The flavonoids hesperidin and rutin promote neural crest cell survival

An updated and comprehensive review of the health benefits and pharmacological activities of hesperidin

OBJECTIVES

This review aims to comprehensively assess the health benefits and pharmacological activities of hesperidin, a flavonoid commonly found in citrus fruits. It consolidates recent research findings to provide insights into hesperidin's diverse health-promoting effects.

KEY FINDINGS

Hesperidin has gained significant attention recently for its notable pharmacological activities and potential health benefits. Studies reveal its antioxidant properties, protecting cells from oxidative damage, and its anti-inflammatory effects, inhibiting pro-inflammatory cytokines and enzymes. Also, hesperidin shows promise in cardiovascular health by reducing blood pressure and cholesterol levels and enhancing endothelial function. It also exhibits anticancer potential by hindering cell proliferation, inducing apoptosis, and suppressing tumour growth. Moreover, hesperidin demonstrates neuroprotective effects, potentially mitigating neuroinflammation and oxidative stress associated with neurodegenerative diseases. Furthermore, it displays beneficial effects in metabolic disorders such as diabetes, obesity, and fatty liver disease by influencing glucose metabolism, lipid profile, and insulin sensitivity.

SUMMARY

Hesperidin exhibits a wide range of health benefits and pharmacological activities, making it a promising candidate for therapeutic interventions in various diseases. Its antioxidant, anti-inflammatory, cardiovascular, anticancer, neuroprotective, and metabolic effects underscore its potential as a valuable natural compound for promoting health and preventing chronic diseases.

Phytomolecules as Alzheimer's therapeutics: A comprehensive review

Alzheimer's disease (AD) is a leading neurodegenerative disorder recognized by progressive cognitive decline and behavioral changes. The pathology of AD is characterized by the accumulation of amyloid-β (Aβ) plaques and the hyperphosphorylation of tau protein, which leads to synaptic loss and subsequent neurodegeneration. Additional contributors to disease progression include metabolic, vascular, and inflammatory factors. Glycogen synthase kinase-3β (GSK-3β) is also implicated, as it plays a crucial role in tau phosphorylation and the progression of neurodegeneration. This review provides a comprehensive analysis of various phytomolecules and their potential to target multiple aspects of AD pathology. We examined natural products from diverse classes, including stilbenes, flavonoids, phenolic acids, alkaloids, coumarins, terpenoids, chromenes, cannabinoids, chalcones, phloroglucinols, and polycyclic polyprenylated acylphloroglucinols (PPAPs). The key mechanisms of action of these phytomolecules include modulating tau protein dynamics to reduce aggregation, inhibiting acetylcholinesterase (AChE) to maintain neurotransmitter levels and enhance cognitive function, and inhibiting β-secretase (BACE1) to decrease Aβ production. Additionally, some phytomolecules were found to influence GSK-3β activity, thereby impacting tau phosphorylation and neurodegeneration. By addressing multiple targets, Aβ production, tau hyperphosphorylation, AChE activity, and GSK-3β, these natural products offer a promising multi-targeted approach to AD therapy. This review highlights their potential to develop effective treatments that not only mitigate core pathological features but also manage the complex, multifactorial aspects of AD progression.

Nano-Rutin: A Promising Solution for Alleviating Various Disorders

BACKGROUND

Rutin, often known as vitamin P, is a natural flavonoid compound, which offers a broad spectrum of therapeutic potentials. Rutin is metabolised to different compounds by the gut bacteria after consumption, therefore, very little is absorbed. Higher plants contribute to rutin synthesis in large quantities, and it may also be found in many fruits and fruity rinds, particularly citrus fruits and berries.

OBJECTIVE

The present paper highlights several studies and patents conducted on rutin along with its nanoformulations regarding its broad spectrum of therapeutic potentials.

METHODS

Numerous electronic databases, including Springer, PubMed, Science Direct, Pubchem, Google Patents etc. were searched to extract relevant published literature demonstrating rutin effectiveness in various ailments.

RESULTS

The reviewed literature showed that rutin and related flavonoids possess a variety of physiological properties that protects human beings, plants and animals. Antioxidant, anti-inflammatory, anti-allergic, cytoprotective, vasoprotective, anticarcinogenic, neuroprotective, cardioprotective, antibacterial, antiviral, antiprotozoal, antitumor, anti-hypertensive antiplatelet, antispasmodic and hypolipidemic, activities. Nanotechnology has been implemented for the improvement of the bioavailability of rutin using novel drug-delivery carriers.

CONCLUSION

The study concludes that the development of rutin nanoformulations for multiple therapeutic approaches contributes towards enhanced aqueous solubility as well as tailored pharmacokinetics compared to conventional delivery of rutin. However, more investigations should be conducted to confirm the improved bioavailability of the rutin nanoformulations.

Aflatoxin B1 exposure exacerbates chemokine receptor expression in the BTBR T+ Itpr3tf/J Mouse Model, unveiling insights into autism spectrum disorder: A focus on brain and spleen

OBJECTIVE

Autism spectrum disorder (ASD) is a neurodevelopmental condition characterized by significant difficulties in social interaction, communication, and repeated stereotypic behaviour. Aflatoxin B1 (AFB1) is the most potent and well-known mycotoxin in various food sources. Despite its propensity to generate significant biochemical and structural changes in human and animal tissues, the influence of AFB1 on ASD has yet to be thoroughly studied. Mounting evidence indicates that chemokine receptors play a crucial function in the central nervous system and are implicated in developing several neuroinflammatory disorders. Chemokine receptors in individuals with ASD were elevated in the anterior cingulate gyrus astrocytes, cerebellum, and brain.

METHODS

The BTBR T+Itpr3tf/J (BTBR) mice are inbred strains that exhibit strong and consistently observed deficits in social interactions, characterized by excessive self-grooming and limited vocalization in social contexts. We examined the impact of AFB1 on CCR3-, CCR7-, CCR9-, CXCR3-, CXCR4-, and CXCR6-expressing I-A/I-E+ cells in the spleen of the BTBR mouse model of autism. We evaluated the mRNA levels of CCR3, CCR7, CCR9, CXCR3, CXCR4, and CXCR6 chemokine receptors in the brain.

RESULTS

The exposure to AFB1 in BTBR mice resulted in a significant rise in the number of I-A/I-E+CCR3+, I-A/I-E+CCR7+, I-A/I-E+CCR9+, I-A/I-E+CXCR3+, I-A/I-E+CXCR4+, and I-A/I-E+CXCR6+ cells. Furthermore, exposure to AFB1 increased mRNA expression levels of CCR3, CCR7, CCR9, CXCR3, CXCR4, and CXCR6 in the brain.

CONCLUSIONS

These findings highlight that AFB1 exposure increases the expression of chemokine receptors in BTBR mice, indicating the necessity for further research into AFB1's role in the development of ASD.

The Flavonol Quercitrin Hinders GSK3 Activity and Potentiates the Wnt/β-Catenin Signaling Pathway

The Wnt/β-catenin signaling pathway dictates cell proliferation and differentiation during embryonic development and tissue homeostasis. Its deregulation is associated with many pathological conditions, including neurodegenerative disease, frequently downregulated. The lack of efficient treatment for these diseases, including Alzheimer’s disease (AD), makes Wnt signaling an attractive target for therapies. Interestingly, novel Wnt signaling activating compounds are less frequently described than inhibitors, turning the quest for novel positive modulators even more appealing. In that sense, natural compounds are an outstanding source of potential drug leads. Here, we combine different experimental models, cell-based approaches, neuronal culture assays, and rodent behavior tests with Xenopus laevis phenotypic analysis to characterize quercitrin, a natural compound, as a novel Wnt signaling potentiator. We find that quercitrin potentiates the signaling in a concentration-dependent manner and increases the occurrence of the Xenopus secondary axis phenotype mediated by Xwnt8 injection. Using a GSK3 biosensor, we describe that quercitrin impairs GSK3 activity and increases phosphorylated GSK3β S9 levels. Treatment with XAV939, an inhibitor downstream of GSK3, impairs the quercitrin-mediated effect. Next, we show that quercitrin potentiates the Wnt3a-synaptogenic effect in hippocampal neurons in culture, which is blocked by XAV939. Quercitrin treatment also rescues the hippocampal synapse loss induced by intracerebroventricular injection of amyloid-β oligomers (AβO) in mice. Finally, quercitrin rescues AβO-mediated memory impairment, which is prevented by XAV939. Thus, our study uncovers a novel function for quercitrin as a Wnt/β-catenin signaling potentiator, describes its mechanism of action, and opens new avenues for AD treatments.

Therapeutic Potential of Quercetin and its Derivatives in Epilepsy: Evidence from Preclinical Studies

Quercetin is a polyphenolic bioactive compound highly enriched in dietary fruits, vegetables, nuts, and berries. Quercetin and its derivatives like rutin and hyperoside are known for their beneficial effects in various neurological conditions including epilepsy. The clinical studies of quercetin and its derivatives in relation to epilepsy are limited. This review provides the evidence of most recent knowledge of anticonvulsant properties of quercetin and its derivatives on preclinical studies. Additionally, the studies demonstrating antiseizure potential of various plants extracts enriched with quercetin and its derivatives has been included in this review. Herein, we have also discussed neuroprotective effect of these bioactive compound and presented underlying mechanisms responsible for anticonvulsant properties in brief. Finally, limitations of quercetin and its derivatives as antiseizure compounds as well as possible strategies to enhance efficacy have also been discussed.

The antioxidant Rutin counteracts the pathological impact of α-synuclein on the enteric nervous system in vitro

Motoric disturbances in Parkinson's disease (PD) derive from the loss of dopaminergic neurons in the substantia nigra. Intestinal dysfunctions often appear long before manifestation of neuronal symptoms, suggesting a strong correlation between gut and brain in PD. Oxidative stress is a key player in neurodegeneration causing neuronal cell death. Using natural antioxidative flavonoids like Rutin, might provide intervening strategies to improve PD pathogenesis. To explore the potential effects of micro (mRutin) compared to nano Rutin (nRutin) upon the brain and the gut during PD, its neuroprotective effects were assessed using an in vitro PD model. Our results demonstrated that Rutin inhibited the neurotoxicity induced by A53T α-synuclein (Syn) administration by decreasing oxidized lipids and increasing cell viability in both, mesencephalic and enteric cells. For enteric cells, neurite outgrowth, number of synaptic vesicles, and tyrosine hydroxylase positive cells were significantly reduced when treated with Syn. This could be reversed by the addition of Rutin. nRutin revealed a more pronounced result in all experiments. In conclusion, our study shows that Rutin, especially the nanocrystals, are promising natural compounds to protect neurons from cell death and oxidative stress during PD. Early intake of Rutin may provide a realizable option to prevent or slow PD pathogenesis.

Rutin improves glutamate uptake and inhibits glutamate excitotoxicity in rat brain slices

Rutin is an important flavonoid consumed in the daily diet. It is also known as vitamin P and has been extensively investigated due to its pharmacological properties. On the other hand, neuronal death induced by glutamate excitotoxicity is present in several diseases including neurodegenerative diseases. The neuroprotective properties of rutin have been under investigation, although its mechanism of action is still poorly understood. We hypothesized that the mechanisms of neuroprotection of rutin are associated with the increase in glutamate metabolism in astrocytes. This study aimed to evaluate the protective effects of rutin with a focus on the modulation of glutamate detoxification. We used brain organotypic cultures from post-natal Wistar rats (P7-P9) treated with rutin to evaluate neural cell protection and levels of proteins involved in the glutamate metabolism. Moreover, we used cerebral cortex slices from adult Wistar rats to evaluate glutamate uptake. We showed that rutin inhibited the cell death and loss of glutamine synthetase (GS) induced by glutamate that was associated with an increase in glutamate-aspartate transporter (GLAST) in brain organotypic cultures from post-natal Wistar rats. Additionally, it was observed that rutin increased the glutamate uptake in cerebral cortex slices from adult Wistar rats. We conclude that rutin is a neuroprotective agent that prevents glutamate excitotoxicity and thereof suggest that this effect involves the regulation of astrocytic metabolism.

Prenatal exposure to hesperidin improves reflexive motor behaviors in mice offspring

Prenatal exposure during the embryonic period has positive or adverse effect on newborn brain development. Neuroprotective activity of the hesperidin is well documented but there is no evidence for maternal exposure to hesperidin on offspring reflexive motor behaviors. So, the aim of the current study was to determine the prenatal exposure to hesperidin on reflexive motor behaviors in mice offspring. Forty pregnant female NMRI mice (8-10 weeks old) were allocated into four groups. Group 1 kept as control and groups 2-4 intraperitoneal (i.p) injected with hesperidin (0.1, 0.5, and 1 mg/kg) on days of 5, 8, 11, 14, and 17 of pregnancy. The control group injected with saline at the same days. Following delivery, 20 pups from each litter were selected and reflexive motor behaviors determined using ambulation, hind-limb foot angle, surface righting, hind-limb strength, grip strength, front-limb suspension, and negative geotaxis tests. At the end of the study serum Malondialdehyde (MDA), Superoxide dismutase (SOD), Glutathione peroxidase (GPx), and total antioxidant status (TAS) levels were determined. According to the results, maternal exposure to hesperidin (0.1, 0.5, and 1 mg/kg) increased ambulation score, front-limb suspension time, and hind-limb suspension score in mice offspring compared to the control group (p < .05). Hesperidin (0.1, 0.5, and 1 mg/kg) decreased hind-limb foot angle in mice offspring compared to the control group (p < .05). Prenatal exposure to hesperidin (0.5 and 1 mg/kg) significantly increased the surface righting and grip strength in comparison to the control group (p < .05). Hesperidin (0.1, 0.5, and 1 mg/kg) decreased MDA and increased SOD and GPx levels in mice offspring (p < .05). These results suggested hesperidin exposure during pregnancy has positive effect on reflexive motor behaviors in mice offspring may be due to its antioxidant activity.

Effect of rutin on anxiety-like behavior and activity of acetylcholinesterase isoforms in specific brain regions of pentylenetetrazol-treated mice

The aim of the present study was to investigate the effect of rutin administration (100 mg/kg/day) to pentylenetetrazol (PTZ)-treated Balb-c mice (60 mg/kg/day), with respect to anxiety-like behavior using both open-field and elevated plus-maze (EPM) tests, and acetylcholinesterase (AChE) activity in salt-soluble (SS) fraction and detergent-soluble (DS) fraction of the cerebral cortex, hippocampus, striatum, midbrain, and diencephalon. Our results demonstrated that the administration of PTZ in 3 doses and the induction of seizures increased significantly anxiety behavior of mice and reduced significantly DS-AChE activity in all brain regions examined, while the reduction in the SS fraction was brain region-specific. Rutin administration to normal mice did not affect their behavior, while it induced a brain region-specific reduction in SS-AChE and a significant decrease in DS-AChE in all brain regions. We demonstrated for the first time that pretreatment of PTZ-mice with rutin (PTZ + Rutin group) prevented the manifestation of anxiety and induced interestingly a further significant reduction on the SS- and DS-AChE activities only in the cerebral cortex and striatum, in comparison with PTZ group. Our results show that rutin exhibits an important anxiolytic effect and an anticholinesterase activity in specific brain areas in the seizure model of PTZ.

Gap junction protein Connexin-43 is a direct transcriptional regulator of N-cadherin in vivo

Connexins are the primary components of gap junctions, providing direct links between cells under many physiological processes. Here, we demonstrate that in addition to this canonical role, Connexins act as transcriptional regulators. We show that Connexin 43 (Cx43) controls neural crest cell migration in vivo by directly regulating N-cadherin transcription. This activity requires interaction between Cx43 carboxy tail and the basic transcription factor-3, which drives the translocation of Cx43 tail to the nucleus. Once in the nucleus they form a complex with PolII which directly binds to the N-cadherin promoter. We found that this mechanism is conserved between amphibian and mammalian cells. Given the strong evolutionary conservation of connexins across vertebrates, this may reflect a common mechanism of gene regulation by a protein whose function was previously ascribed only to gap junctional communication.

Connexins are components of gap junctions that link cells and allow intercellular communication. Here, the authors show that the Connexin 43 carboxy tail interacts with basic transcription factor-3, leading to nuclear translocation and direct regulation of N-cadherin expression and neural crest migration.

Amelioration of oxidative stress in differentiated neuronal cells by rutin regulated by a concentration switch

Increasing studies have implicated superfluous production of reactive oxygen species (ROS) as a significant factor in the progress of neurodegenerative disorders ranging from ischemic stroke to amyotrophic lateral sclerosis. The possible mechanisms relating to oxidative stress and neurodegeneration are yet to be thoroughly understood. Rutin, a flavonoid, has been well documented for its beneficial and pharmacological activities against diverse targets. However, the mechanism involved in the beneficial effects of rutin against neurodegeneration still remains unclear. Our study investigates the concentration switch effects of rutin on differentiated human neuroblastoma cells (IMR32) in vitro to unveil the possible mechanism of its action. IMR32 cells were differentiated using retinoic acid and challenged with different doses of rutin for 24 h duration to study the influence of ROS on differentiated neuronal cells and ROS-mediated apoptosis. The study showed that the high (100 μM) and low (100 nM and 10μM) rutin concentrations significantly avert ROS generation by two different mechanisms, by enhancing apoptosis through the modulation of levels of Bcl2, Caspase-3, survivin and its antioxidant activity via stress-related proteins, JNK and p38 MAPK. Our study suggests that rutin is a multi-targeted therapeutic and preventive agent that may act as an adjuvant complementary therapeutic molecule to treat oxidative stress-mediated neurodegeneration.

Latin American contributions to the neural crest field

The neural crest (NC) is one of the most fascinating structures during embryonic development. Unique to vertebrate embryos, these cells give rise to important components of the craniofacial skeleton, such as the jaws and skull, as well as melanocytes and ganglia of the peripheral nervous system. Worldwide, several groups have been studying NC development and specifically in the Latin America (LA) they have been growing in numbers since the 1990s. It is important for the world to recognize the contributions of LA researchers on the knowledge of NC development, as it can stimulate networking and improvement in the field. We developed a database of LA publications on NC development using ORCID and PUBMED as search engines. We thoroughly describe all of the contributions from LA, collected in five major topics on NC development mechanisms: i) induction and specification; ii) migration; iii) differentiation; iv) adult NC; and, v) neurocristopathies. Further analysis was done to correlate each LA country with topics and animal models, and to access collaboration between LA countries. We observed that some LA countries have made important contributions to the comprehension of NC development. Interestingly, some LA countries have a topic and an animal model as their strength; in addition, collaboration between LA countries is almost inexistent. This review will help LA NC research to be acknowledged, and to facilitate networking between students and researchers worldwide.

Flavonoids as Therapeutic Agents in Alzheimer's and Parkinson's Diseases: A Systematic Review of Preclinical Evidences

Alzheimer's and Parkinson's diseases are considered the most common neurodegenerative disorders, representing a major focus of neuroscience research to understanding the cellular alterations and pathophysiological mechanisms involved. Several natural products, including flavonoids, are considered able to cross the blood-brain barrier and are known for their central nervous system-related activity. Therefore, studies are being conducted with these chemical constituents to analyze their activities in slowing down the progression of neurodegenerative diseases. The present systematic review summarizes the pharmacological effects of flavonoids in animal models for Alzheimer's and Parkinson's diseases. A PRISMA model for systematic review was utilized for this search. The research was conducted in the following databases: PubMed, Web of Science, BIREME, and Science Direct. Based on the inclusion criteria, 31 articles were selected and discussed in this review. The studies listed revealed that the main targets of action for Alzheimer's disease therapy were reduction of reactive oxygen species and amyloid beta-protein production, while for Parkinson's disease reduction of the cellular oxidative potential and the activation of mechanisms of neuronal death. Results showed that a variety of flavonoids is being studied and can be promising for the development of new drugs to treat neurodegenerative diseases. Moreover, it was possible to verify that there is a lack of translational research and clinical evidence of these promising compounds.

Protective effects of flavonoids against Alzheimer's disease-related neural dysfunctions

Senile ages of human life is mostly associated with developmental of several neurological complicated conditions including decreased cognition and reasoning, increased memory loss and impaired language performance. Alzheimer's disease (AD) is the most prevalent neural disorder associated with dementia, consisting of about 70% of dementia reported cases. Failure of currently approved chemical anti-AD therapeutic agents has once again brought up the idea of administering naturally occurring compounds as effective alternative and/or complementary regimens in AD treatment. Polyphenol structured neuroprotecting agents are group of biologically active compounds abundantly found in plants with significant protecting effects against neural injuries and degeneration. As a subclass of this family, Flavonoids are potent anti-oxidant, anti-inflammatory and signalling pathways modulatory agents. Phosphatidylinositol 3-kinase (PI3K)/AKT and mitogen activated protein kinase (MAPK) pathways are both affected by Flavonoids. Regulation of pro-survival transcription factors and induction of specific genes expression in hippocampus are other important anti AD therapeutic activities of Flavonoids. These agents are also capable of inhibiting specific enzymes involved in phosphorylation of tau proteins including β-secretases, cyclin dependent kinase 5 and glycogen synthase. Other significant anti AD effects of Flavonoids include neural rehabilitation and lost cognitive performance recovery. In this review, first we briefly describe the pathophysiology and important pathways involved in pathology of AD and then describe the most important mechanisms through which Flavonoids demonstrate their significant neuroprotective effects in AD therapy.

Flavonoid Hesperidin Induces Synapse Formation and Improves Memory Performance through the Astrocytic TGF-β1

Synapse formation and function are critical events for the brain function and cognition. Astrocytes are active participants in the control of synapses during development and adulthood, but the mechanisms underlying astrocyte synaptogenic potential only began to be better understood recently. Currently, new drugs and molecules, including the flavonoids, have been studied as therapeutic alternatives for modulation of cognitive processes in physiological and pathological conditions. However, the cellular targets and mechanisms of actions of flavonoids remain poorly elucidated. In the present study, we investigated the effects of hesperidin on memory and its cellular and molecular targets in vivo and in vitro, by using a short-term protocol of treatment. The novel object recognition test (NOR) was used to evaluate memory performance of mice intraperitoneally treated with hesperidin 30 min before the training and again before the test phase. The direct effects of hesperidin on synapses and astrocytes were also investigated using in vitro approaches. Here, we described hesperidin as a new drug able to improve memory in healthy adult mice by two main mechanisms: directly, by inducing synapse formation and function between hippocampal and cortical neurons; and indirectly, by enhancing the synaptogenic ability of cortical astrocytes mainly due to increased secretion of transforming growth factor beta-1 (TGF-β1) by these cells. Our data reinforces the known neuroprotective effect of hesperidin and, by the first time, characterizes its synaptogenic action on the central nervous system (CNS), pointing astrocytes and TGF-β1 signaling as new cellular and molecular targets of hesperidin. Our work provides not only new data regarding flavonoid’s actions on the CNS but also shed light on possible new therapeutic alternative based on astrocyte biology.

Organophilic treatments of bentonite increase the adsorption of aflatoxin B1 and protect stem cells against cellular damage

Bentonite clays exhibit high adsorptive capacity for contaminants, including aflatoxin B1 (AFB1), a mycotoxin responsible for causing severe toxicity in several species including pigs, poultry and man. Organophilic treatments is known to increase the adsorption capacity of bentonites, and the primary aim of this study was to evaluate the ability of Brazilian bentonite and two organic salts - benzalkonium chloride (BAC) and cetyltrimethylammonium bromide (CTAB) to adsorb AFB1. For this end, 2(2) factorial designs were used in order to analyze if BAC or CTAB was able to increase AFB1 adsorption when submitted in different temperature and concentration. Both BAC and CTAB treatment (at 30°C and 2% of salt concentration) were found to increase the adsorption of AFB1 significantly compared with untreated bentonite. After organophilic bentonite treatments with BAC or CTAB, a vibration of CH stretch (2850 and 2920cm(-1)) were detected. A frequency of the SiO stretch (1020 and 1090cm(-1)) was changed by intercalation of organic cation. Furthermore, the interlayer spacing of bentonite increases to 1.23nm (d001 reflection at 2θ=7.16) and 1.22 (d001 reflection at 2θ=7.22) after the addition of BAC and CTAB, respectively. Another aim of the study was to observe the effects of these two bentonite salts in neural crest stem cell cultures. The two materials that were created by organophilic treatments were not found to be toxic to stem cells. Furthermore the results indicate that the two materials tested may protect the neural crest stem cells against damage caused by AFB1.

The Pharmacological Potential of Rutin

The contemporary scientific community has presently recognized flavonoids to be a unique class of therapeutic molecules due to their diverse therapeutic properties. Of these, rutin, also known as vitamin P or rutoside, has been explored for a number of pharmacological effects. Tea leaves, apples, and many more possess rutin as one of the active constituents. Today, rutin has been observed for its nutraceutical effect. The present review highlights current information and health-promoting effects of rutin. Along with this, safety pharmacology issues and SAR of the same have also been discussed.

Impact of Plant-Derived Flavonoids on Neurodegenerative Diseases

Neurodegenerative disorders have a common characteristic that is the involvement of different cell types, typically the reactivity of astrocytes and microglia, characterizing gliosis, which in turn contributes to the neuronal dysfunction and or death. Flavonoids are secondary metabolites of plant origin widely investigated at present and represent one of the most important and diversified among natural products phenolic groups. Several biological activities are attributed to this class of polyphenols, such as antitumor activity, antioxidant, antiviral, and anti-inflammatory, among others, which give significant pharmacological importance. Our group have observed that flavonoids derived from Brazilian plants Dimorphandra mollis Bent., Croton betulaster Müll. Arg., e Poincianella pyramidalis Tul., botanical synonymous Caesalpinia pyramidalis Tul. also elicit a broad spectrum of responses in astrocytes and neurons in culture as activation of astrocytes and microglia, astrocyte associated protection of neuronal progenitor cells, neuronal differentiation and neuritogenesis. It was observed the flavonoids also induced neuronal differentiation of mouse embryonic stem cells and human pluripotent stem cells. Moreover, with the objective of seeking preclinical pharmacological evidence of these molecules, in order to assess its future use in the treatment of neurodegenerative disorders, we have evaluated the effects of flavonoids in preclinical in vitro models of neuroinflammation associated with Parkinson's disease and glutamate toxicity associated with ischemia. In particular, our efforts have been directed to identify mechanisms involved in the changes in viability, morphology, and glial cell function induced by flavonoids in cultures of glial cells and neuronal cells alone or in interactions and clarify the relation with their neuroprotective and morphogetic effects.

Flavonoids, derived from traditional Chinese medicines, show roles in the differentiation of neurons: possible targets in developing health food products

Flavonoids, a family of phenolic compounds, are distributed in a variety of fruits, vegetables, tea, and wine. More importantly, many flavonoids are served as the active ingredients in traditional Chinese herbal medicines, which in general do not have side effects. Several lines of evidence support that flavonoids have impacts on many aspects of human health, including anti-tumor, anti-oxidation, and anti-inflammation. Recently, there is significant attention focused on the neuronal beneficial effects of flavonoids, including the promotion of nervous system development, neuroprotection against neurotoxin stress, as well as the promotion of memory, learning, and cognitive functions. Here, the activities of flavonoids on the development of nervous system are being summarized and discussed. The flavonoids from diverse herbal medicines have significant effects in different developmental stages of nervous systems, including neuronal stem cell differentiation, neurite outgrowth, and neuronal plasticity. These findings imply that flavonoids are potential candidates for the development of health supplements in preventing birth defects and neuronal diseases.

EGF-FGF2 stimulates the proliferation and improves the neuronal commitment of mouse epidermal neural crest stem cells (EPI-NCSCs)

Epidermal neural crest stem cells (EPI-NCSCs), which reside in the bulge of hair follicles, are attractive candidates for several applications in cell therapy, drug screening and tissue engineering. As suggested remnants of the embryonic neural crest (NC) in an adult location, EPI-NCSCs are able to generate a wide variety of cell types and are readily accessible by a minimally invasive procedure. Since the combination of epidermal growth factor (EGF) and fibroblast growth factor type 2 (FGF2) is mitogenic and promotes the neuronal commitment of various stem cell populations, we examined its effects in the proliferation and neuronal potential of mouse EPI-NCSCs. By using a recognized culture protocol of bulge whiskers follicles, we were able to isolate a population of EPI-NCSCs, characterized by the migratory potential, cell morphology and expression of phenotypic markers of NC cells. EPI-NCSCs expressed neuronal, glial and smooth muscle markers and exhibited the NC-like fibroblastic morphology. The treatment with the combination EGF and FGF2, however, increased their proliferation rate and promoted the acquisition of a neuronal-like morphology accompanied by reorganization of neural cytoskeletal proteins βIII-tubulin and nestin, as well as upregulation of the pan neuronal marker βIII-tubulin and down regulation of the undifferentiated NC, glial and smooth muscle cell markers. Moreover, the treatment enhanced the response of EPI-NCSCs to neurogenic stimulation, as evidenced by induction of GAP43, and increased expression of Mash-1 in neuron-like cell, both neuronal-specific proteins. Together, the results suggest that the combination of EGF-FGF2 stimulates the proliferation and improves the neuronal potential of EPI-NCSCs similarly to embryonic NC cells, ES cells and neural progenitor/stem cells of the central nervous system and highlights the advantage of using EGF-FGF2 in neuronal differentiation protocols.

Synaptophysin and the dopaminergic system in hippocampus are involved in the protective effect of rutin against trimethyltin-induced learning and memory impairment

OBJECTIVES

This study aimed to investigate the protective effect of rutin against trimethyltin-induced spatial learning and memory impairment in mice. This study focused on the role of synaptophysin, growth-associated protein 43 and the action of the dopaminergic system in mechanisms associated with rutin protection and trimethyltin-induced spatial learning and memory impairment.

METHODS

Cognitive learning and memory was measured by Morris Water Maze. The expression of synaptophysin and growth-associated protein 43 in hippocampus was analyzed by western blot. The concentrations of dopamine, homovanillic acid, and dihyroxyphenylacetic acid in hippocampus were detected using reversed phase high-performance liquid chromatography with electrochemical detection.

RESULTS

Trimethyltin-induced spatial learning impairment showed a dose-dependent mode. Synaptophysin but not growth-associated protein 43 was decreased in the hippocampus after trimethyltin administration. The concentration of dopamine decreased, while homovanillic acid increased in the hippocampus after trimethyltin administration. Mice pretreated with 20 mg/kg of rutin for 7 consecutive days exhibited improved water maze performance. Moreover, rutin pretreatment reversed the decrease of synaptophysin expression and dopamine alteration.

DISCUSSION

These results suggest that rutin may protect against spatial memory impairment induced by trimethyltin. Synaptophysin and the dopaminergic system may be involved in trimethyltin-induced neuronal damage in hippocampus.

Hesperetin alleviates the inhibitory effects of high glucose on the osteoblastic differentiation of periodontal ligament stem cells

Hesperetin (3',5,7-trihydroxy-4-methoxyflavanone) is a metabolite of hesperidin (hesperetin-7-O-rutinoside), which belongs to the flavanone subgroup and is found mainly in citrus fruits. Hesperetin has been reported to be an effective osteoinductive compound in various in vivo and in vitro models. However, how hesperetin effects osteogenic differentiation is not fully understood. In this study, we investigated the capacity of hesperetin to stimulate the osteogenic differentiation of periodontal ligament stem cells (PDLSCs) and to relieve the anti-osteogenic effect of high glucose. Osteogenesis of PDLSCs was assessed by measurement of alkaline phosphatase (ALP) activity, and evaluation of the mRNA expression of ALP, runt-related gene 2 (Runx2), osterix (OSX), and FRA1 as osteogenic transcription factors, as well as assessment of protein expression of osteopontin (OPN) and collagen type IA (COLIA). When PDLSCs were exposed to a high concentration (30 mM) of glucose, osteogenic activity decreased compared to control cells. Hesperetin significantly increased ALP activity at doses of 1, 10, and 100 µM. Pretreatment of cells with hesperetin alleviated the high-glucose-induced suppression of the osteogenic activity of PDLSCs. Hesperetin scavenged intracellular reactive oxygen species (ROS) produced under high glucose condition. Furthermore, hesperetin increased the activity of the PI3K/Akt and β-catenin pathways. Consistent with this, blockage of Akt or β-catenin diminished the protective effect of hesperetin against high glucose-inhibited osteogenic differentiation. Collectively, our results suggest that hesperetin alleviates the high glucose-mediated suppression of osteogenic differentiation in PDLSCs by regulating ROS levels and the PI3K/Akt and β-catenin signaling pathways.

Flavonoid hesperidin protects neural crest cells from death caused by aflatoxin B(1)

The neural crest (NC) corresponds to a collection of multipotent and oligopotent progenitors endowed with both neural and mesenchymal potentials. The derivatives of the NC at trunk level include neurons and glial cells of the peripheral nervous system. Despite the well-known influence of aflatoxins on the development of cancer, the issue of whether they also influence NC cells has not been yet addressed. In the present work, we have investigated the effects of aflatoxin B(1) on quail NC cells and the concomitant effects of the flavonoid hesperidin associated with this mycotoxin. We show for the first time that aflatoxin B(1) decreases the viability and the total number of glial and neuronal cells/field, although their proportions in relation to the total number of cells were not altered. Therefore, aflatoxin has no effect on NC differentiation. However, this compound was able to reduce NC proliferation and NC survival. Furthermore, the co-administration of hesperidin, a well-known polyphenolic protector of cell death, partially prevented the effect of aflatoxin B(1) . Taken together, our results demonstrate that aflatoxin B(1) is toxic to NC cells, an effect partially prevented by the flavonoid hesperidin. This study may contribute to the understanding of the effects of these compounds during early embryonic development and offer potentially more assertive diets and treatments for pregnant animals.