Effects of grape seed proanthocyanidin on Alzheimer's disease in vitro and in vivo

Exploring the Neuroprotective Effects of Grape Seed Procyanidins on Amyloid-β-Induced Toxicity in Caenorhabditis elegans

Alzheimer's disease (AD), a major neurodegenerative disorder, is characterized by the progressive accumulation of amyloid-β (Aβ) plaques, leading to cognitive decline. Despite the existing treatments, their limited efficacy highlights the urgent need for novel therapeutic strategies. The present study investigates the neuroprotective effects of a grape seed polyphenol extract (GSPE) on transgenic Caenorhabditis elegans models specifically expressing human Aβ proteins. The obtained results show that GSPE not only significantly attenuates Aβ-induced paralysis but also extends the lifespan and improves sensory responses in these models, suggesting improved neural function and overall health. Additionally, GSPE treatment reduces proteasomal activity, which could lead to a reduction in the accumulation of misfolded proteins. It also modulates the expression of key genes involved in autophagy and proteostasis, thereby enhancing cellular mechanisms to manage protein aggregation and combat oxidative stress. On the whole, these findings support the potential of grape seed procyanidins (the main components in the extract) to be used as an effective dietary approach to mitigate Alzheimer's disease pathology through the modulation of critical neuroprotective pathways.

Unraveling potential neuroprotective mechanisms of herbal medicine for Alzheimer's diseases through comprehensive molecular docking analyses

Alzheimer's disease (AD) continues to be a worldwide health concern, demanding innovative therapeutic approaches. This study investigates the neuroprotective potential of herbal compounds by scrutinizing their interactions with Beta-Secretase-1 (BACE1). Through comprehensive molecular docking analyses, three compounds, Masticadienonic acid (ΔG: -9.6 kcal/mol), Hederagenin (ΔG: -9.3 kcal/mol), and Anthocyanins (ΔG: -8.1 kcal/mol), emerge as promising BACE1 ligands, displaying low binding energies and strong affinities. ADME parameter predictions, drug-likeness assessments, and toxicity analyses reveal favorable pharmacokinetic profiles for these compounds. Notably, Masticadienonic Acid exhibits optimal drug-likeness (-3.3736) and negligible toxicity concerns. Hederagenin (drug-likeness: -5.3272) and Anthocyanins (drug-likeness: -6.2041) also demonstrate promising safety profiles. Furthermore, pharmacophore modeling elucidates the compounds' unique interaction landscapes within BACE1's active site. Masticadienonic acid showcases seven hydrophobic interactions and a hydrogen bond acceptor interaction with Thr232. Hederagenin exhibits a specific hydrogen bond acceptor interaction with Trp76, emphasizing its selective binding. Anthocyanins reveal a multifaceted engagement, combining hydrophobic contacts and hydrogen bond interactions with key residues. In conclusion, Masticadienonic acid, Hederagenin, and Anthocyanins stand out as promising candidates for further experimental validation, presenting a synergistic balance of efficacy and safety in combating AD through BACE1 inhibition.

The benefits of grape seed extract in neurological disorders and brain aging

Common neurological disorders, including neurodegenerative diseases, stroke, epilepsy, autism and psychiatric disorders, affect many people worldwide and threaten their lives and health by inducing movement disorders, behavioral disorders, or a combination of both. Oxidative stress and neuroinflammation play a central role in neuronal damage and neurological diseases induction and progression. In addition, protein homeostasis (proteostasis) impairment occurs in many neurodegenerative diseases, which plays a critical role in the progression of the pathology. Grape seed contains several flavonoids and non-flavonoids and exerts potent antioxidant and anti-inflammatory effects. In addition, polyphenols and flavanols can maintain cellular proteostasis. Since impaired proteostasis is closely involved in all amyloid diseases, particularly neurodegenerative diseases, grape seeds extract can be a valuable therapeutic agent. Therefore, this review discusses the protective and therapeutic mechanisms of grape seed against neurological disorders and, in the end, links GSE to microRNAs as future therapeutic developments.

Bioactive Compounds and Their Derivatives: An Insight into Prospective Phytotherapeutic Approach against Alzheimer’s Disease

Alzheimer's disease (AD) is a common neurodegenerative brain disorder that causes cellular response alterations, such as impaired cholinergic mechanism, amyloid-beta (Aβ) AD aggregation, neuroinflammation, and several other pathways. AD is still the most prevalent form of dementia and affects many individuals across the globe. The exact cause of the disorder is obscure. There are yet no effective medications for halting, preventing, or curing AD's progress. Plenty of natural products are isolated from several sources and analyzed in preclinical and clinical settings for neuroprotective effects in preventing and treating AD. In addition, natural products and their derivatives have been promising in treating and preventing AD. Natural bioactive compounds play an active modulatory role in the pathological molecular mechanisms of AD development. This review focuses on natural products from plant sources and their derivatives that have demonstrated neuroprotective activities and maybe promising to treat and prevent AD. In addition, this article summarizes the literature pertaining to natural products as agents in the treatment of AD. Rapid metabolism, nonspecific targeting, low solubility, lack of BBB permeability, and limited bioavailability are shortcomings of most bioactive molecules in treating AD. We can use nanotechnology and nanocarriers based on different types of approaches.

Dietary Plant Polyphenols as the Potential Drugs in Neurodegenerative Diseases: Current Evidence, Advances, and Opportunities

Neurodegenerative diseases, including Alzheimer's disease (AD), Parkinson's disease (PD), and Huntington's disease (HD), are characterized by the progressive degeneration of neurons. Although the etiology and pathogenesis of neurodegenerative diseases have been studied intensively, the mechanism is still in its infancy. In general, most neurodegenerative diseases share common molecular mechanisms, and multiple risks interact and promote the pathologic process of neurogenerative diseases. At present, most of the approved drugs only alleviate the clinical symptoms but fail to cure neurodegenerative diseases. Numerous studies indicate that dietary plant polyphenols are safe and exhibit potent neuroprotective effects in various neurodegenerative diseases. However, low bioavailability is the biggest obstacle for polyphenol that largely limits its adoption from evidence into clinical practice. In this review, we summarized the widely recognized mechanisms associated with neurodegenerative diseases, such as misfolded proteins, mitochondrial dysfunction, oxidative damage, and neuroinflammatory responses. In addition, we summarized the research advances about the neuroprotective effect of the most widely reported dietary plant polyphenols. Moreover, we discussed the current clinical study and application of polyphenols and the factors that result in low bioavailability, such as poor stability and low permeability across the blood-brain barrier (BBB). In the future, the improvement of absorption and stability, modification of structure and formulation, and the combination therapy will provide more opportunities from the laboratory into the clinic for polyphenols. Lastly, we hope that the present review will encourage further researches on natural dietary polyphenols in the treatment of neurodegenerative diseases.

Potential of Sorghum Polyphenols to Prevent and Treat Alzheimer's Disease: A Review Article

Alzheimer's disease (AD) is characterized by the excessive deposition of extracellular amyloid-beta peptide (Aβ) and the build-up of intracellular neurofibrillary tangles containing hyperphosphorylated tau proteins. This leads to neuronal damage, cell death and consequently results in memory and learning impairments leading to dementia. Although the exact cause of AD is not yet clear, numerous studies indicate that oxidative stress, inflammation, and mitochondrial dysfunction significantly contribute to its onset and progression. There is no effective therapeutic approach to stop the progression of AD and its associated symptoms. Thus, early intervention, preferably, pre-clinically when the brain is not significantly affected, is a better option for effective treatment. Natural polyphenols (PP) target multiple AD-related pathways such as protecting the brain from Aβ and tau neurotoxicity, ameliorating oxidative damage and mitochondrial dysfunction. Among natural products, the cereal crop sorghum has some unique features. It is one of the major global grain crops but in the developed world, it is primarily used as feed for farm animals. A broad range of PP, including phenolic acids, flavonoids, and condensed tannins are present in sorghum grain including some classes such as proanthocyanidins that are rarely found in others plants. Pigmented varieties of sorghum have the highest polyphenolic content and antioxidant activity which potentially makes their consumption beneficial for human health through different pathways such as oxidative stress reduction and thus the prevention and treatment of neurodegenerative diseases. This review summarizes the potential of sorghum PP to beneficially affect the neuropathology of AD.

Neuroprotective Natural Products for Alzheimer's Disease

Alzheimer's disease (AD) is the number one neurovegetative disease, but its treatment options are relatively few and ineffective. In efforts to discover new strategies for AD therapy, natural products have aroused interest in the research community and in the pharmaceutical industry for their neuroprotective activity, targeting different pathological mechanisms associated with AD. A wide variety of natural products from different origins have been evaluated preclinically and clinically for their neuroprotective mechanisms in preventing and attenuating the multifactorial pathologies of AD. This review mainly focuses on the possible neuroprotective mechanisms from natural products that may be beneficial in AD treatment and the natural product mixtures or extracts from different sources that have demonstrated neuroprotective activity in preclinical and/or clinical studies. It is believed that natural product mixtures or extracts containing multiple bioactive compounds that can work additively or synergistically to exhibit multiple neuroprotective mechanisms might be an effective approach in AD drug discovery.

Natural Food Supplements Reduce Oxidative Stress in Primary Neurons and in the Mouse Brain, Suggesting Applications in the Prevention of Neurodegenerative Diseases

Neurodegenerative diseases pose a major health problem for developed countries, and stress has been identified as one of the main risk factors in the development of these disorders. Here, we have examined the protective properties against oxidative stress of several bioactive natural food supplements. We found that MecobalActive^®, Olews^®, and red and white grape seed polyphenol extracts may have a neuroprotective effect in vitro, both in the SH-SY 5Y cell line and in hippocampal neuron cultures, mainly by reducing reactive oxygen species levels and decreasing caspase-3 activity. In vivo, we demonstrated that oral administration of the supplements reduces the expression of genes involved in inflammation and oxidation mechanisms, whereas it increments the expression of genes related to protection against oxidative stress. Furthermore, we found that preventive treatment with these natural extracts increases the activity of antioxidant enzymes and prevents lipid peroxidation in the brain of stressed mice. Thus, our results indicate that some natural bioactive supplements may have important protective properties against oxidative stress processes occurring in the brain.

Pharmacokinetic Differences of Grape Seed Procyanidins According to the Gavage Administration Between Normal Rats and Alzheimer's Disease Rats

Background:

Grape Seed Procyanidins (GSP) refers to a type of natural polyphenols that have to roust antioxidant capacity. Studies have shed light on the fact that GSP significantly impacts the alleviation of Alzheimer's Disease (AD).

Objective:

This study aimed at investigating whether there exists a pharmacokinetics difference in GSP between normal and AD rats, a rapid UPLC-MS/MS methodology, for the detection of its content in plasma samples was put forward. We carried out an analysis of the plasma concentrations of procyanidin B2, procyanidin B3, catechin and epicatechin in normal and AD rats over time for determining the plasma concentration of GSP.

Methods:

We made use of 400 μL of methanol for the protein precipitation solvent in the plasma treatment. The chromatographic separation was carried out on a C18 column at a temperature of 20 °C. The mobile phase was a gradient of 0.1% formic acid in water and methanol within 15 min.

Results:

: In the current research work, the plasma concentrations of procyanidin B2, procyanidin B3, catechin and epicatechin in AD rats were significantly higher as compared with those in normal rats (P < 0.05) and the content of epicatechin constituted the highest as compared with catechin, procyanidin B2 and procyanidin B3 following the administration of GSP.

Conclusion:

We discovered the better absorptions of these analytes in the AD group as compared with that in the normal group, providing an analytical basis for treating the AD with procyanidins.

Grape Seed Oil as a Natural Therapy in Male Rats with Alzheimer's Diseases

Purpose: Alzheimer's disease (AD) is a chronic neurodegenerative disorder, with an increasing prevalence rate, mostly related to cholinergic system. According to the difficulties and complications in management of AD, this study was carried out to evaluate the efficacy of grape seed oil (GSO) on scopolamine (Scop) induced Alzheimer's in male rats. Methods: 64 healthy male Wistar rats received different treatments such as: normal saline (NS), donepezil (Don), Scop and GSO, according to the previously designed protocol. Morris (MWM) was applied for spatial memory tests. Right after the behavioral tests, the brains were removed and the hippocampus was separated for evaluation of acetylcholine levels as well as cell death and neuro inflammation. Results: The results of the test day indicated that the mean Q2 time was increased in both GSO test groups (P <0.05) and Don treated group (P <0.001).The spectrophotometric findings affirm that both GSO co-treatment and post-treatment were effective in augmenting brain acetylcholine levels (P <0.01 and P <0.05 respectively). The microscopic findings of H&E dyed tissues confirmed the above mentioned results for different treatments except for GSO post treatment, in which the viability of cells were very low. Conclusion: The results implied that supplementation of rats with GSO caused a significant augmentation in spatial memory performance as well as acetylcholine levels and cell viability in the presence of Scop. This effect was comparable to that of Don especially when GSO was used as co-treatment.

Grape Seed Extracts Inhibit the Overexpression of Inflammatory Cytokines in Mouse Retinas and ARPE-19 Cells: Potentially Useful Dietary Supplement for Age-Related Eye Dysfunction

Aging can cause retinal degeneration, which leads to visual impairment among the elderly population. Age-dependent increases in amyloid beta (Aβ) inducesinflammatory cytokine overexpression in the retinal pigment epithelium (RPE), which promotes the progression of age-related retinal degeneration. However, whether dietary antioxidants are useful for the treatment of RPE degeneration remains to be clarified. This study exposited the protective activities and underlying mechanisms of grape seed extracts (GSEs) against Aβ-induced proinflammatory events in mouse retinas and ARPE-19 cells. The experimental data demonstrated that GSEs attenuated the increases in messenger RNA (mRNA) levels of interleukin 12 (IL-12), interleukin 6 (IL-6), interleukin 1β (IL-1β), and interleukin 18 (IL-18) in the retinal tissues of Aβ-treated mice. The experimental results in mice were confirmed by findings in ARPE-19 cells with or without treatment with GSEs. GSEs affected the protein expression levels of endoplasmic reticulum stress markers in ARPE-19 cells exposed to Aβ. Knockdown of Bip blocked the inhibitory activities of GSEs on mRNA levels of IL-6, IL-1β, IL-18, and IL-8. We conclude that GSEs may suppress proinflammatory cytokines partly by increasing the expression of Bip.

The effect of "mavizˮ on memory improvement in university students: A randomized open-label clinical trial

OBJECTIVE

Numerous studies demonstrated the effect of grape on memory improvement. According to Iranian traditional medicine, "mavizˮ as a specific type of dried grapes can effectively improve memory. However, there is no reported clinical trial on the effect of "mavizˮ on memory improvement in humans. Hence, this study was conducted to investigate "mavizˮ effect on memory in university students.

MATERIALS AND METHODS

This randomized open-label clinical trial was conducted on a total number of 53 students of Shahed University, Tehran, Iran, from November 2017 to February 2018. The participants were randomly allocated into an intervention group (receiving "mavizˮ, 25 g in the morning for 4 weeks) or a control group (who did not take "mavizˮ). The Digit Span Task and the N-Back Task were used for the measurement of working memory at the pre- and post-intervention stages.

RESULTS

According to the results, no significant differences were found between the two groups regarding age, gender, marital status, and initial working memory test scores. "mavizˮ consumption produced a highly significant improvement in total working memory score in the Digit Span Task (5.18 vs. 2.35, p<0.001) and Acoustic Memory Span (1.29 vs. 0.62, p=0.021). Moreover, "mavizˮ consumption significantly increased the percentage of true responses in the N-Back Task and reduced the mean reaction time in the first level of the task.

CONCLUSION

"mavizˮ consumption was improved working memory in young healthy adults.

Potential for diet to prevent and remediate cognitive deficits in neurological disorders

The pathophysiology of many neurological disorders involves oxidative stress, neuroinflammation, and mitochondrial dysfunction. There is now substantial evidence that diet can decrease these forms of pathophysiology, and an emerging body of literature relatedly suggests that diet can also prevent or even remediate the cognitive deficits observed in neurological disorders that exhibit such pathology (eg, Alzheimer's disease, multiple sclerosis, age-related cognitive decline, epilepsy). The current review summarizes the emerging evidence in relation to whole diets prominent in the scientific literature-ketogenic, caloric restriction, high polyphenol, and Mediterranean diets-and provides a discussion of the possible underlying neurophysiological mechanisms.

Therapeutic effect of oligomeric proanthocyanidin in cuprizone-induced demyelination

NEW FINDINGS

What is the central question of this study? Oligomeric proanthocyanidin has the capacity to alleviate abnormalities in neurological functioning. However, whether oligomeric proanthocyanidin can reduce the progression of demyelination or promote remyelination in demyelinating diseases remains unknown. What is the main finding and its importance? Oligomeric proanthocyanidin can improve cuprizone-induced demyelination by inhibiting immune cell infiltration, reversing overactivated microglia, decreasing the inflammatory cytokines secreted by inflammatory cells and decreasing the production of myelin oligodendrocyte glycoprotein_35-55 -specific antibody in the brain.

ABSTRACT

Demyelinating diseases of the CNS, including multiple sclerosis, neuromyelitis optica and acute disseminated encephalomylitis, are characterized by recurrent primary demyelination-remyelination and progressive neurodegeneration. In the present study, we investigated the therapeutic effect of oligomeric proanthocyanidin (OPC), the most effective component of grape seed extract, in cuprizone-fed C57BL/6 mice, a classic demyelination-remyelination model. Our results showed that OPC attenuated abnormal behaviour, reduced demyelination and increased expression of myelin basic protein and expression of O4⁺ oligodendrocytes in the corpus callosum. Oligomeric proanthocyanidin also reduced the numbers of B and T cells, activated microglia in the corpus callosum and inhibited secretion of inflammatory factors. Furthermore, concentrations of myelin oligodendrocyte glycoprotein-specific antibodies were significantly reduced in serum and brain homogenates after OPC treatment. Together, these results demonstrate a potent therapeutic effect for OPC in cuprizone-mediated demyelination and clearly highlight multiple effects of this natural product in attenuating myelin-specific autoantibodies and the inflammatory microenvironment in the brain.

Suppression of Presymptomatic Oxidative Stress and Inflammation in Neurodegeneration by Grape-Derived Polyphenols

Neurodegenerative disorders constitute a group of multifaceted conditions characterized by the progressive loss of neurons and synaptic connections consequent to a combination of specific genetic predispositions and stochastic stressors. The neuropathologies observed in both Alzheimer's and Parkinson's disease are in part attributed to compounding intrinsic and extrinsic environmental stressors, which we propose may be limited by the administration of specific grape derived phytochemicals and their metabolized derivatives, specifically polyphenols isolated from grape botanicals. Current therapies for neurodegenerative disorders are limited as they solely target the final disease pathologies including behavioral changes, cognitive deficits, proteinopathies and neuronal loss; however, this strategy is not a sustainable approach toward managing disease onset or progression. This review discusses the application of grape derived polyphenols as an adjunctive treatment paradigm for the prevention of neuropathologies associated with Alzheimer's disease, Parkinson's disease and Chronic Traumatic Encephalopathy by simultaneously ameliorating two stochastic stressors that facilitate their disease pathologies: inflammation and oxidative stress. The biophysical attributes of grape-derived polyphenols buffer against redox potential dependent peripheral and neuroinflammation and down regulate the activation of inflammasomes in microglia and astrocytes, which could provide a novel mechanism through which grape-derived polyphenols simultaneously suppress risk factors across pathologically distinct neurodegenerative conditions. This approach therefore offers a prophylactic mode, not feasible through current pharmacological agents, to target activity dependent risk factors for neurodegenerative disorders that manifest over an individual's lifetime.

Urolithin A alleviates myocardial ischemia/reperfusion injury via PI3K/Akt pathway

Ischemia/reperfusion (I/R) induces additional damage to the restoration of blood flow to ischemic myocardium. This study examined the effects of urolithin A (UA) on myocardial injury of ischemia/reperfusion in vivo and vitro and explored its underlying mechanisms. Mice were subjected to myocardial ischemia followed by reperfusion. Cells were subjected to hypoxia followed by reoxygenation. UA alleviated hypoxia/reoxygenation (H/R) injury in myocardial cells, reduced myocardial infarct size and cell death in mice after ischemia/reperfusion. Meanwhile, UA enhanced antioxidant capacity in cardiomyocytes following hypoxia/reoxygenation. UA reduced myocardial apoptosis following ischemia/reperfusion. The protection of UA was abolished by LY294002, a PI3K/Akt-inhibitor. These results demonstrated that UA alleviates myocardial ischemia/reperfusion injury probably through PI3K/Akt pathway.

Antioxidants and Dementia Risk: Consideration through a Cerebrovascular Perspective

A number of natural and chemical compounds that exert anti-oxidative properties are demonstrated to be beneficial for brain and cognitive function, and some are reported to reduce the risk of dementia. However, the detailed mechanisms by which those anti-oxidative compounds show positive effects on cognition and dementia are still unclear. An emerging body of evidence suggests that the integrity of the cerebrovascular blood-brain barrier (BBB) is centrally involved in the onset and progression of cognitive impairment and dementia. While recent studies revealed that some anti-oxidative agents appear to be protective against the disruption of BBB integrity and structure, few studies considered the neuroprotective effects of antioxidants in the context of cerebrovascular integrity. Therefore, in this review, we examine the mechanistic insights of antioxidants as a pleiotropic agent for cognitive impairment and dementia through a cerebrovascular axis by primarily focusing on the current available data from physiological studies. Conclusively, there is a compelling body of evidence that suggest antioxidants may prevent cognitive decline and dementia by protecting the integrity and function of BBB and, indeed, further studies are needed to directly examine these effects in addition to underlying molecular mechanisms.