Natural antioxidants in the management of Parkinson's disease: Review of evidence from cell line and animal models

Flavonoids: Their putative neurologic roles, epigenetic changes, and gut microbiota alterations in Parkinson's disease

Parkinson's Disease (PD), a neurodegenerative disorder, is characterized by the degeneration of progressive dopaminergic (DA) neurons in the substantia nigra region of the human midbrain. Although just what causes PD remains a mystery, it is known that oxidative stress (OS) as well as mitochondrial dysfunction, neuro-inflammation, and insufficient neurotrophic support play a role in the disease's pathophysiology. Phytochemicals are a diverse small molecule group derived from plants that can be classified into numerous classes on the basis of their biological activities and chemical structure. Of these groups of phytochemicals, the most abundant, which has well-established anti-Parkinson's effects, are polyphenols. Flavonoids, including naringin and naringenin, genistein, kaempferol, anthocyanins, epigallocatechin-3-gallate, and baicalein are plant-based biologically active polyphenols, which have been shown to exhibit therapeutic potential when used as treatment for a variety of pathological illnesses, such as neurodegenerative diseases (NDs) and PD. Recently, it was reported that flavonoids have beneficial effects on PD, such as the protection of DA neurons, improvement of motor and cognitive abilities, regulation of signaling pathways, and modulation of OS and neuro-inflammation. In addition, by changing the composition of bacteria in gut microbiota, flavonoids reduce pathogenic strains and promote the growth of beneficial strains. In this context, the current paper will provide a literature review on the neurological roles that flavonoids play, as one of the most abundant phytochemical families, in PD.

Pharmacological intervention of curcumin via the NLRP3 inflammasome in ischemic stroke

Ischemic-induced neuronal injury arises due to low oxygen/nutrient levels and an inflammatory response that exacerbates neuronal loss. NOD-like receptor family pyrin domain-containing 3 (NLRP3) is an important regulator of inflammation after ischemic stroke, with its inhibition being involved in nerve regeneration. Curcumin, a main active ingredient in Chinese herbs, plays a positive role in neuronal repair and neuroprotection by regulating the NLRP3 signaling pathway. Nevertheless, the signaling mechanisms relating to how curcumin regulates NLRP3 inflammasome in inflammation and neural restoration following ischemic stroke are unknown. In this report, we summarize the main biological functions of the NLRP3 inflammasome along with the neuroprotective effects and underlying mechanisms of curcumin via impairment of the NLRP3 pathway in ischemic brain injury. We also discuss the role of medicinal interventions that target the NLRP3 and potential pathways, as well as possible directions for curcumin therapy to penetrate the blood-brain barrier (BBB) and hinder inflammation in ischemic stroke. This report conclusively demonstrates that curcumin has neuroprotective properties that inhibit inflammation and prevent nerve cell loss, thereby delaying the progression of ischemic brain damage.

Assessment of Bio-Compounds Content, Antioxidant Activity, and Neuroprotective Effect of Red Cabbage (Brassica oleracea var. Capitata rubra) Processed by Convective Drying at Different Temperatures

Parkinson's disease (PD) is the second most common neurodegenerative disorder, and no efficient therapy able to cure or slow down PD is available. In this study, dehydrated red cabbage was evaluated as a novel source of bio-compounds with neuroprotective capacity. Convective drying was carried out at different temperatures. Total phenolics (TPC), flavonoids (TFC), anthocyanins (TAC), and glucosinolates (TGC) were determined using spectrophotometry, amino acid profile by LC-DAD and fatty acid profile by GC-FID. Phenolic characterization was determined by liquid chromatography-high-resolution mass spectrometry. Cytotoxicity and neuroprotection assays were evaluated in SH-SY5Y human cells, observing the effect on preformed fibrils of α-synuclein. Drying kinetic confirmed a shorter processing time with temperature increase. A high concentration of bio-compounds was observed, especially at 90 °C, with TPC = 1544.04 ± 11.4 mg GAE/100 g, TFC = 690.87 ± 4.0 mg QE/100 g and TGC = 5244.9 ± 260.2 µmol SngE/100 g. TAC degraded with temperature. Glutamic acid and arginine were predominant. Fatty acid profiles were relatively stable and were found to be mostly C18:3n3. The neochlorogenic acid was predominant. The extracts had no cytotoxicity and showed a neuroprotective effect at 24 h testing, which can extend in some cases to 48 h. The present findings underpin the use of red cabbage as a functional food ingredient.

Curcumin, inflammation, and neurological disorders: How are they linked?

Background

Despite the extensive research in recent years, the current treatment modalities for neurological disorders are suboptimal. Curcumin, a polyphenol found in Curcuma genus, has been shown to mitigate the pathophysiology and clinical sequalae involved in neuroinflammation and neurodegenerative diseases.

Methods

We searched PubMed database for relevant publications on curcumin and its uses in treating neurological diseases. We also reviewed relevant clinical trials which appeared on searching PubMed database using 'Curcumin and clinical trials'.

Results

This review details the pleiotropic immunomodulatory functions and neuroprotective properties of curcumin, its derivatives and formulations in various preclinical and clinical investigations. The effects of curcumin on neurodegenerative diseases such as Alzheimer's disease (AD), amyotrophic lateral sclerosis (ALS), brain tumors, epilepsy, Huntington's disorder (HD), ischemia, Parkinson's disease (PD), multiple sclerosis (MS), and traumatic brain injury (TBI) with a major focus on associated signalling pathways have been thoroughly discussed.

Conclusion

This review demonstrates curcumin can suppress spinal neuroinflammation by modulating diverse astroglia mediated cascades, ensuring the treatment of neurological disorders.

A novel gene therapy for methamphetamine- induced cognitive disorder with a hyper-acidified fusion variant of DnaJB1

Methamphetamine (MA) is spread worldwide and is a highly addictive psychostimulant that can induce neurodegeneration and cognitive disorder, which lacks effective treatments. We and other researchers have found that the crucial member of Hsp70 chaperone machinery, DnaJ, is liable to be co-aggregated with aberrant proteins, which has been confirmed a risk factor to promote neurodegeneration. In the current study, we demonstrated that tailing with a hyper-acidic fusion partner, tua2, human DnaJB1 could resist the formation of toxic mutant Tau aggregates both in prokaryote and eukaryote models. We found that aberrant Tau aggregates could deplete the antioxidant enzyme pool and disturb Hsp70 molecular chaperone system by co-aggregating with the principal members of these systems. Stability-enhanced DnaJB1-tua2 could stop the chain reaction of Tau aggregates as well as maintain redox balance and protein homeostasis. With an MA-induced cognitive disorder mouse model, we found that the cognitive disorder of MA mice was rescued and the overactivated inflammatory response was relieved by the expression of DnaJB1-tua2 in the hippocampus. Furthermore, the Tau neurofibrillary tangles and apoptotic neurons were diminished with the escorting of DnaJB1-tua2. These findings demonstrate that delivering DnaJB1-tua2 in hippocampus may have a therapeutic potential in the treatment of MA-induced cognitive disorder.

Influence of the Mediterranean Diet on Healthy Aging

The life expectancy of the global population has increased. Aging is a natural physiological process that poses major challenges in an increasingly long-lived and frail population. Several molecular mechanisms are involved in aging. Likewise, the gut microbiota, which is influenced by environmental factors such as diet, plays a crucial role in the modulation of these mechanisms. The Mediterranean diet, as well as the components present in it, offer some proof of this. Achieving healthy aging should be focused on the promotion of healthy lifestyle habits that reduce the development of pathologies that are associated with aging, in order to increase the quality of life of the aging population. In this review we analyze the influence of the Mediterranean diet on the molecular pathways and the microbiota associated with more favorable aging patterns, as well as its possible role as an anti-aging treatment.

Aging and aging-related diseases: from molecular mechanisms to interventions and treatments

Aging is a gradual and irreversible pathophysiological process. It presents with declines in tissue and cell functions and significant increases in the risks of various aging-related diseases, including neurodegenerative diseases, cardiovascular diseases, metabolic diseases, musculoskeletal diseases, and immune system diseases. Although the development of modern medicine has promoted human health and greatly extended life expectancy, with the aging of society, a variety of chronic diseases have gradually become the most important causes of disability and death in elderly individuals. Current research on aging focuses on elucidating how various endogenous and exogenous stresses (such as genomic instability, telomere dysfunction, epigenetic alterations, loss of proteostasis, compromise of autophagy, mitochondrial dysfunction, cellular senescence, stem cell exhaustion, altered intercellular communication, deregulated nutrient sensing) participate in the regulation of aging. Furthermore, thorough research on the pathogenesis of aging to identify interventions that promote health and longevity (such as caloric restriction, microbiota transplantation, and nutritional intervention) and clinical treatment methods for aging-related diseases (depletion of senescent cells, stem cell therapy, antioxidative and anti-inflammatory treatments, and hormone replacement therapy) could decrease the incidence and development of aging-related diseases and in turn promote healthy aging and longevity.

Potential clinical applications of Ashwagandha (Withania somnifera) in medicine and neuropsychiatry

INTRODUCTION

Ashwagandha (ASW) is the extract of the plant Withania somnifera. It is widely used in complementary, alternative, and integrative medicine (CAIM) but is little discussed in mainstream modern medical literature.

AREAS COVERED

We performed a review of potential pharmacotherapeutic properties of ASW. Studies were sourced from relevant online and offline databases. In animal models, ASW displays antioxidant activity. It has GABAergic and other neurotransmitter modulatory effects. It reduces apoptosis and promotes synaptic plasticity. It improves cognition and reverses induced cognitive deficits. It attenuates indices of stress. In human subjects, ASW enhances adaptogenesis in healthy adults. It modestly benefits generalized anxiety disorder and obsessive-compulsive disorder, and symptom severity in schizophrenia, substance use disorders, and attention deficit hyperactivity disorder. It improves sleep quality.

EXPERT OPINION

ASW may confer modest benefit in certain neuropsychiatric conditions. Its benefits may arise from induction of neuroplasticity, antioxidant and anti-inflammatory effects, and modulation of GABA and glutamate, as well as other neurotransmitters. The antioxidant and anti-inflammatory actions may also benefit neurodegenerative states. Reports of clinical benefit with ASW must be interpreted with caution, given the paucity of randomized clinical trials (RCTs). Greater methodological rigor is necessary before clinical recommendations on ASW can be confidently made.

Curcumin-driven reprogramming of the gut microbiota and metabolome ameliorates motor deficits and neuroinflammation in a mouse model of Parkinson's disease

Background

Parkinson's disease (PD) is a common neurodegenerative disorder, accompanied by motor deficits as well as gastrointestinal dysfunctions. Recent studies have proved that the disturbance of gut microbiota and metabolism contributes to the pathogenesis of PD; however, the mechanisms underlying these effects have yet to be elucidated. Curcumin (CUR) has been reported to provide neuroprotective effects on neurological disorders and modulate the gut flora in intestinal-related diseases. Therefore, it is of significant interest to investigate whether CUR could exert a protective effect on PD and whether the effect of CUR is dependent on the intestinal flora and subsequent changes in metabolites.

Methods

In this study, we investigated the neuroprotective effects of CUR on a mouse model of PD induced by 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). 16S rRNA sequencing was performed to explore the profile of the gut microbiota among controls, MPTP-treated mice and CUR-treated mice. Then, antibiotic treatment (ABX) and fecal microbiota transplantation (FMT) experiments were conducted to examine the role of intestinal microbes on the protective effects of CUR in PD mice. Furthermore, ultra-high-performance liquid chromatography-mass spectrometry (UHPLC-MS)-based metabolomics analysis was used to identify the landscape of the CUR-driven serum metabolome. Finally, Pearson's analysis was conducted to investigate correlations between the gut flora-metabolite axis and CUR-driven neuroprotection in PD.

Results

Our results showed that CUR intervention effectively improved motor deficits, glial cell activation, and the aggregation of α-synuclein (α-syn) in MPTP-treated mice. 16S rRNA sequencing showed elevated abundances of Muribaculaceae, Lactobacillaceae, Lachnospiraceae and Eggerthellaceae but depleted abundances of Aerococcaceae and Staphylococcaceae in CUR-treated mice when compared with MPTP mice. ABX and FMT experiments further confirmed that the gut microbiota was required for CUR-induced protection in PD mice. Serum metabolomics analysis showed that CUR notably upregulated the levels of tyrosine, methionine, sarcosine and creatine. Importantly, strong correlations were identified among crucial taxa (Aerococcaceae, Staphylococcaceae, Muribaculaceae, Lactobacillaceae, Lachnospiraceae and Eggerthellaceae), pivotal metabolites (tyrosine, methionine, sarcosine and creatine) and the motor function and pathological results of mice. CUR treatment led to a rapid increase in the brain levels of tyrosine and levodopa (dopa) these changes were related to the abundances of Lactobacillaceae and Aerococcaceae.

Conclusions

CUR exerts a protective effect on the progression of PD by modulating the gut microbiota-metabolite axis. Lactobacillaceae and Aerococcaceae, along with key metabolites such as tyrosine and dopa play a dominant role in CUR-associated neuroprotection in PD mice. Our findings offer unique insights into the pathogenesis and potential treatment of PD.

Paper-based colorimetric sensor array for the rapid and on-site discrimination of green tea samples based on the flavonoid composition

Green tea is a worldwide appreciated food product with Chinese production estimated to reach over 3m tons in 2027 and with many valuable health effects. The development of analytical methods to discriminate among green tea samples is induced by economic benefits and to avoid deliberate origin mislabeling and adulteration. In this study, we present a paper-based colorimetric sensor array comprised of six ordinary reagents tailored for the discrimination of green tea extracts of different brands according to differences in the composition of flavonoids. The colorimetric array was rationally designed based on indicators that differentially react with a variety of flavonoids via specific functional groups. 4 μL of each reagent was impregnated onto the paper surface followed by the addition of the green tea extract. After 1 minute, digital images were acquired using a smartphone and the color changes were employed to build differential maps with a unique fingerprint for each green tea sample. Moreover, principal component analysis (PCA) and hierarchical component analysis (HCA) were employed to successfully discriminate among the samples, enabling the origin and adulteration identification of the samples. Therefore, this study provides a simple, effective, low-cost, and portable method for quick discrimination and quality control of green tea samples.

Ginkgo biloba in the Aging Process: A Narrative Review

Neurodegenerative diseases, cardiovascular disease (CVD), hypertension, insulin resistance, cancer, and other degenerative processes commonly appear with aging. Ginkgo biloba (GB) is associated with several health benefits, including memory and cognitive improvement, in Alzheimer’s disease (AD), Parkinson’s disease (PD), and cancer. Its antiapoptotic, antioxidant, and anti-inflammatory actions have effects on cognition and other conditions associated with aging-related processes, such as insulin resistance, hypertension, and cardiovascular conditions. The aim of this study was to perform a narrative review of the effects of GB in some age-related conditions, such as neurodegenerative diseases, CVD, and cancer. PubMed, Cochrane, and Embase databases were searched, and the PRISMA guidelines were applied. Fourteen clinical trials were selected; the studies showed that GB can improve memory, cognition, memory scores, psychopathology, and the quality of life of patients. Moreover, it can improve cerebral blood flow supply, executive function, attention/concentration, non-verbal memory, and mood, and decrease stress, fasting serum glucose, glycated hemoglobin, insulin levels, body mass index, waist circumference, biomarkers of oxidative stress, the stability and progression of atherosclerotic plaques, and inflammation. Therefore, it is possible to conclude that the use of GB can provide benefits in the prevention and treatment of aging-related conditions.

Comparison of the effect of rotenone and 1‑methyl‑4‑phenyl‑1,2,3,6‑tetrahydropyridine on inducing chronic Parkinson's disease in mouse models

Animal models for Parkinson's disease (PD) are very useful in understanding the pathogenesis of PD and screening for new therapeutic approaches. The present study compared two commonly used neurotoxin‑induced mouse models of chronic PD to guide model selection, explore the pathogenesis and mechanisms underlying PD and develop effective treatments. The chronic PD mouse models were established via treatment with rotenone or 1‑methyl‑4‑phenyl‑1,2,3,6-tetrahydropyridine (MPTP) for 6 weeks. The effects of rotenone and MPTP in the mice were compared by assessing neurobehavior, neuropathology and mitochondrial function through the use of the pole, rotarod and open field tests, immunohistochemistry for tyrosine hydroxylase (TH), glial fibrillary acidic protein (GFAP), ionized calcium‑binding adapter molecule 1 (Iba‑1), neuronal nuclear antigen (NeuN) and (p)S129 α‑synuclein, immunofluorescence for GFAP, Iba‑1 and NeuN, western blotting for TH, oxygen consumption, complex I enzyme activity. The locomotor activity, motor coordination and exploratory behavior in both rotenone and MPTP groups were significantly lower compared with the control group. However, behavioral tests were no significant differences between the two groups. In the MPTP group, the loss of dopaminergic (DA) neurons in the substantia nigra (SN) pars compacta, the reduction of the tyrosine hydroxylase content in the SN and striatum and the astrocyte proliferation and microglial activation in the SN were more significant compared with the rotenone group. Notably, mitochondrial‑dependent oxygen consumption and complex I enzyme activity in the SN were significantly reduced in the rotenone group compared with the MPTP group. In addition, Lewy bodies were present only in SN neurons in the rotenone group. Although no significant differences in neurobehavior were observed between the two mouse models, the MPTP model reproduced the pathological features of PD more precisely in terms of the loss of DA neurons, decreased dopamine levels and neuroinflammation in the SN. On the other hand, the rotenone model was more suitable for studying the role of mitochondrial dysfunction (deficient complex I activity) and Lewy body formation in the SN, which is a characteristic pathological feature of PD. The results indicated that MPTP and rotenone PD models have advantages and disadvantages, therefore one or both should be selected based on the purpose of the study.

New Promising Therapeutic Avenues of Curcumin in Brain Diseases

Curcumin, the dietary polyphenol isolated from Curcuma longa (turmeric), is commonly used as an herb and spice worldwide. Because of its bio-pharmacological effects curcumin is also called "spice of life", in fact it is recognized that curcumin possesses important proprieties such as anti-oxidant, anti-inflammatory, anti-microbial, antiproliferative, anti-tumoral, and anti-aging. Neurodegenerative diseases such as Alzheimer's Diseases, Parkinson's Diseases, and Multiple Sclerosis are a group of diseases characterized by a progressive loss of brain structure and function due to neuronal death; at present there is no effective treatment to cure these diseases. The protective effect of curcumin against some neurodegenerative diseases has been proven by in vivo and in vitro studies. The current review highlights the latest findings on the neuroprotective effects of curcumin, its bioavailability, its mechanism of action and its possible application for the prevention or treatment of neurodegenerative disorders.

The Occurrence of Alzheimer's Disease and Parkinson's Disease in Individuals With Osteoporosis: A Longitudinal Follow-Up Study Using a National Health Screening Database in Korea

Background: Public health concerns regarding the potential link between osteoporosis and the increased occurrence of Alzheimer’s disease (AD) and Parkinson’s disease (PD) have been raised, but the results remain inconsistent and require further validation. Here, we investigated the long-term relationship of osteoporosis with the occurrence of AD/PD using data from a large-scale nationwide cohort.

Methods: This longitudinal follow-up study included 78,994 patients with osteoporosis and 78,994 controls from the Korean National Health Insurance Service-Health Screening Cohort database (2002–2015) who were matched using propensity score matching at a 1:1 ratio based on age, sex, income, and residential area. A Cox proportional hazard model was used to assess the association between osteoporosis and the occurrence of AD/PD after adjusting for multiple covariates.

Results: During the follow-up period, AD occurred in 5,856 patients with osteoporosis and 3,761 controls (incidence rates: 10.4 and 6.8 per 1,000 person-years, respectively), and PD occurred in 1,397 patients and 790 controls (incidence rates: 2.4 and 1.4 per 1,000 person-years, respectively). The incidences of AD and PD were significantly higher in the osteoporosis group than in the matched control group. After adjustment, the osteoporosis group exhibited 1.27-fold and 1.49-fold higher occurrences of AD (95% confidence interval (CI) = 1.22–1.32) and PD (95% CI = 1.36–1.63) than the controls, respectively. The results of subgroup analyses supported the increased occurrence of AD and PD in patients with osteoporosis, independent of income, residential area, obesity, smoking, alcohol consumption, hyperlipidemia, hypertension, or blood glucose level.

Conclusion: Our results indicate that the presence of osteoporosis may increase the likelihood of developing two common neurodegenerative diseases in adults aged ≥40 years.