Molecular basis of inhibitory activities of berberine against pathogenic enzymes in Alzheimer's disease

Preventing amyloid-β oligomerization and aggregation with berberine: Investigating the mechanism of action through computational methods

Neurological disorders (NDs) have become a major cause of both cognitive and physical disabilities worldwide. In NDs, misfolded proteins tend to adopt a β-sheet-rich fibrillar structure called amyloid. Amyloid beta (Aβ) plays a crucial role in the nervous system. The misfolding and aggregation of Aβ are primary factors in the progression of Alzheimer's disease (AD). Inhibiting the oligomerization and aggregation of Aβ is considered as an effective strategy against NDs. While it is known that berberine analogs exhibit anti-Aβ aggregation properties, the precise mechanism of action remains unclear. In this study, we have employed computational approaches to unravel the possible mechanism by which berberine combats Aβ aggregation. The introduction of berberine was observed to delay the equilibrium of Aβ16-21 oligomerization. Initially, within the first 10 ns of simulation, β-sheets content was 12.89 % and gradually increased to 22.19 % within the first 20 ns. This upward trend continued, reaching 32.80 %. However, berberine substantially reduced the formation of β-sheets to 1.36 %. These findings decipher the potency of berberine against Aβ16-21 oligomerization, a crucial step for β-sheet formation. Additionally, a remarkable decrease in total number of hydrogen bonds was found in the presence of berberine. Berberine also led to a slight reduction in the flexibility of Aβ16-21, which may be due to the formation of a more stable structures. This study offers valuable insights at the mechanistic level, which could prove beneficial in the development of new drugs to combat NDs.

A Mechanistic Review on How Berberine Use Combats Diabetes and Related Complications: Molecular, Cellular, and Metabolic Effects

Berberine (BBR) is an isoquinoline alkaloid that can be extracted from herbs such as Coptis, Phellodendron, and Berberis. BBR has been widely used as a folk medicine to treat various disorders. It is a multi-target drug with multiple mechanisms. Studies have shown that it has antioxidant and anti-inflammatory properties and can also adjust intestinal microbial flora. This review focused on the promising antidiabetic effects of BBR in several cellular, animal, and clinical studies. Based on previous research, BBR significantly reduced levels of fasting blood glucose, hemoglobin A1C, inflammatory cytokines, and oxidative stress markers. Furthermore, BBR stimulated insulin secretion and improved insulin resistance through different pathways, including up-regulation of protein expression of proliferator-activated receptor (PPAR)-γ, glucose transporter (GLUT) 4, PI3K/AKT, and AMP-activated protein kinase (AMPK) activation. Interestingly, it was demonstrated that BBR has protective effects against diabetes complications, such as diabetic-induced hepatic damage, cardiovascular disorders, nephropathy, and neuropathy. Furthermore, multiple clinical trial studies have emphasized the ameliorative effects of BBR in type 2 diabetic patients.

Neuroprotective Properties of Berberine: Molecular Mechanisms and Clinical Implications

Berberine (BBR), an isoquinoline alkaloid natural product, is isolated primarily from Coptis chinensis and other Berberis plants. BBR possesses various bioactivities, including antioxidant, anti-inflammation, anticancer, immune-regulation, and antimicrobial activities. Growing scientific evidence underscores BBR's substantial neuroprotective potential, prompting increased interest and scrutiny. In this comprehensive review, we elucidate the neuroprotective attributes of BBR, delineate the underlying molecular mechanisms, and assess its clinical safety and efficacy. The multifaceted molecular mechanisms responsible for BBR's neuroprotection encompass the attenuation of oxidative stress, mitigation of inflammatory responses, inhibition of apoptotic pathways, facilitation of autophagic processes, and modulation of CYP450 enzyme activities, neurotransmitter levels, and gut microbiota composition. Furthermore, BBR engages numerous signaling pathways, including the PI3K/Akt, NF-κB, AMPK, CREB, Nrf2, and MAPK pathways, to confer its neuroprotective effects. This comprehensive review aims to provide a substantial knowledge base, stimulate broader scientific discourse, and facilitate advancements in the application of BBR for neuroprotection.

Neuroprotective potential of berberine against acetamiprid induced toxicity in rats: Implication of oxidative stress, mitochondrial alterations, and structural changes in brain regions

Acetamiprid (ACMP) is an extensively used neonicotinoid pesticide to control sucking and chewing insects and is known to cause nontarget toxicity. The present study aimed to evaluate the ameliorative potential of berberine (BBR)-a polyphenolic alkaloid- on ACMP-induced oxidative stress, mitochondrial dysfunctioning, and structural changes in different rat brain regions. The male Wistar rats were divided into four groups, that is, control, BBR-treated (150 mg/kg b.wt), ACMP-exposed (21.7 mg/kg b.wt) and BBR + ACMP co-treated; and were dosed intragastrically for 21 consecutive days. Results of the biochemical analysis showed that BBR significantly ameliorated ACMP-induced oxidative stress by decreasing lipid peroxidation and protein oxidation along with a marked increase in endogenous antioxidants and lowered AChE activity in rat brain regions. Inside mitochondria, BBR significantly attenuated the toxic effects of ACMP by increasing the activity of mitochondrial complexes. Findings of polymerase chain reaction also demonstrated the modulatory effects of BBR against ACMP-mediated downregulation of ND1, ND2, COX1, and COX4 subunits of mitochondrial complexes. The histopathological and ultrastructural examination also validated the biochemical and transcriptional alterations following toxicity of ACMP exposure and the protective potential of BBR against ACMP-induced neurotoxicity. Thus, the present study indicates the promising ameliorative potential of BBR against ACMP-induced neurotoxicity via its antioxidative and modulatory activities.

History in Perspective: The Prime Pathological Players and Role of Phytochemicals in Alzheimer’s Disease

Alzheimer's disease is a steadily progressive, irreversible neurological disorder that is most frequently categorized under the umbrella term "neurodegeneration". Several attempts are underway to clarify the pathogenic mechanisms, identify the aetiologies, and determine a pathway by which the therapeutic steps can be implemented. Oxidative stress is one of the pathogenic processes, which is commonly believed to be associated with neurodegenerative diseases. Accumulation of extracellular amyloid-β protein (Aβ), hyperphosphorylation of tau, initiation of neurometabolic reactions characterized by the loss of neuronal function and synaptic failure, and decreased or lost learning capability and memory function are the most central neuropathological characteristics of AD. According to the amyloid cascade hypothesis, the enhanced deposition of Aβ deposits and neurofibrillary tangles due to hyperphosphorylation of Tau activates the cascade reactions in the brain. These reactions affect the synaptic activity and activation of microglia, which results in neuroinflammation due to enhanced immune function. Plant-based phytochemicals have also been used long ago against several diseases. Phytoconstituents play a significant neuroprotective property by preventing the pathophysiology of the disease. In this review, we have discussed the formation and crosstalk between amyloid and tau pathologies as well as the effect of neuroinflammation on the progression of AD. We have specifically focused on the formation of NFT, β-amyloids, inflammation, and pathophysiology of AD and the role of phytochemicals in the prevention of AD.

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AD is an insidious, slowly progressive, and neurodegenerative disorder.

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Common symptoms are memory loss, difficulty in recalling, and understanding.

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β-amyloids and Neurofibrillary tangles are the main factors in AD pathogenesis.

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Activated microglia and oxidative stress have different effects on AD progression.

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Phytochemicals show a key role against AD by inhibiting several pathways.

A review on the neuroprotective effect of berberine against chemotherapy-induced cognitive impairment

Chemobrain is one of the major side effects of chemotherapy, despite increased research, the mechanisms underlying chemotherapy-induced cognitive changes remain unknown. Though, several possibly important candidate mechanisms have been identified and will be studied further in the future. Chemobrain is characterized by memory loss, cognitive impairment, difficulty in language, concentration, acceleration, and learning. The major characteristic of chemobrain is oxidative stress, mitochondrial dysfunction, immune dysregulation, hormonal alteration, white matter abnormalities, and DNA damage. Berberine (BBR) is an isoquinoline alkaloid extracted from various berberine species. BBR is a small chemical that easily passes the blood-brain barrier (BBB), making it useful for treating neurodegenerative diseases. Many studies on the pharmacology of BBR have been reported in the past. Furthermore, several clinical and experimental research indicates that BBR has a variety of pharmacological effects. So, in this review, we explore the pathogenesis of chemobrain and the neuroprotective potential of BBR against chemobrain. We also introduced the therapeutic role of BBR in various neurodegenerative and neurological diseases such as Alzheimer's, Parkinson's disease, mental depression, schizophrenia, anxiety, and also some stroke.

Therapeutic Efficacies of Berberine against Neurological Disorders: An Update of Pharmacological Effects and Mechanisms

Neurological disorders are ranked as the leading cause of disability and the second leading cause of death worldwide, underscoring an urgent necessity to develop novel pharmacotherapies. Berberine (BBR) is a well-known phytochemical isolated from a number of medicinal herbs. BBR has attracted much interest for its broad range of pharmacological actions in treating and/or managing neurological disorders. The discoveries in basic and clinical studies of the effects of BBR on neurological disorders in the last decade have provided novel evidence to support the potential therapeutical efficacies of BBR in treating neurological diseases. In this review, we summarized the pharmacological properties and therapeutic applications of BBR against neurological disorders in the last decade. We also emphasized the major pathways modulated by BBR, which provides firm evidence for BBR as a promising drug candidate for neurological disorders.

Neuroprotective Potential of Berberine Against Doxorubicin-Induced Toxicity in Rat's Brain

Chemotherapy-associated neurotoxicity is one of the principal side-effects for doxorubicin (DOX)-treated cancer patients. Despite its poor-penetration across the blood-brain barrier (BBB), DOX is linked to the induction of oxidative stress and neuroinflammation. Berberine (BEB) is a natural polyphenolic alkaloid, which exhibits unique antioxidant activity and anti-inflammatory potential. The present study was performed to investigate the neuroprotective potential of BEB in a rodent model of DOX-induced neurotoxicity. Neurotoxicity was induced in rats via a single acute dose of DOX (20 mg/kg/week, i.p.). BEB was administered at 50 mg/kg/day orally for 10 days before and 4 days after DOX administration. Brain acetylcholinesterase (AChE) activities were evaluated. Oxidative stress was investigated via the colorimetric determination of lipid peroxides, glutathione reduced (GSH) contents and catalase (CAT) activities in the brain tissue. In addition, DOX-induced genotoxicity was evaluated using comet assay. DOX produced a significant elevation in AChE activities. Additionally, DOX provoked oxidative stress as evidenced from the significant elevation in lipid peroxidation along with depletion in GSH contents and CAT activities. Moreover, DOX resulted in neuroinflammation as indicated by the elevation of pro-inflammatory mediator glial fibrillary acid protein (GFAP), as well as, the pro-apoptotic nuclear factor kappa B (NF-κB) and caspase-3 in brain tissue. Co-treatment with BEB significantly counteracted DOX-induced oxidative stress, neuroinflammation and genotoxicity. Histopathological and immunohistochemical examination supported the biochemical results. BEB demonstrated neuroprotective potential through exerting cholinergic, anti-oxidative, genoprotective, anti-inflammatory, and anti-apoptotic activities. Our findings present BEB as a promising "pre-clinical" neuroprotective agent against DOX-induced neurotoxicity during anti-neoplastic therapy.

Effect of Berberine Isolated from Barberry Species by Centrifugal Partition Chromatography on Memory and the Expression of Parvalbumin in the Mouse Hippocampus Proper

Neurodegenerative diseases associated with memory disturbances are important health issues occurring due to a prolonged life span. This article presents the results of a study targeting the emergence of a drug candidate with antiamnesic properties. The effect of berberine (BBR), an isoquinoline alkaloid isolated from the overground parts of Berberis sibirica Pall., on memory and expression of parvalbumin in the mouse hippocampus proper were determined. High-purity BBR was isolated by centrifugal partition chromatography from a methanolic extract from B. sibirica by using a methyl-tert-butyl ether and water (1:1 v/v) solvent system with 10 mmol/L of triethylamine and hydrochloric acid. In an in vivo study, we assessed the influence of the chronic administration of BBR on different stages of memory-related responses in mice. Our results indicated that the chronic administration of BBR in a higher dose (5 mg/kg) improves long-term memory acquisition in mice, as determined in the passive avoidance test. The hippocampal CA1–CA3 fields showed an increased number of parvalbumin-immunoreactive neurons (PV-IR) and nerve fibers as compared to the control. No significant changes in the dentate gyrus were observed between the groups. The HPLC-ESI-QTOF-MS/MS analysis of the biological material revealed the content of BBR as 363.4 ± 15.0 ng (4.11% of RSD) per brain, 15.06 ± 0.89 ng (5.91% of RSD) per hippocampus, and 54.45 ± 1.40 (4.05% of RSD) ng in 100 µL plasma. The study showed that BBR could be a factor influencing the expression of PV in hippocampal neurons. We speculate that BBR may modulate the level of Ca²⁺ in neurons and thus potentially act as a neuroprotective factor against neuronal damages.

Comparative effects of berberine and piperine on the neuroprotective potential of neostigmine

OBJECTIVES

This study examined effect of berberine and piperine on neuroprotective potential of neostigmine in the management of neurological disorders.

METHODS

Berberine and neostigmine were weighed (30 g), dissolved in distilled water (30 mL) separately, while, 30 mg piperine was dissolved in ethanol (0.45 mL), made up to 30 mL with distilled water. Antioxidant activities in 2, 2-diphenyl-1-picrylhydrazyl radical (DPPH), 2, 2-azinobis (3-ethylbenzothiazoline-6-sulfonate) radical (ABTS), Fe-chelation, ferric reducing properties (FRAP), nitric oxide (NO) and hydroxyl (OH) radical scavenging abilities and Fe²⁺, cisplatin and sodium nitroprusside (SNP) induced lipid peroxidation (LPO), and acetylcholinesterase (AChE), butyrylcholinesterase (BChE) and monoamine oxidase (MAO) activities were assessed in vitro.

RESULTS

The result revealed that tested compounds inhibited enzymes activities dose-dependently. However, berberine (IC₅₀=0.17 mg/mL) had slight higher AChE inhibitory effect than piperine and neostigmine (p<0.05). Also, berberine had the highest BChE inhibitory effect (IC₅₀=0.16 mg/mL) while piperine exhibited the highest MAO inhibitory effect (IC₅₀=0.21 mg/mL). Berberine, piperine and neostigmine exhibited high antioxidant properties and inhibited Fe²⁺, cisplatin and SNP induced LPO.

CONCLUSIONS

Both alkaloids demonstrated antiradical scavenging ability comparable to neostigmine action against Alzheimer's disease (AD). The modulatory and antioxidant berberine and piperine properties on these enzymes (AChE, BChE and MAO) could be possible underlying mechanisms in employing these compounds as a complementary therapy in neurodegenerative diseases (NDDs) management.

Berberine-Loaded Thiolated Pluronic F127 Polymeric Micelles for Improving Skin Permeation and Retention

Background

Challenges associated with local antibacterial and anti-inflammatory drugs include low penetration and retention of drugs at the expected action site. Additionally, improving these challenges allows for the prevention of side effects that are caused by drug absorption into the systemic circulation and helps to safely treat local skin diseases.

Methods

In the current study, we successfully prepared a thiolated pluronic F127 polymer micelles (BTFM), which binds to keratin through a disulphide bond, to produce skin retention. In addition, the small particle size of polymer micelles promotes the penetration of carriers into the skin. The current study was divided into two experiments: an in vitro experiment; an in vivo experiment that involved the penetration of the micelle-loaded drugs into the skin of rats, the skin irritation test and the anti-inflammatory activity of the drug-loaded micelles on dimethyl benzene-induced ear edema in mice.

Results

Results from our in vitro transdermal experiment revealed that the amount of drug absorbed through the skin was decreased after the drug was loaded in the BTFM. Further, results from the vivo study, which used fluorescence microscopy to identify the location of the BTFM after penetration, revealed that there was strong fluorescence in the epidermis layer, but there was no strong fluorescence in the deep skin layer. In addition, the BTFM had a very good safety profile with no potentially hazardous skin irritation and transdermal administration of BTFM could significantly suppress ear edema induced by dimethyl benzene. Therefore, these findings indicated that BTFM reduced the amount of drug that entered the systemic circulation. Our results also demonstrated that the BTFM had a certain affinity for keratin.

Conclusion

Our experimental results suggest that the BTFM may be an effective drug carrier for local skin therapy with good safety profile.

Beta-Blockers and Berberine: A Possible Dual Approach to Contrast Neuroblastoma Growth and Progression

The use of nutraceuticals during cancer treatment is a long-lasting debate. Berberine (BBR) is an isoquinoline quaternary alkaloid extracted from a variety of medicinal plants. BBR has been shown to have therapeutic effects in different pathologies, particularly in cancer, where it affects pathways involved in tumor progression. In neuroblastoma, the most common extracranial childhood solid tumor, BBR, reduces tumor growth by regulating both stemness and differentiation features and by inducing apoptosis. At the same time, the inhibition of β-adrenergic signaling leads to a reduction in growth and increase of differentiation of neuroblastoma. In this review, we summarize the possible beneficial effects of BBR in counteracting tumor growth and progression in various types of cancer and, in particular, in neuroblastoma. However, BBR administration, besides its numerous beneficial effects, presents a few side effects due to inhibition of MAO A enzyme in neuroblastoma cells. Therefore, herein, we proposed a novel therapeutic strategy to overcome side effects of BBR administration consisting of concomitant administration of BBR together with β-blockers in neuroblastoma.

Traditional Chinese medicine for anti-Alzheimer's disease: berberine and evodiamine from Evodia rutaecarpa

Alzheimer's disease (AD) is one of the most common diseases in elderly people with a high incidence of dementia at approximately 60-80%. The pathogenesis of AD was quite complicated and currently there is no unified conclusion in the academic community, so no efficiently clinical treatment is available. In recent years, with the development of traditional Chinese medicine (TCM), researchers have proposed the idea of relying on TCM to prevent and treat AD based on the characteristic of multiple targets of TCM. This study reviewed the pathological hypothesis of AD and the potential biomarkers found in the current researches. And the potential targets of berberine and evodiamine from Evodia rutaecarpa in AD were summarized and further analyzed. A compound-targets-pathway network was carried out to clarify the mechanism of action of berberine and evodiamine for AD. Furthermore, the limitations of current researches on the TCM and AD were discussed. It is hoped that this review will provide some references for development of TCM in the prevention and treatment of AD.

Goldenseal (Hydrastis canadensis L.) and its active constituents: A critical review of their efficacy and toxicological issues

Goldenseal (Hydrastis canadensis L.) is a medicinal plant widely used in various traditional systems of medicine and as a food supplement. It has been traditionally used by Native Americans as a coloring agent and as medicinal remedy for common diseases and conditions like wounds, digestive disorders, ulcers, skin and eye ailments, and cancer. Over the years, goldenseal has become a popular food supplement in the USA and other regions. The rhizome of this plant has been used for the treatment of a variety of diseases including, gastrointestinal disorders, ulcers, muscular debility, nervous prostration, constipation, skin and eye infections, cancer, among others. Berberine is one of the most bioactive alkaloid that has been identified in different parts of goldenseal. The goldenseal extract containing berberine showed numerous therapeutic effects such as antimicrobial, anti-inflammatory, hypolipidemic, hypoglycemic, antioxidant, neuroprotective (anti-Alzheimer's disease), cardioprotective, and gastrointestinal protective. Various research finding suggest the health promoting effects of goldenseal components and their extracts. However, few studies have also suggested the possible neurotoxic, hepatotoxic and phototoxic activities of goldenseal extract and its alkaloids. Thus, large randomized, double-blind clinical studies need to be conducted on goldenseal supplements and their main alkaloids to provide more evidence on the mechanisms responsible for the pharmaceutical activity, clinical efficacy and safety of these products. Thus, it is very important to review the scientific information about goldenseal to understand about the current scenario.

Resveratrol Delivery from Implanted Cyclodextrin Polymers Provides Sustained Antioxidant Effect on Implanted Neural Probes

Intracortical microelectrodes are valuable tools used to study and treat neurological diseases. Due in large part to the oxidative stress and inflammatory response occurring after electrode implantation, the signal quality of these electrodes decreases over time. To alleviate this response, resveratrol, a natural antioxidant which elicits neuroprotective effects through reduction of oxidative stress, was utilized. This work compares traditional systemic delivery of resveratrol to the novel cyclodextrin polymer (pCD) local delivery approach presented herein, both in vitro and in vivo. The pCD displayed an extended resveratrol release for 100 days, as well as 60 days of free radical scavenging activity in vitro. In vivo results indicated that our pCD delivery system successfully delivered resveratrol to the brain with a sustained release for the entire short-duration study (up to 7 days). Interestingly, significantly greater concentrations of resveratrol metabolites were found at the intracortical probe implantation site compared to the systemic administration of resveratrol. Together, our pilot results provide support for the possibility of improving the delivery of resveratrol in an attempt to stabilize long-term neural interfacing applications.

Berberine for prevention of dementia associated with diabetes and its comorbidities: A systematic review

BACKGROUND

A growing number of epidemiological studies indicate that metabolic syndrome (MetS) and its associated features play a key role in the development of certain degenerative brain disorders, including Alzheimer's disease and vascular dementia. Produced by several different medicinal plants, berberine is a bioactive alkaloid with a wide range of pharmacological effects, including antidiabetic effects. However, it is not clear whether berberine could prevent the development of dementia in association with diabetes.

OBJECTIVE

To give an overview of the therapeutic potential of berberine as a treatment for dementia associated with diabetes.

SEARCH STRATEGY

Database searches A and B were conducted using PubMed and ScienceDirect. In search A, studies on berberine's antidementia activities were identified using "berberine" and "dementia" as search terms. In search B, recent studies on berberine's effects on diabetes were surveyed using "berberine" and "diabetes" as search terms.

INCLUSION CRITERIA

Clinical and preclinical studies that investigated berberine's effects associated with MetS and cognitive dysfunction were included.

DATA EXTRACTION AND ANALYSIS

Data from studies were extracted by one author, and checked by a second; quality assessments were performed independently by two authors.

RESULTS

In search A, 61 articles were identified, and 22 original research articles were selected. In search B, 458 articles were identified, of which 101 were deemed relevant and selected. Three duplicates were removed, and a total of 120 articles were reviewed for this study. The results demonstrate that berberine exerts beneficial effects directly in the brain: enhancing cholinergic neurotransmission, improving cerebral blood flow, protecting neurons from inflammation, limiting hyperphosphorylation of tau and facilitating β-amyloid peptide clearance. In addition, evidence is growing that berberine is effective against diabetes and associated disorders, such as atherosclerosis, cardiomyopathy, hypertension, hepatic steatosis, diabetic nephropathy, gut dysbiosis, retinopathy and neuropathy, suggesting indirect benefits for the prevention of dementia.

CONCLUSION

Berberine could impede the development of dementia via multiple mechanisms: preventing brain damages and enhancing cognition directly in the brain, and indirectly through alleviating risk factors such as metabolic dysfunction, and cardiovascular, kidney and liver diseases. This study provided evidence to support the value of berberine in the prevention of dementia associated with MetS.

Combating Neurodegenerative Diseases with the Plant Alkaloid Berberine: Molecular Mechanisms and Therapeutic Potential

Abstract: Neurodegenerative diseases are among the most serious health problems affecting millions of people worldwide. Such diseases are characterized by a progressive degeneration and / or death of neurons in the central nervous system. Currently, there are no therapeutic approaches to cure or even halt the progression of neurodegenerative diseases. During the last two decades, much attention has been paid to the neuroprotective and anti-neurodegenerative activities of compounds isolated from natural products with high efficacy and low toxicity. Accumulating evidence indicates that berberine, an isoquinoline alkaloid isolated from traditional Chinese medicinal herbs, may act as a promising anti-neurodegenerative agent by inhibiting the activity of the most important pathogenic enzymes, ameliorating intracellular oxidative stress, attenuating neuroinflammation, triggering autophagy and protecting neurons against apoptotic cell death. This review attempts to summarize the current state of knowledge regarding the therapeutic potential of berberine against neurodegenerative diseases, with a focus on the molecular mechanisms that underlie its effects on Alzheimer’s, Parkinson’s and Huntington’s diseases.

Potent inhibition of acetylcholinesterase by sargachromanol I from Sargassum siliquastrum and by selected natural compounds

Six hundred forty natural compounds were tested for acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) inhibitory activities. Of those, sargachromanol I (SCI) and G (SCG) isolated from the brown alga Sargassum siliquastrum, dihydroberberine (DB) isolated from Coptis chinensis, and macelignan (ML) isolated from Myristica fragrans, potently and effectively inhibited AChE with IC50 values of 0.79, 1.81, 1.18, and 4.16 µM, respectively. SCI, DB, and ML reversibly inhibited AChE and showed mixed, competitive, and noncompetitive inhibition, respectively, with Ki values of 0.63, 0.77, and 4.46 µM, respectively. Broussonin A most potently inhibited BChE (IC50 = 4.16 µM), followed by ML, SCG, and SCI (9.69, 10.79, and 13.69 µM, respectively). In dual-targeting experiments, ML effectively inhibited monoamine oxidase B with the greatest potency (IC50 = 7.42 µM). Molecular docking simulation suggested the binding affinity of SCI (-8.6 kcal/mol) with AChE was greater than those of SCG (-7.9 kcal/mol) and DB (-8.2 kcal/mol). Docking simulation indicated SCI interacts with AChE at Trp81, and that SCG interacts at Ser119. No hydrogen bond was predicted for the interaction between AChE and DB. This study suggests SCI, SCG, DB, and ML be viewed as new reversible AChE inhibitors and useful lead compounds for the development for the treatment of Alzheimer's disease.

Neuroprotective effects of berberine in animal models of Alzheimer's disease: a systematic review of pre-clinical studies

Background

Berberine is an isoquinoline alkaloid extracted from various Berberis species which is widely used in East Asia for a wide range of symptoms. Recently, neuroprotective effects of berberine in Alzheimer’s disease (AD) animal models are being extensively reported. So far, no clinical trial has been carried out on the neuroprotective effects of berberine. However, a review of the experimental data is needed before choosing berberine as a candidate drug for clinical experiments. We conducted a systematic review on AD rodent models to analyze the drug effects with minimal selection bias.

Methods

Five online literature databases were searched to find publications reporting studies of the effect of berberine treatment on animal models of AD. Up to March 2018, 15 papers were identified to describe the efficacy of berberine.

Results

The included 15 articles met our inclusion criteria with different quality ranging from 3 to 5. We analyzed data extracted from full texts with regard to pharmacological effects and potential anti-Alzheimer’s properties. Our analysis revealed that in multiple memory defects animal models, berberine showed significant memory-improving activities with multiple mechanisms, such as anti-inflammation, anti-oxidative stress, cholinesterase (ChE) inhibition and anti-amyloid effects.

Conclusion

AD is likely to be a complex disease driven by multiple factors. Yet, many therapeutic strategies based on lowering β-amyloid have failed in clinical trials. This suggest that the threapy should not base on a single cause of Alzheimer’s disease but rather a number of different pathways that lead to the disease. Overall we think that berberine can be a promising multipotent agent to combat Alzheimer’s disease.

3D-QSAR and in-silico Studies of Natural Products and Related Derivatives as Monoamine Oxidase Inhibitors

BACKGROUND

The computational development of human monoamine oxidase (MAO) inhibitors led to advancement in drug design and the treatment of many neurodegenerative diseases and neuropsychiatric disorders. The computational development of human monoamine oxidase (MAO) inhibitors led to advancement in drug design and the treatment of many neurodegenerative diseases and neuropsychiatric disorders. Different natural heterocyclic structures are reported to display selective MAO inhibitory activity by preclinical and in-silico modeling.

OBJECTIVE

Currently, the major interest is devoted to the study of natural based therapeutic agents from the different categories. Therefore, we presenting the review to critically discuss and outline the recent advances in our knowledge on the importance of natural and natural based ligand-MAO insilico methods for novel MAO inhibitors.

DISCUSSION

Several natural and related synthetic heterocyclic compounds such as coumarins, β- carboline, piperine, naphthoquinone, morpholine, caffeine, amphetamine moreover flavonoids, chalcones, xanthones, curcumin are discussed for their MAO inhibitory profile along with molecular docking and quantitative structure-activity relationship studies.

CONCLUSION

It is clear that, by this computational drug design approach, more particular, reversible and potent compounds can be proposed as MAO inhibitors by exact changes on the fundamental framework.

Toxicological Effects of Berberine and Sanguinarine

Berberine and Sanguinarine alkaloids belong to a group of naturally occurring chemical compounds that mostly contain basic nitrogen atoms. This group also includes some related compounds with neutral or weakly acidic properties. Alkaloids are produced by a large number of organisms including bacteria, fungi, plants, and animals. Berberine and Sanguinarine both are isoquinoline derivatives and belong to protoberberine and benzophenanthridines, respectively. Tyrosine or phenylalanine is common precursor for the biosynthesis of both. Sanguinarine [13-methyl (1,3) benzodioxolo(5,6-c)-1,3-dioxolo (4,5) phenanthridinium] is a toxin that kills animal cells through its action on the Na⁺-K⁺-ATPase transmembrane protein. Berberine, on the other hand, has been reported to cause cytotoxicity and adversely influence the synthesis of DNA. Several workers have reported varied pharmacological properties of these alkaloids as they exhibit antibacterial, antiasthma, anticancer, anti-inflammatory, and antidiabetic activities. This review article illustrates the toxicological effects of berberine and sanguinarine as well as mechanistic part of berberine and sanguinarine mediated toxicity in different living systems. This manuscript has included the lethal doses (LD₅₀) of berberine and sanguinarine in different animals via different routs of exposure. Also, the effects of these alkaloids on the activities of some key enzymes, cell lines and organ development etc. have been summarized.

Neuroprotective effect of berberine against environmental heavy metals-induced neurotoxicity and Alzheimer's-like disease in rats

Heavy metals are reported as neurodegenerative disorders progenitor. They play a role in the precipitation of abnormal β-amyloid protein and hyper-phosphorylated tau, the main hallmarks of Alzheimer's disease (AD). The present study aimed to validate the heavy metals-induced Alzheimer's-like disease in rats as an experimental model of AD and explore the therapeutic effect of berberine via tracking its effect on the oxidative stress-inflammatory pathway. Alzheimer's-like disease was induced in rats orally by a mixture of aluminium, cadmium and fluoride for three months, followed by berberine treatment for another one month. Berberine significantly improved the cognitive behaviors in Morris water maze test and offered a protective effect against heavy metals-induced memory impairment. Docking results showed that berberine inhibited AChE, COX-2 and TACE. Matching with in silico study, berberine downregulated the AChE expression and inhibited its activity in the brain tissues. Also, it normalized the production of TNF- α, IL-12, IL-6 and IL-1β. Moreover, it evoked the production of antioxidant Aβ40 and inhibited the formation of Aβ42, responsible for the aggregations of amyloid-β plaques. Histopathological examination confirmed the neuroprotective effect of berberine. The present data advocate the possible beneficial effect of berberine as therapeutic modality for Alzheimer's disease via its antiinflammatory/antioxidant mechanism.

Berberine Reduces Neurotoxicity Related to Nonalcoholic Steatohepatitis in Rats

Berberine is a plant alkaloid that has several pharmacological effects such as antioxidant, antilipidemic, and anti-inflammatory effects. Nonalcoholic steatohepatitis (NASH) triggers different aspects of disorders such as impaired endogenous lipid metabolism, hypercholesterolemia, oxidative stress, and neurotoxicity. In this study, we examined the mechanism by which NASH induces neurotoxicity and the protective effect of berberine against both NASH and its associated neurotoxicity. NASH induced rats showed significant impairments in lipid metabolism with increased serum triglycerides, cholesterol, and low-density lipoprotein (LDL). The NASH induced group also demonstrated a significant oxidative stress which is characterized by increased TBARs level and decreased antioxidant capacity such as GSH and SOD levels. Moreover, the NASH induction was associated with inflammation which was demonstrated by increased TNFα and nitric oxide levels. Hyperglycemia and hyperinsulinemia were observed in the NASH induced group. Also, our results showed a significant increase in the expression of the acetylcholine esterase (AChE) and amyloid beta precursor protein (AβPP). These changes were significantly correlated with decreased insulin degrading enzyme (IDE) and beta-amyloid40 (Aβ 40) and increased beta-amyloid42 (Aβ 42) in the hippocampal region. Daily administration of berberine (50 mg/kg) for three weeks ameliorated oxidative stress, inflammation, hyperlipidemia, hyperglycemia, hyperinsulinemia, and the observed neurotoxicity.

The neuroprotective effect of berberine in mercury-induced neurotoxicity in rats

The central nervous system is one of the most vulnerable organs affected by mercury toxicity. Both acute and chronic exposure to mercury is also known to cause a variety of neurological or psychiatric disorders. Here, the neuroprotective effect of berberine (BN; 100 mg/kg bwt) on mercuric chloride (HgCl2; 0.4 mg/kg bwt) induced neurotoxicity and oxidative stress was examined in rats. Adult male albino Wistar rats were injected with HgCl2 for 7 days. HgCl2 treatment induced oxidative stress by increasing lipid peroxidation (LPO) and nitrite/nitrate (nitric oxide; NO) production along with a concomitant decrease in glutathione (GSH) and various antioxidant enzymes, namely superoxide dismutase, catalase, glutathione peroxidase and glutathione reductase. Pre-treatment of rats with BN inhibited LPO and NO production, whereas it increased GSH content. Activities of antioxidant enzymes were also restored concomitantly when compared to the control rats after BN administration. Berberine also caused decrease in TNF-α level and caspase-3 activity which was higher with HgCl2. Furthermore, treatment with BN inhibited apoptosis, as indicated by the reduction of Bax/Bcl-2 ratio in brain tissue. These data indicated that BN augments antioxidant defense with anti-inflammatory and anti-apoptotic activities against HgCl2-induced neurotoxicity and provides evidence that it has a therapeutic potential as neuroprotective agent.

Current knowledge and pharmacological profile of berberine: An update

Berberine, a benzylisoquinoline alkaloid, occurs as an active constituent in numerous medicinal plants and has an array of pharmacological properties. It has been used in Ayurvedic and Chinese medicine for its antimicrobial, antiprotozoal, antidiarrheal and antitrachoma activity. Moreover, several clinical and preclinical studies demonstrate ameliorative effect of berberine against several disorders including metabolic, neurological and cardiological problems. This review provides a summary regarding the pharmacokinetic and pharmacodynamic features of berberine, with a focus on the different mechanisms underlying its multispectrum activity. Studies regarding the safety profile, drug interactions and important clinical trials of berberine have also been included. Clinical trials with respect to neurological disorders need to be undertaken to exploit the beneficiary effects of berberine against serious disorders such as Alzheimer's and Parkinson's disease. Also, clinical studies to detect rare adverse effects of berberine need to be initiated to draw a complete safety profile of berberine and strengthen its applicability.

The therapeutic potential of berberine against the altered intrinsic properties of the CA1 neurons induced by Aβ neurotoxicity

It was demonstrated that treatment with beta amyloid (Aβ) led to extreme alterations in the intrinsic electrophysiological properties of CA1 pyramidal neurons. Also, malfunction of the cholinergic system is correlated to the memory and cognitive impairments. Several new studies have suggested that Berberis vulgaris can act as a cholinesterase inhibitor. The present study aimed to investigate the effects of berberine (BER) on the Aβ-induced impairments in learning and memory. The male Wistar rats were divided into 4 groups of Sham, BER, Aβ and Aβ+BER. The administration of BER or its vehicle started immediately after the injection of Aβ and followed by 13 days. Then, the animals were tested for learning and memory performance using the Morris water maze (MWM) and passive avoidance tests. Then, they were sacrificed for the whole cell patch clamp recording. The results of the MWM and passive avoidance tasks indicated that administration of the BER in the Aβ+BER group prevented the memory impairment induced by Aβ. The results of the whole cell patch clamp also showed that administration of the BER restored the Aβ-induced impairments in the firing frequency, half-width and rebound action potential. These results suggested that administration of the BER could ameliorate neurotoxicity induced by Aβ. However, this neuroprotection impact could be resulted from the balance effect of the Ca(2+) entry. The optimal level of Ca(2+) entry by BER could be a major factor that modified the function of the Ca(2+)-activated K(+) channels and decreased the half-width in the Aβ treated rats.

The therapeutic potential of Berberine chloride hydrate against harmaline-induced motor impairments in a rat model of tremor

Essential tremor (ET) is a progressive neurological disorder with motor and non-motor symptoms. It has conclusively been shown that modulation of glutamate receptors could ameliorate ET. Recent studies have suggested that Berberine (BBR) has an inhibitory effect on glutamate receptors. Therefore, BBR may have therapeutic effects on ET. In this study, male Wistar rats (n=10 in each group) weighing 40-60 g were divided into control, harmaline (30 mg/kg, i.p.) and berberine (10, 20 or 50mg/kg, i.p, 15 min before harmaline injection) groups. Open field, rotarod, wire grip and foot print tests were used to evaluate motor performance. The results indicated that the administration of BBR (10 and 20mg/kg) attenuated harmaline-induced tremor in rats, but the beneficial effects of BBR could not be identified at dose 50mg/kg. In addition, BBR ameliorated gait disturbance in doses of 10 and 20mg/kg. The high dose of BBR not only failed to recover step width but also showed an adverse effect on left and right step length. The results indicate that BBR only in dose of 20mg/kg recovers mobility duration. The current study found a dose-dependent manner for the therapeutic effects of BBR in ET. Our study provides the initial evidence for the effects of BBR on motor function. Since BBR exerts its effects mainly through regulation of neurotransmitter release or blocke of NMDA receptors, thus, it is predicted that BBR ameliorate harmaline effect through blockade of NMDA receptors or glutamate release. This is an important issue for future research to evaluate the possible mechanisms involved.

Alkaloids as a source of potential anticholinesterase inhibitors for the treatment of Alzheimer's disease

Objectives

The inhibition of acetylcholinesterase (AChE), the key enzyme in the breakdown of acetylcholine, is currently the main pharmacological strategy available for Alzheimer's disease (AD). In this sense, many alkaloids isolated from natural sources, such as physostigmine, have been long recognized as acetyl- and butyrylcholinesterase (BChE) inhibitors. Since the approval of galantamine for the treatment of AD patients, the search for new anticholinesterase alkaloids has escalated, leading to promising candidates such as huperzine A. This review aims to summarize recent advances in current knowledge on alkaloids as AChE and BChE inhibitors, highlighting structure–activity relationship (SAR) and docking studies.

Key findings

Natural alkaloids belonging to the steroidal/triterpenoidal, quinolizidine, isoquinoline and indole classes, mainly distributed within Buxaceae, Amaryllidaceae and Lycopodiaceae, are considered important sources of alkaloids with anti-enzymatic properties. Investigations into the possible SARs for some active compounds are based on molecular modelling studies, predicting the mode of interaction of the molecules with amino acid residues in the active site of the enzymes. Following this view, an increasing interest in achieving more potent and effective analogues makes alkaloids good chemical templates for the development of new cholinesterase inhibitors.

Summary

The anticholinesterase activity of alkaloids, together with their structural diversity and physicochemical properties, makes them good candidate agents for the treatment of AD.

Nature as a source of metabolites with cholinesterase-inhibitory activity: an approach to Alzheimer's disease treatment

Objectives

Alzheimer's disease (AD) is the most common cause of dementia, being responsible for high healthcare costs and familial hardships. Despite the efforts of researchers, no treatment able to delay or stop AD progress exists. Currently, the available treatments are only symptomatic, cholinesterase inhibitors being the most widely used drugs. Here we describe several natural compounds with anticholinesterase (acetylcholinesterase and butyrylcholinesterase) activity and also some synthetic compounds whose structures are based on those of natural compounds.

Key findings

Galantamine and rivastigmine are two cholinesterase inhibitors used in therapeutics: galantamine is a natural alkaloid that was extracted for the first time from Galanthus nivalis L., while rivastigmine is a synthetic alkaloid, the structure of which is modelled on that of natural physostigmine. Alkaloids include a high number of compounds with anticholinesterases activity at the submicromolar range. Quinones and stilbenes are less well studied regarding cholinesterase inhibition, although some of them, such as sargaquinoic acid or (+)-α-viniferin, show promising activity. Among flavonoids, flavones and isoflavones are the most potent compounds. Xanthones and monoterpenes are generally weak cholinesterase inhibitors.

Summary

Nature is an almost endless source of bioactive compounds. Several natural compounds have anticholinesterase activity and others can be used as leader compounds for the synthesis of new drugs.