Neuroprotective Mechanisms of Three Natural Antioxidants on a Rat Model of Parkinson's Disease: A Comparative Study

Transdermal delivery of resveratrol loaded solid lipid nanoparticle as a microneedle patch: a novel approach for the treatment of Parkinson's disease

Parkinson's disease (PD), affecting millions of people worldwide and expected to impact 10 million by 2030, manifests a spectrum of motor and non-motor symptoms linked to the decline of dopaminergic neurons. Current therapies manage PD symptoms but lack efficacy in slowing disease progression, emphasizing the urgency for more effective treatments. Resveratrol (RSV), recognized for its neuroprotective and antioxidative properties, encounters challenges in clinical use for PD due to limited bioavailability. Researchers have investigated lipid-based nanoformulations, specifically solid lipid nanoparticles (SLNs), to enhance RSV stability. Oral drug delivery via SLNs faces obstacles, prompting exploration into transdermal delivery using SLNs integrated with microneedles (MNs) for improved patient compliance. In this study, an RSV-loaded SLNs (RSV -SLNs) incorporated into the MN patch was developed for transdermal RSV delivery to improve its stability and patient compliance. Characterization studies demonstrated favorable physical properties of SLNs with a sustained drug release profile of 78.36 ± 0.74%. The developed MNs exhibited mechanical robustness and skin penetration capabilities. Ex vivo permeation studies displayed substantial drug permeation of 68.39 ± 1.4% through the skin. In an in vivo pharmacokinetic study, the RSV-SLNs delivered through MNs exhibited a significant increase in Cmax, Tmax, and AUC0 - t values, alongside a reduced elimination rate in blood plasma in contrast to the administration of pure RSV via MNs. Moreover, an in vivo study showcased enhanced behavioral functioning and increased brain antioxidant levels in the treated animals. In-vivo skin irritation study revealed no signs of irritation till 24 h which permits long-term MNs application. Histopathological analysis showed notable changes in the brain regions of the rat, specifically the striatum and substantia nigra, after the completion of the treatment. Based on these findings, the development of an RSV-SLN loaded MNs (RSVSNLMP) patch presents a novel approach, with the potential to enhance the drug's efficiency, patient compliance, and therapeutic outcomes for PD, offering a promising avenue for advanced PD therapy.

Medicinal herbal remedies in neurodegenerative diseases: an update on antioxidant potential

It has been widely documented that medicinal herbal remedies are effective, have fewer side effects than conventional medicine, and have a synergistic effect on health collaborations in the fight against complicated diseases. Traditional treatments for neurological problems in ancient times sometimes involved the use of herbal remedies and conventional methods from East Asian countries including India, Japan, China, and Korea. We collected and reviewed studies on plant-derived neuroprotective drugs and tested them in neurotoxic models. Basic research, preclinical and clinical transgene research can benefit from in silico, in vitro, and in vivo investigations. Research, summaries of the extracts, fractions, and herbal ingredients were compiled from popular scientific databases, which were then examined according to origin and bioactivity. Given the complex and varied causes of neurodegeneration, it may be beneficial to focus on multiple mechanisms of action and a neuroprotection approach. This approach aims to prevent cell death and restore function to damaged neurons, offering promising strategies for preventing and treating neurodegenerative diseases. Neurodegenerative illnesses can potentially be treated with natural compounds that have been identified as neuroprotective agents. To gain deeper insights into the neuropharmacological mechanisms underlying the neuroprotective and therapeutic properties of naturally occurring antioxidant phytochemical compounds in diverse neurodegenerative diseases, this study aims to comprehensively review such compounds, focusing on their modulation of apoptotic markers such as caspase, Bax, Bcl-2, and proinflammatory markers. In addition, we delve into a range of efficacies of antioxidant phytochemical compounds as neuroprotective agents in animal models. They reduce the oxidative stress of the brain and have been shown to have anti-apoptotic effects. Many researches have demonstrated that plant extracts or bioactive compounds can fight neurodegenerative disorders. Herbal medications may offer neurodegenerative disease patients' new treatments. This may be a cheaper and more culturally appropriate alternative to standard drugs for millions of people with age-related NDDs.

Therapeutic Potential of Myrtenal and Its Derivatives-A Review

The investigation of monoterpenes as natural products has gained significant attention in the search for new pharmacological agents due to their ability to exhibit a wide range in biological activities, including antifungal, antibacterial, antioxidant, anticancer, antispasmodic, hypotensive, and vasodilating properties. In vitro and in vivo studies reveal their antidepressant, anxiolytic, and memory-enhancing effects in experimental dementia and Parkinson's disease. Chemical modification of natural substances by conjugation with various synthetic components is a modern method of obtaining new biologically active compounds. The discovery of new potential drugs among monoterpene derivatives is a progressive avenue within experimental pharmacology, offering a promising approach for the therapy of diverse pathological conditions. Biologically active substances such as monoterpenes, for example, borneol, camphor, geraniol, pinene, and thymol, are used to synthesize compounds with analgesic, anti-inflammatory, anticonvulsive, antidepressant, anti-Alzheimer's, antiparkinsonian, antiviral and antibacterial (antituberculosis) properties. Myrtenal is a perspective monoterpenoid with therapeutic potential in various fields of medicine. Its chemical modifications often lead to new or more pronounced biological effects. As an example, the conjugation of myrtenal with the established pharmacophore adamantane enables the augmentation of several of its pivotal properties. Myrtenal-adamantane derivatives exhibited a variety of beneficial characteristics, such as antimicrobial, antifungal, antiviral, anticancer, anxiolytic, and neuroprotective properties, which are worth examining in more detail and at length.

Four-parameter analysis in modified Rotarod test for detecting minor motor deficits in mice

BACKGROUND

The Rotarod test with commercial apparatus is widely used to assess locomotor performance, balance and motor learning as well as the deficits resulting from diverse neurological disorders in laboratory rodents due to its simplicity and objectivity. Traditionally, the test ends when rodents drop from the accelerating, turning rod, and the only parameter used commonly is "latency to fall". The values of individual animals can often vary greatly.

RESULTS

In the present study, we established a procedure for mice with 4 consecutive days of training with 4 trials per day and modified the testing procedure by placing the mice back on the rod repeatedly after each fall until the trial ends (5 min). Data from the fourth training day as baseline results showed that the second, third and fourth trial were more consistent than the first, probably due to habituation or learning. There was no difference between the second, third and fourth trial, two trials may be sufficient in testing. We also introduced 3 additional read-outs: Longest duration on the rod (s), Maximal distance covered (cm), and Number of falls to better evaluate the motor capacity over the 5 min of testing. We then used this 4-parameter analysis to capture the motor deficits of mice with mild to moderate traumatic brain injuries (by a weight dropping on the skull (Marmarou model)). We found that normalization of data to individual baseline performance was needed to reduce individual differences, and 4 trials were more sensitive than two to show motor deficits. The parameter of Maximal distance was the best in detecting statistically significant long-term motor deficits.

CONCLUSIONS

These results show that by making adjustments to the protocol and employing a more refined analysis, it is possible to expand a widely used routine behavioral test with additional accessible parameters that detect relevant deficits in a model of mild to moderate traumatic brain injury. The modified Rotarod test maybe a valuable tool for better preclinical evaluations of drugs and therapies.

Anti-COVID-19 Potential of Ellagic Acid and Polyphenols of Punica granatum L

Pomegranate (Punica granatum L.) is a rich source of polyphenols, including ellagitannins and ellagic acid. The plant is used in traditional medicine, and its purified components can provide anti-inflammatory and antioxidant activity and support of host defenses during viral infection and recovery from disease. Current data show that pomegranate polyphenol extract and its ellagitannin components and metabolites exert their beneficial effects by controlling immune cell infiltration, regulating the cytokine secretion and reactive oxygen and nitrogen species production, and by modulating the activity of the NFκB pathway. In vitro, pomegranate extracts and ellagitannins interact with and inhibit the infectivity of a range of viruses, including SARS-CoV-2. In silico docking studies show that ellagitannins bind to several SARS-CoV-2 and human proteins, including a number of proteases. This warrants further exploration of polyphenol-viral and polyphenol-host interactions in in vitro and in vivo studies. Pomegranate extracts, ellagitannins and ellagic acid are promising agents to target the SARS-CoV-2 virus and to restrict the host inflammatory response to viral infections, as well as to supplement the depleted host antioxidant levels during the stage of recovery from COVID-19.

Myrtenal improves memory deficits in mice exposed to radiofrequency-electromagnetic radiation during gestational and neonatal development via enhancing oxido-inflammatory, and neurotransmitter functions

Objective

Radiofrequency-electromagnetic radiation (RF-EMR) exposure during gestational and neonatal development may interact with the foetus and neonate considered hypersensitive to RF-EMR, consequently resulting in developmental defects associated with neuropsychological and neurobehavioral disorders, including learning and memory impairment. This study assessed the potential of Myrtenal (Myrt) to improve memory deficits in C57BL/6 mice exposed to RF-EMR during gestational and neonatal development.

Method

Thirty-five male mice were randomly allocated into 5 cohorts, each comprising of 7 mice. Group I was administered vehicle, Group II: RF-EMR (900 MHz); Group III: RF-EMR (900 MHz) + 100 mg/kg Myrt; Group IV: RF-EMR (900 MHz) + 200 mg/kg Myrt; and Group V: RF-EMR (900 MHz) + donepezil 0.5 mg/kg.

Results

Myrt treatment improved short-term memory performance in RF-EMR (900 MHz)-exposed mice by augmenting activities of endogenous antioxidant enzymes and proinflammatory cytokines, thereby protecting the brain from oxido-inflammatory stress. Additionally, Myrt restored the homeostasis of neurotransmitters in RF-EMR-exposed animals.

Conclusion

Results from the present study shows that exposure to RF-EMR impaired short-term memory in animals and altered the response of markers of oxido-inflammatory stress, and neurotransmitters. It is therefore conceivable that the recommendation of Myrt-enriched fruits may offer protective benefits for foeti and neonates prone to RF-EMR exposure.

Preventive and Therapeutic Effects of Punica granatum L. Polyphenols in Neurological Conditions

Pomegranate (Punica granatum L.) is a polyphenol-rich food and medicinal plant containing flavonols, anthocyanins, and tannins. Ellagitannins (ETs) are the most abundant polyphenols in pomegranate. A growing body of research shows that polyphenol-rich pomegranate extracts and their metabolites target multiple types of brain cell and support their redox balance, proliferation and survival, as well as cell signaling. Independent studies have demonstrated that the significant neuroprotective effects of ETs are mediated by their antioxidant and anti-inflammatory effects, their chelating properties, by their ability to activate various signaling pathways, as well as the ability to influence mitochondrial damage, thus regulating autophagy, apoptosis and neurotransmitter signaling. The multitude of in vitro and in vivo studies summarized in the present review suggest that pomegranate polyphenols act on both neuronal and glial cells directly, and also affect blood-brain barrier function, restoring redox balance in the blood and brain and increasing blood flow to the brain.

The Impact of Ellagitannins and Their Metabolites through Gut Microbiome on the Gut Health and Brain Wellness within the Gut-Brain Axis

Ellagitannins (ETs) are a large group of bioactive compounds found in plant-source foods, such as pomegranates, berries, and nuts. The consumption of ETs has often been associated with positive effects on many pathologies, including cardiovascular diseases, neurodegenerative syndromes, and cancer. Although multiple biological activities (antioxidant, anti-inflammatory, chemopreventive) have been discussed for ETs, their limited bioavailability prevents reaching significant concentrations in systemic circulation. Instead, urolithins, ET gut microbiota-derived metabolites, are better absorbed and could be the bioactive molecules responsible for the antioxidant and anti-inflammatory activities or anti-tumor cell progression. In this review, we examined the dietary sources, metabolism, and bioavailability of ETs, and analyzed the last recent findings on ETs, ellagic acid, and urolithins, their intestinal and brain activities, the potential mechanisms of action, and the connection between the ET microbiota metabolism and the consequences detected on the gut-brain axis. The current in vitro, in vivo, and clinical studies indicate that ET-rich foods, individual gut microbiomes, or urolithin types could modulate signaling pathways and promote beneficial health effects. A better understanding of the role of these metabolites in disease pathogenesis may assist in the prevention or treatment of pathologies targeting the gut-brain axis.

Interlinked role of ASN, TDP-43 and Miro1 with parkinopathy: Focus on targeted approach against neuropathy in parkinsonism

Parkinsonism is a complex neurodegenerative disease that is difficult to differentiate because of its idiopathic and unknown origins. The hereditary parkinsonism known as autosomal recessive-juvenile parkinsonism (AR-JP) is marked by tremors, dyskinesias, dystonic characteristics, and manifestations that improve sleep but do not include dementia. This was caused by deletions and point mutations in PARK2 (chromosome 6q25.2-27). Diminished or unusual sensations (paresthesias), loss of neuron strength both in the CNS and peripheral nerves, and lack of motor coordination are the hallmarks of neuropathy in parkinsonism. The incidence of parkinsonism during oxidative stress and ageing is associated with parkinopathy. Parkinopathy is hypothesized to be triggered by mutation of the parkin (PRKN) gene and loss of normal physiological functions of PRKN proteins, which triggers their pathogenic aggregation due to conformational changes. Two important genes that control mitochondrial health are PRKN and phosphatase and tensin homologue deleted on chromosome 10-induced putative kinase 1 (PINK1). Overexpression of TAR DNA-binding protein-43 (TDP-43) increases the aggregation of insoluble PRKN proteins in OMM. Foreign α-synuclein (ASN) promotes parkinopathy via S-nitrosylation and hence has a neurotoxic effect on dopaminergic nerves. Miro1 (Miro GTPase1), a member of the RAS superfamily, is expressed in nerve cells. Due to PINK1/PRKN and Miro1's functional relationship, an excess of mitochondrial calcium culminates in the destruction of dopaminergic neurons. An interlinked understanding of TDP-43, PINK1/PRKN, ASN, and Miro1 signalling in the communication among astrocytes, microglia, neurons, and immune cells within the brain explored the pathway of neuronal death and shed light on novel strategies for the diagnosis and treatment of parkinsonism.

The International Natural Product Sciences Taskforce (INPST) and the power of Twitter networking exemplified through #INPST hashtag analysis

BACKGROUND

The development of digital technologies and the evolution of open innovation approaches have enabled the creation of diverse virtual organizations and enterprises coordinating their activities primarily online. The open innovation platform titled "International Natural Product Sciences Taskforce" (INPST) was established in 2018, to bring together in collaborative environment individuals and organizations interested in natural product scientific research, and to empower their interactions by using digital communication tools.

METHODS

In this work, we present a general overview of INPST activities and showcase the specific use of Twitter as a powerful networking tool that was used to host a one-week "2021 INPST Twitter Networking Event" (spanning from 31st May 2021 to 6th June 2021) based on the application of the Twitter hashtag #INPST.

RESULTS AND CONCLUSION

The use of this hashtag during the networking event period was analyzed with Symplur Signals (https://www.symplur.com/), revealing a total of 6,036 tweets, shared by 686 users, which generated a total of 65,004,773 impressions (views of the respective tweets). This networking event's achieved high visibility and participation rate showcases a convincing example of how this social media platform can be used as a highly effective tool to host virtual Twitter-based international biomedical research events.

Ellagic Acid and Its Anti-Aging Effects on Central Nervous System

Aging is an unavoidable biological process that leads to the decline of human function and the reduction in people’s quality of life. Demand for anti-aging medicines has become very urgent. Many studies have shown that ellagic acid (EA), a phenolic compound widely distributed in dicotyledonous plants, has powerful anti-inflammation and antioxidant properties. Moreover, it has been demonstrated that EA can enhance neuronal viability, reduce neuronal defects, and alleviate damage in neurodegenerative diseases such as Alzheimer’s disease, Parkinson’s disease, and cerebral ischemia. This paper reviews the biochemical functions and neuroprotective effects of EA, showing the clinical value of its application.

New Myrtenal–Adamantane Conjugates Alleviate Alzheimer’s-Type Dementia in Rat Model

Alzheimer’s disease (AD) is a neurodegenerative disease associated with memory impairment and other central nervous system (CNS) symptoms. Two myrtenal–adamantane conjugates (MACs) showed excellent CNS potential against Alzheimer’s models. Adamantane is a common pharmacophore for drug design, and myrtenal (M) demonstrated neuroprotective effects in our previous studies. The aim of this study is to evaluate the MACs’ neuroprotective properties in dementia. Methods: Scopolamine (Scop) was applied intraperitoneally in Wistar rats for 11 days, simultaneously with MACs or M as a referent, respectively. Brain acetylcholine esterase (AChE) activity, noradrenaline and serotonin levels, and oxidative brain status determination followed behavioral tests on memory abilities. Molecular descriptors and docking analyses for AChE activity center affinity were performed. Results: M derivatives have favorable physicochemical parameters to enter the CNS. Both MACs restored memory damaged by Scop, showing significant AChE-inhibitory activity in the cortex, in contrast to M, supported by the modeling analysis. Moderate antioxidant properties were manifested by glutathione elevation and catalase activity modulation. MACs also altered noradrenaline and serotonin content in the hippocampus. Conclusion: For the first time, neuroprotective properties of two MACs in a rat dementia model were observed. They were stronger than the natural M effects, which makes the substances promising candidates for AD treatment.

Identification of Human Brain Proteins for Bitter-Sweet Taste Perception: A Joint Proteome-Wide and Transcriptome-Wide Association Study

Objective: Bitter or sweet beverage perception is associated with alterations in brain structure and function. Our aim is to analyze the genetic association between bitter or sweet beverage perception and human brain proteins. Materials and methods: In our study, 8356 and 11,518 proteins were first collected from two reference datasets of human brain proteomes, the ROS/MAP and Banner. The bitter or sweet beverage perception-related proteome-wide association studies (PWAS) were then conducted by integrating recent genome-wide association study (GWAS) data (n = 422,300) of taste perception with human brain proteomes. The human brain gene expression profiles were collected from two reference datasets, including the brain RNA-seq (CBR) and brain RNA-seq splicing (CBRS). The taste perception-related transcriptome-wide association studies (TWAS) were finally performed by integrating the same GWAS data with human brain gene expression profiles to validate the PWAS findings. Results: In PWAS, four statistically significant proteins were identified using the ROS/MAP and then replicated using the Banner reference dataset (all permutated p < 0.05), including ABCG2 for total bitter beverages and tea, CPNE1 for total bitter beverage, ACTR1B for artificially sweetened beverages, FLOT2 for alcoholic bitter beverages and total sweet beverages. In TWAS analysis, six statistically significant genes were detected by CBR and confirmed by the CBRS reference dataset (all permutated p < 0.05), including PIGG for total bitter beverages and non-alcoholic bitter beverages, C3orf18 for total bitter beverages, ZSWIM7 for non-alcoholic bitter beverages, PEX7 for coffee, PKP4 for tea and RPLP2 for grape juice. Further comparison of the PWAS and TWAS found three common statistically significant proteins/genes identified from the Banner and CBR reference datasets, including THBS4 for total bitter beverages, CA4 for non-alcoholic bitter beverages, LIAS for non-grape juices. Conclusions: Our results support the potential effect of bitter or sweet beverage perception on brain function and identify several candidate brain proteins for bitter or sweet beverage perception.

Beneficial Effects of Snail Helix aspersa Extract in an Experimental Model of Alzheimer’s Type Dementia

Background: Alzheimer’s disease (AD) is a complex neurodegenerative disease with multifactorial etiology, unsatisfactory treatment, and a necessity for broad-spectrum active substances for cure. The mucus from Helix aspersa snail is a mixture of bioactive molecules with antimicrobial, anti-inflammatory, antioxidant, and anti-apoptotic effects. So far there are no data concerning the capacity of snail extract (SE) to affect neurodegenerative disorders. Objective: The effects of SE from Helix aspersa on learning and memory deficits in Alzheimer’s type dementia (ATD) induced by scopolamine (Sco) in male Wistar rats were examined and some mechanisms of action underlying these effects were evaluated. Methods: SE (0.5 mL/100 g) was applied orally through a food tube for 16 consecutive days: 5 days before and 11 days simultaneously with Sco (2 mg/kg, intraperitoneally). At the end of Sco treatment, using behavioral methods, we evaluated memory performance. Additionally, in cortex and hippocampus the acetylcholinesterase (AChE) activity, acetylcholine and monoamines (dopamine, noradrenaline, and serotonin) content, levels of main oxidative stress markers, and expression of brain-derived neurotrophic factor (BDNF) and cAMP response element-binding protein (CREB) were determined. Results: We demonstrated that, according to all behavioral tests used, SE significantly improved the cognitive deficits induced by Sco. Furthermore, SE possessed AChE inhibitory activity, moderate antioxidant properties and the ability to modulate monoamines content in two brain structures. Moreover, multiple SE applications not only restored the depressed by Sco expression of CREB and BDNF, but significantly upregulated it. Conclusion: Summarizing results, we conclude that complex mechanisms underlie the beneficial effects of SE on impaired memory in Alzheimer’s type dementia.

Deacetylation of ZKSCAN3 by SIRT1 induces autophagy and protects SN4741 cells against MPP+-induced oxidative stress

Mitochondrial dysfunction, oxidative stress and misfolded protein aggregation are related to autophagy-lysosomal dysregulation and contribute to the pathogenesis of Parkinson' s disease (PD). ZKSCAN3, a transcriptional repressor, plays a crucial role in autophagy and lysosomal biogenesis. However, the role and modification of ZKSCAN3 in the defection of ALP, along with the molecular mechanism involved in pathogenesis of PD, still remain unclear. In this study, we demonstrated that cellular reactive oxygen species (ROS) generated by MPP⁺ exposure and the resulting oxidative damage were counteracted by SIRT1-ZKSCAN3 pathway induction. Here we showed that nuclear ZKSCAN3 significantly increased in ventral midbrain of MPTP-treated mice and MPP⁺-treated SN4741 cells. Knockdown of ZKSCAN3 alleviated MPP⁺-induced ALP defect, Tyrosine Hydroxylase (TH) declination and neuronal death. NAC, a ROS scavenger, reduced the nuclear translocation of ZKSCAN3 and sequentially improved ALP function in MPP⁺-treated SN4741 cells. SRT2104, a SIRT1 activator, attenuated impairment of ALP in MPP⁺-treated SN47417 cells through decreasing nuclear accumulation of ZKSCAN3 and protected dopaminergic neurons from MPTP injury. Moreover, SRT2104 relieved impairment in locomotor activities and coordination skills upon treatment of MPTP in C57/BL6J mice through behavior tests including rotarod, pole climbing and grid. Furthermore, ZKSCAN3 was a novel substrate of SIRT1 which was deacetylated at lysine 148 residues by SIRT1. This subsequently facilitated the shuttling of ZKSCAN3 to the cytoplasm. Therefore, our study identifies a novel acetylation-dependent regulatory mechanism of nuclear translocation of ZKSCAN3. It results in autophagy-lysosomal dysfunction and then leads to DA neuronal death in MPTP/MPP⁺ model of PD.

Neuroprotective Effects of Myrtenal in an Experimental Model of Dementia Induced in Rats

There is growing attention on natural substances capable of stimulating the cholinergic system and of exerting antioxidant effects, as potential therapeutic agents in Alzheimer’s disease (AD). The aim of the present study is to evaluate the expected neuroprotective mechanisms of myrtenal (M) in an experimental model of dementia in rats. Dementia was induced in male Wistar rats by scopolamine (Sc) administration (0.1 mg/kg for 8 days and 20.0 mg/kg on day 9). The animals were divided into 5 groups (1) Controls; (2) Sc; (3) Sc + Myrtenal (40 mg/kg), (4) Sc + Galantamine (1 mg/kg); (5) Sc + Lipoic acid (30 mg/kg). Changes in recognition memory and habituation were evaluated via the Novel Object Recognition and Open Field tests. Acetylcholinesterase (AChE) activity, ACh levels, and changes in oxidative status of the brain were measured biochemically. The histological changes in two brain regions—cortex and hippocampus, were evaluated qualitatively and quantitatively. Myrtenal improved recognition memory and habituation, exerted antioxidant effects and significantly increased ACh brain levels. Histologically, the neuroprotective capacity of myrtenal was also confirmed. For the first time, we have demonstrated the neuroprotective potential of myrtenal in an experimental model of dementia. Our study provides proof-of-concept for the testing of myrtenal, in association with standard of care treatments, in patients affected by cognitive decline.

Myrtenal mitigates streptozotocin-induced spatial memory deficit via improving oxido inflammatory, cholinergic and neurotransmitter functions in mice

The occurrence of chronic neurodegenerative disorders is on the rise, but with no effective treatment due to the paucity of information on the pathological mechanism underlying these disorders. Thus, this study investigated the role of oral administration of myrtenal in mitigating memory deficits and neuro-biochemical alterations in streptozotocin-demented mice model. Mice (n ​= ​35) were randomly allocated into five cohorts consisting of 7 mice each; Group I: Control mice received vehicle alone; Group II: streptozotocin; Group III: streptozotocin + 100 ​mg/kg myrtenal; Group IV: streptozotocin +200 ​mg/kg myrtenal; and Group V: streptozotocin ​+ ​donepezil 0.5 ​mg/kg. Data from this study demonstrated that the administration of streptozotocin (STZ) impaired spatial memory and induced alterations in markers of oxido-inflammatory response, cholinergic function, cytoarchitecture, and neurotransmitter levels in mice hippocampus. Notably, administration of myrtenal enhanced spatial memory performance in STZ-demented mice by improving the activities of endogenous antioxidant enzymes to protect the brain from oxido-inflammatory stress. Treatment with myrtenal also restored cholinergic function and stabilized the homeostasis of neurotransmitters in STZ-demented mice. The authors infer that fruits rich in myrtenal may be beneficial for treating patients living with dementia associated with Alzheimer's disease.

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Data from the present study demonstrates that the administration of streptozotocin impairs spatial memory in mice and induces alterations in markers of oxido-inflammatory response, cholinergic function, histoarchitecture, and neurotransmitter levels in the hippocampus.

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The administration of myrtenal enhances spatial memory performance in streptozotocin-demented mice by improving the activities of endogenous antioxidant enzymes to protect the brain from oxido-inflammatory stress.

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Treatment with myrtenal restores cholinergic function and stabilizes the homeostasis of neurotransmitters in streptozotocin-demented mice.

Pomegranate Juice Ameliorates Dopamine Release and Behavioral Deficits in a Rat Model of Parkinson's Disease

Pomegranate juice (PJ) is a rich source of ellagitannins (ETs), precursors of colonic metabolite urolithin A, which are believed to contribute to pomegranate's neuroprotective effect. While many experimental studies involving PJ's role in Alzheimer's disease and hypoxic-ischemic brain injury have been conducted, our knowledge of pomegranate's effects against Parkinson's disease (PD) is very limited. Previously, we have reported that PJ treatment improved postural stability, which correlated well with enhancement of neuronal survival, protection against oxidative damage, and α-synuclein aggregation. Since olfactory and motor deficits are typical symptoms of PD, in this study, we aimed to investigate the capability of PJ to protect against olfactory, motoric, and neurochemical alterations. To evaluate its efficiency, Wistar rats were given a combined treatment with ROT (1.3 mg/kg b.w./day, s.c.) and PJ (500 mg/kg/day, p.o.) for 35 days. After this, we assessed the olfactory discrimination index (DI) and vertical and horizontal activities as well as levels of dopamine and its main metabolite 3,4-Dihydroxyphenylacetic acid (DOPAC) in the dissected midbrain of animals. Our findings provide the first evidence that PJ treatment protects against ROT-induced DA depletion in the midbrain, which correlates well with improved olfactory function and vertical activity as well as with the presence of urolithin A in the brain.

Therapeutic Potential of Alpha-Lipoic Acid in Viral Infections, including COVID-19

Oxidative stress (OS), resulting from a disrupted balance between reactive oxygen species (ROS) and protective antioxidants, is thought to play an important pathogenetic role in several diseases, including viral infections. Alpha-lipoic acid (LA) is one of the most-studied and used natural compounds, as it is endowed with a well-defined antioxidant and immunomodulatory profile. Owing to these properties, LA has been tested in several chronic immunoinflammatory conditions, such as diabetic neuropathy and metabolic syndrome. In addition, a pharmacological antiviral profile of LA is emerging, that has attracted attention on the possible use of this compound for the cotreatment of several viral infections. Here, we will review the emerging literature on the potential use of LA in viral infections, including COVID-19.

R, Patel B, Manne R, Patel DB. Preparation, Optimization and Evaluation of Chitosan-Based Avanafil Nanocomplex Utilizing Antioxidants for Enhanced Neuroprotective Effect on PC12 Cells

(1) Introduction: in recent decades, interdisciplinary research on the utilization of natural products as “active moiety carriers” was focused on due to their superior safety profile, biodegradability, biocompatibility and the ability for sustained or controlled release activity. The nano-based neuroprotective strategy is explored as an imperative treatment for diabetic neuropathy (DN). Avanafil (AV), that selectively inhibits the degradation of cGMP-specific phosphodiesterase, thereby increasing the levels of cGMP, makes a decisive mediator for cytoprotection. (2) Methods: AVnanocomplex formulations were prepared by a modified anti-solvent precipitation method and the method was optimized by Box–Behnken design. An optimized formulation was characterized and evaluated for various in vitro parameters; (3) results:based on the desirability approach, the formulation containing 2.176 g of chitosan, 7.984 g of zein and 90% v/v ethanol concentration can fulfill the prerequisites of optimum formulation (OB-AV-NC).OB-AV-NC was characterized and evaluated for various parameters. The neuroprotective mechanism of AV was evaluated by pretreatment of PC12 cells with plain AV, avanafil nanocomplex (NC) without antioxidants (AV-NC) and with antioxidants (α-Lipoic acid LP; Ellagic Acid EA), AV-LP-EA-Nanocomplex has also shown considerable attenuation in intracellular reactive oxygen species (ROS) and lipid peroxidation with a significant increase in the PC 12 viability under HG conditions in comparison to pure AV; (4) conclusion: the nanocomplex of AV prepared to utilize natural polymers and antioxidants aided for high solubility of AV and exhibited desired neuroprotective activity.This can be one of the promisingstrategy to translate the AV nanocomplex with safety and efficacy in treating DN.

Natural Phytochemicals as Novel Therapeutic Strategies to Prevent and Treat Parkinson's Disease: Current Knowledge and Future Perspectives

Parkinson's disease (PD) is the second-most common neurodegenerative chronic disease affecting both cognitive performance and motor functions in aged people. Yet despite the prevalence of this disease, the current therapeutic options for the management of PD can only alleviate motor symptoms. Research has explored novel substances for naturally derived antioxidant phytochemicals with potential therapeutic benefits for PD patients through their neuroprotective mechanism, targeting oxidative stress, neuroinflammation, abnormal protein accumulation, mitochondrial dysfunction, endoplasmic reticulum stress, neurotrophic factor deficit, and apoptosis. The aim of the present study is to perform a comprehensive evaluation of naturally derived antioxidant phytochemicals with neuroprotective or therapeutic activities in PD, focusing on their neuropharmacological mechanisms, including modulation of antioxidant and anti-inflammatory activity, growth factor induction, neurotransmitter activity, direct regulation of mitochondrial apoptotic machinery, prevention of protein aggregation via modulation of protein folding, modification of cell signaling pathways, enhanced systemic immunity, autophagy, and proteasome activity. In addition, we provide data showing the relationship between nuclear factor E2-related factor 2 (Nrf2) and PD is supported by studies demonstrating that antiparkinsonian phytochemicals can activate the Nrf2/antioxidant response element (ARE) signaling pathway and Nrf2-dependent protein expression, preventing cellular oxidative damage and PD. Furthermore, we explore several experimental models that evaluated the potential neuroprotective efficacy of antioxidant phytochemical derivatives for their inhibitory effects on oxidative stress and neuroinflammation in the brain. Finally, we highlight recent developments in the nanodelivery of antioxidant phytochemicals and its neuroprotective application against pathological conditions associated with oxidative stress. In conclusion, naturally derived antioxidant phytochemicals can be considered as future pharmaceutical drug candidates to potentially alleviate symptoms or slow the progression of PD. However, further well-designed clinical studies are required to evaluate the protective and therapeutic benefits of phytochemicals as promising drugs in the management of PD.

Redox-active phytoconstituents ameliorate cell damage and inflammation in rat hippocampal neurons exposed to hyperglycemia+Aβ1-42 peptide

Alzheimer's disease (AD) is the most common dementia causing progressive loss of memory and compromised cognitive functions. Although the neurotoxic mechanisms underlying AD have yet to be fully elucidated, hyperglycemia seems to trigger oxidative and inflammatory responses in the brain of afflicted patients. Removal of free radicals reduces the neurotoxic effects of hyperglycemia in AD models. In this study we investigated the neuroprotective effects of the antioxidant phytoconstituents oleuropein (OLE), rutin (RUT), luteolin (LUT) and S-allylcysteine (SAC) in an experimental model combining the exposure to high glucose (HG, mimicking chronic hyperglycemia) plus amyloid-β peptide 1-42 (Aβ_1-42, mimicking AD) in primary hippocampal neurons. Cells were pre-treated with OLE, RUT, LUT or SAC (10-1000 nM), and then co-treated with high glucose (GLU, 150 mM) for 24 h plus 500 nM oligomeric Aβ_1-42 for 24 h more. Cell viability and reactive oxygen species (ROS) formation were assessed as indices of survival/toxicity and oxidative stress, respectively. Activity/expression of antioxidant enzymes, toxic adducts, inflammatory molecules, mitochondrial membrane potential (ΔΨm) and the pattern of amyloid aggregation were also assessed. The GLU + Aβ_1-42 treatment significantly decreased cell viability, increased ROS formation, reduced superoxide dismutase, catalase, glutathione peroxidase and glutathione reductase activities, augmented Advanced Glycation End Products- and 4-hydroxynonenal-adducts generation, increased 3-nitrotyrosine and inflammatory outcomes such as inducible nitric oxide synthase, interleukin 1β and Tumor Necrosis Factor α, decreased MMP and augmented amyloid aggregation. All phytoconstituents reduced in a differential manner all toxic endpoints, with SAC showing the highest efficacy in preventing loss of cell viability and oxidative damage, whereas RUT was most efficacious in mitigating inflammatory endpoints. Combined, the results of this study suggest that protection afforded by these compounds against GLU + Aβ_1-42-induced cell damage in hippocampal neurons is attributable to their properties as redox modulators, which might act through a concerted mechanism oriented to reduce oxidative stress and neuroinflammation.

Natural Molecules and Neuroprotection: Kynurenic Acid, Pantethine and α-Lipoic Acid

The incidence of neurodegenerative diseases has increased greatly worldwide due to the rise in life expectancy. In spite of notable development in the understanding of these disorders, there has been limited success in the development of neuroprotective agents that can slow the progression of the disease and prevent neuronal death. Some natural products and molecules are very promising neuroprotective agents because of their structural diversity and wide variety of biological activities. In addition to their neuroprotective effect, they are known for their antioxidant, anti-inflammatory and antiapoptotic effects and often serve as a starting point for drug discovery. In this review, the following natural molecules are discussed: firstly, kynurenic acid, the main neuroprotective agent formed via the kynurenine pathway of tryptophan metabolism, as it is known mainly for its role in glutamate excitotoxicity, secondly, the dietary supplement pantethine, that is many sided, well tolerated and safe, and the third molecule, α-lipoic acid is a universal antioxidant. As a conclusion, because of their beneficial properties, these molecules are potential candidates for neuroprotective therapies suitable in managing neurodegenerative diseases.

Ellagic Acid Prevents Dopamine Neuron Degeneration from Oxidative Stress and Neuroinflammation in MPTP Model of Parkinson's Disease

Parkinson's disease (PD) is one of the most common neurodegenerative diseases and is characterized by progressive dopaminergic neurodegeneration in the substantia nigra pars compacta area. In the present study, treatment of EA for 1 week at a dose of 10 mg/kg body weight prior to MPTP (25 mg/kg body weight) was carried out. MPTP administration caused oxidative stress, as evidenced by decreased activities of superoxide dismutase and catalase, and the depletion of reduced glutathione with a concomitant rise in the lipid peroxidation product, malondialdehyde. It also significantly increased the pro-inflammatory cytokines and elevated the inflammatory mediators like cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS) in the striatum. Immunohistochemical analysis revealed a loss of dopamine neurons in the SNc area and a decrease in dopamine transporter in the striatum following MPTP administration. However, treatment with EA prior to MPTP injection significantly rescued the dopaminergic neurons and dopamine transporter. EA treatment further restored antioxidant enzymes, prevented the depletion of glutathione and inhibited lipid peroxidation, in addition to the attenuation of pro-inflammatory cytokines. EA also reduced the levels of COX-2 and iNOS. The findings of the present study demonstrate that EA protects against MPTP-induced PD and the observed neuroprotective effects can be attributed to its potent antioxidant and anti-inflammatory properties.

The glutathione system in Parkinson's disease and its progression

Redox dysfunctions and neuro-oxidative stress play a major role in the pathophysiology and progression of Parkinson's disease (PD). Glutathione (GSH) and the reduced/oxidized glutathione (GSH/GSSG) ratio are lowered in oxidative stress conditions and may lead to increased oxidative toxicity. GSH is involved not only in neuro-immune and neuro-oxidative processes, including thiol redox signaling, but also in cell proliferation and differentiation and in the regulation of cell death, including apoptotic pathways. Lowered GSH metabolism and a low GSH/GSSG ratio following oxidative stress are associated with mitochondrial dysfunctions and constitute a critical factor in the neuroinflammatory and neurodegenerative processes accompanying PD. This review provides indirect evidence that GSH redox signaling is associated with the pathophysiology of PD. Nevertheless, it has not been delineated whether GSH redox imbalances are a causative factor in PD or whether PD-associated pathways cause the GSH redox imbalances in PD. The results show that antioxidant approaches, including neuroprotective and anti-neuroinflammatory agents, which neutralize reactive oxygen species, may have therapeutic efficacy in the treatment of PD and its progression.