Phenolic Compounds from Tropea Red Onion as Dietary Agents for Protection against Heavy Metals Toxicity.

The present study aims to highlight the cell protective effect of Tropea red onion (TRO) hydroalcoholic extract and some of its components against "non-essential" heavy metals. For this purpose, the cytoprotective roles of cyanidin, cyanidin-3--glucoside and quercetin against Cd, Hg and Pb and of TRO extract against Hg and Pb have been investigated, and data are reported here. To the best of our knowledge, this is the first detailed evaluation of the protective effect against cell damage induced by "non-essential" heavy metals through the simultaneous administration of cyanidin, cyanidin-3--glucoside and quercetin with CdCl, HgCl or PbCl and the TRO extract against HgCl and PbCl.

Potential Protective Effects of Spirulina () against In Vitro Toxicity Induced by Heavy Metals (Cadmium, Mercury, and Lead) on SH-SY5Y Neuroblastoma Cells.

, a filamentous microalga, is used all over the world as a nutraceutical dietary supplement. Recent studies have focused on examining its chelating activity and antioxidant properties, especially as a candidate for protection against neurotoxicity caused by heavy metals. The MTT test and LDH assay were used to examine the viability of the SH-SY5Y cells for 24, 48, and 72 h, to Cd, Hg, and Pb, individually or in combination with , and the effects of necrotic cell death.

The Effect of Calcium Ions on hIAPP Channel Activity: Possible Implications in T2DM.

The calcium ion (Ca) has been linked to type 2 diabetes mellitus (T2DM), although the role of Ca in this disorder is the subject of intense investigation. Serum Ca dyshomeostasis is associated with the development of insulin resistance, reduced insulin sensitivity, and impaired glucose tolerance. However, the molecular mechanisms involving Ca ions in pancreatic β-cell loss and subsequently in T2DM remain poorly understood.

Interaction of Quercetin, Cyanidin, and Their -Glucosides with Planar Lipid Models: Implications for Their Biological Effects.

Flavonoids are specialized metabolites produced by plants, as free aglycones or as glycosylated derivatives, which are particularly endowed with a variety of beneficial health properties. The antioxidant, anti-inflammatory, antimicrobial, anticancer, antifungal, antiviral, anti-Alzheimer's, anti-obesity, antidiabetic, and antihypertensive effects of flavonoids are now known. These bioactive phytochemicals have been shown to act on different molecular targets in cells including the plasma membrane.

Antioxidant activity and protective effect of the outer scales hydroalcoholic extract of Allium cepa L. var. Tropea on toxicity damage induced by Cadmium in Caco-2 cells.

The characterization of bioactive metabolites and the protective effects against Cadmium (Cd) of the hydroalcoholic extract from Allium cepa var. Tropea (Tropea red onion) in human Caco-2 colon adenocarcinoma cells and in vitro antioxidant effects were investigated. Tropea red onion extract showed high levels of bioactive compounds and a strong activity as radical scavenger and inhibitor of lipid peroxidation.

Evidence of the different effect of mercury and cadmium on the hIAPP aggregation process.

hIAPP is a hormone consisting of 37 aminoacids that shows a strong tendency to self-assemble into β-sheet-rich aggregates, which evolve to form insoluble aggregates that seem to be associated with β-cell degeneration in Type 2 Diabetes Mellitus. Numerous factors, intrinsic and extrinsic to the peptide molecule, appear to influence the hIAPP aggregation process. Different metal ions are able to interact with the hIAPP molecule, modulating its secondary structure and subsequently the peptide's capacity to aggregate.

Study of Resveratrol's Interaction with Planar Lipid Models: Insights into Its Location in Lipid Bilayers.

Resveratrol, a polyphenolic molecule found in edible fruits and vegetables, shows a wide range of beneficial effects on human health, including anti-microbial, anti-inflammatory, anti-cancer, and anti-aging properties. Due to its poor water solubility and high liposome-water partition coefficient, the biomembrane seems to be the main target of resveratrol, although the mode of interaction with membrane lipids and its location within the cell membrane are still unclear. In this study, using electrophysiological measurements, we study the interaction of resveratrol with planar lipid membranes (PLMs) of different composition.

Levels of Mercury, Methylmercury and Selenium in Fish: Insights into Children Food Safety.

Total mercury (THg), methylmercury (MeHg), and selenium (Se) concentrations were measured in various commercially important fish species. The benefit-risk binomial associated with these chemicals was assessed in children through the probability of exceeding the provisional tolerable weekly intakes (PTWIs) of the contaminants and the Se recommended dietary allowance (RDA). The Se:Hg molar ratios, selenium health benefit values (HBV), and monthly consumption rate limits (CR) for each species were also calculated.

Trace Metals in Pork Meat Products Marketed in Italy: Occurrence and Health Risk Characterization.

This study provides valuable information on the levels of various trace metals (Pb, Cd, Hg, Zn, Cu, Cr) in meat products (baked ham, raw ham, mortadella, cured sausage, würstel, salami) from South Italy and calculates potential health risk toxicity associated with their consumption for the total population and for children. In the samples studied metal concentrations are within the permissible legal limits (Cd: 0.01-0.

Evidence of cadmium and mercury involvement in the Aβ42 aggregation process.

Aβ42 is a small peptide formed from 42 aminoacids that presents a great propensity to aggregate until it forms fibrils. Aβ42 aggregation and fibrillation are very complex processes whose molecular mechanisms seem to depend on characteristics intrinsic to the peptide molecule, as well as extrinsic factors. Peptide concentration, mean pH and several substances, including metal ions, are principal extrinsic factors for the oligomerization process.

Concentration-dependent effects of mercury and lead on Aβ42: possible implications for Alzheimer's disease.

Mercury (Hg) and lead (Pb) are known to be toxic non-radioactive elements, with well-described neurotoxicology. Much evidence supports the implication of metals as potential risk cofactors in Alzheimer's disease (AD). Although the action mechanism of the two metals remains unclear, Hg and Pb toxicity in AD could depend on their ability to favour misfolding and aggregation of amyloid beta proteins (Aβs) that seem to have toxic properties, particularly in their aggregated state.

Effect of calcium ions on human calcitonin. Possible implications for bone resorption by osteoclasts.

Calcium ions (Ca(2+)) are indispensable for life and are involved in important physiological actions, which makes maintaining a constant level of blood Ca(2+) essential. Ca(2+) is mainly stored in bones which serve as a reservoir and its homeostasis is modulated by various hormones. Human calcitonin (hCt) is a small peptide hormone that exerts its physiological effect on Ca(2+) metabolism by means of osteoclast-mediated bone resorption inhibition.

Heavy metals toxicity: effect of cadmium ions on amyloid beta protein 1-42. Possible implications for Alzheimer's disease.

Cadmium (Cd) is an environmental contaminant, highly toxic to humans. This biologically non-essential element accumulates in the body, especially in the kidney, liver, lung and brain and can induce several toxic effects, depending on the concentration and the exposure time. Cd has been linked to Alzheimer's disease (AD) as a probable risk factor, as it shows higher concentrations in brain tissues of AD patients than in healthy people, its implication in the formation of neurofibrillary tangles and in the aggregation process of amyloid beta peptides (AβPs).

AβP1-42 incorporation and channel formation in planar lipid membranes: the role of cholesterol and its oxidation products.

Amyloid beta peptide (AβP) is a natural peptide, normally released into the cerebrospinal fluid (CSF), that plays a key role in Alzheimer's disease. The conversion of the peptide from a native soluble form to a non-native and often insoluble form, such as small and large aggregates, protofibrils and fibrils of AβP appears to be implicated in the pathogenesis of AD. Although the molecular mechanisms of AβP neurotoxicity are not fully understood, a large body of data suggests that the primary target of amyloid peptides is the cell membrane of neurons, that may modulate the structural and functional conversion of AβP into assemblies involved in pathological processes.

Choline modulation of the aβ p1-40 channel reconstituted into a model lipid membrane.

Nicotinic acetylcholine receptors (AChRs), implicated in memory and learning, in subjects affected by Alzheimer's disease result altered. Stimulation of α7-nAChRs inhibits amyloid plaques and increases ACh release. β-amyloid peptide (AβP) forms ion channels in the cell and model phospholipid membranes that are retained responsible in Alzheimer disease.

Kissper, a kiwi fruit peptide with channel-like activity: structural and functional features.

Kissper is a 39-residue peptide isolated from kiwi fruit (Actinidia deliciosa). Its primary structure, elucidated by direct protein sequencing, is identical to the N-terminal region of kiwellin, a recently reported kiwi fruit allergenic protein, suggesting that kissper derives from the in vivo processing of kiwellin. The peptide does not show high sequence identity with any other polypeptide of known function.

Frog intestinal sac as an in vitro method for the assessment of intestinal permeability in humans: Application to carrier transported drugs.

The aim of this study was to investigate the presence of pharmaceutically relevant drug transporters in frog intestine which has been proposed as model for intestinal permeability screening assays of passively absorbed drugs in humans [Trapani, G., Franco, M., Trapani, A.

Acetyl-[Asn30,Tyr32]-calcitonin fragment 8-32 forms channels in phospholipid planar lipid membranes.

The N-terminally truncated derivative of salmon calcitonin (sCt) (acetyl-[Asn(30),Tyr(32)]-calcitonin fragment 8-32) (AC 187) lacks hormonal activity and is a potent and selective antagonist of the hormone and amylin receptor. It was investigated for its capability to interact and form channels in palmitoleoylphosphatidylcholine:dioleoylphosphatidylglycerol planar lipid membranes. Interestingly, AC 187 exhibits channel activity, whose parameters, i.

Water permeability of rat liver mitochondria: A biophysical study.

The movement of water accompanying solutes between the cytoplasm and the mitochondrial spaces is central for mitochondrial volume homeostasis, an important function for mitochondrial activities and for preventing the deleterious effects of excess matrix swelling or contraction. While the discovery of aquaporin water channels in the inner mitochondrial membrane provided valuable insights into the basis of mitochondrial plasticity, questions regarding the identity of mitochondrial water permeability and its regulatory mechanism remain open. Here, we use a stopped flow light scattering approach to define the water permeability and Arrhenius activation energy of the rat liver whole intact mitochondrion and its membrane subcompartments.

Effect of pH-variation on insertion and ion channel formation of human calcitonin into planar lipid bilayers.

Human calcitonin is the physiological hormone involved in calcium-phosphorus homeostasis. However, its use is limited by its propensity to form aggregates. We find that the type of host lipid has a pronounced influence on human calcitonin fibrillation or incorporation, as assessed by channel formation, in planar lipid membranes at neutral pH.

Effect of eel calcitonin glycosylation on incorporation and channel formation in planar phospholipid membranes.

Previous studies have shown that different calcitonins interact with planar lipid membranes to form ion channels. In this study, glycosylation of eel calcitonin (eCt) at different positions (Ct3-GlcNAc, Ct14-GlcNAc, Ct20-GlcNAc, Ct26-GlcNAc) is shown to preserve molecular structure and slightly change the energy of incorporation and channel formation in planar lipid bilayers made up of palmitoyl-oleoyl-phosphatidylcholine:dioleoyl phosphatidyl-glycerol (85:15, w:w). The voltage needed to form channels decreased as the attached carbohydrate moved toward the C-terminal (eCt = Ct3-GlcNAc > Ct14-GlcNAc = Ct20-GlcNAc > Ct26-GlcNAc).

Effect of nanomolar concentrations of sodium dodecyl sulfate, a catalytic inductor of alpha-helices, on human calcitonin incorporation and channel formation in planar lipid membranes.

Human Calcitonin (hCt) is a peptide hormone which has a regulatory action in calcium-phosphorus metabolism. It is currently used as a therapeutic tool in bone pathologies such as osteoporosis and Paget's disease. However, due to its amphiphilic property tends to form a gelatinous solution in water which consists of fibrils that limits its therapeutic use.

Effect of sterols on beta-amyloid peptide (AbetaP 1-40) channel formation and their properties in planar lipid membranes.

We investigate the role played by membrane composition on the interaction and self-assembly of beta-amyloid peptide (AbetaP1-40) during pore formation in planar lipid membranes (PLMs). Incorporation studies showed that AbetaP does not interact with zwitterionic membranes made up of phosphatidylcholine, whereas the addition of cholesterol or ergosterol to the membranes leads to channel formation. Among the PLMs used, a higher propensity of AbetaP to form channels at low applied potential (+/-20 mV) was observed in 7-dehydrocholesterol and in oxidized cholesterol PLMs.