Hemolysis Of Human Erythrocytes Research Articles

Hematin- and Hemin-Induced Spherization and Hemolysis of Human Erythrocytes Are Independent of Extracellular Calcium Concentration.

Pathologies such as malaria, hemorrhagic stroke, sickle cell disease, and thalassemia are characterized by the release of hemoglobin degradation products from damaged RBCs. Hematin (liganded with OH-) and hemin (liganded with Cl-)-are the oxidized forms of heme with toxic properties due to their hydrophobicity and the presence of redox-active Fe3. In the present study, using the original LaSca-TM laser particle analyzer, flow cytometry, and confocal microscopy, we showed that both hematin and hemin induce dose-dependent RBC spherization and hemolysis with ghost formation. Hematin and hemin at nanomolar concentrations increased [Ca2+]i in RBC; however, spherization and hemolysis occurred in the presence and absence of calcium, indicating that both processes are independent of [Ca2+]i. Both compounds triggered acute phosphatidylserine exposure on the membrane surface, reversible after 60 min of incubation. A comparison of hematin and hemin effects on RBCs revealed that hematin is a more reactive toxic metabolite than hemin towards human RBCs. The toxic effects of heme derivatives were reduced and even reversed in the presence of albumin, indicating the presence in RBCs of the own recovery system against the toxic effects of heme derivatives.

Accelerating Antimicrobial Peptide Discovery for WHO Priority Pathogens through Predictive and Interpretable Machine Learning Models.

The escalating menace of multidrug-resistant (MDR) pathogens necessitates a paradigm shift from conventional antibiotics to innovative alternatives. Antimicrobial peptides (AMPs) emerge as a compelling contender in this arena. Employing in silico methodologies, we can usher in a new era of AMP discovery, streamlining the identification process from vast candidate sequences, thereby optimizing laboratory screening expenditures. Here, we unveil cutting-edge machine learning (ML) models that are both predictive and interpretable, tailored for the identification of potent AMPs targeting World Health Organization's (WHO) high-priority pathogens. Furthermore, we have developed ML models that consider the hemolysis of human erythrocytes, emphasizing their therapeutic potential. Anchored in the nuanced physical-chemical attributes gleaned from the three-dimensional (3D) helical conformations of AMPs, our optimized models have demonstrated commendable performance-boasting an accuracy exceeding 75% when evaluated against both low-sequence-identified peptides and recently unveiled AMPs. As a testament to their efficacy, we deployed these models to prioritize peptide sequences stemming from PEM-2 and subsequently probed the bioactivity of our algorithm-predicted peptides vis-à-vis WHO's priority pathogens. Intriguingly, several of these new AMPs outperformed the native PEM-2 in their antimicrobial prowess, thereby underscoring the robustness of our modeling approach. To elucidate ML model outcomes, we probe via Shapley Additive exPlanations (SHAP) values, uncovering intricate mechanisms guiding diverse actions against bacteria. Our state-of-the-art predictive models expedite the design of new AMPs, offering a robust countermeasure to antibiotic resistance. Our prediction tool is available to the public at https://ai-meta.chem.ncu.edu.tw/amp-meta.

Coumarins derived from natural methoxystilbene as oxidative stress-related disease alleviators: Synthesis and in vitro-in silico study

3,4,5-Trimethoxy-3′-hydroxy-4′-methoxystilbene (TMHMS) is an anticancer natural stilbene that targets tubulin polymerization. According to research, oxidative stress and inflammation are linked to cancer, and lowering both of these hazards may have a detrimental influence on tumor development. TMHMS was used as a building block in this investigation to generate 28 coumarins with increased medicinal value. TMHMS-COU-1, the first coumarin derivative, was activated by thionyl chloride and subsequently linked with different phenols, yielding 27 TMHMS-COU variants. This natural product was used as a reference for oxidative stress-alleviated activities such as anticancer activity against eight cancerous cellular lines, antioxidant activity on H2O2-treated human SH-SY5Y populations, and anti-inflammatory activity against three enzyme-based representatives of inflammation. TMHMS and its coumarins were tested for their impact on the normal development of three cell types as well as human erythrocyte hemolysis in biocompatibility tests. Finally, utilizing two web-based programs, the pharmacokinetic profiles of the building component and its variants were computed. The inclusion of an electron-donating group on the off-side aromatic ring directly boosted the oxidative stress-alleviated activities, according to the results. These activities were also boosted when this group occupied the para or meta position. When this aromatic ring was trisubstituted with this group type, the greatest activities were found, with the trimethoxy aromatic ring having preferential activities. In terms of biocompatibility, the synthesized coumarins showed a high level of compatibility with the tested normal cells as well as human erythrocytes. Furthermore, the in silico research confirmed the synthesized coumarins' ability to provide prospective therapeutic candidates. According to the author, the coumarin-structural change might open the way for the development of novel, powerful, and biosafe TMHMS derivatives. This work provided various insights into the structure-function connections that can direct subsequent studies on TMHMS-based derivatives.

Prehemolytic impact of phenothiazine drugs on the attachment of spectrin network in red blood cells.

Chlorpromazine, thioridazine, and trifluoperazine are phenothiazine drugs that cause colloid-osmotic hemolysis of human erythrocytes by unknown mechanism. To clarify this mechanism, the impact of these drugs on the βsp (1.4 MHz) and γ1sp (9 MHz) dielectric relaxations was investigated. Each relaxation was shown to reduce its strength on the severing specific bridge that connects the spectrin network with the lipid membrane. For βsp relaxation, this is the spectrin-actin-glycophorin C bridge while for γ1sp relaxation this is the spectrin-ankyrin-band 3 bridge.

Therapeutic Dosage of Antipsychotic Drug Aripiprazole Induces Persistent Mitochondrial Hyperpolarisation, Moderate Oxidative Stress in Liver Cells, and Haemolysis.

Aripiprazole has fewer metabolic side effects than other antipsychotics; however, there are some severe ones in the liver, leading to drug-induced liver injury. Repeated treatment with aripiprazole affects cell division. Since this process requires a lot of energy, we decided to investigate the impact of aripiprazole on rat liver cells and mitochondria as the main source of cellular energy production by measuring the mitochondrial membrane potential, respiration, adenosine triphosphate (ATP) production, oxidative stress, antioxidative response, and human blood haemolysis. Here, we report that mitochondrial hyperpolarisation from aripiprazole treatment is accompanied by higher reactive oxygen species (ROS) production and increased antioxidative response. Lower mitochondrial and increased glycolytic ATP synthesis demand more glucose through glycolysis for equal ATP production and may change the partition between the glycolysis and pentose phosphate pathway in the liver. The uniform low amounts of the haemolysis of erythrocytes in the presence of aripiprazole in 25 individuals indicate lower quantities of the reduced form of nicotinamide adenine dinucleotide phosphate (NADPH+H+), which is in accordance with a decreased activity of glucose 6-phosphate dehydrogenase and the lower dehydrogenase activity upon aripiprazole treatment. The lower activity of glucose 6-phosphate dehydrogenase supports a shift to glycolysis, thus rescuing the decreased mitochondrial ATP synthesis. The putative reduction in NADPH+H+ did not seem to affect the oxidised-to-reduced glutathione ratio, as it remained equal to that in the untreated cells. The effect of aripiprazole on glutathione reduction is likely through direct binding, thus reducing its total amount. As a consequence, the low haemolysis of human erythrocytes was observed. Aripiprazole causes moderate perturbations in metabolism, possibly with one defect rescuing the other. The result of the increased antioxidant enzyme activity upon treatment with aripiprazole is increased resilience to oxidative stress, which makes it an effective drug for schizophrenia in which oxidative stress is constantly present because of disease and treatment.

Alpha hemolysin of E. coli induces hemolysis of human erythrocytes independently of toxin interaction with membrane proteins

Alpha hemolysin (HlyA) is a hemolytic and cytotoxic protein secreted by uropathogenic strains of E. coli. The role of glycophorins (GPs) as putative receptors for HlyA binding to red blood cells (RBCs) has been debated.Experiments using anti-GPA/GPB antibodies and a GPA-specific epitope nanobody to block HlyA-GP binding on hRBCs, showed no effect on hemolytic activity. Similarly, the hemolysis induced by HlyA remained unaffected when hRBCs from a GPAnull/GPBnull variant were used. Surface Plasmon Resonance experiments revealed similar values of the dissociation constant between GPA and either HlyA, ProHlyA (inactive protoxin), HlyAΔ914-936 (mutant of HlyA lacking the binding domain to GPA) or human serum albumin, indicating that the binding between the proteins and GPA is not specific.Although far Western blot followed by mass spectroscopy analyses suggested that HlyA interacts with Band 3 and spectrins, hemolytic experiments on spectrin-depleted hRBCs and spherocytes, indicated these proteins do not mediate the hemolytic process.Our results unequivocally demonstrate that neither glycophorins, nor Band 3 and spectrins mediate the cytotoxic activity of HlyA on hRBCs, thereby challenging the HlyA-receptor hypothesis. This finding holds significant relevance for the design of anti-toxin therapeutic strategies, particularly in light of the growing antibiotic resistance exhibited by bacteria.

Thymoquinone enhances the antioxidant and anticancer activity of Lebanese propolis.

Reactive oxygen species (ROS) are produced by multiple cellular processes and are maintained at optimal levels in normal cells by endogenous antioxidants. In recent years, the search for potential exogenous antioxidants from dietary sources has gained considerable attention to eliminate excess ROS that is associated with oxidative stress related diseases including cancer. Propolis, a resinous honeybee product, has been shown to have protective effects against oxidative stress and anticancer effects against several types of neoplasms. To investigate the antioxidant and anticancer potential of Lebanese propolis when applied alone or in combination with the promising anticancer compound Thymoquinone (TQ) the main constituent of Nigella sativa essential oil. Crude extracts of Lebanese propolis collected from two locations, Rashaya and Akkar-Danniyeh, were prepared in methanol and the total phenolic content was determined by Folin-Ciocalteu method. The antioxidant activity was assessed by the ability to scavenge 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical and to inhibit H2O2-induced oxidative hemolysis of human erythrocytes. The anticancer activity was evaluated by [3-(4,5-dimethylthiazol-2-yl)-2,5 diphenyl tetrazolium bromide] MTT assay against HCT-116 human colorectal cancer cells and MDA-MB-231 human breast cancer cells. The total phenolic content of propolis extract from Rashaya and Akkar-Danniyeh were 56.81 µg and 83.503 µg of gallic acid equivalent /mg of propolis, respectively. Both natural agents exhibited strong antioxidant activities as evidenced by their ability to scavenge DPPH free radical and to protect erythrocytes against H2O2-induced hemolysis. They also dose-dependently decreased the viability of both cancer cell lines. The IC50 value of each of propolis extract from Rashaya and Akkar-Danniyeh or TQ was 22.3, 61.7, 40.44 µg/mL for breast cancer cells at 72 h and 33.3, 50.9, 33.5 µg/mL for colorectal cancer cells at the same time point, respectively. Importantly, the inhibitory effects of propolis on DPPH radicals and cancer cell viability were achieved at half its concentration when combined with TQ. Our results indicate that Lebanese propolis extract has antioxidant and anticancer potential and its combination with TQ could possibly prevent ROS- mediated diseases.

Antibacterial, Antibiofilm and Anti-Inflammatory Activities of Eugenol Clove Essential Oil against Resistant Helicobacter pylori.

Eugenol essential oil (EEO) is the major component in aromatic extracts of Syzygium aromaticum (clove) and has several biological properties, such as antibacterial, antioxidant, and anti-inflammatory activities, as well as controlling vomiting, coughing, nausea, flatulence, diarrhea, dyspepsia, stomach distension, and gastrointestinal spasm pain. It also stimulates the nerves. Therefore, the aim of this study was to extract and purify EEO from clove buds and assess its ability to combat resistant Helicobacter pylori. Additionally, EEO's anti-inflammatory activity and its ability to suppress H. pylori biofilm formation, which is responsible for antibiotic resistance, was also investigated. Syzygium aromaticum buds were purchased from a local market, ground, and the EEO was extracted by using hydro-distillation and then purified and chemically characterized using gas chromatography-mass spectrometry (GC-MS). A disk-diffusion assay showed that Helicobacter pylori is sensitive to EEO, with an inhibition zone ranging from 10 ± 06 to 22 ± 04 mm. The minimum inhibition concentration (MIC) of EEO ranged from 23.0 to 51.0 μg/mL against both Helicobacter pylori clinical isolates and standard strains. In addition, EEO showed antibiofilm activity at 25 µg/mL and 50 µg/mL against various Helicobacter pylori strains, with suppression percentages of 49.32% and 73.21%, respectively. The results obtained from the anti-inflammatory assay revealed that EEO possesses strong anti-inflammatory activity, with human erythrocyte hemolysis inhibition percentages of 53.04, 58.74, 61.07, and 63.64% at concentrations of 4, 8, 16, and 32 μg/L, respectively. GC-MS analysis revealed that EEO is a major component of Syzygium aromaticum when extracted with a hydro-distillation technique, which was confirmed by its purification using a chemical separation process. EEO exhibited antibacterial action against resistant Helicobacter pylori strains, as well as antibiofilm and anti-inflammatory activities, and is a promising natural alternative in clinical therapy.

Biological Effects in Cancer Cells of Mono- and Bidentate Conjugation of Cisplatin on PAMAM Dendrimers: A Comparative Study.

Cisplatin (cis-diamminedichloroplatinum(II)) is a potent chemotherapeutic agent commonly used to treat cancer. However, its use also leads to serious side effects, such as nephrotoxicity, ototoxicity, and cardiotoxicity, which limit the dose that can be safely administered to patients. To minimize these problems, dendrimers may be used as carriers for cisplatin through the coordination of their terminal functional groups to platinum. Here, cisplatin was conjugated to half-generation anionic PAMAM dendrimers in mono- and bidentate forms, and their biological effects were assessed in vitro. After preparation and characterization of the metallodendrimers, their cytotoxicity was evaluated against several cancer cell lines (A2780, A2780cisR, MCF-7, and CACO-2 cells) and a non-cancer cell line (BJ cells). The results showed that all the metallodendrimers were cytotoxic and that the cytotoxicity level depended on the cell line and the type of coordination mode (mono- or bidentate). Although, in this study, a correlation between dendrimer generation (number of carried metallic fragments) and cytotoxicity could not be completely established, the monodentate coordination form of cisplatin resulted in lower IC50 values, thus revealing a more accessible cisplatin release from the dendritic scaffold. Moreover, most of the metallodendrimers were more potent than the cisplatin, especially for the A2780 and A2780cisR cell lines, which showed higher selectivity than for non-cancer cells (BJ cells). The monodentate G0.5COO(Pt(NH3)2Cl)8 and G2.5COO(Pt(NH3)2Cl)32 metallodendrimers, as well as the bidentate G2.5COO(Pt(NH3)2)16 metallodendrimer, were even more active towards the cisplatin-resistant cell line (A2780cisR cells) than the correspondent cisplatin-sensitive one (A2780 cells). Finally, the effect of the metallodendrimers on the hemolysis of human erythrocytes was neglectable, and metallodendrimers' interaction with calf thymus DNA seemed to be stronger than that of free cisplatin.

Protective Effects of Auraptene against Free Radical-Induced Erythrocytes Damage.

Auraptene is the most abundant natural prenyloxycoumarin. Recent studies have shown that it has multiple biological and therapeutic properties, including antioxidant properties. Erythrocytes are constantly subjected to oxidative damage that can affect proteins and lipids within the erythrocyte membrane and lead to some hemoglobinopathies. Due to the lack of sufficient information about the antioxidant effects of auraptene on erythrocytes, this study intended to evaluate the potential of this compound in protecting radical-induced erythrocytes damages. The antioxidant activity of auraptene was measured based on DPPH and FRAP assays. Notably, oxidative hemolysis of human erythrocytes was used as a model to study the ability of auraptene to protect biological membranes from free radical-induced damage. Also, the effects of auraptene in different concentrations (25-400 µM) on AAPH-induced lipid/protein peroxidation, glutathione (GSH) content and morphological changes of erythrocytes were determined. Oxidative hemolysis and lipid/protein peroxidation of erythrocytes were significantly suppressed by auraptene in a time and concentration-dependent manner. Auraptene prevented the depletion of the cytosolic antioxidant GSH in erythrocytes. Furthermore, it inhibited lipid and protein peroxidation in a time and concentration-dependent manner. Likewise, FESEM results demonstrated that auraptene reduced AAPH-induced morphological changes in erythrocytes. Auraptene efficiently protects human erythrocytes against free radicals. Therefore, it can be a potent candidate for treating oxidative stress-related diseases.

Specific refraction-index increments of oxygenated hemoglobin from thalassemia-minor patients are not significantly different than those from healthy individuals.

The mass and concentration of hemoglobin per erythrocyte are important hematological parameters. Measuring these parameters from intact erythrocytes requires the value of specific refraction-index increment (RII) of oxygenated hemoglobin, which diverges in the literature. Refractive indices of hemoglobin solutions are measured directly by digital holographic microscopy on a microfluidic channel filled with hemoglobin solutions prepared by hemolysis of fresh human erythrocytes and refractive-index standards sequentially. Hemoglobin extracted from thalassemic patients shows 3-4% higher RII than that from healthy volunteers, but the difference is not significant in comparison to inter-subject variations within each group. The quantified RIIs are applied to quantify mean corpuscular hemoglobin mass of blood from 37 human subjects, and results are in accord with standard clinical test results.

Practical Synthesis of Antimicrobial Long Linear Polyamine Succinamides.

There are many severe bacterial infections notorious for their ability to become resistant to clinically relevant antibiotics. Indeed, antibiotic resistance is a growing threat to human health, further exacerbated by the lack of new antibiotics. We now describe the practical synthesis of a series of substituted long linear polyamines that produce rapid antibacterial activity against both Gram-positive and Gram-negative bacteria, including meticillin-resistant Staphylococcus aureus. These compounds also reduce biofilm formation in Pseudomonas aeruginosa. The most potent analogues are thermine, spermine, and 1,12-diaminododecane homo- and heterodimeric polyamine succinic acid amides. They are of the order of activity of the aminoglycoside antibiotics kanamycin and tobramycin as positive controls. Their low human cell toxicity is demonstrated in ex vivo hemolytic assays where they did not produce even 5% hemolysis of human erythrocytes. These long, linear polyamines are a new class of broad-spectrum antibacterials active against drug-resistant pathogens.

A new synthetic protegrin as a promising peptide with antibacterial activity against MDR Gram-negative pathogens.

Protegrins are a family of natural peptides from the innate immune system of vertebrates, with broad-spectrum antimicrobial activity. However, the toxicity and haemolysis of protegrin-1 (PG-1) at low concentrations renders it useless for therapeutic application. We rationally designed PLP-3, a novel synthetic PG-1-like peptide, comprising key activity features of protegrins in a constrained bicyclic structure. Our main objective was to investigate PLP-3's activity against MDR strains of Acinetobacter baumannii, Pseudomonas aeruginosa and Klebsiella pneumoniae and to analyse its haemolysis and cytotoxicity. Peptide synthesis was performed via solid phase and intramolecular ligation in solution, and the correct folding of the peptide was verified by circular dichroism. Antimicrobial activity was performed through broth microdilution. The test panel contained 45 bacterial strains belonging to A. baumannii, P. aeruginosa and K. pneumoniae (15 strains per species) comprising colistin-resistant and MDR strains. Cytotoxicity was assessed by XTT cell viability assays using HeLa and A549 cells and haemolysis of human erythrocytes. PLP-3 was successfully synthesized, and its antiparallel β-sheet conformation was confirmed. Antimicrobial activity screening showed MIC90 values of 2 mg/L for A. baumannii, 16 mg/L for K. pneumoniae and 8 mg/L for P. aeruginosa. The haemolysis IC50 value was 48.53 mg/L. Cytotoxicity against human HeLa and A549 cells showed values of ca. 200 mg/L in both cell lines resulting in a 100-fold selectivity window for bacterial over human cells. PLP-3 has potent antimicrobial activity, especially against A. baumannii, while maintaining low haemolysis and toxicity against human cell lines at antimicrobial concentrations. These characteristics make PLP-3 a promising peptide with an interesting therapeutic window.

In vitro assessment of the bioactive potential of Artemisia campestris L. fractions growing in Khenchela (Algeria)

In order to valorize Algerian medicinal plants, this work aims to characterize quantitatively and qualitatively Artemisia campestris L. fractions, a medicinal plant from the Aures-Algeria area, and investigate its biological activities in vitro. During preliminary phytochemical screening, flavonoids, saponins, tannins, alkaloids, reducing compounds, and coumarins were discovered. Total polyphenols and flavonoids are greater in the n-butanolic fraction than in ethyl acetate and petroleum ether. The resulting antioxidant capability was assessed in vitro using three methods: DPPH free radical scavenging, hydrogen peroxide trapping, and iron reduction. The n-butanolic extract suppresses DPPH oxidation with an IC50 of 2.239±0.32mg/ml, which is comparable to that of standard (1.824±0.97mg/ml). Despite the fact that similar findings were seen in the neutralization of hydrogen peroxide and the iron chelating activity, The anti-inflammatory action was proven in vitro by inhibiting protein denaturation and increasing HRBC membrane stability (Human Red Blood Cells). The n-butanolic fraction was more effective than diclofenac in preventing BSA degradation. It also inhibited membrane hemolysis in human erythrocytes by up to 83%. Activated partial thromboplastin and prothrombin times were used to analyze extrinsic and intrinsic coagulation pathways in A. campestris in order to determine its anticoagulant activity. The n-butanol fraction had the greatest impact on PT and aPTT lengthening, with 75.2s and 351s at 3 mg/ml concentration, respectively. The n-butanolic fraction of the A. campestris aerial part exhibited antioxidant, anti-inflammatory, and anticoagulant activities. As a result, it may be a viable natural resource for mitigating the impact of stress, which causes inflammatory and cardiovascular disorders.

Interaction of mancozeb with human hemoglobin: Spectroscopic, molecular docking and molecular dynamic simulation studies

Mancozeb is a broad-spectrum fungicide used extensively in agriculture to protect plants from numerous diseases. Hemolysis of human erythrocytes on exposure to mancozeb has been reported. In the present study, we investigated the interaction of mancozeb with human hemoglobin (Hb) using multi-spectroscopic techniques, molecular docking and molecular dynamic simulation. UV–visible spectroscopy studies suggested intimate binding of mancozeb to Hb. Mancozeb quenched the intrinsic fluorescence of Hb and Stern-Volmer plots revealed that the quenching mechanism was of static type. Evaluation of thermodynamic parameters indicated that the binding of Hb to mancozeb was spontaneous, with van der Waals forces and hydrogen bonding being the key contributors in the binding reaction. Synchronous fluorescence experiments demonstrated that mancozeb altered the microenvironment around tryptophan residues, whereas polarity around tyrosine residues was not changed. Circular dichroism studies showed a decrease in the α helical content of Hb upon interaction with mancozeb. The inhibition of esterase activity showed that mancozeb can impair the enzymatic functions of Hb. Molecular docking study revealed that strong binding affinity existed between mancozeb and Hb, with hydrophobic forces playing a crucial role in the interaction. Molecular dynamic simulation showed that mancozeb formed a stable complex with Hb resulting in slight unfolding of the protein. To sum up, the results of this study show that mancozeb binds strongly to Hb, induces conformational changes in Hb and adversely affects its function.

Hemocompatibility of Galactomannan and Galactoglucomannan Sulfates in In Vitro Experiments

We identified compounds that do not independently provoke aggregation of human platelets and do not affect hemolysis of human erythrocytes in vitro: lacking anticoagulant activity sulfated galactoglucomannan (polydispersity 1.43; degree of sulfation 0.66) in concentrations ≤0.2 mg/ml; exhibiting anticoagulant activity (in concentrations up to 0.002 mg/ml) sulfated galactoglucomannan (polydispersity 1.5; degree of sulfation 1.81) and galactomannan obtained by sulfation with the sulfamic acid-urea complex (polydispersity 2.75; degree of sulfation 1.25) and galactomannans obtained by sulfation with chlorosulfonic acid in 1,4-dioxane (polydispersity 1.61/22.27; degree of sulfation 1.00/0.74).

Relative bioefficacy of seventeen Poaceae extracts targeting oxidative stress-related diseases coupled with elemental profiling using ICP-MS

Free radicals produced in vivo increases ‘oxidative stress’ and leads to lipid peroxidation, DNA damage and other disorders such as hemolysis. Present study aimed at evaluating the biological potentials of seventeen Poaceae species in order to scientifically confirm their traditional uses and to identify elements involved in regulating reactive oxygen species. Extracts of seventeen grass species were prepared to determine antioxidant activity using ferric thiocyanate and thiobarbituric acid assays. Sorghum halepense, Eleusine indica, Ochthocloa compressa, Saccharum spontaneum, Dactyloctenium aegyptium and Cymbopogon citratus showed highest antioxidant potential. Antihemolytic potential was assessed by hydrogen peroxide (H2O2) induced hemolysis in human erythrocytes and was found to be highest in C. citratus (96%) followed by S. spontaneum (95%), O. compressa (66%) and D. annulatum (60%). DNA damage activity was performed using p1391Z plasmid DNA. In the end, samples were digested using nitric acid and the concentration of twenty elements was determined using inductively coupled plasma mass spectrometry (ICP-MS) method. Principal component analysis (PCA) of essential elements showed 70% variability and non-essential elements displayed 52% in total variance. Hence, the selected botanicals can be used commercially in the treatment of oxidative-stress related diseases as the concentration of different elements validate their safety and efficacy for human body.

Interactive Dynamics of Cell Volume and Cell Death in Human Erythrocytes Exposed to α-Hemolysin from Escherichia coli.

α-hemolysin (HlyA) of E. coli binds irreversibly to human erythrocytes and induces cell swelling, ultimately leading to hemolysis. We characterized the mechanism involved in water transport induced by HlyA and analyzed how swelling and hemolysis might be coupled. Osmotic water permeability (Pf) was assessed by stopped-flow light scattering. Preincubation with HlyA strongly reduced Pf in control- and aquaporin 1-null red blood cells, although the relative Pf decrease was similar in both cell types. The dynamics of cell volume and hemolysis on RBCs was assessed by electrical impedance, light dispersion and hemoglobin release. Results show that HlyA induced erythrocyte swelling, which is enhanced by purinergic signaling, and is coupled to osmotic hemolysis. We propose a mathematical model of HlyA activity where the kinetics of cell volume and hemolysis in human erythrocytes depend on the flux of osmolytes across the membrane, and on the maximum volume that these cells can tolerate. Our results provide new insights for understanding signaling and cytotoxicity mediated by HlyA in erythrocytes.

Protective Effect of Bergapten against Human Erythrocyte Hemolysis and Protein Denaturation In Vitro.

Bergapten, a furocoumarin found in many medicinal plants, is used for the management of various conditions. The present in vitro study evaluated the ability of bergapten to prevent human erythrocyte hemolysis and protein denaturation. Bergapten administered at 10, 30, and 100 μg/ml exhibited a significant concentration-dependent protection on the erythrocyte membrane exposed to hypotonicity and heat-induced hemolysis. The concentration at which bergapten inhibited 50% of the cells from hemolysis (IC50) was determined on a dose-response curve, plotted as logarithmic (concentration) against percentage inhibition, keeping the hemolysis produced within the control group at 100%. Bergapten treatment produced an IC50 value of 7.71 ± 0.27 μg/ml and 4.23 ± 0.42 μg/ml for hypotonicity and heat-induced hemolysis, respectively. Diclofenac sodium at similar concentrations produced an IC50 value of 12.22 ± 0.30 μg/ml and 9.44 ± 0.23 μg/ml in the hypotonicity and heat-induced hemolysis, respectively. The ability of bergapten to inhibit protein denaturation was studied as part of an investigation on its mechanism of action. The results showed a significant concentration-dependent reduction in protein denaturation. When administered at 10, 30, and 100 μg/ml, bergapten produced a concentration-dependent reduction in albumin denaturation. Bergapten inhibited protein denaturation with IC50 values of 5.34 ± 0.30 μg/ml and 12.18 ± 0.20 μg/ml in the heat-treated egg albumin and bovine serum albumin denaturation experiments, respectively. Diclofenac sodium (10, 30, and 100 μg/ml) exhibited a similar protection against heat-treated egg albumin and bovine serum albumin denaturation experiments with IC50 values of 8.93 ± 0.17 μg/ml and 12.72 ± 0.11 μg/ml, respectively. Taken together, data from this study show that the pharmacological properties of bergapten may in part be related to its membrane-stabilizing and antidenaturation properties.

Antioxidant and anti-hemolytic activities of different parts (leaves, stems and heart) of the artichoke (Cynara scolymus L) cooked with different methods in west Algeria

This study was undertaken to estimate antioxidant and anti-hemolytic activi-ties of different parts (leaves, stem and heart) of the artichoke (Cynara scoly-mus L) cooked with different methods. The leaves, stems and hearts were used either raw or cooked according to four cooking methods: evaporated, boiled, oven-baked and sautéed. On the different extracts prepared from artichoke parts (raw or cooked), total polyphenols and flavonoids contents, anti-oxidant and anti-hemolytic activities were evaluated. According to the four cooking methods, the polyphenol and flavonoids contents of baked leaves were the highest. Polyphenol contents were higher in boiled stems while flavonoids contents were elevated in evaporated stems. Evaporated and boiled hearts exhibited the best polyphenols and flavonoids contents. The three parts of the artichoke had a scavenger effect against the DPPH radical and baked leaves showed the higher activity compared to raw leaves. The evaporated, sautéed and boiled cooking modes indicated reduced H2O2 entrapment activity by 41%, 42% and 37%, respectively compared to raw artichoke. In addition, cooked hearts had reduced H2O2 trapping activity compared to the raw heart. Compared to raw products, NO trapping activity increased in sautéed leaves and hearts while this activity was smaller in boiled leaves, stems and hearts. Boiled and sautéed leaves increased the percentage of inhibition of hemolysis of human erythrocyte by 68% and 65%, respectively, compared to raw leaves. The present results demonstrated that common cooking methods applied to artichoke have increased the nutrition-al quality of this vegetable and that effect depends upon the vegetable part.