Control of Reactive Oxygen Species for the Prevention of Parkinson's Disease: The Possible Application of Flavonoids

Dietary Polyphenols: Review on Chemistry/Sources, Bioavailability/Metabolism, Antioxidant Effects, and Their Role in Disease Management

Polyphenols, as secondary metabolites ubiquitous in plant sources, have emerged as pivotal bioactive compounds with far-reaching implications for human health. Plant polyphenols exhibit direct or indirect associations with biomolecules capable of modulating diverse physiological pathways. Due to their inherent abundance and structural diversity, polyphenols have garnered substantial attention from both the scientific and clinical communities. The review begins by providing an in-depth analysis of the chemical intricacies of polyphenols, shedding light on their structural diversity and the implications of such diversity on their biological activities. Subsequently, an exploration of the dietary origins of polyphenols elucidates the natural plant-based sources that contribute to their global availability. The discussion extends to the bioavailability and metabolism of polyphenols within the human body, unraveling the complex journey from ingestion to systemic effects. A central focus of the review is dedicated to unravelling the antioxidant effects of polyphenols, highlighting their role in combating oxidative stress and associated health conditions. The comprehensive analysis encompasses their impact on diverse health concerns such as hypertension, allergies, aging, and chronic diseases like heart stroke and diabetes. Insights into the global beneficial effects of polyphenols further underscore their potential as preventive and therapeutic agents. This review article critically examines the multifaceted aspects of dietary polyphenols, encompassing their chemistry, dietary origins, bioavailability/metabolism dynamics, and profound antioxidant effects. The synthesis of information presented herein aims to provide a valuable resource for researchers, clinicians, and health enthusiasts, fostering a deeper understanding of the intricate relationship between polyphenols and human health.

Polymeric nanocomposite electrode for enhanced electrochemical detection of α-lipoic acid: Application in neuroinflammation prevention and clinical analysis

Using poly (vanillin-co-chitosan)/functionalized MWCNTs/GCE (PV-CS/f-MWCNTs/GCE) as a polymeric nanocomposite modified electrode, the present investigation has been conducted on the electrochemical detection of α-lipoic acid (α-LA) to prevent the activation of microglia inflammation of the nervous system. The manufacture of modified polymeric nanocomposite electrodes was carried out using the established electropolymerization process. Field emission scanning electron microscopy (FE-SEM) and X-ray diffraction (XRD) analyses of structure revealed that the electropolymerization of poly (vanillin-co-chitosan) on the surface of the f-MWCNTs modified electrode was successful. Vanillin-co-chitosan electropolymerization on f-MWCNTs as electroactive sheets can enhance the signal for α-LA electrochemical sensors, according to research on the electrochemical characteristics utilizing cyclic voltammetry (CV) and differential pulse voltammetry (DPV) methodologies. The PV-CS/f-MWCNTs/GCE demonstrated that it had a sensitivity of 0.04664 μA/μM, a detection limit of 0.012 μM, and an excellent response, linear range, and wide linear range to α-LA from 0 to 3000 μM. The results of the application of PV-CS/f-MWCNTs/GCE for determining the concentration of α-LA in a prepared real sample of human serum by DPV and human lipoic acid ELISA Kit analyses via standard addition method illustrated the substantial conformity between the findings of both assays. The results of the DPV analyses resulted in acceptable recovery values (97.60%-99.10%) and appropriate values of the Relative Standard Deviation (RSD) (3.58%-5.07%), which demonstrated the great applicability and accuracy of the results of PV-CS/f-MWCNTs/GCE for determining α-LA concentration in biological fluids and pharmaceutical specimens.

Tremendous Fidelity of Vitamin D3 in Age-related Neurological Disorders

Vitamin D3 (VD) is a secosteroid hormone and shows a pleiotropic effect in brain-related disorders where it regulates redox imbalance, inflammation, apoptosis, energy production, and growth factor synthesis. Vitamin D3's active metabolic form, 1,25-dihydroxy Vitamin D3 (1,25(OH)2D3 or calcitriol), is a known regulator of several genes involved in neuroplasticity, neuroprotection, neurotropism, and neuroinflammation. Multiple studies suggest that VD deficiency can be proposed as a risk factor for the development of several age-related neurological disorders. The evidence for low serum levels of 25-hydroxy Vitamin D3 (25(OH)D3 or calcidiol), the major circulating form of VD, is associated with an increased risk of Alzheimer's disease (AD), Parkinson's disease (PD), Huntington's disease (HD), dementia, and cognitive impairment. Despite decades of evidence on low VD association with neurological disorders, the precise molecular mechanism behind its beneficial effect remains controversial. Here, we will be delving into the neurobiological importance of VD and discuss its benefits in different neuropsychiatric disorders. The focus will be on AD, PD, and HD as they share some common clinical, pathological, and epidemiological features. The central focus will be on the different attributes of VD in the aspect of its anti-oxidative, anti-inflammatory, anti-apoptotic, anti-cholinesterase activity, and psychotropic effect in different neurodegenerative diseases.

Gold Nanoparticles in Parkinson's Disease Therapy: A Focus on Plant-Based Green Synthesis

Parkinson's disease (PD) is a progressive neurodegenerative disease that affects approximately 1% of people over the age of 60 and 5% of those over the age of 85. Current drugs for Parkinson's disease mainly affect the symptoms and cannot stop its progression. Nanotechnology provides a solution to address some challenges in therapy, such as overcoming the blood-brain barrier (BBB), adverse pharmacokinetics, and the limited bioavailability of therapeutics. The reformulation of drugs into nanoparticles (NPs) can improve their biodistribution, protect them from degradation, reduce the required dose, and ensure target accumulation. Furthermore, appropriately designed nanoparticles enable the combination of diagnosis and therapy with a single nanoagent. In recent years, gold nanoparticles (AuNPs) have been studied with increasing interest due to their intrinsic nanozyme activity. They can mimic the action of superoxide dismutase, catalase, and peroxidase. The use of 13-nm gold nanoparticles (CNM-Au8®) in bicarbonate solution is being studied as a potential treatment for Parkinson's disease and other neurological illnesses. CNM-Au8® improves remyelination and motor functions in experimental animals. Among the many techniques for nanoparticle synthesis, green synthesis is increasingly used due to its simplicity and therapeutic potential. Green synthesis relies on natural and environmentally friendly materials, such as plant extracts, to reduce metal ions and form nanoparticles. Moreover, the presence of bioactive plant compounds on their surface increases the therapeutic potential of these nanoparticles. The present article reviews the possibilities of nanoparticles obtained by green synthesis to combine the therapeutic effects of plant components with gold.

Dietary flavonoids may have a protective and therapeutic effect in Parkinson disease: A systematic review

Parkinson disease (PD) is characterized by the loss of dopaminergic neurons because of oxidative stress and neuroinflammation. Polyphenols in vegetables, known for their high antioxidant capacity, may prevent the onset, or delay the progression of the disease; among these, flavonoids are the most abundant class of polyphenols in foods. Clinical and cohort studies have evaluated the effect of polyphenol consumption on the risk of developing PD or of attenuating the symptoms after diagnosis; therefore, it is necessary to integrate the scientific evidence into making dietary recommendations. The objective of this study was to perform a systematic review of randomized controlled trials and cohort studies that have investigated the use of polyphenols in PD. The studies were identified through the PubMed, Science Direct, Scielo, and Web of Science databases. A total of 1100 studies were found; these were analyzed and filtered by 2 independent reviewers. After completion, 5 studies were included (3 randomized controlled trials and 2 cohort studies). The consumption of flavonoids, anthocyanins, or 2-5 servings/week of specific foods (apples, red wine, blueberries, and strawberries) reduces the risk of PD and associated mortality. Treatment with licorice, curcumin, or cocoa, which are rich in flavonoids and other polyphenols, improves motor function in PD patients. No statistically significant differences were found in quality of life, disease progression or nonmotor symptoms such as cognitive ability and mood. Although cohort studies suggest a neuroprotective effect, further clinical studies are urgently needed to evaluate the effect of specific flavonoids and other polyphenols in PD.

Insights on Natural Products Against Amyotrophic Lateral Sclerosis (ALS)

Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disease that causes the death of motor neurons and consequent muscle paralysis. Despite many efforts to address it, current therapy targeting ALS remains limited, increasing the interest in complementary therapies. Over the years, several herbal preparations and medicinal plants have been studied to prevent and treat this disease, which has received remarkable attention due to their blood-brain barrier penetration properties and low toxicity. Thus, this review presents the therapeutic potential of a variety of medicinal herbs and their relationship with ALS and their physiopathological pathways.

The Neuropharmacological Evaluation of Seaweed: A Potential Therapeutic Source

The most common neurodegenerative diseases (NDDs), such as Alzheimer's disease (AD) and Parkinson's disease (PD), are the seventh leading cause of mortality and morbidity in developed countries. Clinical observations of NDD patients are characterized by a progressive loss of neurons in the brain along with memory decline. The common pathological hallmarks of NDDs include oxidative stress, the dysregulation of calcium, protein aggregation, a defective protein clearance system, mitochondrial dysfunction, neuroinflammation, neuronal apoptosis, and damage to cholinergic neurons. Therefore, managing this pathology requires screening drugs with different pathological targets, and suitable drugs for slowing the progression or prevention of NDDs remain to be discovered. Among the pharmacological strategies used to manage NDDs, natural drugs represent a promising therapeutic strategy. This review discusses the neuroprotective potential of seaweed and its bioactive compounds, and safety issues, which may provide several beneficial insights that warrant further investigation.

Membrane-stabilizing and protective effects of curcumin in a rotenone-induced rat model of Parkinson disease

Parkinson disease (PD) is a chronic progressive neurodegenerative disease characterized by both motor and non-motor features. Numerous risk factors (oxidative stress, free radical formation, and several environmental toxins) have been associated with PD. The experimental studies were carried out under in vivo conditions. Biochemical data analysis indicated that compared with the parameters of control (C) rats, rotenone-induced PD rats showed a significant decrease in the specific content of the total fraction of isoforms of O2--producing, heat-stable, NADPH-containing associates (NLP-Nox) from membrane formations of tissues (brain, liver, lung, and small intestine). Compared with the C group indices, in the PD and PD + curcumin (PD + CU) groups there is some change in the shape of the optical absorption spectra of isoforms associated with a change in the amount of Nox in the isoform composition of the total fraction of the NLP-Nox associate. Thus, daily administration of CU (200 mg/kg, i.p.) to PD rats for 63 days had a regulatory effect, bringing the specific content and O2--producing activity of the total fraction of NLP-Nox isoforms closer to the norm. CU has membrane-stabilizing effects in rotenone-induced PD.

The pathology of oxidative stress-induced autophagy in a chronic rotator cuff enthesis tear

Partial-thickness rotator cuff tears (PTRCTs) are often found in daily orthopedic practice, with most of the tears occurring in middle-aged patients. An anaerobic process and imbalanced oxygenation have been observed in PTRCTs, resulting in oxidative stress. Studies have shown the roles of oxidative stress in autophagy and the potential of unregulated mechanisms causing disturbance in soft tissue healing. This article aims to review literature works and summarize the potential pathology of oxidative stress and unregulated autophagy in the rotator cuff enthesis correlated with chronicity. We collected and reviewed the literature using appropriate keywords, in addition to the manually retrieved literature. Autophagy is a normal mechanism of tissue repair or conversion to energy needed for the repair of rotator cuff tears. However, excessive mechanisms will degenerate the tendon, resulting in an abnormal state. Chronic overloading of the enthesis in PTRCTs and the hypovascular nature of the proximal tendon insertion will lead to hypoxia. The hypoxia state results in oxidative stress. An autophagy mechanism is induced in hypoxia via hypoxia-inducible factors (HIFs) 1/Bcl-2 adenovirus E1B 19-kDa interacting protein (BNIP) 3, releasing beclin-1, which results in autophagy induction. Reactive oxygen species (ROS) accumulation would induce autophagy as the regulator of cell oxidation. Oxidative stress will also remove the mammalian target of rapamycin (mTOR) from the induction complex, causing phosphorylation and initiating autophagy. Hypoxia and endoplasmic reticulum (ER) stress would initiate unfolded protein response (UPR) through protein kinase RNA-like ER kinase (PERK) and activate transcription factor 4, which induces autophagy. Oxidative stress occurring in the hypovascularized chronic rotator cuff tear due to hypoxia and ROS accumulation would result in unregulated autophagy directly or autophagy mediated by HIF-1, mTOR, and UPR. These mechanisms would disrupt enthesis healing.

Pinocembrin alleviates pyroptosis and apoptosis through ROS elimination in random skin flaps via activation of SIRT3

Random skin flap grafting is the most common skin grafting technique in reconstructive surgery. Despite progress in techniques, the incidence of distal flap necrosis still exceeds 3%, which limits its use in clinical practice. Current methods for treating distal flap necrosis are still lacking. Pinocembrin (Pino) can inhibit reactive oxygen species (ROS) and cell death in a variety of diseases, such as cardiovascular diseases, but the role of Pino in random flaps has not been explored. Therefore, we explore how Pino can enhance flap survival and its specific upstream mechanisms via macroscopic examination, Doppler, immunohistochemistry, and western blot. The results suggested that Pino can enhance the viability of random flaps by inhibiting ROS, pyroptosis and apoptosis. The above effects were reversed by co-administration of Pino with adeno-associated virus-silencing information regulator 2 homolog 3 (SIRT3) shRNA, proving the beneficial effect of Pino on the flaps relied on SIRT3. In addition, we also found that Pino up-regulates SIRT3 expression by activating the AMP-activated protein kinase (AMPK) pathway. This study proved that Pino can improve random flap viability by eliminating ROS, and ROS-induced cell death through the activation of SIRT3, which are triggered by the AMPK/PGC-1α signaling pathway.

Antioxidant Polymers with Enhanced Neuroprotection Against Insulin Fibrillation

Lipoic acid (LA) and dihydrolipoic acid (DHLA) are well established antioxidants to scavenge reactive oxygen species (ROS). However, they are carboxylates with ≈4.7 pKa making them negatively charged at physiological pH (7.4) reducing their passive diffusion through cell membranes. LA is known to be capable of reducing protein fibrillation. Incorporation of LA and especially DHLA in polymer side chains are scarce. Herein, the first examples of the anti-amyloidogenic effect of LA and DHLA incorporated into the side-chain of a block copolymer with a water-soluble poly(polyethylene glycol methyl ether methacrylate) (PPEGMA) segment are presented. The resultant polymers show improved ROS scavenging activity and improved ability to reduce insulin fibrillation compared to free LA and DHLA. Furthermore, the resultant polymers are also capable of disintegrating preformed insulin firbrils. Interestingly, polymers with dihydro-lipoate moieties showed 93% free radical scavenging activity with 91% anti-fibrillating efficacies for insulin protein confirmed by 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay and Thioflavin T (ThT) dye binding study, respectively. Further, the antioxidant polymers increase the cell viability against fibrillar insulin aggregates that may be involved in the etiology of several diseases. Overall, this work reveals that antioxidant polymer-based therapeutic agents can serve as a powerful modulation strategy for developing novel drugs in future against amyloid-related disorders.

Retinoic Acid Has Neuroprotective effects by Modulating Thioredoxin in Ischemic Brain Damage and Glutamate-exposed Neurons

Ischemic stroke is a neurological disorder that causes pathological changes by increasing oxidative stress. Retinoic acid is one of the metabolites of vitamin A. It regulates oxidative stress and exerts neuroprotective effects. Thioredoxin is a small redox protein with antioxidant activity. The aim of this study was to investigate whether retinoic acid modulates the expression of thioredoxin in ischemic brain injury. Cerebral ischemia was induced by middle cerebral artery occlusion (MCAO) surgery and retinoic acid (5 mg/kg) or vehicle was administered to adult male rats for four days prior to surgery. MCAO induced neurological deficits and increased oxidative stress and retinoic acid attenuated these changes. Retinoic acid ameliorated the MCAO-induced decrease in thioredoxin expression. MCAO decreases the interaction between thioredoxin and apoptosis signal-regulating kinase 1 (ASK1), and retinoic acid treatment alleviates this decrease. Glutamate (5 mM) exposure induced cell death and decreased thioredoxin expression in cultured neurons. Retinoic acid treatment attenuated these changes in a dose-dependent manner. Retinoic acid prevented the decrease of bcl-2 expression and the increase of bax expression caused by glutamate exposure. Moreover, retinoic acid attenuated the increases in caspase-3, cleaved caspase-3, and cytochrome c in glutamate-exposed neurons. However, the mitigation effects of retinoic acid were lower in thioredoxin siRNA-transfected neurons than in non-transfected neurons. These results demonstrate that retinoic acid regulates oxidative stress and thioredoxin expression, maintains the interaction between thioredoxin and ASK1, and modulates apoptosis-associated proteins. Taken together, these results suggest that retinoic acid has neuroprotective effects by regulating thioredoxin expression and modulating apoptotic pathway.

Elnosary M, L. Ashour M, M. Abd El-Moneam N, A. Shreadah M. Flavonoids Biosynthesis in Plants as a Defense Mechanism: Role and Function Concerning Pharmacodynamics and Pharmacokinetic Properties

Flavonoids are a major class of secondary metabolites that comprises more than 6000 compounds that have been identified. They are biosynthesized via the phenylpropanoid metabolic pathway that involves groups of enzymes such as isomerases, hydroxylases, and reductases that greatly affect the determination of the flavonoid skeleton. For example, transferase enzymes responsible for the modification of sugar result in changes in the physiological activity of the flavonoids and changes in their physical properties, such as solubility, reactivity, and interaction with cellular target molecules, which affect their pharmacodynamics and pharmacokinetic properties. In addition, flavonoids have diverse biological activities such as antioxidants, anticancer, and antiviral in managing Alzheimer’s disease. However, most marine flavonoids are still incompletely discovered because marine flavonoid biosynthesis is produced and possesses unique substitutions that are not commonly found in terrestrial bioactive compounds. The current chapter will illustrate the importance of flavonoids’ role in metabolism and the main difference between marine and terrestrial flavonoids.

Methanolic fraction of Cassia fistula L. bark exhibits potential to combat oxidative stress and possess antiproliferative activity

Cassia fistula L. is well known for its traditional medicinal properties as an anti-inflammatory, hepatoprotective, antifungal, antibacterial, antimutagenic, and wound healing agent. The aim of the present study was to determine antioxidant, genoprotective, and cytotoxic potential of different fractions of C. fistula bark including hexane (CaMH), chloroform (CaMC), ethyl acetate (CaME), and methanol (CaMM). Among all the fractions studied, CaMM exhibited maximal radical scavenging activity in antioxidant DPPH assay, Superoxide anion radical scavenging assay and nitric oxide radical scavenging assay displayed an IC₅₀ value of 18.95, 29.41, and 13.38 µg/ml, respectively. CaMM fraction possessed the highest phenolic (130.37 mg gallic acid equivalent/g dry weight of extract) and flavonoid (36.96 mg rutin equivalent/g dry weight of fraction) content. Data demonstrated significant positive correlation between polyphenol levels and radical scavenging activity. Single cell gel electrophoresis (Comet assay) exhibited genoprotective potential of C. fistula bark fractions against DNA damage induced by hydrogen peroxide (H₂O₂) in human lymphocytes. CaMM fraction displayed highest protective ability against H₂O₂ induced-toxicity as evidenced by significant decrease in % tail DNA content from 30 to 7% at highest concentration (200 µg/ml). CaMM was found to be rich in catechin, gallic acid, chlorogenic acid, and kaempferol. The phenolic content and antioxidant ability of the fractions was markedly negatively correlated with H₂O₂- induced DNA damage in human lymphocytes. Cytotoxic potential was evaluated against dermal epidermoid carcinoma (A431), pancreatic (MIA PaCa-2) and brain glioblastoma (LN-18) cancer cell lines using MTT assay. Results showed that C. fistula bark fractions possessed highest toxicity against the skin carcinoma cells. CaMM fraction reduced over 50% cell growth at the concentration of 76.72 µg/ml in A431 cells. These findings suggest that fractions of C. fistula bark exhibit potential to be considered as therapeutic agents in various carcinomas.

Exploring Glycosylated Soy Isoflavones Affinities toward G-tetrads as Studied by Survival Yield Method

Taking soy-based food supplements for menopausal symptoms by women may reduce the risk of cancer. Therefore, the interaction between nucleic acids (or their constituents) and ingredients of the supplements, e. g., isoflavone glucosides, on the molecular level, has been of interest with respect to cancer therapy. In this work, the interaction between isoflavone glucosides and G-tetrads, namely [4G+Na]⁺ ions (G stands for guanosine or deoxyguanosine), were analyzed by using electrospray ionization-collision induced dissociation-mass spectrometry (ESI-CID-MS) and survival yields method. The strength of isoflavone glucosides-[4G+Na]⁺ interaction in the gas phase was determined from E_com50 - the energy required to fragment 50 % of selected precursor ions. Glycitin-[4G+Na]⁺ interaction was found to be the strongest, and the interaction between isoflavone glucosides and guanosine tetrad was established to be stronger than that between isoflavone glucosides and deoxyguanosine tetrad.

PPARs and Their Neuroprotective Effects in Parkinson's Disease: A Novel Therapeutic Approach in α-Synucleinopathy?

Parkinson's disease (PD) is the most common α-synucleinopathy worldwide. The pathognomonic hallmark of PD is the misfolding and propagation of the α-synuclein (α-syn) protein, observed in post-mortem histopathology. It has been hypothesized that α-synucleinopathy triggers oxidative stress, mitochondrial dysfunction, neuroinflammation, and synaptic dysfunction, leading to neurodegeneration. To this date, there are no disease-modifying drugs that generate neuroprotection against these neuropathological events and especially against α-synucleinopathy. Growing evidence suggests that peroxisome proliferator-activated receptor (PPAR) agonists confer neuroprotective effects in PD, however, whether they also confer an anti-α-synucleinopathy effect is unknown. Here we analyze the reported therapeutic effects of PPARs, specifically the gamma isoform (PPARγ), in preclinical PD animal models and clinical trials for PD, and we suggest possible anti-α-synucleinopathy mechanisms acting downstream from these receptors. Elucidating the neuroprotective mechanisms of PPARs through preclinical models that mimic PD as closely as possible will facilitate the execution of better clinical trials for disease-modifying drugs in PD.

A role for flavonoids in the prevention and/or treatment of cognitive dysfunction, learning, and memory deficits: a review of preclinical and clinical studies

OBJECTIVE

Natural food substances, due to high rates of antioxidants, antiviral and anti-inflammatory properties, have been proposed to have the potential for the prevention or treatment of cognitive deficits, learning and memory deficits and neuro inflammation. In particular, medicinal plants with rich amounts of beneficial components such as flavonoids are one of the most promising therapeutic candidates for the cognitive deficit and memory loss. Herein, we aimed to review the impact of medicinal plants with focus on flavonoids on cognitive dysfunction, learning and memory loss by considering their signaling pathways.

METHODS

We extracted 93 preclinical and clinical studies related to the effects of flavonoids on learning and memory and cognition from published papers between 2000 and 2021 in the MEDLINE/PubMed, Cochrane Library, SCOPUS, and Airiti Library databases.

RESULTS

In the preclinical studies, at least there seem to be two main neurological and biological processes in which flavonoids contribute to the improvement and/or prevention of learning, memory deficit and cognitive dysfunction: (1) Regulation of neurotransmission system and (2) Enhancement of neurogenesis, synaptic plasticity and neuronal survival.

CONCLUSION

Although useful effects of flavonoids on learning and memory in preclinical investigations have been approved, more clinical trials are required to find out whether flavonoids and/or other ingredients of plants have the potent to prevent or treat neurodegenerative disorders.

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.

Bridging the Chemical Profile and Biological Activities of a New Variety of Agastache foeniculum (Pursh) Kuntze Extracts and Essential Oil

This study investigated the phytochemical content of alcoholic extracts and essential oil of a new variety of medicinal plants, Agastache foeniculum (Pursh), which Kuntze adapted for cultivation in Romania, namely “Aromat de Buzău”. The essential oil was investigated by GC-MS, while the identification and quantification of various compounds from alcoholic extracts were performed by HPLC-DAD. The total phenol and flavonoid contents of the extracts were evaluated by using standard phytochemical methods. The antioxidant activities of ethanol, methanol extracts, and essential oil of the plant were also assessed against 2,2′-diphenyl-1-picrylhydrazyl (DPPH•), 2,2′-azino-bis-(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS•+), and by ferric reducing power (FRAP) using spectroscopic methods. Cyclic voltammetry was used to evaluate the antioxidant capacity of the essential oil. The concentrations of phenolic compounds were higher in methanolic extract compared to ethanolic extract. A significant correlation was found between total phenol and total flavonoid contents (r = 0.9087). Significant high correlations were also found between the total phenolic compounds and the antioxidant activities of the extracts (r ≥ 0.8600, p < 0.05). In addition, the extracts and essential oil showed good antioxidant and xanthine oxidase inhibitory activities. Estragole was detected as the major constituent of the essential oil (94.89%). The cytotoxic activity of the essential oil was evaluated by the MTT assay. At lower concentrations (1 µg/mL) high cytotoxicity against MCF-7 breast cancer cells was observed but not on the non-tumoral dermal fibroblasts (HDF) which indicated selectivity for cancer cells and suggests the presence of biologically active components that contribute to the observed high cytotoxic effect. Findings from the present study offer new perspectives on the use of A. foeniculum as a potential source of bioactive compounds and a good candidate for pharmaceutical plant-based products.

Luteolin alleviated damage caused by blue light to Drosophila

Short-wavelength blue light is commonly found in daily life and is harmful to health. In this experiment, we investigated the effect of luteolin on the survival time of Drosophila under the blue light condition of 3000 Lux using Drosophila as the model organism. The results showed that luteolin alleviated the damage suffered by Drosophila under blue light irradiation, significantly prolonged the survival time of Drosophila, prolonged the survival time of male Drosophila in the heat stress assay, increased the activity of female Drosophila in the spontaneous activity assay, and increased the egg production of female Drosophila at the highest concentration, and there was no significant difference in the food intake experiment. We suggest that the increase in survival time of Drosophila under blue light conditions is due to the function of luteolin in resisting oxidative stress.

Targets and mechanisms of Alpinia oxyphylla Miquel fruits in treating neurodegenerative dementia

The dried and ripe fruits of Alpinia oxyphylla and ripe fruits of Alpinia oxyphylla Miquel (AO) have the effects of tonifying kidney-essence and nourishing intelligence and thus have been widely used in treating dementia. Alzheimer's disease (AD) is a typical form of neurodegenerative dementia with kidney-essence deficiency in Traditional Chinese Medicine (TCM). So far, there is a lack of systematic studies on the biological basis of tonifying kidney-essence and nourishing intelligence and the corresponding phytochemicals. In this study, we investigated the targets of AO in tonifying kidney-essence and nourishing intelligence based on the key pathophysiological processes of neurodegenerative dementia. According to ultra-high-performance liquid chromatography with triple quadrupole mass spectrometry data and Lipinski's rule of five, 49 bioactive phytochemicals from AO were identified, and 26 of them were found to target 168 key molecules in the treatment of neurodegenerative dementia. Nine phytochemicals of AO were shown to target acetylcholinesterase (ACHE), and 19 phytochemicals were shown to target butyrylcholinesterase (BCHE). A database of neurodegenerative dementia with kidney-essence deficiency involving 731 genes was constructed. Furthermore, yakuchinone B, 5-hydroxy-1,7-bis (4-hydroxy-3-methoxyphenyl) heptan-3-one (5-HYD), oxyhylladiketone, oxyphyllacinol, butyl-β-D-fructopyranoside, dibutyl phthalate, chrysin, yakuchinone A, rhamnetin, and rhamnocitrin were identified as the key phytochemicals from AO that regulate the pathogenesis of neurodegenerative dementia in a multitargeted manner. The approach of studying the pharmacological mechanism underlying the effects of medicinal plants and the biological basis of TCM syndrome may be helpful in studying the translation of TCM.

Marine Natural Products from the Russian Pacific as Sources of Drugs for Neurodegenerative Diseases

Neurodegenerative diseases are growing to become one of humanity's biggest health problems, given the number of individuals affected by them. They cause enough mortalities and severe economic impact to rival cancers and infections. With the current diversity of pathophysiological mechanisms involved in neurodegenerative diseases, on the one hand, and scarcity of efficient prevention and treatment strategies, on the other, all possible sources for novel drug discovery must be employed. Marine pharmacology represents a relatively uncharted territory to seek promising compounds, despite the enormous chemodiversity it offers. The current work discusses one vast marine region-the Northwestern or Russian Pacific-as the treasure chest for marine-based drug discovery targeting neurodegenerative diseases. We overview the natural products of neurological properties already discovered from its waters and survey the existing molecular and cellular targets for pharmacological modulation of the disease. We further provide a general assessment of the drug discovery potential of the Russian Pacific in case of its systematic development to tackle neurodegenerative diseases.

Molecular and Cellular Interactions in Pathogenesis of Sporadic Parkinson Disease

An increasing number of the population all around the world suffer from age-associated neurodegenerative diseases including Parkinson’s disease (PD). This disorder presents different signs of genetic, epigenetic and environmental origin, and molecular, cellular and intracellular dysfunction. At the molecular level, α-synuclein (αSyn) was identified as the principal molecule constituting the Lewy bodies (LB). The gut microbiota participates in the pathogenesis of PD and may contribute to the loss of dopaminergic neurons through mitochondrial dysfunction. The most important pathogenetic link is an imbalance of Ca²⁺ ions, which is associated with redox imbalance in the cells and increased generation of reactive oxygen species (ROS). In this review, genetic, epigenetic and environmental factors that cause these disorders and their cause-and-effect relationships are considered. As a constituent of environmental factors, the example of organophosphates (OPs) is also reviewed. The role of endothelial damage in the pathogenesis of PD is discussed, and a ‘triple hit hypothesis’ is proposed as a modification of Braak’s dual hit one. In the absence of effective therapies for neurodegenerative diseases, more and more evidence is emerging about the positive impact of nutritional structure and healthy lifestyle on the state of blood vessels and the risk of developing these diseases.

Highly efficient Ag doped δ-MnO2 decorated graphene: Comparison and application in electrochemical detection of H2O2

Cytotoxic H₂O₂ is an inevitable part of our life, even during this contemporary pandemic COVID-19. Personal protective equipment of the front line fighter against coronavirus could be sterilized easily by H₂O₂ for reuse. In this study, Ag doped δ-MnO₂ nanorods supported graphene nanocomposite (denoted as Ag@δ-MnO₂/G) was synthesized as a nonenzymatic electrochemical sensor for the sensitive detection of H₂O₂. The ternary nanocomposite has overcome the poor electrical conductivity of δ-MnO₂ and also the severe aggregation of Ag NPs. Furthermore, δ-MnO₂/G provided a rougher surface and large numbers of functional groups for doping more numbers of Ag atoms, which effectively modulate the electronic properties of the nanocomposite. As a result, electroactive surface area and electrical conductivity of Ag@δ-MnO₂/G increased remarkably as well as excellent catalytic activity observed towards H₂O₂ reduction. The modified glassy carbon electrode exhibited fast amperometric response time (<2 s) in H₂O₂ determination. The limit of detection was calculated as 68 nM in the broad linear range (0.005-90.64 mM) with high sensitivity of 104.43 µA mM^-1 cm^-2. No significant interference, long-term stability, excellent reproducibility, satisfactory repeatability, practical applicability towards food samples and wastewater proved the efficiency of the proposed sensor.

Exploring the Anti-inflammatory Effects of Protopine Total Alkaloids of Macleaya Cordata (Willd.) R. Br

Macleaya cordata (Willd). R. Br. is a Chinese medicinal plant commonly used externally to treat inflammatory-related diseases such as arthritis, sores, and carbuncles. This study aimed to evaluate the anti-inflammatory activity of protopine total alkaloids (MPTAs) in Macleaya cordata (Willd.) R. Br. in vivo tests in rats with acute inflammation showed that MPTA (2.54 and 5.08 mg/kg) showed significant anti-inflammatory activity 6 h after carrageenan injection. Similarly, MPTA (3.67 and 7.33 mg/kg) showed significant anti-inflammatory activity in the mouse ear swelling test. In addition, the potential mechanisms of the anti-inflammatory effects of MPTA were explored based on network pharmacology and molecular docking. The two main active components of MPTA, protopine and allocryptopine, were identified, and the potential targets and signaling pathways of MPTA's anti-inflammatory effects were initially revealed using tools and databases (such as SwissTargetPrediction, GeneCards, and STRING) combined with molecular docking results. This study provides the basis for the application of MPTA as an anti-inflammatory agent.

Comparative evaluation of flavonoids reveals the superiority and promising inhibition activity of silibinin against SARS-CoV-2

Flavonoids are phenolic compounds naturally found in plants and commonly consumed in diets. Herein, flavonoids were sequentially evaluated by a comparative in silico study associated with systematic literature search. This was followed by an in vitro study and enzyme inhibition assays against vital SARS-CoV-2 proteins including spike (S) protein, main protease (M^pro ), RNA-dependent RNA-polymerase (RdRp), and human transmembrane serine protease (TMPRSS2). The results obtained revealed 10 flavonoids with potential antiviral activity. Out of them, silibinin showed promising selectivity index against SARS-CoV-2 in vitro. Screening against S protein discloses the highest inhibition activity of silibinin. Mapping the activity of silibinin indicated its excellent binding inhibition activity against SARS-CoV-2 S protein, M^pro and RdRP at IC₅₀ 0.029, 0.021, and 0.042 μM, respectively, while it showed no inhibition activity against TMPRSS2 at its IC_{50(SARS-CoV-2)} . Silibinin was tested safe on human mammalian cells at >7-fold its IC_{50(SARS-CoV-2)} . Additionally, silibinin exhibited >90% virucidal activity at 0.031 μM. Comparative molecular docking (MD) showed that silibinin possesses the highest binding affinity to S protein and RdRP at -7.78 and -7.15 kcal/mol, respectively. MDs showed that silibinin exhibited stable interaction with key amino acids of SARS-CoV-2 targets. Collectively, silibinin, an FDA-approved drug, can significantly interfere with SARS-CoV-2 entry and replication through multi-targeting activity.

Oxidative Stress in Ageing and Chronic Degenerative Pathologies: Molecular Mechanisms Involved in Counteracting Oxidative Stress and Chronic Inflammation

Ageing and chronic degenerative pathologies demonstrate the shared characteristics of high bioavailability of reactive oxygen species (ROS) and oxidative stress, chronic/persistent inflammation, glycation, and mitochondrial abnormalities. Excessive ROS production results in nucleic acid and protein destruction, thereby altering the cellular structure and functional outcome. To stabilise increased ROS production and modulate oxidative stress, the human body produces antioxidants, “free radical scavengers”, that inhibit or delay cell damage. Reinforcing the antioxidant defence system and/or counteracting the deleterious repercussions of immoderate reactive oxygen and nitrogen species (RONS) is critical and may curb the progression of ageing and chronic degenerative syndromes. Various therapeutic methods for ROS and oxidative stress reduction have been developed. However, scientific investigations are required to assess their efficacy. In this review, we summarise the interconnected mechanism of oxidative stress and chronic inflammation that contributes to ageing and chronic degenerative pathologies, including neurodegenerative diseases, such as Alzheimer’s disease (AD) and Parkinson’s disease (PD), cardiovascular diseases CVD, diabetes mellitus (DM), and chronic kidney disease (CKD). We also highlight potential counteractive measures to combat ageing and chronic degenerative diseases.

The role of NURR1 in metabolic abnormalities of Parkinson's disease

A constant metabolism and energy supply are crucial to all organs, particularly the brain. Age-dependent neurodegenerative diseases, such as Parkinson’s disease (PD), are associated with alterations in cellular metabolism. These changes have been recognized as a novel hot topic that may provide new insights to help identify risk in the pre-symptomatic phase of the disease, understand disease pathogenesis, track disease progression, and determine critical endpoints. Nuclear receptor-related factor 1 (NURR1), an orphan member of the nuclear receptor superfamily of transcription factors, is a major risk factor in the pathogenesis of PD, and changes in NURR1 expression can have a detrimental effect on cellular metabolism. In this review, we discuss recent evidence that suggests a vital role of NURR1 in dopaminergic (DAergic) neuron development and the pathogenesis of PD. The association between NURR1 and cellular metabolic abnormalities and its implications for PD therapy have been further highlighted.

Brain Protective Effect of Resveratrol via Ameliorating Interleukin-1β-Induced MMP-9-Mediated Disruption of ZO-1 Arranged Integrity

In the central nervous system (CNS), the matrix metalloproteinase-9 (MMP-9) is induced by several factors and contributes to CNS disorders, including inflammation and neurodegeneration. Thus, the upregulation of MMP-9 has been considered to be an indicator of inflammation. Interleukin-1β (IL-1β) is an important proinflammatory cytokine which can induce various inflammatory factors, such as MMP-9, in many inflammatory disorders. Several phytochemicals are believed to reduce the risk of several inflammatory disorders, including the CNS diseases. Among them, the resveratrol, a principal phenolic compound of the grape, blueberry, and mulberry peels and Cassia plants, has been shown to possess several medicinal properties, including antioxidative, anti-inflammatory, and antitumor function. Herein, we used mouse-brain microvascular endothelial cells (bMECs) to demonstrate the signaling mechanisms of IL-1β-induced MMP-9 expression via zymographic, RT-PCR, Western blot, reactive oxygen species (ROS) detection, immunofluorescence stain, and promoter reporter analyses. Then we evaluated the effects of resveratrol on IL-1β-induced MMP-9 expression in bMECs and its mechanism of action. We first demonstrated that IL-1β induced MMP-9 expression in bMECs. Subsequently, IL-1β induced MMP-9 expression via ROS-mediated c-Src-dependent transactivation of EGFR, and then activation of the ERK1/2, p38 MAPK, JNK1/2, and NF-κB signaling pathway. Finally, we determined that IL-1β-induced upregulation of MMP-9 may cause the disruption of the arranged integrity of zonula occludens-1 (ZO-1), but this could be inhibited by resveratrol. These data indicated that resveratrol may have antioxidative and brain-protective activities by reducing these related pathways of ROS-mediated MMP-9 expression and tight junction disruption in brain microvascular endothelial cells.

Modulation of TLR/NF-κB/NLRP Signaling by Bioactive Phytocompounds: A Promising Strategy to Augment Cancer Chemotherapy and Immunotherapy

Background

Tumors often progress to a more aggressive phenotype to resist drugs. Multiple dysregulated pathways are behind this tumor behavior which is known as cancer chemoresistance. Thus, there is an emerging need to discover pivotal signaling pathways involved in the resistance to chemotherapeutic agents and cancer immunotherapy. Reports indicate the critical role of the toll-like receptor (TLR)/nuclear factor-κB (NF-κB)/Nod-like receptor pyrin domain-containing (NLRP) pathway in cancer initiation, progression, and development. Therefore, targeting TLR/NF-κB/NLRP signaling is a promising strategy to augment cancer chemotherapy and immunotherapy and to combat chemoresistance. Considering the potential of phytochemicals in the regulation of multiple dysregulated pathways during cancer initiation, promotion, and progression, such compounds could be suitable candidates against cancer chemoresistance.

Objectives

This is the first comprehensive and systematic review regarding the role of phytochemicals in the mitigation of chemoresistance by regulating the TLR/NF-κB/NLRP signaling pathway in chemotherapy and immunotherapy.

Methods

A comprehensive and systematic review was designed based on Web of Science, PubMed, Scopus, and Cochrane electronic databases. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines were followed to include papers on TLR/NF-κB/NLRP and chemotherapy/immunotherapy/chemoresistance by phytochemicals.

Results

Phytochemicals are promising multi-targeting candidates against the TLR/NF-κB/NLRP signaling pathway and interconnected mediators. Employing phenolic compounds, alkaloids, terpenoids, and sulfur compounds could be a promising strategy for managing cancer chemoresistance through the modulation of the TLR/NF-κB/NLRP signaling pathway. Novel delivery systems of phytochemicals in cancer chemotherapy/immunotherapy are also highlighted.

Conclusion

Targeting TLR/NF-κB/NLRP signaling with bioactive phytocompounds reverses chemoresistance and improves the outcome for chemotherapy and immunotherapy in both preclinical and clinical stages.

Seedling-stage salinity tolerance in rice: Decoding the role of transcription factors

Rice is an important staple food crop that feeds over half of the human population, particularly in developing countries. Increasing salinity is a major challenge for continuing rice production. Though rice is affected by salinity at all the developmental stages, it is most sensitive at the early seedling stage. The yield thus depends on how many seedlings can withstand saline water at the stage of transplantation, especially in coastal farms. The rapid development of "omics" approaches has assisted researchers in identifying biological molecules that are responsive to salt stress. Several salinity-responsive quantitative trait loci (QTL) contributing to salinity tolerance have been identified and validated, making it essential to narrow down the search for the key genes within QTLs. Owing to the impressive progress of molecular tools, it is now clear that the response of plants toward salinity is highly complex, involving multiple genes, with a specific role assigned to the repertoire of transcription factors (TF). Targeting the TFs for improving salinity tolerance can have an inbuilt advantage of influencing multiple downstream genes, which in turn can contribute toward tolerance to multiple stresses. This is the first comparative study for TF-driven salinity tolerance in contrasting rice cultivars at the seedling stage that shows how tolerant genotypes behave differently than sensitive ones in terms of stress tolerance. Understanding the complexity of salt-responsive TF networks at the seedling stage will be helpful to alleviate crop resilience and prevent crop damage at an early growth stage in rice.

Quercetin improves the apoptotic index and oxidative stress in post-thaw dog sperm

Freeze storage of ejaculated sperms is a crucial technique for the semen preservation of valuable pet animals such as dogs. The current study was conducted to investigate if quercetin (QRN) may ameliorate apoptosis and oxidative stress in post-thaw dog sperm. Herein, we evaluated the post-thaw apoptosis and oxidative stress after treatment with QRN (control, 25, 50, and 100 μM) in the freezing of dog semen. Reactive oxygen species levels were significantly affected (p < 0.05) between the various concentrations of QRN and the control (17.56 ± 1.02, 7.54 ± 0.48, 5.66 ± 0.80, and 10.41 ± 0.69), respectively. The apoptosis index was 9.1 ± 1.34, 6.66 ± 0.58, 6.77 ± 0.66, and 5.38 ± 0.86 in the control, and 25, 50, and 100 μM QRN treatment groups, respectively (p < 0.05). The effects of ameliorated cryo-induced damage by QRN on post-thaw sperm quality were also observed through improved structural and functional tests. Sperm treated with 50 μM QRN showed significantly higher motility (51.8 ± 2.1% vs. 43.1 ± 1.4%, P < 0.05), survival rates (46.9 ± 0.7% vs. 43.9 ± 0.4%, P < 0.05), and mucus penetration than control group, respectively. Results also indicated that higher concentrations of QRN (100 μM) were not effective on sperm quality and parameters when compared with the medium levels (50 μM). In conclusion, supplementation of freezing buffer with 50 μM QRN reduced oxidative damage and improved the quality of post-thaw dog sperm.

Neuroprotective effect of YIAEDAER peptide against Parkinson's disease like pathology in zebrafish

Parkinson's disease (PD) is characterized by the loss of dopaminergic (DA) neurons in the substantia nigra (SN) and aggregation of α-synuclein (α-syn). Current PD therapies merely provide symptomatic relief, lacking the disease-modifying therapeutic strategies against that could reverse the ongoing neurodegeneration. In the quest of exploring novel disease modifying therapeutic strategies, compounds from natural sources have gained much attention in recent days. YIAEDAER (Tyr-Ile-Ala-Glu-Asp-Ala-Glu-Arg) peptide is a multi-functional peptide isolated and purified from the visceral mass extract of Neptunea arthritica cumingii (NAC) with plethora of pharmacological activities, however its neuroprotective effect against MPTP induced PD model is not yet reported. We found YIAEDAER peptide co-treatment could suppressed the MPTP-induced locomotor impairment in zebrafish, ameliorates the MPTP induced degeneration of DA neurons, inhibited the loss of vasculature and loss of cerebral vessels, suppressed α-syn levels. Moreover, YIAEDAER peptide modulates several genes related to autophagy (α-syn, pink1, parkin, atg5, atg7, beclin1, ulk1b, ulk2, and ambra1a), and oxidative stress (sod1, sod2, gss, gpx4a, gsto2, and cat). Hence, our finding suggests that YIAEDAER peptide might be a potential therapeutic candidate against MPTP-induced PD like condition.

NRF2 Activation and Downstream Effects: Focus on Parkinson's Disease and Brain Angiotensin

Reactive oxygen species (ROS) are signalling molecules used to regulate cellular metabolism and homeostasis. However, excessive ROS production causes oxidative stress, one of the main mechanisms associated with the origin and progression of neurodegenerative disorders such as Parkinson's disease. NRF2 (Nuclear Factor-Erythroid 2 Like 2) is a transcription factor that orchestrates the cellular response to oxidative stress. The regulation of NRF2 signalling has been shown to be a promising strategy to modulate the progression of the neurodegeneration associated to Parkinson's disease. The NRF2 pathway has been shown to be affected in patients with this disease, and activation of NRF2 has neuroprotective effects in preclinical models, demonstrating the therapeutic potential of this pathway. In this review, we highlight recent advances regarding the regulation of NRF2, including the effect of Angiotensin II as an endogenous signalling molecule able to regulate ROS production and oxidative stress in dopaminergic neurons. The genes regulated and the downstream effects of activation, with special focus on Kruppel Like Factor 9 (KLF9) transcription factor, provide clues about the mechanisms involved in the neurodegenerative process as well as future therapeutic approaches.

Bromophenol Bis (2,3,6-Tribromo-4,5-dihydroxybenzyl) Ether Protects HaCaT Skin Cells from Oxidative Damage via Nrf2-Mediated Pathways

Excessive reactive oxygen species (ROS) promotes the oxidative stress of keratinocytes, eventually causing cell damage. The natural bromophenol bis (2,3,6-tribromo-4,5-dihydroxybenzyl) ether (BTDE) from marine red algae has been reported to have a varied bioactivity; however, its antioxidant effect has yet to be investigated systemically. Our present work aimed to explore the antioxidant effect of BTDE both on the molecular and cellular models and also to illustrate the antioxidant mechanisms. Our results showed that BTDE could effectively scavenge ABTS free radicals and protect HaCaT cells from damage induced by H₂O₂. Mechanism studies in HaCaT cells demonstrated that BTDE attenuated hydrogen peroxide (H₂O₂)-induced ROS production, reduced the malondialdehyde (MDA) level, decreased the oxidized glutathione (GSSG)/glutathione (GSH) ratio, and increased the antioxidant enzyme superoxide dismutase (SOD). Moreover, BTDE could inhibit the expression of Kelch-like epichlorohydrin-associated protein 1 (Keap1) and increase the expression of both nuclear factor erythroid 2-related factor 2 (Nrf2) and its downstream proteins TrXR1, HO-1, and NQO1. BTDE also activated the upstream signaling pathway of Nrf2 such as AKT pathway, while not activating the ERK or AMPKα pathways. In general, BTDE is a promising antioxidant to protect HaCaT cells against oxidative damage via Nrf2-mediated pathways.

Pinocembrin ameliorates post-infarct heart failure through activation of Nrf2/HO-1 signaling pathway

Background

Oxidative stress is an important factor involved in the progress of heart failure. The current study was performed to investigate whether pinocembrin was able to ameliorate post-infarct heart failure (PIHF) and the underlying mechanisms.

Methods

Rats were carried out left anterior descending artery ligation to induce myocardial infarction and subsequently raised for 6 weeks to produce chronic heart failure. Then pinocembrin was administrated every other day for 2 weeks. The effects were evaluated by echocardiography, western blot, Masson’s staining, biochemical examinations, immunohistochemistry, and fluorescence. In vitro we also cultured H9c2 cardiomyocytes and cardiac myofibroblasts to further testify the mechanisms.

Results

We found that PIHF-induced deteriorations of cardiac functions were significantly ameliorated by administrating pinocembrin. In addition, the pinocembrin treatment also attenuated collagen deposition and augmented vascular endothelial growth factor receptor 2 in infarct border zone along with an attenuated apoptosis, which were related to an amelioration of oxidative stress evidenced by reduction of reactive oxygen species (ROS) in heart tissue and malondialdehyde (MDA) in serum, and increase of superoxide dismutase (SOD). This were accompanied by upregulation of nuclear factor erythroid 2-related factor 2 (Nrf2)/ heme oxygenase-1 (HO-1) pathway. In vitro experiments we found that specific Nrf2 inhibitor significantly reversed the effects resulted from pinocembrin including antioxidant, anti-apoptosis, anti-fibrosis and neovascularization, which further indicated the amelioration of PIHF by pinocembrin was in a Nrf2/HO-1 pathway-dependent manner.

Conclusion

Pinocembrin ameliorated cardiac functions and remodeling resulted from PIHF by ROS scavenging and Nrf2/HO-1 pathway activation which further attenuated collagen fibers deposition and apoptosis, and facilitated angiogenesis.

Supplementary Information

The online version contains supplementary material available at 10.1186/s10020-021-00363-7.

Reappraisal of metabolic dysfunction in neurodegeneration: Focus on mitochondrial function and calcium signaling

The cellular and molecular mechanisms that drive neurodegeneration remain poorly defined. Recent clinical trial failures, difficult diagnosis, uncertain etiology, and lack of curative therapies prompted us to re-examine other hypotheses of neurodegenerative pathogenesis. Recent reports establish that mitochondrial and calcium dysregulation occur early in many neurodegenerative diseases (NDDs), including Alzheimer's disease, Parkinson's disease, Huntington's disease, and others. However, causal molecular evidence of mitochondrial and metabolic contributions to pathogenesis remains insufficient. Here we summarize the data supporting the hypothesis that mitochondrial and metabolic dysfunction result from diverse etiologies of neuropathology. We provide a current and comprehensive review of the literature and interpret that defective mitochondrial metabolism is upstream and primary to protein aggregation and other dogmatic hypotheses of NDDs. Finally, we identify gaps in knowledge and propose therapeutic modulation of mCa2+ exchange and mitochondrial function to alleviate metabolic impairments and treat NDDs.

The Effect of Cream and Gel Vehicles on the Percutaneous Absorption and Skin Retention of a New Eugenol Derivative With Antioxidant Activity

The effect of cream and gel vehicles containing clove water on skin permeability was compared for a new eugenol derivative (eugenyl dichloroacetate-EDChA) with antioxidant activity. In vitro permeation experiments were conducted in a Franz cell with porcine skin. The cumulative mass and skin accumulation of EDChA were investigated and compared. The antioxidative capacity of the studied vehicles was determined by using the diphenylpicrylhydrazyl (DPPH) free radical reduction method. The antioxidant activity (evaluated with DPPH, ABTS, and the Folin-Ciocalteu methods) of the fluid that penetrated through the pig skin and of the fluid obtained after the skin extraction, were also determined. For comparison, eugenol was also tested. The results of this work could contribute to the development of vehicles with antioxidant potential estimated after 24 h of conducting the experiment, which indicates long-term protection against reactive oxygen species (ROS) in the deeper layers of the skin. The waste water from the clove buds steam distillation -contains several valuable biologically active compounds, and its use is environmentally friendly. We observed that gel vehicles were the best enhancer of skin permeation for both eugenol and its derivative. In most cases, -similar cumulative masses of eugenol and its ester were found in the acceptor fluid. The accumulation of EDChA was higher for cream vehicles in relation to the parent eugenol when applied onto the skin. The greatest amounts of eugenol were accumulated in the skin when these compounds were used in gel vehicles.

Enhancement of the Antioxidant and Skin Permeation Properties of Betulin and Its Derivatives

This study investigated the antioxidant activity DPPH, ABTS, and Folin-Ciocalteu methods of betulin (compound 1) and its derivatives (compounds 2-11). Skin permeability and accumulation associated with compounds 1 and 8 were also examined. Identification of the obtained products (compound 2-11) and betulin isolated from plant material was based on the analysis of 1H- NMR and 13C-NMR spectra. The partition coefficient was calculated to determine the lipophilicity of all compounds. In the next stage, the penetration through pig skin and its accumulation in the skin were evaluated of ethanol vehicles containing compound 8 (at a concentration of 0.226 mmol/dm3), which was characterized by the highest antioxidant activity. For comparison, penetration studies of betulin itself were also carried out. Poor solubility and the bioavailability of pure compounds are major constraints in combination therapy. However, we observed that the ethanol vehicle was an enhancer of skin permeation for both the initial betulin and compound 8. The betulin 8 derivative showed increased permeability through biological membranes compared to the parent betulin. The paper presents the transformation of polycyclic compounds to produce novel derivatives with marked antioxidant activities and as valuable intermediates for the pharmaceutical industry. Moreover, the compounds contained in the vehicles, due to their mechanism of action, can have a beneficial effect on the balance between oxidants and antioxidants in the body, minimizing the effects of oxidative stress. The results of this work may contribute to knowledge regarding vehicles with antioxidant potential. The use of vehicles for this type of research is therefore justified.

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.

Plant-Derived Natural Compounds for the treatment of Amyotrophic Lateral Sclerosis: An Update

Background

Amyotrophic lateral sclerosis (ALS) is a motor neuron disease (MND) that typically causes death within 3-5 years after diagnosis. Regardless of the substantial scientific knowledge accrued more than a century ago, truly effective therapeutic strategies remain distant. Various conventional drugs are being used but are having several adverse effects.

Objective/Aim

The current study aims to thoroughly review plant-derived compounds with well-defined ALS activities and their structure-activity relationships. Moreover, the review also focuses on complex genetics, clinical trials, and the use of natural products that might decrypt the future and novel therapeutics in ALS.

Methods

The collection of data for the compilation of this review work was searched in PubMed Scopus, Google Scholar, and Science Direct.

Results

Results showed that phytochemicals like-Ginkgolides, Protopanaxatriol, Genistein, epigallocatechingallate, resveratrol, cassoside, and others possess Amyotrophic lateral sclerosis (ALS) activity by various mechanisms.

Conclusion

These plant-derived compounds may be considered as supplements for conventional (ALS). Moreover, further preclinical and clinical studies are required to understand the structure-activity relationships, metabolism, absorption, and mechanisms of plant-derived natural agents.

Flavonoids from edible fruits as therapeutic agents in neuroinflammation - a comprehensive review and update

Neuroinflammation is a key process in the pathogenesis of many neurological disorders, i.e. Alzheimer's disease and Parkinson's disease. However, there are no anti-inflammatory medical interventions recommended so far in the treatment of neuroinflammation-related brain disorders. Therefore, the burden of searching for effective and safe antineuroinflammatory agents is well founded, especially in the aging society. Compounds of plant origin, mainly (poly)phenols, have attracted considerable attention in recent years. Notably, the role of flavonoids in ameliorating neuroinflammation is in the limelight. Thus, we used comprehensive literature retrieval to summarize the effects and active components of edible fruits and their phenolic compounds. As a result, this review presents a valuable summary of results of in vitro, ex vivo, and in vivo studies on the antineuroinflammatory effects of edible fruits and their (poly)phenolic extracts as well as dietary flavonoids and other selected (poly)phenols based on the detailed description of foregoing studies. Additionally, problems resulting from the limited bioavailability of (poly)phenols were discussed.

Luteolin attenuates Fipronil-induced neurotoxicity through reduction of the ROS-mediated oxidative stress in rat brain mitochondria

Luteolin (LUT) as a natural compound found in vegetables and fruits has various pharmacological effects. Fipronil (FPN), as a pesticide, has been considered for its effect on the antioxidant system and induction of oxidative stress. This study was designed to investigate the protective effects of LUT against the oxidative stress and mitochondrial toxicity induced by FPN on the rat brain. Several parameters such as mitochondrial reactive oxygen species (ROS) level, mitochondrial membrane potential (MMP) collapse, mitochondrial swelling, cytochrome c release, mitochondrial glutathione (GSH), lipid peroxidation (LPO) and Adenosine triphosphate (ATP) levels were assessed. Results indicated that the administration of LUT (25 μM) significantly improved oxidative stress and mitochondrial damages induced via FPN (6, 12 and 24 μM) in isolated mitochondria from the brain. These results show that LUT exerted protective effects against FPN-induced neurotoxicity in vitro through improving oxidative stress and mitochondrial damages.

Biomaterials in the treatment of Parkinson's disease

Parkinson's disease is a neurodegenerative disease, the treatment of which is mainly centred around supplementation of dopamine. Additional targets have been identified and newer chemotherapeutic agents have been introduced but their clinical efficacy is limited due to solubility, bioavailability issues and inability to cross the blood-brain barrier (BBB). A wide range of biomaterials ranging from biomolecules, polymers, inorganic metal and metal oxide nanoparticles have been employed to assist the delivery of these therapeutic agents into the brain. Additionally, strategies to deliver cells to restore the dopaminergic neurons also have shown promise due to the integration of biocompatible materials that aid neurogenesis through a combination of topographical, chemical and mechanical cues. Neuroprosthetics is an area that may become significant in treatment of motor deficits associated with Parkinson's disease, and involves development of highly conductive and robust electrode materials with excellent cytocompatibility. This review summarizes the major role played by biomaterials in design of novel strategies and in the improvement of existing therapeutic methods as well as the emerging trends in this domain.

Identification and optimization of piperlongumine analogues as potential antioxidant and anti-inflammatory agents via activation of Nrf2

Oxidative stress and inflammation are significant risk factors for neurodegenerative disease. The Keap1-Nrf2-ARE pathway is one of the most promising defensive systems against oxidative stress. Here, dozens of piperlongumine analogues were designed, synthesized, and tested on PC12 cells to examine neuroprotective effects against H2O2 and 6-OHDA induced damage. Among them, 6d was found to be able to alleviate the accumulation of ROS, inhibit the production of NO and downregulate the level of IL-6, which indicated its potential antioxidant and anti-inflammatory activity. Further studies proved that 6d could activate Nrf2 signaling pathway, induce the translocation of Nrf2 from cell cytosol to nucleus and upregulate the related phase II antioxidant enzymes including NQO1, HO-1, GCLC, GCLM and TrxR1. These results confirmed that 6d exerted antioxidant and anti-inflammatory activities by activating Nrf2 signaling pathway. Moreover, the parallel artificial membrane permeability assay indicated that 6d can cross the blood-brain barrier. In general, 6d is promising for further development as a therapeutic drug against oxidative stress and inflammation related neurodegenerative disorders.

Beneficial Effects of Epigallocatechin-3-O-Gallate, Chlorogenic Acid, Resveratrol, and Curcumin on Neurodegenerative Diseases

Many observational and clinical studies have shown that consumption of diets rich in plant polyphenols have beneficial effects on various diseases such as cancer, obesity, diabetes, cardiovascular diseases, and neurodegenerative diseases (NDDs). Animal and cellular studies have indicated that these polyphenolic compounds contribute to such effects. The representative polyphenols are epigallocatechin-3-O-gallate in tea, chlorogenic acids in coffee, resveratrol in wine, and curcumin in curry. The results of human studies have suggested the beneficial effects of consumption of these foods on NDDs including Alzheimer's and Parkinson's diseases, and cellular animal experiments have provided molecular basis to indicate contribution of these representative polyphenols to these effects. This article provides updated information on the effects of these foods and their polyphenols on NDDs with discussions on mechanistic aspects of their actions mainly based on the findings derived from basic experiments.

A Triple Role for a Bilayer: Using Nanoliposomes to Cross and Protect Cellular Membranes

Thanks in large part to the seminal work of Steve White and his colleagues, we appreciate the "ordered complexity" of the lipid bilayer and how it impacts the incorporation of integral membrane proteins as well as more peripherally associated proteins. Steve's work also provides a vital foundation to tackle another challenge: cytotoxic oligomeric complexes which accumulate in various neurodegenerative diseases. These oligomers have a relatively fluid structure and interact with many different proteins in the cell, but their main target is thought to be the phospholipid membrane, either the plasma membrane or internal organelles such as the mitochondria. This fascinating encounter between two essentially fluid phases generates a more disordered membrane, and presumably promotes uncontrolled transport of small metal ions across the membrane barrier. Happily, this unwanted interaction may be suppressed by mobilizing the phospholipid bilayer into its own defense. Extruded nanolipoparticles (NLPs) consisting of DPPC lipids, cholesterol and PEG2000 are excellent vehicles to take up small "oligomer-bashing" hydrophobic molecules such as baicalein and transport them with increased half-life in the plasma and with markedly more efficient crossing of the blood-brain barrier. Thus the bilayer has a triple role in this account: a safe space for a reactive hydrophobic small molecule, a barrier to cross to deliver a drug payload and a target to protect against oligomer attacks. NLPs containing small hydrophobic molecules show great promise in combating neurodegenerative diseases in animal models and may serve as an example of the White approach: applying robust physical-chemical principles to deal with biological problems involving phospholipid membranes.

The subgroup of 2'-hydroxy-flavonoids: Molecular diversity, mechanism of action, and anticancer properties

Flavonoids are abundant in nature, structurally very diversified and largely investigated. However, the subgroup of 2'-hydroxyflavonoids is much less known and not frequently studied. The present review identifies the major naturally-occurring and synthetic 2'-hydroxyflavonoid derivatives and discusses their structural characteristics and biological properties, with a focus on anticancer activities. The pharmacological properties of 2'-hydroxyflavone (2'-HF) and 2'-hydroxyflavanone (2'-HFa) are detailed. Upon binding to the Ral-interacting protein Rlip implicated in the transport of glutathione conjugates, 2'-HFa inhibits tumor cell proliferation and restrict tumor growth, in particular in breast cancer models. Among the synthetic derivatives, the characteristics of the anticancer product 2D08 (2',3',4'-trihydroxy flavone) are detailed to shed light on the molecular mechanism of action of this compound, as a regulator of protein SUMOylation. Inhibition of protein SUMOylation by 2D08 blocks cancer cell migration and invasion, and the compound greatly enhances the anticancer effects of conventional cytotoxic drugs like etoposide. The structural role of the 2'-hydroxyl group on the phenyl C-ring of the flavonoid is discussed, notably the capacity to engage intramolecular H-bonding interactions with the O1 atom on the B-ring of the chromone unit (or the oxygen of a 3-OH group when it is presents). The 2'-hydroxyl group of flavonoid appears as a regulator of the conformational freedom between the bicyclic A-B unit and the appended phenyl C-ring, favoring the planarity of the molecule. It is an essential group accounting for the biological properties of 2'-HF, 2'-HFa and structurally related compounds. This review shed light on 2'-hydroxyflavonoids to encourage their use and chemical development.