this review could be helpful for further successful research in this area.

Therapeutic Effects of Baicalin on Diseases Related to Gut-Brain Axis Dysfunctions

The gut-brain axis is an active area of research. Several representative diseases, including central nervous system disorders (Alzheimer's disease, Parkinson's disease, and depression), metabolic disorders (obesity-related diseases), and intestinal disorders (inflammatory bowel disease and dysbiosis), are associated with the dysfunctional gut-brain axis. Baicalin, a bioactive flavonoid extracted from Scutellaria baicalensis, is reported to exert various pharmacological effects. This narrative review summarizes the molecular mechanisms and potential targets of baicalin in disorders of the gut-brain axis. Baicalin protects the central nervous system through anti-neuroinflammatory and anti-neuronal apoptotic effects, suppresses obesity through anti-inflammatory and antioxidant effects, and alleviates intestinal disorders through regulatory effects on intestinal microorganisms and short-chain fatty acid production. The bioactivities of baicalin are mediated through the gut-brain axis. This review comprehensively summarizes the regulatory role of baicalin in gut-brain axis disorders, laying a foundation for future research, although further confirmatory basic research is required.

Oxidative Stress Contributes to Inflammatory and Cellular Damage in Systemic Lupus Erythematosus: Cellular Markers and Molecular Mechanism

Systemic lupus erythematosus (SLE) is a multifactorial autoimmune disease with complex pathogenesis, the treatment of which relies exclusively on the use of immunosuppressants. Increased oxidative stress is involved in causing inflammatory and cellular defects in the pathogenesis of SLE. Various inflammatory and cellular markers including oxidative modifications of proteins, lipids, and DNA contribute to immune system dysregulation and trigger an aggressive autoimmune attack through molecular mechanisms like enhanced NETosis, mTOR pathway activation, and imbalanced T-cell differentiation. Accordingly, the detection of inflammatory and cellular markers is important for providing an accurate assessment of the extent of oxidative stress. Oxidative stress also reduces DNA methylation, thus allowing the increased expression of affected genes. As a result, pharmacological approaches targeting oxidative stress yield promising results in treating patients with SLE. The purpose of this review is to examine the involvement of oxidative stress in the pathogenesis and management of SLE.

An interventional study of baicalin on neuronal pentraxin-1, neuronal pentraxin-2, and C-reactive protein in Alzheimer's disease rat model

Background

Baicalin has been shown to promote spatial learning and neural regeneration, which might increase the differentiation of neural stem cells in Alzheimer's disease (AD) rat models. We aimed to study the role of baicalin on neuronal pentraxin-1 (NPTX-1), neuronal pentraxin-2 (NPTX-2), and C-reactive protein (CRP) in AD model rats.

Methods

The 30 male Sprague Dawley rats were divided into three groups: the control group, the AD model group, and the AD + baicalin group. Then, the Morris water maze was used to verify the effect of baicalin on the memory and spatial learning of rats. Immunohistochemistry and immunofluorescence were used to observe the expression of NPTX-1, NPTX-2, and CRP in brain tissue.

Results

Compared with the AD model group, the AD rats treated with baicalin spent significantly less time finding escape latencies (P = 0.008) and had longer cross-platform times in the target quadrant (P = 0.015). In addition, the AD + baicalin group had significantly higher numbers of hippocampal neurons compared with the AD model group (P < 0.05). Baicalin also obviously decreased the apoptosis of neurons. Moreover, compared with the AD model group, the NPTX-1 and CRP expression in the AD + baicalin group was significantly reduced (P = 0.000) while the expression of NPTX-2 in the brain tissue of AD rats was significantly increased (P = 0.000).

Conclusions

Baicalin can play a therapeutic role by downregulating NPTX-1, upregulating NPTX-2, and downregulating CPR in AD model rats.

Screening of the active Ingredients in Huanglian Jiedu decoction through amide bond-Immobilized magnetic nanoparticle-assisted cell membrane chromatography

Introduction: The Huanglian Jiedu decoction (HLJDD) is a Chinese herbal formula that exerts neuroprotective effects by alleviating oxidative stress injuries and may potentially be prescribed for treating Alzheimer's disease; however, its active ingredients have not yet been identified. Cell membrane chromatography is a high-throughput method for screening active ingredients, but traditional cell membrane chromatography requires multiple centrifugation steps, which affects its separation efficiency. Magnetic nanoparticles are unparalleled in solid-liquid separation and can overcome the shortcomings of traditional cell membrane chromatography. Methods: In this study, the neuroprotective effects of the components of HLJDD were screened through a novel magnetic nanoparticle-assisted cell membrane chromatography method. Magnetic nanoparticles and cell membranes were stably immobilized by amide bonds. Magnetic bead (MB)-immobilized cell membranes of HT-22 cells were incubated with the HLJDD extract to isolate specific binding components. The specific binding components were then identified by ultraperformance liquid chromatography (UPLC)-Orbitrap Fusion Tribrid MS after solid-phase extraction. The bioactivity of these components was analyzed in an HT-22 cellular model of glutamate-induced injury. Results and Discussion: The preparation method of the composite of cell membrane and MBs has the advantages of simple preparation and no introduction of toxic organic reagents. MBs not only provide support for cell membranes, but also greatly improve the separation efficiency compared with traditional cell membrane chromatography. Fifteen of these components were found to specifically bind to the cell membranes, and seven of them were confirmed to reduce varying degrees of glutamate-induced toxicity in HT-22 cells. In conclusion, our findings suggest that the amide bond-based immobilization of magnetic nanoparticles on cell membranes, along with solid-phase extraction and UPLC, is an effective method for isolating and discovering the bioactive components of traditional Chinese medicines.

Scutellaria baicalensis and its constituents baicalin and baicalein as antidotes or protective agents against chemical toxicities: a comprehensive review

Scutellaria baicalensis (SB), also known as the Chinese skullcap, has a long history of being used in Chinese medicine to treat a variety of conditions ranging from microbial infections to metabolic syndrome and malignancies. Numerous studies have reported that treatment with total SB extract or two main flavonoids found in its root and leaves, baicalin (BA) and baicalein (BE), can prevent or alleviate the detrimental toxic effects of exposure to various chemical compounds. It has been shown that BA and BE are generally behind the protective effects of SB against toxicants. This paper aimed to review the protective and therapeutic effects of SB and its main components BA and BE against chemical compounds that can cause intoxication after acute or chronic exposure and seriously affect different vital organs including the brain, heart, liver, and kidneys. In this review paper, we had a look into a total of 221 in vitro and in vivo studies from 1995 to 2021 from the scientific databases PubMed, Scopus, and Web of Science which reported protective or therapeutic effects of BA, BE, or SB against drugs and chemicals that one might be exposed to on a professional or accidental basis and compounds that are primarily used to simulate disease models. In conclusion, the protective effects of SB and its flavonoids can be mainly attributed to increase in antioxidants enzymes, inhibition of lipid peroxidation, reduction of inflammatory cytokines, and suppression of apoptosis pathway.

Postnatal baicalin ameliorates behavioral and neurochemical alterations in valproic acid-induced rodent model of autism: The possible implication of sirtuin-1/mitofusin-2/ Bcl-2 pathway

Autism spectrum disorder (ASD) is characterized by pervasive impairments in social communication along with repetitive or stereotyped behaviors. Although its distinctive etiology isn`t completely understood, genetic and environmental risk factors were incriminated. Being a flavonoid of high biomedical value, baicalin was recently verified as an emerging medicinal herb with numerous pharmacological activities. The objective of this study was to investigate the feasible effects of baicalin on valproic acid (VPA)-induced autism regarding its potential mitochondrial modulatory, antioxidant, and antiapoptotic effects. The present study was performed using a rodent model of autism by exposing rat fetuses to VPA on the 12.5th day of gestation. Ten male Wistar rats that were born from control pregnant females were considered as group I (control group). Twenty male Wistar rats that were born from prenatal VPA- treated females were further divided into two groups: Group II (VPA- induced ASD) and group III (VPA + Baicalin). Postnatal baicalin promoted postnatal growth and maturation. In addition, it improved motor development and ameliorated repetitive behavior as well as social deficits in prenatally exposed VPA rats. Moreover, baicalin enhanced neuronal mitochondrial functions as evidenced by elevation of mitochondrial adenosine triphosphate (ATP) level and promotion of mitofusin-2 expression. Furthermore, baicalin elevated sirtuin-1 (SIRT1) level in VPA rats' brain tissues and restored the antioxidant defense mechanisms. Besides, it abrogated the neuronal histopathological changes in the brain tissues. Based on the data herein, baicalin may provide a promising pre-clinical therapeutic line in ASD as a mitochondrial function modulator, antioxidant and anti-apoptotic agent.

Erigeron breviscapus (Vant.) Hand-Mazz.: A Promising Natural Neuroprotective Agent for Alzheimer's Disease

Alzheimer’s disease (AD) is the most common neurodegenerative disease and is characterized by progressive cognitive dysfunction and memory loss in the elderly, which seriously affects the quality of their lives. Currently, the pathogenesis of AD remains unclear. Molecular biologists have proposed a variety of hypotheses, including the amyloid-β hypothesis, tau hyperphosphorylation hypothesis, cholinergic neuron injury, inflammation caused by an abnormal immune response, and gene mutation. Drugs based on these pathological studies, including cholinesterase inhibitors and N-methyl-D-aspartate receptor antagonists, have achieved a certain level of efficacy but are far from meeting clinical needs. In the recent years, some important advances have been made in the traditional Chinese medicine treatment of AD. Erigeron breviscapus (Vant.) Hand-Mazz. (EBHM) is an important medicinal plant distributed in Yunnan Province, China. Studies have shown that EBHM and its active ingredients have a variety of pharmacological effects with good therapeutic effects and wide application prospects for cognitive disability-related diseases. However, to our best knowledge, only few review articles have been published on the anti-AD effects of EBHM. Through a literature review, we identified the possible pathogenesis of AD, discussed the cultivation and phytochemistry of EBHM, and summarized the pharmacological mechanism of EBHM and its active ingredients in the treatment of AD to provide suggestions regarding anti-AD therapy as well as a broader insight into the therapeutic potential of EBHM.

Network Pharmacology and Molecular Docking-Based Strategy to Investigate the Multitarget Mechanisms of Shenqi Yizhi Granule on Alzheimer's Disease

Background

Traditional Chinese herbal medicine draws more attention to explore an effective therapeutic strategy for Alzheimer's disease (AD). Shenqi Yizhi granule (SQYG), a Chinese herbal recipe, has been applied to ameliorate cognitive impairment in mild-to-moderate AD patients. However, the overall molecular mechanism of SQYG in treating AD has not been clarified.

Objective

This study aimed to investigate the molecular mechanism of SQYG on AD using an integration strategy of network pharmacology and molecular docking.

Methods

The active compounds of SQYG and common targets between SQYG and AD were screened from databases. The herb-compound network, compound-target network, and protein-protein interaction network were constructed. The enrichment analysis of common targets and molecular docking were performed.

Results

816 compounds and 307 common targets between SQYG and AD were screened. KEGG analysis revealed that common targets were mainly enriched in lipid metabolism, metal ion metabolism, IL-17 signaling pathway, GABA receptor signaling, and neuroactive ligand-receptor interaction. Molecular docking analysis showed high binding affinity between ginsenoside Rg1 and Aβ _1-42, tanshinone IIA and BACE1, baicalin, and AchE.

Conclusions

The therapeutic mechanisms of SQYG on AD were associated with regulating lipid metabolism, metal ion metabolism, IL-17 signaling pathway, and GABA receptor signaling. Ginsenoside Rg1, tanshinone IIA, baicalin, astragaloside IV, and folic acid may play an important role in AD treatment.

Baicalin Attenuated Aβ1-42-Induced Apoptosis in SH-SY5Y Cells by Inhibiting the Ras-ERK Signaling Pathway

Alzheimer's disease (AD) is a serious neurodegenerative disease. It is widely believed that the accumulation of amyloid beta (Aβ) in neurons around neurofibrillary plaques is the main pathological characteristic of AD; however, the molecular mechanism underlying these pathological changes is not clear. Baicalin is a flavonoid extracted from the dry root of Scutellaria baicalensis Georgi. Studies have shown that baicalin exerts excellent anti-inflammatory and neuroprotective effects. In this study, an AD cell model was established by exposing SH-SY5Y cells to Aβ_1-42 and treating them with baicalin. Cell survival, cell cycle progression, and apoptosis were measured by MTT, flow cytometry, and immunofluorescence assays, respectively. The expression levels of Ras, ERK/ERK phosphorylation (p-ERK), and cyclin D1 were measured by Western blotting. In addition, whether the MEK activator could reverse the regulatory effect of baicalin on Ras-ERK signaling was investigated using Western blotting. We found that baicalin improved the survival, promoted the proliferation, and inhibited the apoptosis of SH-SY5Y cells after Aβ_1-42 treatment. Baicalin also ameliorated Aβ_1-42-induced cell cycle arrest at the S phase and induced apoptosis. Furthermore, baicalin inhibited the levels of Ras, p-ERK, and cyclin D1 induced by Aβ, and this effect could be reversed by the MEK activator. Therefore, we suggest that baicalin may regulate neuronal cell cycle progression and apoptosis in Aβ_1-42-treated SH-SY5Y cells by inhibiting the Ras-ERK signaling pathway. This study suggested that baicalin might be a useful therapeutic agent for senile dementia, especially AD.

Baicalin attenuates amyloid β oligomers induced memory deficits and mitochondria fragmentation through regulation of PDE-PKA-Drp1 signalling

RATIONALE

Mitochondrial fragmentation contributes to the initiation of Alzheimer's disease (AD) pathology. Baicalin plays a significant role in rescuing mitochondrial dysfunction. However, the effect of baicalin treatment on the modulation of mitochondrial fragmentation has not yet been assessed.

OBJECTIVES

The present study was designed to evaluate the effect of baicalin on memory and understand its mechanism of action.

RESULTS

Baicalin treatment significantly reversed the altered learning and memory behaviours in AD mouse model. We found that baicalin treatment significantly improved the levels of microtubule association protein-2 and enhanced the expression of synaptophysin and postsynaptic density protein 95 (PSD95). Moreover, treatment with baicalin reversed amyloid-β oligomer (AβO)-induced abnormalities in the succinate dehydrogenase complex iron sulphur subunit B (SDHB) and cytochrome c oxidase components I (COXI) and mitochondrial fragmentation in the hippocampus. Further, we found that baicalin decreased the PDE4 levels and upregulated the levels of phosphorylated Ser157 site of vasodilator-stimulated phosphoprotein (pVASP^s157) and phosphorylated Ser637 site of mitochondrial dynamin-related protein 1 (pDrp1^S637). Moreover, in AβO-treated HT-22 cells, H89 inhibited the effect of baicalin on PSD95, mitochondrial fragmentation, SDHB and COXI, PDE4, pVASP^s157, and pDrp1^S637.

CONCLUSION

The effect of baicalin on memory improvement may be due to improved synaptic plasticity, mitochondrial fragmentation, and rescue of dysfunction via the inhibition of PDE4, which leads to activation of pDrp1^S637 in the AβO-induced model.

Cilostazol induces angiogenesis and regulates oxidative stress in a dose-dependent manner: A chorioallantoic membrane study

Background

In this study, we aimed to investigate the effects of cilostazol on angiogenesis and oxidative stress using the chorioallantoic membrane model.

Methods

In this experimental study, the Ross 308 chick embryos were used. The negative control group (n=10) received no intervention. The positive control group (n=10) consisted of eggs treated with epidermal growth factor for inducing angiogenesis. Three cilostazol groups were designed with 10-7 (n=10), 10-6 (n=10), and 10-5 (n=10) M concentrations. Each egg was punctured on the sixth day of incubation, and drug pellets were introduced to the positive control and drug groups at the prespecified doses. Vascular development was evaluated on the eighth day of application. The total oxidant status, total antioxidant capacity, and oxidative stress index levels were determined from albumen liquids obtained with a syringe before and after drug application.

Results

Lower oxidative stress index levels were obtained from the positive control and cilostazol groups compared to the negative control albumens (p=0.001). The increments in vascular junctions and newly developed vascular nodules were evaluated in drug-free and drug-applied chorioallantoic membranes. The highest activity was obtained in the 10-7 M concentration cilostazol group. An increased angiogenic activity was detected in all drug groups in each concentration compared to the negative control group (p=0.001). Angiogenic activity was similar in all the cilostazol-treated groups (p=0.43).

Conclusion

Cilostazol has a positive stimulant effect on angiogenesis and it seems to suppress oxidative stress during embryonic growth. Cilostazol exerts these effects significantly and similarly at different doses.

Exposure to footshock stress downregulates antioxidant genes and increases neuronal apoptosis in an Aβ(1-42) rat model of Alzheimer's disease

Post-traumatic stress disorder (PTSD) is a neuropsychiatric disorder that develops from exposure to trauma, mostly when normal psychological mechanisms fail. Studies have shown that people who have PTSD are susceptible to developing dementia, mostly Alzheimer's disease (AD), suggesting common underlying risk factors in the comorbidity. However, data elucidating links between these conditions is scarce. Here we show that footshock stress exacerbates AD-like pathology. To induce a trauma-like condition, the rats were exposed to multiple intense footshocks followed by a single reminder. This was followed by bilateral intrahippocampal lesions with amyloid-beta (Aβ) (1-42), to model AD-like pathology. We found that footshocks increased anxiety behavior and impaired fear memory extinction in Aβ(1-42) lesioned rats. We also found a reduced expression of nuclear factor erythroid 2-related factor 2 (Nrf2), NAD (P) H: quinone oxidoreductase 1 (NQO1), heme oxygenase-1 (HO-1), and an increased expression of Kelch-like ECH-associated protein 1 (Keap1) in the amygdala and hippocampus. Furthermore, oxidative stress level was sustained, which was associated with increased apoptosis in the amygdala and hippocampus. Our finding suggests that AD-like pathology can induce oxidative changes in the amygdala and hippocampus, which can be exaggerated by footshock stress.

Thioredoxin-interacting protein (TXNIP) as a target for Alzheimer's disease: flavonoids and phenols

Alzheimer's disease (AD) is a neurodegenerative disease characterized by amyloid plaques and tangles that have become the fifth leading cause of death worldwide. Previous studies have found that thioredoxin interacting protein (TXNIP) expression was increased during the development of AD neurons. TXNIP separates from the TXNIP-thioredoxin complex, and the TXNIP-NLRP3 complex assembles ASC and pro-caspase-1 to form the NLRP3 inflammasome, which triggers AD inflammation and apoptosis. CB-dock was used to explore whether 21 natural flavonoids and phenols target TXNIP based on references. Docking results showed that rutin, puerarin, baicalin, luteolin and quercetin are the most potent TXNIP inhibitors, and among them, rutin as the most effective flavonoid. And rosmarinic acid is the most potent TXNIP inhibitor of phenols. These phytochemicals could be helpful to find the lead compounds in designing and developing novel agents for Alzheimer's disease.

Role of natural plant products against Alzheimer's disease

Alzheimer's disease (AD) is one of the major neurodegenerative disorder. Deposition of amyloid fibrils and tau protein are associated with various pathological symptoms. Currently limited medication is available for AD treatment. Most of the drugs are basically cholinesterase inhibitors and associated with various side effects. Natural plant products have shown potential as a therapeutic agent for the treatment of AD symptoms. Variety of secondary metabolites like flavonoids, tannins, terpenoids, alkaloids and phenols are used to reduce the progression of the disease. Plant products have less or no side effect and are easily available. The present review gives a detailed account of the potential of natural plant products against the AD symptoms.

The involvement of NLRP3 inflammasome in the treatment of Alzheimer's disease

Alzheimer's disease (AD) is one of the most common neurodegenerative diseases, and it is characterised by progressive deterioration in cognitive and memory abilities, which can severely influence the elderly population's daily living abilities. Although researchers have made great efforts in the field of AD, there are still no well-established strategies to prevent and treat this disease. Therefore, better clarification of the molecular mechanisms associated with the onset and progression of AD is critical to provide a theoretical basis for the establishment of novel preventive and therapeutic strategies. Currently, it is generally believed that neuroinflammation plays a key role in the pathogenesis of AD. Inflammasome, a multiprotein complex, is involved in the innate immune system, and it can mediate inflammatory responses and pyroptosis, which lead to neurodegeneration. Among the various types of inflammasomes, the NLRP3 inflammasome is the most characterised in neurodegenerative diseases, especially in AD. The activation of the NLRP3 inflammasome causes the generation of caspase-1-mediated interleukin (IL)-1β and IL-18 in microglia cells, where neuroinflammation is involved in the development and progression of AD. Thus, the NLRP3 inflammasome is likely to be a crucial therapeutic molecular target for AD via regulating neuroinflammation. In this review, we summarise the current knowledge on the role and regulatory mechanisms of the NLRP3 inflammasome in the pathogenic mechanisms of AD. We also focus on a series of potential therapeutic treatments targeting NLRP3 inflammasome for AD. Further clarification of the regulatory mechanisms of the NLRP3 inflammasome in AD may provide more useful clues to develop novel AD treatment strategies.

Anti-inflammatory and immunomodulatory effects of baicalin in cerebrovascular and neurological disorders

Inflammatory responses play an extraordinary role in the pathogenesis of cerebrovascular and neurological disorders. Baicalin is one of the important flavonoids, which is extracted from Scutellaria baicalensis Georgi. Recently, numerous in vivo and in vitro studies have shown that baicalin has salutary effects for anti-inflammatory and immunomodulatory and has been demonstrated to exert beneficial therapeutic properties in cerebrovascular and neurological diseases. In this review, we aim to discuss that baicalin exerts anti-inflammatory effects through multiple pathways and targets, thus affecting the production of a variety of inflammatory cytokines and neuroprotective process of neurological diseases; furthermore, the related targets of the anti-inflammatory effects of baicalin were analyzed via using the tools of network pharmacology, to provide theoretical basis and innovative ideas for the future clinical application of baicalin.

Active form of vitamin D analogue mitigates neurodegenerative changes in Alzheimer's disease in rats by targeting Keap1/Nrf2 and MAPK-38p/ERK signaling pathways

BACKGROUND

The nuclear factor erythroid2-related factor2 (Nrf2), a chief transcriptional regulator of antioxidant response element (ARE), is considered a promising target for the prevention of Alzheimer's disease (AD). Vitamin D has been recognized to have a crucial role in improving AD cognitive functions. The present study was conducted to evaluate the effects of active vitamin D analogue, Maxacalcitol, on Keap1-Nrf2 signaling pathway in experimental Alzheimer's disease in rats.

MATERIALS AND METHODS

The study was conducted on thirty female white albino rats divided equally into 3 groups: control group, Alzheimer group induced by Lipopolysaccharide and Alzheimer group treated with active vitamin D3 analogue, Maxacalcitol. The following parameters were assessed in rat brain tissues: Gene expression of Nrf2, Keap1 and MAF by RT-PCR, protein levels of phosphorylated MAPK-38p and ERK1/2 by Western Blot Technique, estimation of HO-1, Amyloid β, p-Tau levels and serum levels of TNFα, IL-10 and total 25-hydroxyvitamin D, serum calcium levels, GSH and MDA levels were also estimated in addition to cognitive function tests and histo-pathological examination of rat brain tissues.

RESULTS

In Alzheimer group, there was a significant deficit in cognition along with down-regulation of gene expression of Nrf2 and the protein levels of its downstream antioxidant effectors (HO-1 and GSH) with increased levels of the lipid peroxidation biomarker MDA. Also, there was increased neuro-inflammation as evidenced by increased levels of TNFα and decreased levels of IL-10. Moreover, there were increased amyloid β load and enhanced levels of phosphorylation of MAPK-38 and ERK1/2 leading to hyperphosphorylation of Tau protein. In addition, there were decreased serum levels of both total 25-hydroxyvitamin D and calcium. Treatment with vitamin D3 analogue, Maxacalcitol significantly improved cognitive dysfunction and histopathological picture of the brains of Alzheimer rats. Also, Vitamin D analogue significantly increased expression of Nrf2 and its downstream effectors (HO-1 and GSH), improved serum levels of total 25-hydroxyvitamin D and calcium, decreased neuro-inflammation and Amyloid β load as well as hyperphosphorylation of MAPK-38, ERK1/2 and tau proteins were also observed. Therefore, these data suggest that vitamin D analogue, Maxacalcitol could be used as a therapeutic agent in treatment of Alzheimer disease.

Neuroprotective Effect of New Nanochelating-Based Nano Complex, ALZc3, Against Aβ (1-42)-Induced Toxicity in Rat: a Comparison with Memantine

PURPOSE

The current drugs for Alzheimer's disease (AD) are only used to slow or delay the progression of the pathology. So using a novel technology is a necessity to synthesize more effective medications to control this most common cause of dementia. In this study, using nanochelating technology, ALZc3 was synthesized and its therapeutic effects were evaluated in comparison with memantine on a well-known rat model of AD, which is based on Amyloid-βeta (Aβ) injection into the brain.

MATERIALS AND METHODS

Aβ (1-42) was injected bilaterally into the CA1 area of the hippocampus of male rats and then animals were treated daily by oral administration of Alz-C3, memantine or their vehicles. Activities of antioxidant enzymes catalase and superoxide dismutase (SOD), glutathione (GSH) and malondialdehyde (MDA) levels, as well as Bax/Bcl-2 ratio, caspase-3 activation, and TNF-α expression were evaluated 7 days after Aβ injection. Finally, learning and memory of the rats were assessed by Morris water maze test.

RESULTS

ALZc3 and memantine improved memory impairment and antioxidant activity and reduced TNF-α expression, caspase-3 activity and Bax/Bcl-2 ratio in the rat's hippocampus. The results showed a superiority of ALZC3 compared to memantine in reducing caspase-3, increasing CAT activity in Aβ (1-42)-injected groups and improving apoptosis factor in healthy mice.

CONCLUSION

These results indicated that ALZc3 could significantly prevent the memory impairment and Aβ (1-42) toxicity. Thus, ALZc3 could be a promising novel anti-AD agent.

OCIAD1 contributes to neurodegeneration in Alzheimer's disease by inducing mitochondria dysfunction, neuronal vulnerability and synaptic damages

BACKGROUND

Hyperamyloidosis in the brain is known as the earliest neuropathological change and a unique etiological factor in Alzheimer's disease (AD), while progressive neurodegeneration in certain vulnerable brain regions forms the basis of clinical syndromes. It is not clear how early hyperamyloidosis is implicated in progressive neurodegeneration and what factors contribute to the selective brain vulnerability in AD.

METHODS

Bioinformatics and experimental neurobiology methods were integrated to identify novel factors involved in the hyperamyloidosis-induced brain vulnerability in AD. We first examined neurodegeneration-specific gene signatures from sporadic AD patients and synaptic protein changes in young transgenic AD mice. Then, we systematically assessed the association of a top candidate gene with AD and investigated its mechanistic role in neurodegeneration.

FINDINGS

We identified the ovary-orientated protein OCIAD1 (Ovarian-Carcinoma-Immunoreactive-Antigen-Domain-Containing-1) as a neurodegeneration-associated factor for AD. Higher levels of OCIAD1, found in vulnerable brain areas and dystrophic neurites, were correlated with disease severity. Multiple early AD pathological events, particularly Aβ/GSK-3β signaling, elevate OCIAD1, which in turn interacts with BCL-2 to impair mitochondrial function and facilitates mitochondria-associated neuronal injury. Notably, elevated OCIAD1 by Aβ increases cell susceptibility to other AD pathological challenges.

INTERPRETATION

Our findings suggest that OCIAD1 contributes to neurodegeneration in AD by impairing mitochondria function, and subsequently leading to neuronal vulnerability, and synaptic damages.

FUNDING

Ting Tsung & Wei Fong Chao Foundation, John S Dunn Research Foundation, Cure Alzheimer's Fund, and NIH R01AG057635 to STCW.

Effect of the flavonoid baicalin on the proliferative capacity of bovine mammary cells and their ability to regulate oxidative stress

Background

High-yielding dairy cows are prone to oxidative stress due to the high metabolic needs of homeostasis and milk production. Oxidative stress and inflammation are tightly linked; therefore, anti-inflammatory and/or natural antioxidant compounds may help improve mammary cell health. Baicalin, one of the major flavonoids in Scutellaria baicalensis, has natural antioxidant and anti-inflammatory properties in various cell types, but its effects on bovine mammary epithelial cells (BMECs) have not been investigated.

Methods

Explants from bovine mammary glands were collected by biopsy at the peak of lactation (approximately 60 days after the start of lactation) (n = three animals) to isolate BMECs corresponding to mature secretory cells. Cell viability, apoptosis, proliferative capacity and reactive oxygen species (ROS) production by BMECs were measured after increasing doses of baicalin were added to the culture media in the absence or presence of H₂O₂, which was used as an in vitro model of oxidative stress.

Results

Low doses of baicalin (1–10 µg/mL) had no or only slightly positive effects on the proliferation and viability of BMECs, whereas higher doses (100 or 200 µg/mL) markedly decreased BMEC proliferation. Baicalin decreased apoptosis rate at low concentrations (10 µg/mL) but increased apoptosis at higher doses. ROS production was decreased in BMECs treated with increasing doses of baicalin compared with untreated cells, and this decreased production was associated with increased intracellular concentrations of catalase and NRF-2. Irrespective of the dose, baicalin pretreatment attenuated H₂O₂-induced ROS production.

Discussion

These results indicate that baicalin exerts protective antioxidant effects on bovine mammary cells. This finding suggests that baicalin could be used to prevent oxidative metabolic disorders in dairy cows.

Baicalin mitigates cognitive impairment and protects neurons from microglia-mediated neuroinflammation via suppressing NLRP3 inflammasomes and TLR4/NF-κB signaling pathway

Aims

Baicalin (BAI), a flavonoid compound isolated from the root of Scutellaria baicalensis Georgi, has been established to have potent anti‐inflammation and neuroprotective properties; however, its effects during Alzheimer's disease (AD) treatment have not been well studied. This study aimed to investigate the effects of BAI pretreatment on cognitive impairment and neuronal protection against microglia‐induced neuroinflammation and to explore the mechanisms underlying its anti‐inflammation effects.

Methods

To determine whether BAI plays a positive role in ameliorating the memory and cognition deficits in APP (amyloid beta precursor protein)/PS1 (presenilin‐1) mice, behavioral experiments were conducted. We assessed the effects of BAI on microglial activation, the production of proinflammatory cytokines, and neuroinflammation‐mediated neuron apoptosis in vivo and in vitro using Western blot, RT‐PCR, ELISA, immunohistochemistry, and immunofluorescence. Finally, to elucidate the anti‐inflammation mechanisms underlying the effects of BAI, the protein expression of NLRP3 inflammasomes and the expression of proteins involved in the TLR4/NF‐κB signaling pathway were measured using Western blot and immunofluorescence.

Results

The results indicated that BAI treatment attenuated spatial memory dysfunction in APP/PS1 mice, as assessed by the passive avoidance test and the Morris water maze test. Additionally, BAI administration effectively decreased the number of activated microglia and proinflammatory cytokines, as well as neuroinflammation‐mediated neuron apoptosis, in APP/PS1 mice and LPS (lipopolysaccharides)/Aβ‐stimulated BV2 microglial cells. Lastly, the molecular mechanistic study revealed that BAI inhibited microglia‐induced neuroinflammation via suppression of the activation of NLRP3 inflammasomes and the TLR4/NF‐κB signaling pathway.

Conclusion

Overall, the results of the present study indicated that BAI is a promising neuroprotective compound for use in the prevention and treatment of microglia‐mediated neuroinflammation during AD progression.

Anti-amyloidogenic properties of an ethyl acetate fraction from Actinidia arguta in Aβ1-42-induced ICR mice

This study aimed to investigate the ameliorating effect of an ethyl acetate fraction from the fruit Actinidia arguta (EFAA) on amyloid beta (Aβ)-induced neurotoxicity and cognitive deficits in ICR mice. EFAA showed potent protective effects against Aβ-induced neurotoxicity through 2',7'-dichlorofluorescein diacetate (DCF-DA), 2',3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) and lactate dehydrogenase (LDH) release into the assay medium. EFAA treatment reduced the intracellular ROS level and lactate dehydrogenase (LDH) release in the mitochondria, and increased cell viability in Aβ-induced neuroblastoma MC-IXC cells. The administration of EFAA significantly attenuated Aβ-induced learning and memory deficits, which were evaluated by Y-maze, passive avoidance, and Morris water maze tests. Furthermore, EFAA showed the ameliorating effect of cholinergic functions by increasing acetylcholine (ACh) levels and decreasing acetylcholinesterase (AChE) activity, and protected antioxidant systems by increasing superoxide dismutase (SOD) and decreasing the oxidized glutathione (GSH)/total GSH and malondialdehyde (MDA) in the brain. Finally, EFAA prevented mitochondrial dysfunction via regulating apoptotic signaling molecules including phosphorylated Akt (p-Akt), phosphorylated tau (p-tau), Bax, and cytochrome c in the brain tissues. Therefore, the present study suggests that EFAA might be a potential source of natural antioxidants with the ability to ameliorate Aβ-induced amnesia.

Baicalin provides neuroprotection in traumatic brain injury mice model through Akt/Nrf2 pathway

Background

The neuroprotective effects of Baicalin have been confirmed in several central nervous system (CNS) diseases. However, its possible effect on traumatic brain injury (TBI) model is still not clear. The present study is aimed to investigate the role and the underling mechanisms of 7-D-glucuronic acid-5,6-dihydroxyflavone (Baicalin) on TBI model.

Methods

The weight-drop model of TBI in Institute of Cancer Research mice was treated with Baicalin intraperitoneally at 30 minutes after TBI. LY294002 (LY) (a commonly used PI3K/Akt pathway inhibitor) was injected into the left ventricle at 30 minutes before TBI. All mice were euthanized at 24 hours after TBI to collect the brain tissue for a series of tests except for neurological function, which was measured at 2 hours and 1 and 3 days post-TBI.

Results

Baicalin administration significantly improved neurobehavioral function, alleviated brain edema, and reduced apoptosis-positive cells by terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay accompanied with the upregulation of B-cell lymphoma 2 (Bcl-2) and downregulation of Bcl-2-associated X protein (Bax) and cleaved-caspase 3 by Western blot. Besides, TBI-induced oxidant stress status was also restored in the Baicalin group by measuring malondialdehyde (MDA) content, glutathione peroxidase (GPx), and superoxide dismutase (SOD) levels in the injured brain cortex. Furthermore, translocation of Nrf2 to the nucleus was dramatically enhanced by Baicalin verified by immunofluorescence and Western blot analyses. Accordingly, its downstream antioxidative enzymes nicotinamide adenine dinucleotide phosphate:quinine oxidoreductase 1 (NQO-1) and heme oxygenase 1 (HO-1) were also activated by Baicalin confirmed by quantitative reverse transcription polymerase chain reaction (RT-qPCR) and Western blot. However, cotreatment with Baicalin and LY could partly abolish Baicalin-induced activation of Nrf2 and its neuroprotective effects in TBI.

Conclusion

This study demonstrates that Baicalin provides a neuroprotective effect in TBI mice model via activating the Akt/Nrf2 pathway.

Neuroprotective and Cognitive Enhancement Potentials of Baicalin: A Review

Neurodegenerative diseases are a heterogeneous group of disorders that are characterized by the gradual loss of neurons. The development of effective neuroprotective agents to prevent and control neurodegenerative diseases is specifically important. Recently, there has been an increasing interest in selecting flavonoid compounds as potential neuroprotective agents, owing to their high effectiveness with low side effects. Baicalin is one of the important flavonoid compounds, which is mainly isolated from the root of Scutellaria baicalensis Georgi (an important Chinese medicinal herb). In recent years, a number of studies have shown that baicalin has a potent neuroprotective effect in various in vitro and in vivo models of neuronal injury. In particular, baicalin effectively prevents neurodegenerative diseases through various pharmacological mechanisms, including antioxidative stress, anti-excitotoxicity, anti-apoptotic, anti-inflammatory, stimulating neurogenesis, promoting the expression of neuronal protective factors, etc. This review mainly focuses on the neuroprotective and cognitive enhancement effects of baicalin. The aim of the present review is to compile all information in relation to the neuroprotective and cognitive enhancement effects of baicalin and its molecular mechanisms of action in various in vitro and in vivo experimental models.

Huangqin flavonoid extraction for spinal cord injury in a rat model

Flavonoids from Huangqin (dried roots of Scutellaria baicalensis Georgi) have anti-inflammatory effects, and are considered useful for treatment of spinal cord injury. To verify this hypothesis, the T9–10 spinal cord segments of rats were damaged using Allen's method to establish a rat spinal cord injury model. Before model establishment, Huangqin flavonoid extraction (12.5 g/kg) was administered intragastrically for 1 week until 28 days after model establishment. Methylprednisolone (30 mg/kg) was injected into the tail vein at 30 minutes after model establishment as a positive control. Basso, Beattie, and Bresnahan locomotor scale scores were used to assess hind limb motor function. Hematoxylin-eosin staining was used to detect pathological changes in the injured spinal cord. Immunofluorescence and western blot assays were performed to measure immunoreactivity and expression levels of brain-derived neurotrophic factor, neuronal marker neurofilament protein, microglial marker CD11b and astrocyte marker glial fibrillary acidic protein in the injured spinal cord. Huangqin flavonoid extraction markedly reduced spinal cord hematoma, inflammatory cell infiltration and cavities and scars, and increased the Basso, Beattie, and Bresnahan locomotor scale scores; these effects were identical to those of methylprednisolone. Huangqin flavonoid extraction also increased immunoreactivity and expression levels of brain-derived neurotrophic factor and neurofilament protein, and reduced immunoreactivity and expression levels of CD11b and glial fibrillary acidic protein, in the injured spinal cord. Overall, these data suggest that Huangqin flavonoid extraction can promote recovery of spinal cord injury by inducing brain-derived neurotrophic factor and neurofilament protein expression, reducing microglia activation and regulating reactive astrocytes.

Cilostazol Suppresses Aβ-induced Neurotoxicity in SH-SY5Y Cells through Inhibition of Oxidative Stress and MAPK Signaling Pathway

Alzheimer's disease (AD) is a slowly progressive form of dementia, characterized by memory impairment and cognitive dysfunction. AD is mainly characterized by the deposition of amyloid β (Aβ) plaques and intracellular neurofibrillary tangles in the brain, along with neuronal degeneration and high levels of oxidative stress. Cilostazol (CSZ) was recently found to suppress the progression of cognitive decline in patients with stable AD receiving acetylcholinesterase inhibitors. This present study aimed to clarify the mechanism by which CSZ protects neurons from degeneration associated with Aβ(1-42). We used Aβ(1-42) to induce neurotoxicity in human neuroblastoma SH-SY5Y cells. Cells were pretreated with CSZ before co-treatment with Aβ. To evaluate the effect of CSZ on oxidative stress, we examined levels of reactive oxygen species (ROS), nicotinamide adenine dinucleotide phosphate oxidase (Nox) activity, mRNA expression of NOX4, and Cu/Zn-Superoxide Dismutase (SOD), as well as apoptosis biomarkers [MTT, (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide), caspase-3 and -9 activities and staining of annexin V]. We also assayed the activity of mitogen-activated protein kinases (MAPK): p38 MAPK and extracellular signal-regulated kinase1/2 (ERK1/2), and biomarkers of mitochondrial function (Bcl-2 and Bax), and cyclic adenosine monophosphate response element-binding protein (CREB). Aβ-induced oxidative stress (ROS, NOX4 activity, and expression of NOX mRNA), caspase activation (caspase-3 and -9), and p38 MAPK phosphorylation were suppressed by co-treatment with CSZ, but not by ERK1/2 activation. In addition, pretreatment with CSZ suppressed Aβ-induced apoptosis and increased cell viability via suppression of Bax (a proapoptotic protein), upregulation of Bcl-2 (an antiapoptotic protein) and Cu/Zn-SOD (a superoxide scavenging enzyme), and phosphorylation of CREB. These findings suggested that CSZ could counteract neurotoxicity through multiple mechanisms, one mechanism involving the attenuation of oxidative stress by suppressing NOX activity and Nox mRNA expression in Aβ-induced neurotoxicity and another involving the anti-neurotoxic effect via the ERK1/2/phosphorylated CREB pathway.

A modified formulation of Huanglian-Jie-Du-Tang reduces memory impairments and β-amyloid plaques in a triple transgenic mouse model of Alzheimer's disease

Alzheimer's disease (AD) is a degenerative disorder typified by progressive deterioration of memory and the appearance of β-amyloid peptide (Aβ)-rich senile plaques. Recently we have identified a novel function of a patented formulation of modified Huanglian-Jie-Tu-Tang (HLJDT-M), a Chinese herbal medicine, in treating AD in in vitro studies (US patent No. 9,375,457). HLJDT-M is a formulation composed of Rhizoma Coptitis, Cortex Phellodendri and Fructus Gardeniae without Radix Scutellariae. Here, we assessed the efficacy of HLJDT-M on a triple transgenic mouse model of AD (3XTg-AD). Oral administration of HLJDT-M ameliorated the cognitive dysfunction of 3XTg-AD mice and lessened the plaque burden. In addition, biochemical assays revealed a significant decrease in levels of detergent-soluble and acid-soluble Aβ via decreasing the levels of full length amyloid-β precursor protein (FL-APP) and C-terminal fragments of APP (CTFs) in brain lysates of HLJDT-M-treated mice. HLJDT-M treatment also significantly reduced the levels of FL-APP and CTFs in N2a/SweAPP cells. In contrast, treatment using the classical formula HLJDT did not reduce the memory impairment of 3XTg-AD mice and, rather, increased the Aβ/Fl-APP/CTFs in both animal and cell culture studies. Altogether, our study indicates that HLJDT-M is a promising herbal formulation to prevent and/or cure AD.

Metal ions influx is a double edged sword for the pathogenesis of Alzheimer's disease

Alzheimer's disease (AD) is a common form of dementia in aged people, which is defined by two pathological characteristics: β-amyloid protein (Aβ) deposition and tau hyperphosphorylation. Although the mechanisms of AD development are still being debated, a series of evidence supports the idea that metals, such as copper, iron, zinc, magnesium and aluminium, are involved in the pathogenesis of the disease. In particular, the processes of Aβ deposition in senile plaques (SP) and the inclusion of phosphorylated tau in neurofibrillary tangles (NFTs) are markedly influenced by alterations in the homeostasis of the aforementioned metal ions. Moreover, the mechanisms of oxidative stress, synaptic plasticity, neurotoxicity, autophagy and apoptosis mediate the effects of metal ions-induced the aggregation state of Aβ and phosphorylated tau on AD development. More importantly, imbalance of these mechanisms finally caused cognitive decline in different experiment models. Collectively, reconstructing the signaling network that regulates AD progression by metal ions may provide novel insights for developing chelators specific for metal ions to combat AD.

Direct Keap1-Nrf2 disruption as a potential therapeutic target for Alzheimer's disease

Nrf2, a transcriptional activator of cell protection genes, is an attractive therapeutic target for the prevention of neurodegenerative diseases, including Alzheimer’s disease (AD). Current Nrf2 activators, however, may exert toxicity and pathway over-activation can induce detrimental effects. An understanding of the mechanisms mediating Nrf2 inhibition in neurodegenerative conditions may therefore direct the design of drugs targeted for the prevention of these diseases with minimal side-effects. Our study provides the first in vivo evidence that specific inhibition of Keap1, a negative regulator of Nrf2, can prevent neuronal toxicity in response to the AD-initiating Aβ42 peptide, in correlation with Nrf2 activation. Comparatively, lithium, an inhibitor of the Nrf2 suppressor GSK-3, prevented Aβ42 toxicity by mechanisms independent of Nrf2. A new direct inhibitor of the Keap1-Nrf2 binding domain also prevented synaptotoxicity mediated by naturally-derived Aβ oligomers in mouse cortical neurons. Overall, our findings highlight Keap1 specifically as an efficient target for the re-activation of Nrf2 in AD, and support the further investigation of direct Keap1 inhibitors for the prevention of neurodegeneration in vivo.

As our population ages the incidence of neurodegenerative diseases, including Alzheimer’s disease (AD), is predicted to increase dramatically. Despite providing important symptomatic relief, existing treatments for such conditions do not slow-down disease progression, and this will cause an overwhelming future burden on our healthcare system and immense suffering for many more patients and their families. Nrf2 is a gene that normally protects cells from stressful conditions. Although we don’t know why, Nrf2 is reduced in the brains of AD patients and this may explain the increased susceptibility of neurons to damage in neurodegenerative diseases. Our research, using a fruit fly model, identifies Keap1, a negative regulator of Nrf2, as a valid target for the rescue of AD-related Nrf2 defects and the subsequent prevention of neuronal degeneration. Moreover, we show that a new compound, which directly blocks the binding between Nrf2 and Keap1, can prevent toxicity of the AD-initiating Aβ peptide in mouse neurons. Hence, our study provides strong evidence that direct Keap1-Nrf2 disruptors can specifically target the defects in Nrf2 activity observed in neurodegenerative diseases, and supports the further development of such compounds as potential new drugs to prevent neuronal decline AD and other neurodegenerative conditions.

Protective effects of linalool against amyloid beta-induced cognitive deficits and damages in mice

AIM

Amyloid-beta (Aβ)-mediated neurotoxicity plays a pivotal role in the pathogenesis of Alzheimer's disease (AD), which induces oxidative stress and apoptosis. Linalool (LI) is a volatile monoterpene showing positive effect in AD treatment. This study was designed to research the protective effect of LI against neurotoxicity and cognitive deficits induced by Aβ_1-40 in mice.

MAIN METHODS

Aβ_1-40 (4μg) solution was injected in the bilateral hippocampus to induce cognitive deficits of mice. The protective effects of LI were evaluated by behavioral tests and the related mechanism was further explored by observing the apoptosis and oxidative stress changes in the hippocampus of mice.

KEY FINDINGS

LI (100mg/kg, i.p.) administration significantly improved the cognitive performance of model mice in Morris water maze test and step-through test. Meanwhile, LI effectively reversed the Aβ_1-40 induced hippocampal cell injury in histological examination, apoptosis in TUNEL assay, changes of oxidative stress indicators (SOD, GPX, AChE). Besides, the activated cleaved caspase (caspase-3, caspase-9) was suppressed and Nrf2, HO-1 expression was elevated by LI treatment.

SIGNIFICANCE

LI could attenuate cognitive deficits induced by Aβ, and the neuroprotective effect of LI might be mediated by alleviation of apoptosis, oxidative stress depending on activation of Nrf2/HO-1 signaling. We could assume that LI has the potential to be a neuroprotective substance for AD therapy.

Oxidative Stress and Treg and Th17 Dysfunction in Systemic Lupus Erythematosus

Systemic lupus erythematosus (SLE) is an autoimmune disease that involves multiple organ systems. The pathogenic mechanisms that cause SLE remain unclear; however, it is well recognized that the immune balance is disturbed and that this imbalance contributes to the autoimmune symptoms of SLE. Oxidative stress represents an imbalance between the production and manifestation of reactive oxygen species and the ability of the biological system to readily detoxify the reactive intermediates or to repair the resulting damage. In humans, oxidative stress is involved in many diseases, including atherosclerosis, myocardial infarction, and autoimmune diseases. Numerous studies have confirmed that oxidative stress plays an important role in the pathogenesis of SLE. This review mainly focuses on the recent research advances with respect to oxidative stress and regulatory T (Treg)/helper T 17 (Th17) cell dysfunction in the pathogenesis of SLE.

P2X7-pannexin-1 and amyloid β-induced oxysterol input in human retinal cell: Role in age-related macular degeneration?

Age-related macular degeneration (AMD) is the most common cause of severe vision loss worldwide. Amyloid β involvement in degenerative diseases such as AMD is well known and its toxicity has been related to P2X7 receptor-pannexin-1. Recently, oxysterols (oxidized derivatives of cholesterol) have been implicated in AMD pathogenesis. The aim of our study was to highlight amyloid β/oxysterols relationship and to describe P2X7 receptor-pannexin-1 role in oxysterols toxicity. Using retinal epithelial cells, we first quantified sterols levels after amyloid β incubation and second we investigated the cytotoxic effects induced by oxysterols. For the first time, our results showed that amyloid β induced oxysterols formation in human retinal pigmented epithelial cells. We showed that oxysterol toxicity is mediated by P2X7 receptor activation. This activation was dependent on pannexin-1 with 25-hydroxycholesterol whereas P2X7 receptor signaling pathway was pannexin-1-independent for 7-ketocholesterol. Taken together our data suggest a pivotal role of P2X7 receptor-pannexin-1 in oxysterols toxicity in retinal cells which could be an important target to develop new treatments for AMD.

Therapeutic effect of baicalin on experimental autoimmune encephalomyelitis is mediated by SOCS3 regulatory pathway

Natural compounds derived from medicinal plants have long been considered a rich source of novel therapeutic agents. Baicalin (Ba) is a bioactive flavonoid compound derived from the root of Scutellaria baicalensis, an herb widely used in traditional medicine for the treatment of various inflammatory diseases. In this study, we investigate the effects and mechanism of action of Ba in experimental autoimmune encephalomyelitis (EAE), an animal model of multiple sclerosis (MS). Ba treatment effectively ameliorated clinical disease severity in myelin oligodendrocyte glycoprotein (MOG)35–55 peptide-induced EAE, and reduced inflammation and demyelination of the central nervous system (CNS). Ba reduced infiltration of immune cells into the CNS, inhibited expression of proinflammatory molecules and chemokines, and prevented Th1 and Th17 cell differentiation via STAT/NFκB signaling pathways. Further, we showed that SOCS3 induction is essential to the effects of Ba, given that the inhibitory effect of Ba on pathogenic Th17 responses was largely abolished when SOCS3 signaling was knocked down. Taken together, our findings demonstrate that Ba has significant potential as a novel anti-inflammatory agent for therapy of autoimmune diseases such as MS.

Neuronal differentiation of human iPS cells induced by baicalin via regulation of bHLH gene expression

Efficient differentiation is important for regenerative medicine based on pluripotent stem cells, including treatment of neurodegenerative disorders and trauma. Baicalin promotes neuronal differentiation of neural stem/progenitor cells of rats and mice. To evaluate the suitability of baicalin for neuronal differentiation of human iPS cells, we investigated whether it promotes neuronal differentiation in human iPS cells and monitored basic helix-loop-helix (bHLH) gene expression during neuronal differentiation. Baicalin promoted neuronal differentiation and inhibited glial differentiation, suggesting that baicalin can influence the neuronal fate decision in human iPS cells. Notch signaling, which is upstream of bHLH proteins, was not involved in baicalin-induced neuronal differentiation. Baicalin treatment did not down-regulate Hes1 gene expression, but it reduced Hes1 protein levels and up-regulated Ascl1 gene expression. Thus, baicalin promoted neuronal differentiation via modulation of bHLH transcriptional factors. Therefore, baicalin has potential to be used as a small-molecule drug for regenerative treatment of neurodegenerative disorders.