Role of Plant-Derived Flavonoids and Their Mechanism in Attenuation of Alzheimer's and Parkinson's Diseases: An Update of Recent Data

Antioxidant responses driven by Hesperetin and Hesperidin counteract Parkinson's disease-like phenotypes in Drosophila melanogaster

The study investigated the protective effects of Hesperetin (HSP) and Hesperidin (HSD) on 1 methyl, 4 phenyl, 1,2,3,6 tetrahydropyridine hydrochloride (MPTP)-induced Parkinsonism in Drosophila melanogaster (D. melanogaster). After a lifespan study to select exposure time and concentrations, flies were co-exposed to MPTP (0.4 mg/g diet), Hesperetin (0.2 and 0.4 mg/g diet), and Hesperidin (0.1 and 0.4 mg/g) for 7 days. In addition to in vivo parameters, we assayed some markers of oxidative stress and antioxidant status (lipid peroxidation, protein carbonylation, thiol content, hydrogen peroxide, and nitrate/nitrite levels, mRNA expression of Keap-1 (Kelch-like ECH associated protein 1), /Nrf2 (Nuclear factor erythroid 2 related factor 2), catalase, and glutathione-S-transferase (GST) activities), and cholinergic (acetyl cholinesterase activity (AChE) and dopaminergic signaling content and the mRNA expression of tyrosine hydroxylase (TH), monoamine oxidase (MAO-like) activity). In addition to increasing the lifespan of flies, we found that both flavonoids counteracted the adverse effects of MPTP on survival, offspring emergence, and climbing ability of flies. Both flavonoids also reduced the oxidative damage on lipids and proteins and reestablished the basal levels of pro-oxidant species and activities of antioxidant enzymes in MPTP-exposed flies. These responses were accompanied by the normalization of the mRNA expression of Keap1/Nrf2 disrupted in flies exposed to MPTP. MPTP exposure also elicited changes in mRNA expression and content of TH as well as in MAO and AChE activity, which were reversed by HST and HSD. By efficiently hindering the oxidative stress in MPTP-exposed flies, our findings support the promising role of Hesperetin and Hesperidin as adjuvant therapy to manage Parkinsonism induced by chemicals such as MPTP.

Natural flavonoids as potential therapeutics in the management of Alzheimer's disease: a review

Alzheimer's disease (AD) is an age-dependent neurodegenerative disorder which is associated with the accumulation of proteotoxic Aβ peptides, and pathologically characterized by the deposition of Aβ-enriched plaques and neurofibrillary tangles. Given the social and economic burden caused by the rising frequency of AD, there is an urgent need for the development of appropriate therapeutics. Natural compounds are gaining popularity as alternatives to synthetic drugs due to their neuroprotective properties and higher biocompatibility. While natural compound's therapeutic effects for AD have been recently investigated in numerous in vitro and in vivo studies, only few have developed to clinical trials. The present review aims to provide a brief overview of the therapeutic effects, new insights, and upcoming perspectives of the preclinical and clinical trials of flavonoids for the treatment of Alzheimer's disease.

Flavonoid intake and risk of Parkinson's disease

BACKGROUND

Flavonoids have been proposed to reduce the risk of Parkinson's disease (PD). However, results from epidemiological studies have been inconclusive.

OBJECTIVE

To prospectively examine the association between the intake of flavonoids and their subclasses and the risk of PD and how pesticides may confound or modify that association.

METHODS

The study population comprised 80 701 women (1984-2016) and 48 782 men (1986-2016) from two large US cohorts. Flavonoid intake was ascertained at baseline and every 4 years thereafter using a semiquantitative Food Frequency Questionnaire. We conducted multivariable-adjusted Cox regression models to estimate HRs and 95% CIs of PD according to quintiles of baseline and cumulative average intakes of flavonoids and subclasses. We repeated the analyses, adjusting for intakes of high-pesticide-residue fruits and vegetables (FVs) and stratifying by servings/day of high-pesticide-residue FV intake.

RESULTS

We identified 676 incident PD cases in women and 714 in men after 30-32 years of follow-up. Higher total flavonoid intake at baseline was not associated with a lower PD risk, neither in men (HR comparing highest to lowest quintile: 0.89, 95% CI: 0.69 to 1.14) nor in women (HR comparing highest to lowest quintile: 1.27, 95% CI: 0.98 to 1.64). Similar results were observed for cumulative average intakes and flavonoid subclasses. Results remained similar after adjustment for and stratification by high-pesticide-residue FV and when analyses were restricted to younger PD cases.

CONCLUSION

These results do not support a protective effect of flavonoid intake on PD risk. Pesticide residues do not confound or modify the association.

Adult neurogenesis: a real hope or a delusion?

Adult neurogenesis, the process of creating new neurons, involves the coordinated division, migration, and differentiation of neural stem cells. This process is restricted to neurogenic niches located in two distinct areas of the brain: the subgranular zone of the dentate gyrus of the hippocampus and the subventricular zone of the lateral ventricle, where new neurons are generated and then migrate to the olfactory bulb. Neurogenesis has been thought to occur only during the embryonic and early postnatal stages and to decline with age due to a continuous depletion of neural stem cells. Interestingly, recent years have seen tremendous progress in our understanding of adult brain neurogenesis, bridging the knowledge gap between embryonic and adult neurogenesis. Here, we discuss the current status of adult brain neurogenesis in light of what we know about neural stem cells. In this notion, we talk about the importance of intracellular signaling molecules in mobilizing endogenous neural stem cell proliferation. Based on the current understanding, we can declare that these molecules play a role in targeting neurogenesis in the mature brain. However, to achieve this goal, we need to avoid the undesired proliferation of neural stem cells by controlling the necessary checkpoints, which can lead to tumorigenesis and prove to be a curse instead of a blessing or hope.

Pathogenesis of Neurodegenerative Diseases and the Protective Role of Natural Bioactive Components

Neurodegenerative diseases are a serious problem throughout the world. There are several causes of neurodegenerative diseases; these include genetic predisposition, accumulation of misfolded proteins, oxidative stress, neuroinflammation, and excitotoxicity. Oxidative stress increases the production of reactive oxygen species (ROS) that advance lipid peroxidation, DNA damage, and neuroinflammation. The cellular antioxidant system (superoxide dismutase, catalase, peroxidase, and reduced glutathione) plays a crucial role in scavenging free radicals. An imbalance in the defensive actions of antioxidants and overproduction of ROS intensify neurodegeneration. The formation of misfolded proteins, glutamate toxicity, oxidative stress, and cytokine imbalance promote the pathogenesis of Alzheimer's disease, Parkinson's disease, Huntington's disease, and amyotrophic lateral sclerosis. Antioxidants are now attractive molecules to fight against neurodegeneration. Certain vitamins (A, E, C) and polyphenolic compounds (flavonoids) show excellent antioxidant properties. Diet is the major source of antioxidants. However, diet medicinal herbs are also rich sources of numerous flavonoids. Antioxidants prevent ROS-mediated neuronal degeneration in post-oxidative stress conditions. The present review is focused on the pathogenesis of neurodegenerative diseases and the protective role of antioxidants. KEY TEACHING POINTSThis review shows that multiple factors are directly or indirectly associated with the pathogenesis of neurodegenerative diseases.Failure to cellular antioxidant capacity increases oxidative stress that intensifies neuroinflammation and disease progression.Different vitamins, carotenoids, and flavonoids, having antioxidant capacity, can be considered protective agents.

Does hazelnut consumption affect brain health and function against neurodegenerative diseases?

INTRODUCTION

A healthy daily diet and consuming certain nutrients, such as polyphenols, vitamins, and unsaturated fatty acids, may help neuronal health maintenance. Polyphenolic chemicals, which have antioxidant and anti-inflammatory properties, are involved in the neuroprotective pathway. Because of their nutritional value, nuts have been shown in recent research to be helpful in neuroprotection.

OBJECTIVE

Hazelnut is often consumed worldwide in various items, including processed foods, particularly in bakery, chocolate, and confectionery products. This nut is an excellent source of vitamins, amino acids, tocopherols, phytosterols, polyphenols, minerals, and unsaturated fatty acids. Consuming hazelnut may attenuate the risk of neurodegenerative disorders including Alzheimer's disease, Parkinson's disease, amyotrophic lateral sclerosis, multiple sclerosis, and Huntington's disease due to its anti-inflammatory and anti-oxidant qualities.

RESULTS

Many documents introduce hazelnut as an excellent choice to provide neuroprotection against neurodegenerative disorders and there is some direct proof of its neuroprotective effects.

DISCUSSION

So hazelnut consumption in daily diet may reduce neurodegenerative disease risk and be advantageous in reducing the imposed costs of dealing with neurodegenerative diseases.

Combination of Secondary Plant Metabolites and Micronutrients Improves Mitochondrial Function in a Cell Model of Early Alzheimer's Disease

Alzheimer's disease (AD) is characterized by excessive formation of beta-amyloid peptides (Aβ), mitochondrial dysfunction, enhanced production of reactive oxygen species (ROS), and altered glycolysis. Since the disease is currently not curable, preventive and supportive approaches are in the focus of science. Based on studies of promising single substances, the present study used a mixture (cocktail, SC) of compounds consisting of hesperetin (HstP), magnesium-orotate (MgOr), and folic acid (Fol), as well as the combination (KCC) of caffeine (Cof), kahweol (KW) and cafestol (CF). For all compounds, we showed positive results in SH-SY5Y-APP695 cells-a model of early AD. Thus, SH-SY5Y-APP695 cells were incubated with SC and the activity of the mitochondrial respiration chain complexes were measured, as well as levels of ATP, Aβ, ROS, lactate and pyruvate. Incubation of SH-SY5Y-APP695 cells with SC significantly increased the endogenous respiration of mitochondria and ATP levels, while Aβ1-40 levels were significantly decreased. Incubation with SC showed no significant effects on oxidative stress and glycolysis. In summary, this combination of compounds with proven effects on mitochondrial parameters has the potential to improve mitochondrial dysfunction in a cellular model of AD.

A comprehensive perspective of traditional Arabic or Islamic medicinal plants as an adjuvant therapy against COVID-19

COVID-19 is a pulmonary disease caused by SARS-CoV-2. More than 200 million individuals are infected by this globally. Pyrexia, coughing, shortness of breath, headaches, diarrhoea, sore throats, and body aches are among the typical symptoms of COVID-19. The virus enters into the host body by interacting with the ACE2 receptor. Despite many SARS-CoV-2 vaccines manufactured by distinct strategies but any evidence-based particular medication to combat COVID-19 is not available yet. However, further research is required to determine the safety and effectiveness profile of the present therapeutic approaches. In this study, we provide a summary of Traditional Arabic or Islamic medicinal (TAIM) plants' historical use and their present role as adjuvant therapy for COVID-19. Herein, six medicinal plants Aloe barbadensis Miller, Olea europaea, Trigonella foenum-graecum, Nigella sativa, Cassia angustifolia, and Ficus carica have been studied based upon their pharmacological activities against viral infections. These plants include phytochemicals that have antiviral, immunomodulatory, antiasthmatic, antipyretic, and antitussive properties. These bioactive substances could be employed to control symptoms and enhance the development of a possible COVID-19 medicinal synthesis. To determine whether or if these TAIMs may be used as adjuvant therapy and are appropriate, a detailed evaluation is advised.

HR LC-MS/MS metabolomic profiling of Yucca aloifolia fruit and the potential neuroprotective effect on rotenone-induced Parkinson's disease in rats

Yucca aloifolia L. fruit (Yucca or Spanish bayonet, family Asparagaceae) is recognized for its purplish red color reflecting its anthocyanin content, which has a powerful antioxidant activity. This study aimed to investigate yucca (YA) fruit extract's protective effect on Parkinson's disease (PD). In vitro study, the anti-inflammatory activity of yucca fruit extracts was explored by measuring tumor necrosis factor receptor 2 (TNF-R2) and nuclear factor kappa B (NF-KB) to choose the most effective extract. Afterward, a detailed in vivo investigation of the protective effect of the most active extract on rotenone-induced PD was performed on male albino Wister rats. First, the safety of the extract in two different doses (50 and 100 mg/kg in 0.9% saline orally) was confirmed by a toxicological study. The rats were divided into four groups: 1) normal control (NC); 2) rotenone group; and third and fourth groups received 50 and 100 mg/kg yucca extract, respectively. The neurobehavioral and locomotor activities of the rats were tested by rotarod, open field, and forced swim tests. Striatal dopamine, renal and liver functions, and oxidative stress markers were assessed. Western blot analysis of brain tissue samples was performed for p-AMPK, Wnt3a, and β-catenin. Histopathological examination of striatal tissue samples was performed by light and electron microscopy (EM). The metabolites of the active extract were characterized using high-resolution LC-MS/MS, and the results showed the prevalence of anthocyanins, saponins, phenolics, and choline. Biochemical and histopathological tests revealed a dose-dependent improvement with oral Yucca extract. The current study suggests a possible neuroprotective effect of the acidified 50% ethanol extract (YA-C) of the edible Yucca fruit, making it a promising therapeutic target for PD.

A critical analysis on the concentrations of phenolic compounds tested using in vitro and in vivo Parkinson's disease models

Phenolic compounds (PCs) have neuroprotective effects with potential to prevent or slower the progression of Parkinson's disease (PD). However, whether the PCs neuroprotective effects can be observed under their dietary concentrations remains unclear. Therefore, we searched for the most cited articles in density on PCs and PD in the Web of Science Core Collection and All-Database (WoS-CC/AD) and selected the articles based on our eligibility criteria. From these 81 articles selected, we extracted information on experimental design, compounds tested, concentration and/or dose administered, route of administration, and main results obtained. We compared the concentrations of PCs evaluated in vitro with the concentrations bioavailable in the human bloodstream. Further, after extrapolation to humans, we compared the doses administered to animals in vivo with the daily consumed amounts of PCs. Concentrations evaluated in 21 in vitro laboratory studies were higher than those bioavailable in the bloodstream. In the case of in vivo laboratory studies, only one study administered doses of PCs in normal daily amount. The results of the comparisons demonstrate that the neuroprotective effects of the selected articles are mainly associated with concentrations, amounts and routes of administration that do not correspond to the consumption of phenolic compounds through the diet.

Long-Term Supplementation of Syzygium cumini (L.) Skeels Concentrate Alleviates Age-Related Cognitive Deficit and Oxidative Damage: A Comparative Study of Young vs. Old Mice

The Syzygium cumini (L.) Skeels is reported to have medicinal properties, but its benefits on age-related neurological changes have not been previously explored. In the current study, after phytochemical analysis of the pulp of Syzygium cumini (L.) Skeels fruit (Sy. cmi), young BALB/c mice have been supplemented with its 5, 15, and 30% dilution for 16 months, followed by behavioral experimentation and biochemical evaluation of isolated brains. The Sy. cmi has been found enriched with phenols/flavonoids while the occurrence of nine phytocompounds has been identified through GC-MS analysis. Further, Sy. cmi supplementation has caused significant (p < 0.05) protection from anxiety-like behavior in aged mice, and they have explored open, illuminated, and exposed areas of open field, light/dark, and an elevated plus maze, respectively. Furthermore, these animals have shown improved cognitive abilities as their percent (%) spontaneous alteration and novelty preference are significantly greater in T-maze and Y-maze and familiarity/novelty recognition tests. Further, Sy. cmi-supplemented mice remember the aversive stimuli zone and escape box location in passive avoidance and Barnes maze tests, and their brains have low levels of malondialdehyde and acetylcholinesterase with elevated antioxidant enzymes. The outcomes have provided scientific insight into the beneficial effects of Sy. cmi on age-associated amnesia that might be attributed to antioxidant and anticholinergic effects exerted by phytocompounds (caryophyllene, humulene, β-Farnesene, and phytol) owned by Syzygium cumini.

Analysis of phenolic compounds in Parkinson's disease: a bibliometric assessment of the 100 most cited papers

Objective

The aim of this study was to identify and characterize the 100 most cited articles on Parkinson's disease (PD) and phenolic compounds (PCs).

Methods

Articles were selected in the Web of Science Core Collection up to June 2022 based on predetermined inclusion criteria, and the following bibliometric parameters were extracted: the number of citations, title, keywords, authors, year, study design, tested PC and therapeutic target. MapChart was used to create worldwide networks, and VOSviewer software was used to create bibliometric networks. Descriptive statistical analysis was used to identify the most researched PCs and therapeutic targets in PD.

Results

The most cited article was also the oldest. The most recent article was published in 2020. Asia and China were the continent and the country with the most articles in the list (55 and 29%, respectively). In vitro studies were the most common experimental designs among the 100 most cited articles (46%). The most evaluated PC was epigallocatechin. Oxidative stress was the most studied therapeutic target.

Conclusion

Despite the demonstrations in laboratorial studies, the results obtained point to the need for clinical studies to better elucidate this association.

Hyperglycemia-associated Alzheimer's-like symptoms and other behavioral effects attenuated by Plumeria obtusa L. Extract in alloxan-induced diabetic rats

Diabetes mellitus is a chronic metabolic complaint with numerous short- and long-term complications that harm a person's physical and psychological health. Plumeria obtusa L. is a traditional medicine used in the treatment of diabetes to reduce complications related to behavior. Plumeria is a genus with antipsychotic activities. The objective of this study was to examine the effects of a methanolic extract of Plumeria obtusa L. in the attenuation of diabetes, on symptoms of Alzheimer disease, and on other associated behavioral aspects. A single dose of alloxan was administered to an experimental group of rats to induce development of diabetes (150 mg/kg, intraperitoneal) and the rats were then administered selected doses of methanolic extract of Plumeria obtusa L. (Po.Cr) or glibenclamide (0.6 mg/kg) for 45 consecutive days. Behavioral effects were evaluated using three validated assays of anxiety-related behavior: the open field test, the light and dark test, and the elevated plus maze. Anti-depressant effects of Plumeria obtusa L. were evaluated using the forced swim test (FST) and memory and learning were assessed using the Morris water maze (MWM) task. Po.Cr was also evaluated for phytochemicals using total phenolic content (TPC), total flavonoid content (TFC), and high-performance liquid chromatography assays, and antioxidant capability was assessed through assays of DPPH radical scavenging, total oxidation capacity, and total reducing capacity. In the alloxan-induced model of diabetes, the administration of Po.Cr and glibenclamide for 45 days produced a marked decrease (p < 0.001) in hyperglycemia compared to control animals. Po.Cr treatment also resulted in improvement in indicators, such as body weight and lipid profile (p < 0.05), as well as restoration of normal levels of alanine transaminase (ALT) (p < 0.001), a biomarker of liver function. Diabetic rats presented more Alzheimer-like symptoms, with greater impairment of memory and learning, and increased anxiety and depression compared to non-diabetic normal rats, whereas treated diabetic rats showed significant improvements in memory and behavioral outcomes. These results demonstrate that Po.Cr reversed alloxan-induced hyperglycemia and ameliorated Alzheimer-related behavioral changes, which supports additional study and assessment of conventional use of the plant to treat diabetes and associated behavioral complications.

Therapeutic approaches of nutraceuticals in the prevention of Alzheimer's disease

Alzheimer's disease (AD) is a neurological illness that causes memory loss over time. Currently, available pharmaceutical medicines and products are limited, and they have side effects at a higher price. Researchers and scientists have observed significant effects of nutraceuticals. Various preclinical and clinical studies were investigated for the Anti-Alzheimer's activity of nutraceuticals. The increasing ability of the pathogenesis of AD has led to the analysis of novel therapeutic targets, including the pathophysiological mechanisms and distinct cascades. So, current improvement will show the most adequate and prominent nutraceuticals and suggested concise mechanisms involving autophagy regulation, anti-inflammatory, antioxidant, mitochondrial homeostasis, and others. The effects of nutraceuticals cannot be ignored; it is important to investigate high-quality clinical trials. Given the potential of nutraceuticals to battle AD as multi-targeted therapies, it's vital to evaluate them as viable lead compounds for drug discovery and development. To the best of the authors 'knowledge, modification of blood-brain barrier permeability, bioavailability, and aspects of randomized clinical trials should be considered in prospective investigations. PRACTICAL APPLICATIONS: Advancements in molecular diagnostic and fundamentals have implemented particular usefulness for drug evaluation. An excess of experimental knowledge occurs regarding the effect of nutraceuticals on AD. There are various preclinical and clinical studies that have been done on nutraceuticals. In addition, various substitute inhibit and enhance some pathophysiological levels associated with AD. Nutraceuticals are easily available and have fewer side effects with cost-effective advantages. However, further investigations and clinical trials are required to encourage its effect on disease.

Basic mechanisms of peripheral nerve injury and treatment via electrical stimulation

Previous studies on the mechanisms of peripheral nerve injury (PNI) have mainly focused on the pathophysiological changes within a single injury site. However, recent studies have indicated that within the central nervous system, PNI can lead to changes in both injury sites and target organs at the cellular and molecular levels. Therefore, the basic mechanisms of PNI have not been comprehensively understood. Although electrical stimulation was found to promote axonal regeneration and functional rehabilitation after PNI, as well as to alleviate neuropathic pain, the specific mechanisms of successful PNI treatment are unclear. We summarize and discuss the basic mechanisms of PNI and of treatment via electrical stimulation. After PNI, activity in the central nervous system (spinal cord) is altered, which can limit regeneration of the damaged nerve. For example, cell apoptosis and synaptic stripping in the anterior horn of the spinal cord can reduce the speed of nerve regeneration. The pathological changes in the posterior horn of the spinal cord can modulate sensory abnormalities after PNI. This can be observed in cases of ectopic discharge of the dorsal root ganglion leading to increased pain signal transmission. The injured site of the peripheral nerve is also an important factor affecting post-PNI repair. After PNI, the proximal end of the injured site sends out axial buds to innervate both the skin and muscle at the injury site. A slow speed of axon regeneration leads to low nerve regeneration. Therefore, it can take a long time for the proximal nerve to reinnervate the skin and muscle at the injured site. From the perspective of target organs, long-term denervation can cause atrophy of the corresponding skeletal muscle, which leads to abnormal sensory perception and hyperalgesia, and finally, the loss of target organ function. The mechanisms underlying the use of electrical stimulation to treat PNI include the inhibition of synaptic stripping, addressing the excessive excitability of the dorsal root ganglion, alleviating neuropathic pain, improving neurological function, and accelerating nerve regeneration. Electrical stimulation of target organs can reduce the atrophy of denervated skeletal muscle and promote the recovery of sensory function. Findings from the included studies confirm that after PNI, a series of physiological and pathological changes occur in the spinal cord, injury site, and target organs, leading to dysfunction. Electrical stimulation may address the pathophysiological changes mentioned above, thus promoting nerve regeneration and ameliorating dysfunction.

Polyphenolic Compounds from Lespedeza bicolor Protect Neuronal Cells from Oxidative Stress

Pterocarpans and related polyphenolics are known as promising neuroprotective agents. We used models of rotenone-, paraquat-, and 6-hydroxydopamine-induced neurotoxicity to study the neuroprotective activity of polyphenolic compounds from Lespedeza bicolor and their effects on mitochondrial membrane potential. We isolated 11 polyphenolic compounds: a novel coumestan lespebicoumestan A (10) and a novel stilbenoid 5’-isoprenylbicoloketon (11) as well as three previously known pterocarpans, two pterocarpens, one coumestan, one stilbenoid, and a dimeric flavonoid. Pterocarpans 3 and 6, stilbenoid 5, and dimeric flavonoid 8 significantly increased the percentage of living cells after treatment with paraquat (PQ), but only pterocarpan 6 slightly decreased the ROS level in PQ-treated cells. Pterocarpan 3 and stilbenoid 5 were shown to effectively increase mitochondrial membrane potential in PQ-treated cells. We showed that pterocarpans 2 and 3, containing a 3’-methyl-3’-isohexenylpyran ring; pterocarpens 4 and 9, with a double bond between C-6a and C-11a; and coumestan 10 significantly increased the percentage of living cells by decreasing ROS levels in 6-OHDA-treated cells, which is in accordance with their rather high activity in DPPH^• and FRAP tests. Compounds 9 and 10 effectively increased the percentage of living cells after treatment with rotenone but did not significantly decrease ROS levels.

Potential of flavonoids as anti-Alzheimer's agents: bench to bedside

Developing therapies for neurodegenerative diseases are challenging because of the presence of blood-brain barrier and Alzheimer being one of the commonest and uprising neurodegenerative disorders possess the need for developing novel therapies. Alzheimer's is attributed to be the sixth leading cause of death in the USA and the number of cases is estimated to be increased from 58 million in 2021 to 88 million by 2050. Natural drugs have benefits of being cost-effective, widely available, fewer side effects, and immuno-booster can be useful in managing Alzheimer. Flavonoids can slow the neuronal degeneration as they have shown activity in central nervous system and are able to cross the blood-brain barrier. These can be easily extracted from fruits, vegetable, and plants. In Alzheimer disease, flavonoids scavenges the reactive oxygen species and reduces the production of amyloid beta protein. Agents from sub-classes of flavonoids such as flavanones, flavanols, flavones, flavonols, anthocyanins, and isoflavones having pharmacological action in treating Alzheimer disease are discussed in this review.

Dietary biomolecules as promising regenerative agents for peripheral nerve injury: An emerging nutraceutical-based therapeutic approach

Peripheral nerve damage is a debilitating condition that can result in partial or complete functional loss as a result of axonal degeneration, as well as lifelong dependence. Many therapies have been imbued with a plethora of positive features while posing little risks. It is worth noting that these biomolecules work by activating several intrinsic pathways that are known to be important in peripheral nerve regeneration. Although the underlying mechanism is used for accurate and speedy functional recovery, none of them are without side effects. As a result, it is believed that effective therapy is currently lacking. The dietary biomolecules-based intervention, among other ways, is appealing, safe, and effective. Upregulation of transcription factors, neurotrophic factors, and growth factors such as NGF, GDNF, BDNF, and CTNF may occur as a result of these substances' dietary intake. Upregulation of the signaling pathways ERK, JNK, p38, and PKA has also been seen, which aids in axonal regeneration. Although several mechanistic approaches to understanding their involvement have been suggested, more work is needed to reveal the amazing properties of these biomolecules. We have discussed in this article that how different dietary biomolecules can help with functional recovery and regeneration after an injury. PRACTICAL APPLICATIONS: Based on the information known to date, we may conclude that treatment techniques for peripheral nerve injury have downsides, such as complications, donor shortages, adverse effects, unaffordability, and a lack of precision in efficacy. These difficulties cast doubt on their efficacy and raise severe concerns about the prescription. In this situation, the need for safe and effective therapeutic techniques is unavoidable, and dietary biomolecules appear to be a safe, cost-efficient, and effective way to promote nerve regeneration following an injury. The information on these biomolecules has been summarized here. Upregulation of transcription factors, neurotrophic factors, and growth factors, such as NGF, GDNF, BDNF, and CTNF, as well as the ERK, JNK, p38, and PKA, signaling pathways, may stimulate axonal regeneration.

Calotropis procera (leaves) supplementation exerts curative effects on promoting functional recovery in a mouse model of peripheral nerve injury

Peripheral nerve injuries are among those complicated medical conditions, which are still waiting for their highly effective first-line therapies. In this study, the role of Calotropis procera crude leaves was evaluated at different doses for their effectiveness in improving functional recovery following sciatic nerve injury-induced in the mouse model. Thirty-two healthy albino mice were divided into four groups as Normal chow group (control, n = 8) and C. procera chow groups (50 mg/kg (n = 8), 100 mg/kg (n = 8) and 200 mg/kg (n = 8)). Behavioral analyses were performed to assess and compare improved functional recovery along with skeletal muscle mass measurement in all groups. Serum samples were analyzed for oxidative stress markers. Results showed that C. procera leaves at dose-dependent manner showed statistically prominent (p < .05) increase in sensorimotor functions reclamation as confirmed by behavioral analyses along with muscle mass restoration and prominent decline in TOS and momentous increase in TAC along with the augmented activity of antioxidative enzymes.

Flavonoids, the Family of Plant-derived Antioxidants making inroads into Novel Therapeutic Design against IR-induced Oxidative Stress in Parkinson's Disease

Background:

Ionizing radiation from telluric sources is unceasingly an unprotected pitfall to humans. Thus, the foremost contributors to human exposure are global and medical radiations. Various evidences assembled during preceding years reveal the pertinent role of ionizing radiation-induced oxidative stress in the progression of neurodegenerative insults, such as Parkinson’s disease, which have been contributing to increased proliferation and generation of reactive oxygen species.

Objective:

This review delineates the role of ionizing radiation-induced oxidative stress in Parkinson’s disease and proposes novel therapeutic interventions of flavonoid family, offering effective management and slowing down the progression of Parkinson’s disease.

Methods:

Published papers were searched in MEDLINE, PubMed, etc., published to date for in-depth database collection.

Results:

The oxidative damage may harm the non-targeted cells. It can also modulate the functions of the central nervous system, such as protein misfolding, mitochondria dysfunction, increased levels of oxidized lipids, and dopaminergic cell death, which accelerate the progression of Parkinson’s disease at the molecular, cellular, or tissue levels. In Parkinson’s disease, reactive oxygen species exacerbate the production of nitric oxides and superoxides by activated microglia, rendering death of dopaminergic neuronal cell through different mechanisms.

Conclusion:

Rising interest has extensively engrossed in the clinical trial designs based on the plant-derived family of antioxidants. They are known to exert multifarious impact on neuroprotection via directly suppressing ionizing radiation-induced oxidative stress and reactive oxygen species production or indirectly increasing the dopamine levels and activating the glial cells.

Nutraceuticals-based therapeutic approach: recent advances to combat pathogenesis of Alzheimer's disease

Introduction: Alzheimer's disease (AD) is a progressive neurodegenerative disease accompanying memory deficits. The available pharmaceutical care has some limitations mostly entailing side effects, shelf-life, and patient's compliance. The momentous implications of nutraceuticals in AD have attracted scientists. Several preclinical studies for the investigation of nutraceuticals have been conducted.Areas covered: This review focuses on the potential use of a nutraceuticals-based therapeutic approach to treat and prevent AD. Increasing knowledge of AD pathogenesis has led to the discovery of new therapeutic targets including pathophysiological mechanisms and various cascades. Hence, the present contribution will attend to the most popular and effective nutraceuticals with proposed brief mechanisms entailing antioxidant, anti-inflammatory, autophagy regulation, mitochondrial homeostasis, and more. Therefore, even though the effectiveness of nutraceuticals cannot be dismissed, it is essential to do further high-quality randomized clinical trials.Expert opinion: According to the potential of nutraceuticals to combat AD as multi-target directed drugs, there is critical importance to assess them as feasible lead compounds for drug discovery and development. To the best of the authors' knowledge, modification of blood-brain barrier permeability, bioavailability, and features of randomized clinical trials should be considered in prospective studies.

The Roles of Flavonols/Flavonoids in Neurodegeneration and Neuroinflammation

The inflammatory process in the human body is a physiological response involving many cellular types and mediators. It results in scar formation to separate the damaged area from the surrounding healthy tissue. Because of increased blood-brain barrier permeability following inflammation, leukocytes infiltrate the CNS and are also supplemented by proinflammatory mediators. However, an acute inflammatory process after cerebral trauma or stroke may also result in a prolonged lesion formation, leading to a severe neuronal loss. The prolonged inflammatory process in the CNS may cause serious damage to the neuronal system. It may lead to CNS damage in such a way that endangers functional integration and proinflammatory system balance. Effects of different flavonoid species on ischemia-reperfusion injury and cognition and function have also been shown in experimental studies. Flavonoids are presented broadly in plants and diets. They are believed to have various bioactive effects including anti-viral, anti-inflammatory, cardioprotective, anti-diabetic, anti-cancer, anti-aging, etc. Quercetine is the predominant dietary flavonoid. Main sources are tea, onion, and apple. It is demonstrated that the frequently consumed food like soybean, peanut, mustard, rice, sesame, olive, potatoes, onion, and oats contain flavonoids. Catechin and its derivates which are isolated from tea leaves have antioxidant activity but in low doses, their prooxidant effects are also reported. Ipriflavone which is a synthetic flavonoid may increase total calcium in bone. In this review, the effects of flavonoids species on the inflammatory process in the neurodegenerative process were examined as general.

Fermented Soy Products: Beneficial Potential in Neurodegenerative Diseases

Fermented soybean products, such as cheonggukjang (Japanese natto), doenjang (soy paste), ganjang (soy sauce), and douchi, are widely consumed in East Asian countries and are major sources of bioactive compounds. The fermentation of cooked soybean with bacteria (Bacillus spp.) and fungi (Aspergillus spp. and Rhizopus spp.) produces a variety of novel compounds, most of which possess health benefits. This review is focused on the preventive and ameliorative potential of fermented soy foods and their components to manage neurodegenerative diseases, including Alzheimer's and Parkinson's diseases.

Chemical Profiling and Dose-Dependent Assessment of Fear Reducing and Memory-Enhancing Effects of Solanum virginianum in Rats

The current study was planned to investigate the pharmacological basis of Solanum virginianum extract (SV.CR) pertaining to anxiolytic, antidepressant and memory-enhancing effects in rats. The SV.CR was analyzed in-vitro for phytoconstituents, antioxidant potential and anticholinesterase activity. The rats treated in a dose-dependent manner (25, 50 and 100 mg/kg of SV.CR) were subjected to behavioral tests for anxiety, depression and memory judgment followed by biochemical studies. A notable dose-dependent anxiolytic potential of SV.CR was observed in elevated plus maze and open field tests (P < 0.05). The decreased immobility time of the treated rats in the forced swim test (P < 0.01) unveiled the plant’s potential to reduce depression. Moreover, SV.CR treatment also reversed scopolamine-impaired cognition (P < 0.05) in various deployed memory and learning tasks. Biochemical studies of brain homogenates of SV.CR treated animals demonstrated decreased anticholinesterase activity and lipid peroxidation levels whereas increased levels of superoxide dismutase and glutathione peroxidase (P < 0.05 vs scopolamine group) were noted. The scientific validation of the study supported the use of Solanum virginianum in reducing anxiety, depression and amnesia in experimental models. Phytoconstituents in SV.CR such as oleanolic acid and caffeic acid might have played a significant neuroprotective role via modulation of oxidative stress and neurochemical aspects.

Flavonoid-Based Nanomedicines in Alzheimer's Disease Therapeutics: Promises Made, a Long Way To Go

Alzheimer's disease (AD) is characterized by the continuous decline of the cognitive abilities manifested due to the accumulation of large aggregates of amyloid-beta 42 (Aβ42), the formation of neurofibrillary tangles of hyper-phosphorylated forms of microtubule-associated tau protein, which may lead to many alterations at the cellular and systemic level. The current therapeutic strategies primarily focus on alleviating pathological symptoms rather than providing a possible cure. AD is one of the highly studied but least understood neurological problems and remains an unresolved condition of human brain degeneration. Over the years, multiple naturally derived small molecules, including plant products, microbial isolates, and some metabolic byproducts, have been projected as supplements reducing the risk or possible treatment of the disease. However, unfortunately, none has met the expected success. One major challenge for most medications is their ability to cross the blood-brain barrier (BBB). In past decades, nanotechnology-based interventions have offered an alternative platform to address the problem of the successful delivery of the drugs to the specific targets. Interestingly, the exciting interface of natural products and nanomedicine is delivering promising results in AD treatment. The potential applications of flavonoids, the plant-derived compounds best known for their antioxidant activities, and their amalgamation with nanomedicinal approaches may lead to highly effective therapeutic strategies for treating well-known neurodegenerative diseases. In the present review, we explore the possibilities and recent developments on an exciting combination of flavonoids and nanoparticles in AD.

Antioxidant vs. Prooxidant Properties of the Flavonoid, Kaempferol, in the Presence of Cu(II) Ions: A ROS-Scavenging Activity, Fenton Reaction and DNA Damage Study

Kaempferol is a flavonoid that occurs in tea and in many vegetables and fruits, including broccoli, cabbage, beans, grapes, apples, and strawberries. The efficacy of Kaempferol has been demonstrated in the treatment of breast, esophageal, cervical, ovarian, and liver cancers and leukemia, which very likely arises from its prooxidant properties and the activation of pro-apoptotic pathways. Indeed, this matter has already been the focus of a number of published studies and reviews. The aim of the present study was to elucidate the antioxidant vs. prooxidant properties of flavonoids in the presence of the redox-active metal, copper (II) ion, by means of the Fenton reaction. The specific motivation of this work is that, since an increased level of Cu(II) ions is known to be associated with many disease states such as neurological conditions (Alzheimer’s disease) and cancer, any interaction between these ions and flavonoids might affect the outcome of therapeutic uses of the latter. The structure of the Cu-kaempferol complex in DMSO was investigated by means of low temperature EPR spectroscopy, which confirmed the existence of at least two distinct coordination environments around the copper (II) ion. UV vis-spectra of kaempferol and its Cu(II) complex in DMSO revealed an interaction between the 5-OH (A ring) group and the 4-CO (C ring) group of kaempferol with Cu(II) ions. An ABTS assay confirmed that kaempferol acted as an effective radical scavenger, and that this effect was further enhanced in the form of the Cu(II)-kaempferol complex. Quantitative EPR spin trapping experiments, using DMPO as the spin trap, confirmed suppression of the formation of a mixture of hydroxyl, superoxide, and methyl radicals, in a Fenton reaction system, upon coordination of kaempferol to the redox-active Cu(II) ions, by 80% with respect to the free Cu(II) ions. A viscometric study revealed a better DNA-intercalating ability of the Cu-kaempferol complex than for free kaempferol, essential for conferring anticancer activity of these substances. The results of the viscometric measurements were compared with those from a DNA damage study of Cu-kaempferol complexes in a Fenton reaction system, using gel electrophoresis. At low concentrations of kaempferol (Cu–kaempferol ratios of 1:1 and 1:2), a very weak protective effect on DNA was noted, whereas when kaempferol was present in excess, a significant DNA-protective effect was found. This can be explained if the weakly intercalated kaempferol molecules present at the surface of DNA provide protection against attack by ROS that originate from the Fenton reaction involving intercalated Cu(II)-kaempferol complexes. Following the application of ROS scavengers, L-histidine, DMSO, and SOD, gel electrophoresis confirmed the formation of singlet oxygen, hydroxyl radicals, and superoxide radical anions, respectively. We propose that the prooxidant properties of Cu-kaempferol complexes may provide anticancer activity of these substances. When present in excess, kaempferol displays antioxidant properties under Cu-Fenton conditions. This suggests that kaempferol might prove a suitable candidate for the prevention or treatment of oxidative stress related medical conditions that involve a disturbed metabolism of redox metals such as copper, for example, Menkes disease, and neurological disorders, including Alzheimer’s disease. For the potential use of kaempferol in clinical practice, it will be necessary to optimize the dose size and critical age of the patient so that this flavonoid may be beneficial as a preventive drug against cancer and neurological disorders.

Role of Flavonoids in Neurodegenerative Diseases: Limitations and Future Perspectives

BACKGROUND

Flavonoids, a group of natural dietary polyphenols, are known for their beneficial effects on human health. By virtue of their various pharmacological effects, like anti-oxidative, antiinflammatory, anti-carcinogenic and neuroprotective effects, flavonoids have now become an important component of herbal supplements, pharmaceuticals, medicinals and cosmetics. There has been enormous literature supporting neuroprotective effect of flavonoids. Recently their efficacy in various neurodegenerative diseases, like Alzheimer's disease and Parkinson diseases, has received particular attention.

OBJECTIVE

The mechanism of flavanoids neuroprotection might include antioxidant, antiapoptotic, antineuroinflammatory and modulation of various cellular and intracellular targets. In in-vivo systems, before reaching to brain, they have to cross barriers like extensive first pass metabolism, intestinal barrier and ultimately blood brain barrier. Different flavonoids have varied pharmacokinetic characteristics, which affect their pharmacodynamic profile. Therefore, brain accessibility of flavonoids is still debatable.

METHODS

This review emphasized on current trends of research and development on flavonoids, especially in neurodegenerative diseases, possible challenges and strategies to encounter using novel drug delivery system.

RESULTS

Various flavonoids have elicited their therapeutic potential against neurodegenerative diseases, however by using nanotechnology and novel drug delivery systems, the bioavailability of favonoids could be enhanced.

CONCLUSION

This study bridges a significant opinion on medicinal chemistry, ethanopharmacology and new drug delivery research regarding use of flavonoids in management of neurodegeneration.

Grewia asiatica Berry Juice Diminishes Anxiety, Depression, and Scopolamine-Induced Learning and Memory Impairment in Behavioral Experimental Animal Models

Grewia asiatica L. fruit natively called phalsa is a popular berry of Pakistan and widely consumed in the form of fresh juices and carbonated drinks in the summer season. The berry is enriched with antioxidants such as phenols, flavonoids, anthocyanins, and vitamin C. Scientifically, it is the least explored berry in terms of neuromodulatory activities, and therefore, in the designed study, chronically fed rats with the different dilutions (5%-30%) of fruit juice were subjected to behavioral assessment for anxiety, depression, and cognition (spatial memory) followed by biochemical analysis of isolated brains. Results revealed a prominent impact of 20 and 30% dilutions of fruit exudate as treated animals showed anxiolytic behavior to central zone (P < 0.05) of open field test (OFT) and open arms of elevated plus maze (EPM) (P < 0.05) in anxiety models. Overall, immobility of rats treated with a higher concentration of exudate in forced swim test (FST) was reduced (P < 0.05) presenting antidepressant-like activity. Moreover, in learning and memory experimental models, the treated animals reversed scopolamine-induced amnesic effects as evident from improved step-through latencies (P < 0.05 vs. scopolamine; passive avoidance test), spontaneous alternation behavior (P < 0.05 vs. scopolamine; Y-maze test), discrimination index (P < 0.05 vs. scopolamine; novel object recognition test), and escape latencies (P < 0.05 vs. scopolamine; Morris water maze). Biochemical studies of isolated brains from treated rats demonstrated significantly elevated levels of superoxide dismutase and glutathione peroxidase (P < 0.05), whereas levels of acetylcholinesterase and malondialdehyde level (P < 0.05) were reduced, indicating its potential to reduce oxidative damage in the brain and modulation with the cholinergic system. The outcomes of studies support the benefits of phytoconstituents possessed by G. asiatica fruit in the amelioration of neurological disorders that could be due to their antioxidative capacity or due to interaction with GABAergic, serotonergic, and cholinergic systems in the brain.

Environmentally Friendly Methods for Flavonoid Extraction from Plant Material: Impact of Their Operating Conditions on Yield and Antioxidant Properties

The flavonoids are compounds synthesized by plants, and they have properties such as antioxidant, anticancer, anti-inflammatory, and antibacterial, among others. One of the most important bioactive properties of flavonoids is their antioxidant effect. Synthetic antioxidants have side toxic effects whilst natural antioxidants, such as flavonoids from natural sources, have relatively low toxicity. Therefore, it is important to incorporate flavonoids derived from natural sources in several products such as foods, cosmetics, and drugs. For this reason, there is currently a need to extract flavonoids from plant resources. In this review are described the most important parameters involved in the extraction of flavonoids by unconventional methods such as ultrasound, pressurized liquid extraction, mechanochemical, high hydrostatic pressure, supercritical fluid, negative pressure cavitation, intensification of vaporization by decompression to the vacuum, microwave, infrared, pulsed electric field, high-voltage electrical discharges, and enzyme-assisted extraction. There are no unified operation conditions to achieve high yields and purity. Notwithstanding, progress has been achieved in the development of more advanced and environmentally friendly methods of extraction. Although in literature are found important advances, a complete understanding of the extraction process in each of the unconventional techniques is needed to determine the thermodynamic and kinetic mechanisms that govern each of the techniques.

Moringa oleifera Lam.ameliorates the muscles function recovery following an induced insult to the Sciatic nerve in a mouse model

Peripheral nerve injury (PNI) is an incapacitating situation and has no effective therapy until now. We examined the possible role of crude leaves of Moringa oleifera Lam. at 200 mg/kg body weight in accelerating the functional regain in the sciatic nerve lesion induced mouse model (Adult male albino mice (BALB/c). Motor functions were evaluated by using the sciatic functional index, muscle mass, and muscle grip strength measurement, whereas the sensory functions were evaluated by using the hot plate test. Blood glucose levels and blood cell composition were also analyzed. We found that the Moringa oleifera crude leaves endorse the sensory and motor functions reclamation following the PNI with a statistically significant difference (p < .05). It also revitalizes the gastrocnemius muscle by mass restoration with glycemic management perspective. Conclusively, the crude powder of Moringa oleifera leaves exhibited a function restoration boosting property and further detailed studies for its application as a therapeutic agent are strongly recommended.

Status and future directions of clinical trials in Parkinson's disease

Novel therapies are needed to treat Parkinson's disease (PD) in which the clinical unmet need is pressing. Currently, no clinically available therapeutic strategy can either retard or reverse PD or repair its pathological consequences. l-DOPA (levodopa) is still the gold standard therapy for motor symptoms yet symptomatic therapies for both motor and non-motor symptoms are improving. Many on-going, intervention trials cover a broad range of targets, including cell replacement and gene therapy approaches, quality of life improving technologies, and disease-modifying strategies (e.g., controlling aberrant α-synuclein accumulation and regulating cellular/neuronal bioenergetics). Notably, the repurposing of glucagon-like peptide-1 analogues with potential disease-modifying effects based on metabolic pathology associated with PD has been promising. Nevertheless, there is a clear need for improved therapeutic and diagnostic options, disease progression tracking and patient stratification capabilities to deliver personalized treatment and optimize trial design. This review discusses some of the risk factors and consequent pathology associated with PD and particularly the metabolic aspects of PD, novel therapies targeting these pathologies (e.g., mitochondrial and lysosomal dysfunction, oxidative stress, and inflammation/neuroinflammation), including the repurposing of metabolic therapies, and unmet needs as potential drivers for future clinical trials and research in PD.

Strychnos nux-vomica L. seed preparation promotes functional recovery and attenuates oxidative stress in a mouse model of sciatic nerve crush injury

Background

Peripheral nerve injury is a debilitating condition that may lead to partial or complete motor, sensory and autonomic function loss and lacks effective therapy until date. Therefore, it is quite imperative to explore impending remedies for rapid and accurate functional retrieval following such conditions. Natural product-based intervention can prove effective to facilitate the process of functions regain.

Methods

Here, we investigated the effect of processed Strychnos nux-vomica seeds at a dose of 250 mg/kg body weight in a mouse model of induced Sciatic nerve lesion in promoting the recovery of the functions. A compression injury was induced in the Sciatic nerve of the right leg in the mice. Sensory function recovery was evaluated by hot-plate and formalin tests, whereas the motor function retrieval was assessed by measuring muscle grip strength, sciatic functional index, and muscle mass restoration. Oxidative stress and blood cell count were measured by biochemistry and haematological analyses.

Results

This study indicates that Strychnos nux-vomica seeds enhance the rate of recovery of both sensory and motor functions. It helps restore the muscle mass, attenuates total oxidant status and enhances the total anti-oxidant capacity of the biological system. Moreover, the treated animals manifested an enhanced glucose tolerance aptitude and augmented granulocyte and platelet counts. Improved oxidant control, enhanced glucose sensitivity and amended granulocyte and platelet counts are likely to contribute to the advantageous effects of Strychnos nux-vomica, and warrant further in-depth studies for deciphering possible mechanisms and identification of active constituent(s) responsible for these effects.

Conclusion

Strychnos nux-vomica seed offers functional recovery promoting effects following a mechanical injury to the Sciatic nerve and the possible reasons behind this effect can be reduced oxidative stress and improved glycaemic control. Further and detailed investigations can unravel this mystery.

Natural Products, Traditional Uses and Pharmacological Activities of the Genus Biebersteinia (Biebersteiniaceae)

Medicinal plants have been known as a rich source of natural products (NPs). Due to their diverse chemical structures and remarkable pharmacological activities, NPs are regarded as important repertoires for drug discovery and development. Biebersteinia plant species belong to the Biebersteiniaceae family, and have been used in folk medicines in China and Iran for ages. However, the chemical properties, bioactivities and modes of action of the NPs produced by medicinal Biebersteinia species are poorly understood despite the fact that there are only four known Biebersteinia species worldwide. Here, we reviewed the chemical classifications and diversity of the various NPs found in the four known Biebersteinia species. We found that the major chemical categories in these plants include flavonoids, alkaloids, phenylpropanoids, terpenoids, essential oils and fatty acids. We also discussed the anti-inflammatory, analgesic, antibacterial, antioxidant, antihypertensive and hypoglycemic effects of the four Biebersteinia species. We believe that the present review will facilitate the exploration of traditional uses and pharmacological properties of Biebersteinia species, extraction of the NPs and elucidation of their molecular mechanisms, as well as the development of novel drugs based on the reported properties and mode-of-action.

Impact of Natural Compounds on Neurodegenerative Disorders: From Preclinical to Pharmacotherapeutics

Among the major neurodegenerative disorders (NDDs), Alzheimer’s disease (AD) and Parkinson’s disease (PD), are a huge socioeconomic burden. Over many centuries, people have sought a cure for NDDs from the natural herbals. Many medicinal plants and their secondary metabolites are reported with the ability to alleviate the symptoms of NDDs. The major mechanisms identified, through which phytochemicals exert their neuroprotective effects and potential maintenance of neurological health in ageing, include antioxidant, anti-inflammatory, antithrombotic, antiapoptotic, acetylcholinesterase and monoamine oxidase inhibition and neurotrophic activities. This article reviews the mechanisms of action of some of the major herbal products with potential in the treatment of NDDs according to their molecular targets, as well as their regional sources (Asia, America and Africa). A number of studies demonstrated the beneficial properties of plant extracts or their bioactive compounds against NDDs. Herbal products may potentially offer new treatment options for patients with NDDs, which is a cheaper and culturally suitable alternative to conventional therapies for millions of people in the world with age-related NDDs.

Neurobehavioral Consequences Associated with Long Term Tramadol Utilization and Pathological Mechanisms

:

Tramadol is a synthetic analog of codeine used to treat pain of moderate to severe intensity and is reported to have neurotoxic potential. At therapeutic dose, tramadol does not cause major side effects in comparison to other opioid analgesics, and is useful for the management of neurological problems like anxiety and depression. Long term utilization of tramadol is associated with various neurological disorders like seizures, serotonin syndrome, Alzheimer’s disease and Parkinson’s disease. Tramadol produces seizures through inhibition of nitric oxide, serotonin reuptake and inhibitory effects on GABA receptors. Extensive tramadol intake alters redox balance through elevating lipid peroxidation and free radical leading to neurotoxicity and produces neurobehavioral deficits. During Alzheimer’s disease progression, low level of intracellular signalling molecules like cGMP, cAMP, PKC and PKA affect both learning and memory. Pharmacologically tramadol produces actions similar to Selective Serotonin Reuptake Inhibitors (SSRIs), increasing the concentration of serotonin, which causes serotonin syndrome. In addition, tramadol also inhibits GABAA receptors in the CNS has been evidenced to interfere with dopamine synthesis and release, responsible for motor symptoms. The reduced level of dopamine may produce bradykinesia and tremors which are chief motor abnormalities in Parkinson’s Disease (PD).

Current Status of Therapeutic Approaches against Peripheral Nerve Injuries: A Detailed Story from Injury to Recovery

Peripheral nerve injury is a complex condition with a variety of signs and symptoms such as numbness, tingling, jabbing, throbbing, burning or sharp pain. Peripheral nerves are fragile in nature and can easily get damaged due to acute compression or trauma which may lead to the sensory and motor functions deficits and even lifelong disability. After lesion, the neuronal cell body becomes disconnected from the axon's distal portion to the injury site leading to the axonal degeneration and dismantlement of neuromuscular junctions of targeted muscles. In spite of extensive research on this aspect, complete functional recovery still remains a challenge to be resolved. This review highlights detailed pathophysiological events after an injury to a peripheral nerve and the associated factors that can either hinder or promote the regenerative machinery. In addition, it throws light on the available therapeutic strategies including supporting therapies, surgical and non-surgical interventions to ameliorate the axonal regeneration, neuronal survival, and reinnervation of peripheral targets. Despite the availability of various treatment options, we are still lacking the optimal treatments for a perfect and complete functional regain. The need for the present age is to discover or design such potent compounds that would be able to execute the complete functional retrieval. In this regard, plant-derived compounds are getting more attention and several recent reports validate their remedial effects. A plethora of plants and plant-derived phytochemicals have been suggested with curative effects against a number of diseases in general and neuronal injury in particular. They can be a ray of hope for the suffering individuals.

Genistein protects against amyloid-beta-induced toxicity in SH-SY5Y cells by regulation of Akt and Tau phosphorylation

Alzheimer's disease is a neurodegenerative disorder characterized by extracellular deposition of amyloid-β (Aβ) peptide and hyperphosphorylation of Tau protein, which ultimately leads to the formation of intracellular neurofibrillary tangles and cell death. Increasing evidence indicates that genistein, a soy isoflavone, has neuroprotective effects against Aβ-induced toxicity. However, the molecular mechanisms involved in its neuroprotection are not well understood. In this study, we have established a neuronal damage model using retinoic-acid differentiated SH-SY5Y cells treated with different concentrations of Aβ_25-35 to investigate the effect of genistein against Aβ-induced cell death and the possible involvement of protein kinase B (PKB, also termed Akt), glycogen synthase kinase 3β (GSK-3β), and Tau as an underlying mechanism to this neuroprotection. Differentiated SH-SY5Y cells were pre-treated for 24 hr with genistein (1 and 10 nM) and exposed to Aβ_25-35 (25 μM), and we found that genistein partially inhibited Aβ induced cell death, primarily apoptosis. Furthermore, the protective effect of genistein was associated with the inhibition of Aβ-induced Akt inactivation and Tau hyperphosphorylation. These findings reinforce the neuroprotective effects of genistein against Aβ toxicity and provide evidence that its mechanism may involve regulation of Akt and Tau proteins.

A Switch between Antioxidant and Prooxidant Properties of the Phenolic Compounds Myricetin, Morin, 3',4'-Dihydroxyflavone, Taxifolin and 4-Hydroxy-Coumarin in the Presence of Copper(II) Ions: A Spectroscopic, Absorption Titration and DNA Damage Study

The beneficial effects of polyphenols, predominantly in the context of oxidative stress-related diseases such as cancer, cardiovascular diseases and neurological conditions including Alzheimer's and Parkinson's diseases, have been documented by a number of papers and reviews. The antioxidant/prooxidant properties of phenolic compounds are related mainly to the number and positions of hydroxyl groups and to their redox metal (Cu, Fe) chelating capacity. In this work we studied structurally distinct phenolic molecules such as myricetin, morin, 3',4'-dihydroxy-flavone, taxifolin and 4-hydroxycoumarin, either alone or as interacting with Cu2+ ions. EPR and UV-Vis spectroscopy confirmed that the effective binding of cupric ions to phenolic compounds requires the presence of the 3-OH and 4-CO groups on the flavonoid C ring and unsaturated C2-C3 bond of the C-ring, which permits through-conjugation with the B-ring. An ABTS assay revealed that radical scavenging activities of phenolic compounds are related to their number of hydroxyl groups, planarity of the molecular skeleton, extent of delocalization and they decrease in the order: myricetin > morin > 3',4'-dihydroxyflavone ~ 4-hydroxy coumarin > taxifolin. Absorption titrations indicate that copper ions can modulate the DNA binding affinity of flavonoids via the formation of their Cu-chelates. Gel electrophoresis measurements indicated that the protective effect of the phenolic compounds decreases in the order: 3',4'-dihydroxyflavone > 4-OH coumarin > morin > taxifolin ~ myricetin. This can be explained by the fact that myricetin, taxifolin and morin form stable Cu(II) complexes capable of causing DNA damage via interaction with DNA and ROS formation via the Fenton reaction. Application of ROS scavengers revealed the formation of singlet oxygen, superoxide and hydroxyl radicals and their concerted synergistic effect on the DNA. The overall results suggest that the most pronounced DNA damage has been observed for flavonoids containing higher number of hydroxyl groups (including 3-OH group of the C ring), such as myricetin (six hydroxyl groups), morin and taxifolin (five hydroxyl groups) in the presence of Cu(II) ions. The proposed mechanism of action by which Cu(II) complexes of myricetin, morin and taxifolin interact with DNA predispose these substances to act as potential anticancer agents. The anticancer activity of phenolic compounds can be explained by their moderate prooxidant properties, which can boost ROS formation and kill cancer cells. Alternatively, slight prooxidant properties may activate antioxidant systems, including antioxidant enzymes and low molecular antioxidants such as glutathione and thus act as preventive anticancer agents.

Cognitive Function and Consumption of Fruit and Vegetable Polyphenols in a Young Population: Is There a Relationship?

Scientific evidence has shown the relationship between consumption of fruits and vegetables and their polyphenols with the prevention or treatment of diseases. The aim of this review was to find out whether the same relationship exists between fruits and vegetables and cognitive function, especially memory, in a young population. The mechanisms by which polyphenols of fruits and vegetables can exert cognitive benefits were also evaluated. These compounds act to improve neuronal plasticity through the protein CREB (Camp Response Element Binding) in the hippocampus, modulating pathways of signaling and transcription factors (ERK/Akt). In the same way, brain-derived neurotrophic factor (BDNF) is implicated in the maintenance, survival, growth, and differentiation of neurons. All these effects are produced by an increase of cerebral blood flow and an increase of the blood’s nitric oxide levels and oxygenation.

Herpes simplex virus type 1 and Alzheimer's disease: link and potential impact on treatment

Introduction: Alzheimer's disease (AD), the most common form of dementia worldwide, is a multifactorial disease with a still unknown etiology. Herpes simplex virus 1 (HSV-1) has long been suspected to be one of the factors involved in the pathogenesis of the disease. Areas covered: We review the literature focusing on viral characteristics of HSV-1, the mechanisms this virus uses to infect neural cells, its interaction with the host immune system and genetic background and summarizes results and research that support the hypothesis of an association between AD and HSV-1. The possible usefulness of virus-directed pharmaceutical approaches as potential treatments for AD will be discussed as well. Expert opinion: We highlight crucial aspects that must be addressed to clarify the possible role of HSV-1 in the pathogenesis of the disease, and to allow the design of new therapeutical approaches for AD.

Foeniculum vulgare (Fennel) promotes functional recovery and ameliorates oxidative stress following a lesion to the sciatic nerve in mouse model

Peripheral nerve injury is one of the major health concerns of the present era which can lead to the long-lasting disability and even demise. Currently, no effective and side effect free remedy exists and exploration of effective therapeutic strategies to regain functional outcome is a need of hour. In the present study, we used BALB/c mice (N = 14 age, 10-12 weeks & weight 32-34 g) that were divided into two groups: Normal chow (n = 7) and Fennel chow (n = 7) group. Here, we have explored the role of crude Foeniculum vulgare mill seeds in promoting functional recovery following a mechanical insult to the sciatic nerve by an oral administration of a crude dose of 500 mg/kg BW. The recovery of both sensory and motor functions was significantly (p > .05) accelerated in the treatment group, assessed by behavioral analyses alongside total antioxidant capacity increase. Conclusively, F. vulgare can be a potential therapeutic candidate for accelerating functional recovery after peripheral nerve injury. PRACTICAL APPLICATIONS: The outcomes of study have vital practical application both for scientists and consumers. The therapeutic role of phytochemicals on functional recovery has not been explored yet. This study will help figure out plant based regimen as booster for brain health and intervention against traumatic nerve injuries. Moreover, it may also attract the food and pharmaceutical industries to formulate cost effective therapeutic products. Likewise, it can prove instrumental for scientists for advance research on this aspect with more mechanistic targets.

Putative Roles of Plant-Derived Tannins in Neurodegenerative and Neuropsychiatry Disorders: An Updated Review

Neurodegenerative and neuropsychiatric diseases are characterized by the structural and functional abnormalities of neurons in certain regions of the brain. These abnormalities, which can result in progressive neuronal degeneration and functional disability, are incurable to date. Although comprehensive efforts have been made to figure out effective therapies against these diseases, partial success has been achieved and complete functional recovery is still not a reality. At present, plants and plant-derived compounds are getting more attention because of a plethora of pharmacological properties, and they are proving to be a better and safer target as therapeutic interventions. This review aims to highlight the roles of tannins, 'the polyphenol phytochemicals', in tackling neurodegenerative diseases including Alzheimer's and Parkinson's diseases as well as neuropsychiatric disorders like depression. Among the multifarious pharmacological properties of tannins, anti-oxidative, anti-inflammatory, and anti-cholinesterase activities are emphasized more in terms of neuroprotection. The current review also throws light on mechanistic pathways by which various classes of tannins execute neuroprotective effects. Despite their beneficial properties, some harmful effects of tannins have also been elaborated.

Curcumol: From Plant Roots to Cancer Roots

Natural products, an infinite treasure of bioactive scaffolds, have provided an excellent reservoir for the discovery of drugs since millennium. These naturally occurring, biologically active and therapeutically effective chemical entities have emerged as novel paradigm for the prevention of various diseases. This review aims to give an update on the sources as well as pharmacological profile of curcumol, a pharmacologically active sesquiterpenoid, which is an imperative bioactive constituent of several plants mainly from genus Curcuma. Curcumol has potential to fight against cancer, oxidative stress, neurodegeneration, microbial infections, and inflammation. Curcumol has been documented as potent inducer of apoptosis in numerous cancer cells via targeting key signaling pathways as MAPK/ERK, PI3K/Akt and NF-κB which are generally deregulated in several cancers. The reported data reveals multitarget activity of curcumol in cancer treatment suggesting its importance as anticancer drug in future. It is speculated that curcumol may provide an excellent opportunity for the cure of cancer but further investigations on mechanism of its action and preclinical trials are still mandatory to further validate the potential of this natural cancer killer in anticancer therapies.