Anti-Aggregative and Protective Effects of Vicenin-2 on Heat and Oxidative Stress-Induced Damage on Protein Structures.

Vicenin-2, a flavonoid categorized as a flavones subclass, exhibits a distinctive and uncommon C-glycosidic linkage. Emerging evidence challenges the notion that deglycosylation is not a prerequisite for the absorption of C-glycosyl flavonoid in the small intestine. Capitalizing on this experimental insight and considering its biological attributes, we conducted different assays to test the anti-aggregative and antioxidant capabilities of vicenin-2 on human serum albumin under stressful conditions. Within the concentration range of 0.1-25.0 µM, vicenin-2 effectively thwarted the heat-induced HSA fibrillation and aggregation of HSA. Furthermore, in this study, we have observed that vicenin-2 demonstrated protective effects against superoxide anion and hydroxyl radicals, but it did not provide defense against active chlorine. To elucidate the underlying mechanisms, behind this biological activity, various spectroscopy techniques were employed. UV-visible spectroscopy revealed an interaction between HSA and vicenin-2. This interaction involves the cinnamoyl system found in vicenin-2, with a peak of absorbance observed at around 338 nm. Further evidence of the interaction comes from circular dichroism spectrum, which shows that the formation of bimolecular complex causes a reduction in α-helix structures. Fluorescence and displacement investigations indicated modifications near Trp214, identifying Sudlow's site I, similarly to the primary binding site. Molecular modeling revealed that vicenin-2, in nonplanar conformation, generated hydrophobic interactions, Pi-pi stacking, and hydrogen bonds inside Sudlow's site I. These findings expand our understanding of how flavonoids bind to HSA, demonstrating the potential of the complex to counteract fibrillation and oxidative stress.

Ferroptosis: Emerging Role in Diseases and Potential Implication of Bioactive Compounds.

Ferroptosis is a form of cell death that is distinguished from other types of death for its peculiar characteristics of death regulated by iron accumulation, increase in ROS, and lipid peroxidation. In the past few years, experimental evidence has correlated ferroptosis with various pathological processes including neurodegenerative and cardiovascular diseases. Ferroptosis also is involved in several types of cancer because it has been shown to induce tumor cell death. In particular, the pharmacological induction of ferroptosis, contributing to the inhibition of the proliferative process, provides new ideas for the pharmacological treatment of cancer. Emerging evidence suggests that certain mechanisms including the Xc- system, GPx4, and iron chelators play a key role in the regulation of ferroptosis and can be used to block the progression of many diseases. This review summarizes current knowledge on the mechanism of ferroptosis and the latest advances in its multiple regulatory pathways, underlining ferroptosis' involvement in the diseases. Finally, we focused on several types of ferroptosis inducers and inhibitors, evaluating their impact on the cell death principal targets to provide new perspectives in the treatment of the diseases and a potential pharmacological development of new clinical therapies.

Catechins and Proanthocyanidins Involvement in Metabolic Syndrome.

Recent studies on natural antioxidant compounds have highlighted their potentiality against various pathological conditions. The present review aims to selectively evaluate the benefits of catechins and their polymeric structure on metabolic syndrome, a common disorder characterized by a cluster of three main risk factors: obesity, hypertension, and hyperglycemia. Patients with metabolic syndrome suffer chronic low inflammation state and oxidative stress both conditions effectively countered by flavanols and their polymers. The mechanism behind the activity of these molecules has been highlighted and correlated with the characteristic features present on their basic flavonoidic skelethon, as well as the efficient doses needed to perform their activity in both in vitro and in vivo studies. The amount of evidence provided in this review offers a starting point for flavanol dietary supplementation as a potential strategy to counteract several metabolic targets associated with metabolic syndrome and suggests a key role of albumin as flavanol-delivery system to the different target of action inside the organism.

The Neuroprotective Potentiality of Flavonoids on Alzheimer's Disease.

Alzheimer's disease (AD), due to its spread, has become a global health priority, and is characterized by senile dementia and progressive disability. The main cause of AD and other neurodegenerations (Huntington, Parkinson, Amyotrophic Lateral Sclerosis) are aggregated protein accumulation and oxidative damage. Recent research on secondary metabolites of plants such as polyphenols demonstrated that they may slow the progression of AD. The flavonoids' mechanism of action in AD involved the inhibition of acetylcholinesterase, butyrylcholinesterase, Tau protein aggregation, ß-secretase, oxidative stress, inflammation, and apoptosis through modulation of signaling pathways which are implicated in cognitive and neuroprotective functions, such as ERK, PI3-kinase/Akt, NFKB, MAPKs, and endogenous antioxidant enzymatic systems. This review focuses on flavonoids and their role in AD, in terms of therapeutic potentiality for human health, antioxidant potential, and specific AD molecular targets.

Biotechnological Applications and Health-Promoting Properties of Flavonols: An Updated View.

Flavonols are a subclass of natural flavonoids characterized by a remarkable number of biotechnological applications and health-promoting properties. They attract researchers' attention due to many epidemiological studies supporting their usage. They are phytochemicals commonly present in our diet, being ubiquitous in the plant kingdom and, in particular, relatively very abundant in fruits and vegetables. All these aspects make flavonols candidates of choice for the valorization of products, based on the presence of a remarkable number of different chemical structures, each one characterized by specific chemical features capable of influencing biological targets inside the living organisms in very different manners. In this review, we analyzed the biochemical and physiological characteristics of flavonols focalizing our attention on the most promising compounds to shed some light on their increasing utilization in biotechnological applications in processing industries, as well as their suitable employment to improve the overall wellness of the humankind.

Implication of COVID-19 on Erythrocytes Functionality: Red Blood Cell Biochemical Implications and Morpho-Functional Aspects.

Several diseases (such as diabetes, cancer, and neurodegenerative disorders) affect the morpho-functional aspects of red blood cells, sometimes altering their normal metabolism. In this review, the hematological changes are evaluated, with particular focus on the morphology and metabolic aspects of erythrocytes. Changes in the functionality of such cells may, in fact, help provide important information about disease severity and progression. The viral infection causes significant damage to the blood cells that are altered in size, rigidity, and distribution width. Lower levels of hemoglobin and anemia have been reported in several studies, and an alteration in the concentration of antioxidant enzymes has been shown to promote a dangerous state of oxidative stress in red blood cells. Patients with severe COVID-19 showed an increase in hematological changes, indicating a progressive worsening as COVID-19 severity progressed. Therefore, monitored hematological alterations in patients with COVID-19 may play an important role in the management of the disease and prevent the risk of a severe course of the disease. Finally, monitored changes in erythrocytes and blood, in general, may be one of the causes of the condition known as Long COVID.

Reviewing Biochemical Implications of Normal and Mutated Huntingtin in Huntington's Disease.

Huntingtin (Htt) is a multi-function protein of the brain. Normal Htt shows a common alpha-helical structure but conformational changes in the form with beta strands are the principal cause of Huntington's disease. Huntington's disease is a genetic neurological disorder caused by a repeated expansion of the CAG trinucleotide, causing instability in the N-terminal of the gene coding for the Huntingtin protein. The mutation leads to the abnormal expansion of the production of the polyglutamine tract (polyQ) resulting in the form of an unstable Huntingtin protein commonly referred to as mutant Huntingtin. Mutant Huntingtin is the cause of the complex neurological metabolic alteration of Huntington's disease, resulting in both the loss of all the functions of normal Huntingtin and the genesis of abnormal interactions due to the presence of this mutation. One of the problems arising from the misfolded Huntingtin is the increase in oxidative stress, which is common in many neurological diseases such as Alzheimer's, Parkinson's, Amyotrophic Lateral Sclerosis and Creutzfeldt-Jakob disease. In the last few years, the use of antioxidants had a strong incentive to find valid therapies for defence against neurodegenerations. Although further studies are needed, the use of antioxidant mixtures to counteract neuronal damages seems promising.

New role for an old molecule: The 2,3-diphosphoglycerate case.

BACKGROUND: Aerobic organisms have to overcame the dangerous species derived from the unquestionable favorable effects due to the utilization of oxygen in the cellular respiration. 2,3-Diphosphoglycerate (DPG) could be one of the molecules able to perform different role inside the cells and (from the data obtained from our experimental work) may help cellular components, in particular hemoglobin, to scavenge reactive oxygen species (ROS) and reactive nitrogen species (RNS). METHODS: Therefore, we have investigated the kinetic and antioxidant properties of this molecule against the main biological reactive species and the protective role of this molecules on hemoglobin treated with strong oxidant. RESULTS: DPG, at the physiological concentration is able to scavenge hydroxyl radical, peroxyl radical, cation radicals and to chelate iron in the reduced state. Moreover it is able to avoid oxidation of iron inside the hemoglobin following treatment with nitrite and tert-butyl hydroperoxide (t-BOOH). On the other side, it is not able to protect membrane components from oxidative burning. This different behavior towards radical species is probably linked to the polarity of the molecule and also the high levels of charged groups present on the surface of DPG, that avoid the possibility to act in an environment almost completely hydrophobic, as inside the membrane, where reactive species produce the main damages during the reactions of peroxidation. CONCLUSIONS: This is the first paper dealing with the potential role of DPG not only as a modulator of oxygen affinity in hemoglobin, but also as a scavenger of radicals.

Protective Effects of the Caffeine Against Neurodegenerative Diseases.

BACKGROUND: Recent studies and increased interest of the scientific community helped to clarify the neurological health property of caffeine, one of the pharmacologically active substances most consumed in the world. METHODS: This article is a review search to provide an overview on the current state of understanding neurobiochemical impact of caffeine, focusing on the ability of the drug to effectively counteract several neurodegenerative disorders such as Alzheimer's, Parkinson's, Huntington's diseases, Multiple sclerosis and Amyotrophic lateral sclerosis. RESULTS: Data collection shown in this review provide a significant therapeutic and prophylactic potentiality of caffeine which acts on human brain through several pathways because of its antioxidant activity combined with multiple molecular targets. However, the need to adjust the CF dosage to individuals, because some people are more sensitive to drugs than others, may constituted a limit to the CF effectiveness. CONCLUSION: What emerges from the complex of clinical and epidemiological studies is a significant CF potential impact against all neurological disorders. Although, further studies are needed to fully elucidate the several mechanisms of drug action which in part are still elusive.

Neuroprotective effects of honokiol: from chemistry to medicine.

The incidence of neurological disorders is growing in developed countries together with increased lifespan. Nowadays, there are still no effective treatments for neurodegenerative pathologies, which make necessary to search for new therapeutic agents. Natural products, most of them used in traditional medicine, are considered promising alternatives for the treatment of neurodegenerative diseases. Honokiol is a natural bioactive phenylpropanoid compound, belonging to the class of neolignan, found in notable amounts in the bark of Magnolia tree, and has been reported to exert diverse pharmacological properties including neuroprotective activities. Honokiol can permeate the blood brain barrier and the blood-cerebrospinal fluid to increase its bioavailability in neurological tissues. Diverse studies have provided evidence on the neuroprotective effect of honokiol in the central nervous system, due to its potent antioxidant activity, and amelioration of the excitotoxicity mainly related to the blockade of glutamate receptors and reduction in neuroinflammation. In addition, recent studies suggest that honokiol can attenuate neurotoxicity exerted by abnormally aggregated Aß in Alzheimer's disease. The present work summarizes what is currently known concerning the neuroprotective effects of honokiol and its potential molecular mechanisms of action, which make it considered as a promising agent in the treatment and management of neurodegenerative diseases. © 2017 BioFactors, 43(6):760-769, 2017.

Neuroprotective effects of phloretin and its glycosylated derivative on rotenone-induced toxicity in human SH-SY5Y neuronal-like cells.

Phloretin and phlorizin are the two strong natural antioxidants whose biological and pharmacological applications are rapidly growing in different human pathological conditions. The neuroprotective activity of the two flavonoids has been analyzed on cell culture of neuroblastoma cells. The neuroprotective activity of the two flavonoids has been analyzed on cell culture of neuroblastoma cells and evaluated by testing cell vitality, mitochondrial transmembrane potential and ROS production, antioxidant enzymes detection, activation of caspase 3, DNA damage, protein carbonylation, lipid peroxidation, and superoxide anion scavenging activity. Incubation of cells with rotenone caused cell death and significant increase in intracellular reactive oxygen species, activation of caspase 3, and variation in mitochondrial transmembrane potential. Although, rotenone exposure caused a significant increase of antioxidant enzymes, high levels of lipid peroxidation were also observed. Phloretin or phlorizin, at micromolar concentration, reduced rotenone-induced cell death by scavenging ability against superoxide anion radical, one of the main effectors of rotenone toxicity at level of mitochondrial respiratory chain complex I. Under our experimental conditions, a reduction of the intracellular ROS levels with consequent normalization of the aforementioned antioxidant enzymes occurred. Concomitantly, we observed the inhibition of caspase 3 activity and DNA damage. This study shows the promising neuroprotective ability of the two dihydrochalcones able to protect human differentiated neuroblastoma cells (commonly used as model of Parkinson's disease) from injury induced by rotenone, actively scavenging ROS, normalizing mitochondrial transmembrane potential and consequently avoiding energy depletion. © 2017 BioFactors, 43(4):549-557, 2017.

Short-Term Effects of Chlorpromazine on Oxidative Stress in Erythrocyte Functionality: Activation of Metabolism and Membrane Perturbation.

The purpose of this paper is to focus on the short-term effects of chlorpromazine on erythrocytes because it is reported that the drug, unstable in plasma but more stable in erythrocytes, interacts with erythrocyte membranes, membrane lipids, and hemoglobin. There is a rich literature about the side and therapeutic effects or complications due to chlorpromazine, but most of these studies explore the influence of long-term treatment. We think that evaluating the short-term effects of the drug may help to clarify the sequence of chlorpromazine molecular targets from which some long-term effects derive. Our results indicate that although the drug is primarily intercalated in the innermost side of the membrane, it does not influence band 3 anionic flux, lipid peroxidation, and protein carbonylation processes. On the other hand, it destabilizes and increases the autooxidation of haemoglobin, induces activation of caspase 3, and, markedly, influences the ATP and reduced glutathione levels, with subsequent exposure of phosphatidylserine at the erythrocyte surface. Overall our observations on the early stage of chlorpromazine influence on erythrocytes may contribute to better understanding of new and interesting characteristics of this compound improving knowledge of erythrocyte metabolism.

Alterations in Red Blood Cell Functionality Induced by an Indole Scaffold Containing a Y-Iminodiketo Moiety: Potential Antiproliferative Conditions.

We have recently proposed a new erythrocyte-based model of study to predict the antiproliferative effects of selected heterocyclic scaffolds. Starting from the metabolic similarity between erythrocytes and cancer cells, we have demonstrated how the metabolic derangement induced by an indolone-based compound (DPIT) could be related to its antiproliferative effects. In order to prove the validity of our biochemical approach, in the present study the effects on erythrocyte functionality of its chemical precursor (PID), whose synthesis we reported, were investigated. The influence of the tested compound on band 3 protein (B3), oxidative state, ATP efflux, caspase 3, metabolism, intracellular pH, and Ca(2+) homeostasis has been evaluated. PID crosses the membrane localizing into the cytosol, increases anion exchange, induces direct caspase activation, shifts the erythrocytes towards an oxidative state, and releases less ATP than in normal conditions. Analysis of phosphatidylserine externalization shows that PID slightly induces apoptosis. Our findings indicate that, due to its unique features, erythrocyte responses to exogenous molecular stimuli can be fruitfully correlated at structurally more complex cells, such as cancer cells. Overall, our work indicates that erythrocyte is a powerful study tool to elucidate the biochemical/biological effects of selected heterocycles opening considerable perspectives in the field of drug discovery.

Insights into the properties of the two enantiomers of trans-δ-viniferin, a resveratrol derivative: antioxidant activity, biochemical and molecular modeling studies of its interactions with hemoglobin.

Resveratrol is widely known as an antioxidant and anti-inflammatory molecule. The present study first reports the effects of trans-δ-viniferin (TVN), a dimer of resveratrol, on human erythrocytes. The antioxidant activity of TVN was tested using in vitro model systems such as hydroxy radical scavenging, DPPH and lipid peroxidation. In addition we have examined the influence of the 15R,22R- and 15S,22S-enantiomers (abbreviated R,R-TVN, and S,S-TVN, respectively) on anion transport, ATP release, caspase 3 activation. Given that hemoglobin (Hb) redox reactions are the major source of RBC oxidative stress, we also explored the effects of TVN on hemoglobin function. TVN showed moderate antioxidant properties and good protective activity from hemoglobin oxidation. Potential binding sites of R,R-TVN and S,S-TVN with oxy- and deoxy-Hb were also investigated through an extensive in silico docking approach and molecular dynamics calculations. The whole molecular modeling studies indicate that binding of R,R-TVN and S,S-TVN to Hb lacks of specific ligand-target interactions. This is the first report on the biological activity of the individual enantiomers of a resveratrol-related dimer.

Involvement of acetylcholinesterase and protein kinase C in the protective effect of caffeine against ß-amyloid-induced alterations in red blood cells.

It is well known the role of oxidative stress in the pathophysiology of Alzheimer's disease (AD) and of other neurodegenerative pathologies. We have previously documented that Amyloid beta peptide (1-42) (Abeta) dependent-oxidative modifications affect red blood cell (RBC) morphology and function. Experimental studies show that caffeine (CF) consumption is inversely correlated with AD. In this study, we investigated the role played by RBC in the protective mechanism elicited by CF against Abeta mediated toxicity. PS exposure levels by FACS analysis, as well as protein band 3 functionality analysis, indicated that CF at 100 µM protected against Abeta-mediated membrane alterations, which are known to occur in AD. Moreover, CF counteracts inhibition of ATP release from RBC by Abeta, restoring its ability to modulate vasodilation. Concurrently, analysis of protein kinase C (PKC) and caspase 3 activities, responsible for cytoskeleton alterations, revealed that unlike to caspase 3, PKCα activation induced by Abeta was fully abolished by CF through a mechanism involving Acetylcholinesterase (AChE), located on external face of RBC plasma membrane. These results provide support for the hypothesis concerning the protective role of CF in AD patients could include also a peripheral mechanism involving RBC.

Resveratrol: A Focus on Several Neurodegenerative Diseases.

Molecules of the plant world are proving their effectiveness in countering, slowing down, and regressing many diseases. The resveratrol for its intrinsic properties related to its stilbene structure has been proven to be a universal panacea, especially for a wide range of neurodegenerative diseases. This paper evaluates (in vivo and in vitro) the various molecular targets of this peculiar polyphenol and its ability to effectively counter several neurodegenerative disorders such as Parkinson's, Alzheimer's, and Huntington's diseases and amyotrophic lateral sclerosis. What emerges is that, in the deep heterogeneity of the pathologies evaluated, resveratrol through a convergence on the protein targets is able to give therapeutic responses in neuronal cells deeply diversified not only in morphological structure but especially in their function performed in the anatomical district to which they belong.

A new erythrocyte-based biochemical approach to predict the antiproliferative effects of heterocyclic scaffolds: The case of indolone.

BACKGROUND: The indole core is a key structural feature of many natural products and biomolecules with broad spectrum chemotherapeutic properties. Some of us have recently synthesized a library of biologically promising indolone-based compounds. The present study focuses on the effects of one of them, namely DPIT, on human erythrocytes. METHODS: We have examined the influence of DPIT on band 3 protein, intracellular ATP concentration and transport, caspase 3 activation, metabolic adaptation and membrane stability. RESULTS: Our study elucidates that DPIT, intercalated into the phospholipid bilayer, decreases the anion transport, the intracellular ATP concentration and the cytosolic pH, inducing a direct activation of caspase 3. CONCLUSIONS: Starting from the metabolic similarity between erythrocytes and cancer cells, we investigate how the metabolic derangements and membrane alterations induced by selected heterocycles could be related to the antiproliferative effects. GENERAL SIGNIFICANCE: Our work aims to propose a new model of study to predict the antiproliferative effects of heterocyclic scaffolds, pointing out that only one of the listed conditions would be unfavorable to the life cycle of neoplastic cells.

NO Metabolites Levels in Human Red Blood Cells are Affected by Palytoxin, an Inhibitor of Na(+)/K(+)-ATPase Pump.

Palytoxin (PTX), a marine toxin, represents an increasing hazard for human health. Despite its high toxicity for biological systems, the mechanisms triggered by PTX, are not well understood. The high affinity of PTX for erythrocyte Na(+)/K(+)-ATPase pump is largely known, and it indicates PTX as a sensitive tool to characterize the signal transducer role for Na(+)/K(+)-ATPase pump. Previously, it has been reported that in red blood cells (RBC), probably via a signal transduction generated by the formation of a PTX-Na(+)/K(+)-ATPase complex, PTX alters band 3 functions and glucose metabolism. The present study addresses the question of which other signaling pathways are regulated by Na(+)/K(+)-ATPase in RBC. Here it has been evidenced that PTX following its interaction with Na(+)/K(+)-ATPase pump, alters RBC morphology and this event is correlated to decreases by 30% in nitrites and nitrates levels, known as markers of plasma membrane eNOS activity. Orthovanadate (OV), an antagonist of PTX binding to Na(+)/K(+)-ATPase pump, was able to reverse the effects elicited by PTX. Finally, current investigation firstly suggests that Na(+)/K(+)-ATPase pump, following its interaction with PTX, triggers a signal transduction involved in NO metabolism regulation.

Molecular interactions of hemoglobin with resveratrol: potential protective antioxidant role and metabolic adaptations of the erythrocyte.

This article reports the role of resveratrol in the erythrocyte as a result of its interaction with hemoglobin and describes the effect of this interaction on the metabolism, the redox state, and the release of ATP. The drug crosses the erythrocyte membrane and binds to hemoglobin, altering its modulation and the release of ATP. Our study correlates the variation of the phosphorylation balance induced by resveratrol with the change in the intracellular concentration of ATP and with the decrease in ATP release from red blood cell and the consequent paracrine alteration on the vascular epithelium. Molecular docking calculations indicate larger specificity of binding for oxy-hemoglobin that correlates well with the stabilization of the R-quaternary structure and with the functional modulation of resveratrol on the protein. Finally, we locate a putative binding site at the central cavity of hemoglobin and characterize its key interacting residues with the drug. Computational results support the assumption that resveratrol may act as a protector agent against oxidative protein damage by interacting with hemoglobin.