Oxidative Damage In Human Erythrocytes Research Articles

Nickel chloride generates cytotoxic ROS that cause oxidative damage in human erythrocytes

BackgroundNickel is a heavy metal that is regarded as a possible hazard to living organisms due to its toxicity and carcinogenicity. Nickel chloride (NiCl2), an inorganic divalent Ni compound, has been shown to cause oxidative stress in cells by altering the redox equilibrium. We have investigated the effect of NiCl2 on isolated human erythrocytes under in vitro condition. MethodsIsolated erythrocytes were treated with different concentrations of NiCl2 (25–500 µM) for 24 h at 37 ºC. Hemolysates were prepared and several biochemical parameters were analyzed in them. ResultsTreatment of erythrocytes with NiCl2 enhanced the intracellular generation of reactive oxygen species (ROS). A significant increase in hydrogen peroxide levels and oxidation of proteins and lipids was also seen. This was accompanied by a reduction in levels of nitric oxide, glutathione, free amino groups and total sulfhydryl groups. NiCl2 treatment impaired both enzymatic and non-enzymatic defense systems, resulting in lowered antioxidant capacity and diminished ability of cells to quench free radicals and reduce metal ions. NiCl2 exposure also had an inhibitory effect on the activity of enzymes involved in pathways of glucose metabolism (glycolytic and pentose phosphate shunt pathways). Increased level of methemoglobin, which is inactive in oxygen transport, was also seen. The rate of heme breakdown increased resulting in the release of free iron. Exposure to NiCl2 led to considerable cell lysis, indicating damage to the erythrocyte membrane. This was supported by the inhibition of membrane bound enzymes and increase in the osmotic fragility of NiCl2 treated cells. NiCl2 treatment caused severe morphological alterations with the conversion of normal discocytes to echinocytes. All changes were seen in a NiCl2 concentration-dependent manner. ConclusionNiCl2 generates cytotoxic ROS in human erythrocytes which cause oxidative damage that can decrease the oxygen carrying capacity of blood and also lead to anemia.

Stevia rebaudiana Methanolic Leaf Extract in Egypt: Phytochemical Analysis, Antioxidant, Antilipid Peroxidation, Antihemolytic, Antimetastatic, and Anticancer Properties

The phenolic and flavonoid content of the Stevia rebaudiana hydromethanolic extract (SRHME) was examined, and phytochemical identification using GC-mass spectrometry was achieved. Also, the antioxidant, antihemolytic, and antilipid peroxidation capabilities of the extract were assessed. The extract’s potential to induce apoptosis, inhibit cell proliferation, and reduce metastasis in SKVO3 cells was also checked. The findings of the GC-MS chromatogram demonstrated the existence of bioactive antioxidants and anticancer components in SRHME. Moreover, the extract demonstrated protection against cellular oxidative damage in human erythrocytes by preventing lipid peroxidation and hemolysis. Besides, SRHME demonstrated a selective cytotoxic effect with a strong IC50 value (17.5 µg/ml) on SKVO3 cells without any harmful effects on normal WI-38 cells using the MTT and LDH tests. Additionally, according to assays for wound healing and transwell chamber, the studied extract suppressed the ability of SKOV3 cells from migrating and invading, respectively. Also, the extract-treated SKVO3 cells showed rise in the percentage of apoptotic cells with a prominent comet nucleus, according to apoptotic assays in comparison to untreated cells. Furthermore, a flow cytometry analysis of SRHME-treated SKVO3 cells showed a halt in the S phase and an increase in sub-G1 apoptotic cells (25.44%). Also, the tested extract significantly decreased the levels of ROS in the treated cells, indicating that ROS was involved in the production of SKVO3 apoptosis. Lastly, SRHME strongly impacted the expression levels of proteins related to apoptosis, S-phase cell cycle arrest, and antimetastatic capacity in the treated SKVO3 cells.

Protective effect of rutin against thiram-induced cytotoxicity and oxidative damage in human erythrocytes

Thiram is a fungicide that is used to prevent fungal diseases in seeds and crops and also as an animal repellent. The pro-oxidant activity of thiram is well established. Rutin is a flavonoid glycoside present in many fruits and plants and has several beneficial properties, including antioxidant effects. We have previously shown that thiram causes oxidative damage in human erythrocytes. The present study was designed to evaluate the protective effect of rutin against thiram-induced damage in human erythrocytes. Treatment of erythrocytes with 0.5 mM thiram for 4 h increased the level of oxidative stress markers, decreased antioxidant power and lowered the activity of antioxidant and membrane bound enzymes. It also enhanced the generation of reactive oxygen and nitrogen species (ROS and RNS) and altered the morphology of erythrocytes. However, prior treatment of erythrocytes with rutin (0.5, 1 and 2 mM) for 2 h, followed by 4 h incubation with 0.5 mM thiram, led to a decrease in the level of oxidative stress markers in a rutin concentration-dependent manner. A significant restoration in the antioxidant power and activity of antioxidant enzymes was observed upon the treatment of erythrocytes with 1 and 2 mM rutin. Pre-incubation with rutin lowered the generation of ROS and RNS which will reduce oxidative damage in erythrocytes. The thiram-induced changes in cell morphology and activity of membrane-bound enzymes were also attenuated by rutin. These results suggest that rutin can be used to mitigate thiram-induced oxidative damage in human erythrocytes.

Hyperglycemia enhances the generation of ROS and RNS that impair antioxidant power and cause oxidative damage in human erythrocytes.

Hyperglycemia is a state in which excess glucose circulates in blood. Erythrocytes are in direct contact with this high glucose concentration and are greatly affected by it. We have examined the effect of hyperglycemic condition on isolated human erythrocytes under in vitro conditions. Erythrocytes were incubated with different concentrations of glucose (5, 15, 30, 45 mmol/L) for 24 h, and several biochemical parameters were determined. Treatment with high glucose concentrations increased heme degradation and methemoglobin level, while methemoglobin reductase activity was decreased. A significant increase in protein oxidation and lipid hydroperoxides with a decrease in total sulfhydryl content was seen. This suggested the generation of oxidative stress, which was confirmed by an enhanced production of reactive oxygen and nitrogen species. Hyperglycemia led to a significant decline in the antioxidant power of erythrocytes, lowering their ability to quench free radicals and reduce metal ions to lower oxidation states. The plasma membrane redox system was upregulated, while ascorbate free radical reductase activity was lowered. Glucose exposure inhibited the enzymes of glycolysis and hexose monophosphate shunt. Electron microscopy showed morphological changes resulting in the formation of echinocytes. Thus, the hyperglycemic condition generates reactive species that oxidize proteins, hemoglobin, and lipids; impair the total antioxidant capacity; and alter morphology in human erythrocytes.

Chemical and Antioxidant Characterization of the Portuguese Heather Honey from Calluna vulgaris

The Calluna vulgaris honey produced in Portugal, concerning its phenolic compounds and abscisic acids profiles, as well as its antioxidant activity and the protective effect against oxidative damage in human erythrocytes were herein performed for the first time. The phenolic and abscisic acid profiles were tentatively identified by LC-MS/MS (17 compounds). The total content of phenolics and abscisic acids was 15,446.4 µg/g of honey extract, with catechin derivatives and abscisic acids being major constituents. The highest scavenging capacity was found against reactive nitrogen species. Additionally, the honey extract prevented ROO•-induced oxidative damage in erythrocytes collected from human blood, by inhibiting hemolysis, lipid peroxidation and hemoglobin oxidation. In conclusion, C. vulgaris honey contains high content of catechin derivatives and abscisic acids that may be responsible for its biological activity, characterized by a strong antioxidant capacity, which adds up to the nutritional value of this delicacy.

Determination of antioxidant capacity and flavonoid composition of onion (Allium cepa L.) landrace ‘Krishnapuram’ bulb using HPLC-ESI-ITMS

This study reports for the first-time antioxidant activity and flavonoid composition of KP onion landrace which is useful for future breeding programs and to obtain geographical indication (GI) tag for the benefit of farmers. The present study was aimed to determine antioxidant capacity and flavonoid composition of bulbs of red onion (Allium cepa L.) landrace 'Krishnapuram' (KP) from India using high-performance liquid chromatography (HPLC)-Electrospray Ionization (ESI)-multistage Ion Trap Mass Spectrometry (ITMS). The antioxidant activity was assayed by Ferric Reducing Antioxidant Power (FRAP) and hypochlorous acid (HClO)-induced oxidative damage in human erythrocytes. The total phenolic (TPC) contents in KP onion bulb extract (with 80% methanol) found to be 1.10 ± 0.2 mg GAE/g FW and 38.88 ± 1.0 lM QE/g. The FRAP activity measured for the bulb extract was 13.20 ± 0.1 μM QE/g. KP onion bulb extracts protected red blood cells (RBC) effectively (23%) against the oxidative damage induced by HClO. HPLC-ESI-ITMS analysis showed the presence of eight flavonols and five anthocyanins. Quercetin 3,4' -O-diglucoside (384.71 ± 0.49 mg/kg FW) and cyanidin 3-(6″-malonylglucoside) (20.95 ± 0.60 mg/kg FW) were detected as major flavonol and anthocyanin, respectively. The study suggests that KP onion has a considerable antioxidant activity due to the presence of high TPC. Moreover, quercetin glucosides are found to be more abundant than quercetin. The differences in quercetin glycosides content among different red onions could be useful for breeding programmes in the future.

Alleviation Effects of Diosmetin on H2O2-Induced Oxidative Damage in Human Erythrocytes

Free radicals (FRs) are formed in the high amounts result of the metabolic imbalance in cells and tissue. These radicals-induced oxidative damages constitute the basis of many diseases. Organisms have antioxidant defence systems (ADS) to eliminate the destructive effects of the oxidative damage. In addition to these antioxidant systems, dietary flavonoids have the antioxidant effect and the protective role against oxidative damage. In the present study, it was investigated whether a flavonoid derived diosmetin (10, 50, and 100 µM) have the elimination potential on hydrogen peroxide (H2O2)-induced oxidative damage in erythrocyte culture by using biomarkers such as lipid peroxidation (LP) level, catalase (CAT), total superoxide dismutase (SOD) activity and changes of SOD isozymes containing the manganese SOD (Mn SOD) and the cupper-zinc SOD (CuZn SOD). CAT, total SOD, Mn SOD and CuZn SOD activities showed a serious decline with H2O2 treatment, but diosmetin addition significantly increased their activities. While the H2O2 application critically increased LP products in erythrocytes, diosmetin considerably reduced these oxidative damage products. In conclusion, it has been determined that diosmetin can moderate oxidative damage in human erythrocytes by activating or protecting the ADS.

Protective Effect of the Intracellular Content from Potential Probiotic Bacteria against Oxidative Damage Induced by Acrylamide in Human Erythrocytes

The aim of this study was to assess the protective effect of the intracellular content obtained from potential probiotic bacteria against acrylamide-induced oxidative damage in human erythrocytes. First, the antioxidant properties of 12 potential probiotic strains was evaluated. Two commercial probiotic bacteria were included as reference strains, namely, Lactobacillus casei Shirota and Lactobacillus paracasei 431. Data showed that the intracellular content from four strains, i.e., Lactobacillus fermentum J10, Lactobacillus pentosus J24 and J26, and Lactobacillus pentosus J27, showed higher (P < 0.05) antioxidant capacity in most methods used. Thereafter, the intracellular content of such pre-selected strains was able to prevent the disturbance of the antioxidant system of human erythrocytes exposed to acrylamide, thereby reducing cell disruption and eryptosis development (P < 0.05). Additionally, the degree of oxidative stress in erythrocytes exposed to acrylamide was significantly (P < 0.05) reduced to levels similar to the basal conditions when the intracellular content of Lact. fermentum J10, Lact. pentosus J27, and Lact. paracasei 431 were employed. Hence, our findings suggest that the intracellular contents of specific Lactobacillus strains represent a potential source of metabolites with antioxidant properties that may help reduce the oxidative stress induced by acrylamide in human erythrocytes.

In vitro antioxidant activity of olive leaf extract (Olea europaea L.) and its protective effect on oxidative damage in human erythrocytes

AimsThis study aimed to evaluate in vitro antioxidant capacity of olive leaf extract (OLE), Olea europaea L., and its protective effect on peroxyl radical-induced oxidative damage in human erythrocytes. Main methodsThe OLE was evaluated by the following assays: i) total phenolic and flavonoid content; ii) oleuropein content; iii) Ferric reducing antioxidant power (FRAP); iv) antioxidant activity against ABTS+, DPPH and reactive oxygen and nitrogen species: superoxide anion (O2·−), hypochlorous acid (HOCl) and nitric oxide (NO) and v) protective effect on peroxyl radical-induced oxidative damages in human erythrocytes as hemolysis, thiobarbituric acid reactive substances (TBARS) formation and oxyhemoglobin oxidation. Key findingsTotal phenolic and flavonoid contents were 131.7 ± 9.4 mg gallic acid equivalents/g dry weight (dw) and 19.4 ± 1.3 mg quercetin equivalents/g dw, respectively. Oleuropein content was 25.5 ± 5.2 mg/g dw. FRAP analysis was 281.8 ± 22.8 mg trolox equivalent/g dw and OLE inhibited ABTS+ (50% effective concentration (EC50) = 16.1 ± 1.2 μg/mL) and DPPH (EC50 = 13.8 ± 0.8 μg/mL). The extract demonstrated effective ability to scavenge O2·− (EC50 = 52.6 ± 2.1 μg/mL), NO (EC50 = 48.4 ± 6.8 μg/mL) and HOCl (EC50 = 714.1 ± 31.4 μg/mL). The extract inhibited peroxyl radical-induced hemolysis (EC50 = 11.5 ± 1.5 μg/mL), TBARS formation (EC50 = 38.0 ± 11.7 μg/mL) and hemoglobin oxidation (EC50 = 186.3 ± 29.7 μg/mL) in erythrocytes. SignificanceOLE is an important source of natural antioxidants; it has effective antioxidant activity against different reactive species and protects human erythrocytes against oxidative damage.

Two novel polysaccharides from the torus of Saussurea laniceps protect against AAPH-induced oxidative damage in human erythrocytes

Two major polysaccharides (SLT-3, SLT-4) were isolated from the torus of Saussurea laniceps. Their molecular weight, monosaccharide compositions and the ability to protect human erythrocytes from oxidative damage induced by AAPH were assessed. Results showed that the Mw of SLT-3 and SLT-4 were 10,113 Da and 12,392 Da. SLT-3 was composed of mannose, rhamnose, glucuronic acid, galacturonic acid, glucose, galactose, xylose, and arabinose in a molar ratio of 0.25:0.53:0.19:15.35:0.51:1.10:0.63:1.73, whereas SLT-4 was composed of mannose, rhamnose, glucuronic acid, galacturonic acid, glucose, galactose, and arabinose in a molar ratio of 0.92:5.61:0.93:19.50:2.42:5.27:3.01. Pretreatment with SLT-3 and SLT-4 reduced MDA content, inhibited the generation of intracellular ROS and maintained the balance of GSH and GSSG in AAPH-treated erythrocytes. Furthermore, the activities of intracellular antioxidant enzymes, such as SOD, GSH-Px and CAT, were attenuated in polysaccharide treated cells. The results provide an important basis for the development of S. laniceps as a natural antioxidant.

Assessing the phenolic profile, antioxidant, antidiabetic and protective effects against oxidative damage in human erythrocytes of peaches from Fundão

In this work, the phenolic profile and biological potential of six peach cultivars from Fundão region (Portugal) were evaluated. The LC-DAD analysis revealed a total of 3 anthocyanins, and 14 non-colored phenolics. The antioxidant potential was evaluated against DPPH and NO radicals. Royal Lu proved to be the most active against DPPH (IC50 = 62.1 ± 1.5 μg/mL), and Sweet Dreams was the most active against NO radical (IC50 = 256.7 ± 60.4 μg/mL). Regarding the α-glucosidase inhibitory activity, Royal Magister and Royal Glory present the highest activity (IC50 = 11.7 ± 1.4 and 17.1 ± 1.7 μg/mL, respectively). Finally, the protective effect of Royal Lu to prevent oxidative damage in human erythrocytes induced by ROO was performed. Royal Lu proved to be quite efficient with promising results for hemolysis (IC50 = 110.0 ± 4.5 μg/mL) and hemoglobin oxidation inhibition (IC50 = 83.8 ± 6.5 μg/mL).

24 - Protective effect of creatine against hyperglycemia induced oxidative damage in human erythrocytes

According to International Diabetes Federation data, in 2015 there were 415 million people suffering from diabetes worldwide and this number is expected to increase to 642 million in 2040. Studies have shown a strong relationship between hyperglycemia and oxidative stress (OS) that seems to play a crucial role in progression of diabetes mellitus (DM). In hyperglycemia associated oxidative stress conditions, reactive oxygen species (ROS) induced injury of erythrocytes results in abnormalities in their function, morphology and metabolism. Moreover, the ROS present in erythrocytes can be transferred to other cells, thus inducing and spreading tissue damage and inflammation. Hyperglycemia mediated erythrocyte redox state alterations might be a potential risk factor for the development of non-proliferative diabetic retinopathy in poorly controlled diabetic subjects. Antioxidants (AO) are now being looked upon as persuasive therapeutics to combat free radicals. AO are expected to prevent oxidative stress and diabetes-related complications by inhibiting the formation of and/or scavenging free radicals or by enhancing the capability of the endogenous antioxidant system. Creatine (Cr) is naturally produced in the body and stored in muscles where it is involved in energy generation. It is widely used, especially by athletes, as a staple supplement for improving physical performance. Our previous work suggests that Cr can function as a blood antioxidant, protecting cells from oxidative damage, genotoxicity and can potentially increase erythrocyte lifespan. In this study, glucose cytoxicity is induced in erythrocytes and various biochemical parameters for assessing OS, ROS and nitrogen species were assayed in packed erythrocytes and cell lysates. Protection from oxidative damage to erythrocytes was analyzed using Cr and carnosine.

Comparative analysis of BPA and HQ toxic impacts on human erythrocytes, protective effect mechanism of tannins (Rhus typhina)

Several studies reported that bisphenol A (BPA) and its metabolite hydroquinone (HQ) have adverse effects on human and animal health. In this work, a comparative study of influence of the BPA and HQ, environment pollutants, on human erythrocytes was carried out. It was shown that BPA and HQ to varying extents caused oxidative damage in human erythrocytes: hemolysis, decreased GSH level, and methemoglobin formation. It was demonstrated that hydrolysable tannins 3,6-bis-O-di-O-galloyl-1,2,4-tri-O-galloyl-β-d-glucose (C55H40O34) and 1,2,3,4,6-penta-O-galloyl-β-d-glucose (C41H32O26) (PGG) isolated from the Rhus typhina L. leaves in the range of 1–50 μM concentrations inhibited hemolysis and methemoglobin formation and also increased intracellular reduced glutathione in erythrocytes treated with BPA or HQ. It was revealed by electron paramagnetic resonance (EPR) using 5-doxyl-stearic acid (5-DS) that C55H40O34 and C41H32O26 increased the rigidity of erythrocyte membranes at the depth of 5th carbon atom of the fatty acid hydrocarbon chain. Taken together, these results allow to conclude that tannins from the Rhus typhina L. leaves protect erythrocytes from oxidative stress caused by BPA or HQ both due to their antioxidant activity as well as their interaction with the erythrocyte membrane components.

Taurine mitigates nitrite-induced methemoglobin formation and oxidative damage in human erythrocytes.

Nitrite is present as a noxious contaminant in drinking water and causes oxidative damage in various tissues of humans and animals. It is a well-known methemoglobin-forming agent that has been shown to damage blood cells. The protective effect of taurine, a semi-essential sulfur-containing amino acid, was studied on sodium nitrite (NaNO2)-induced oxidative damage in human erythrocytes. Erythrocytes were incubated with NaNO2, in the presence and absence of taurine, and changes in oxidative stress parameters determined. Pretreatment with taurine significantly ameliorated NaNO2-induced oxidative damage to lipids, proteins, and plasma membrane. It also reduced the NaNO2-induced increase in methemoglobin levels and ROS production. Taurine improved the antioxidant capacity of cells, restored the alterations in the activities of various metabolic enzymes, and prevented morphological changes in erythrocytes. Thus, taurine can be potentially used as a protective agent against the damaging effects of nitrite.

Sodium chlorate, a herbicide and major water disinfectant byproduct, generates reactive oxygen species and induces oxidative damage in human erythrocytes.

Sodium chlorate (NaClO3) is a widely used non-selective herbicide. It is also generated as a byproduct during disinfection of drinking water by chlorine dioxide. In the present work, the effects of NaClO3 on human erythrocytes were studied under in vitro conditions. Incubation of erythrocytes with different concentrations of NaClO3 at 37°C for 90min resulted in significant hemolysis. Cell lysates were prepared from NaClO3-treated and untreated (control) erythrocytes and assayed for various biochemical parameters. Methemoglobin levels were significantly increased and methemoglobin reductase activity was reduced upon NaClO3 treatment. There was a significant increase in protein oxidation and lipid peroxidation with a decrease in reduced glutathione and total sulfhydryl content. This suggests the induction of oxidative stress in erythrocytes upon exposure to NaClO3. The occurrence of oxidative stress was confirmed by significantly increased generation of reactive oxygen species and lowered antioxidant response of the cells. NaClO3 treatment also increased nitric oxide levels showing induction of nitrosative stress. The activities of major antioxidant and membrane-bound and metabolic enzymes were significantly altered upon incubation of erythrocytes with NaClO3. The erythrocytes became more osmotically fragile while electron microscopic images showed gross morphological alterations in NaClO3-treated cells. These results show that NaClO3 induces oxidative stress in human erythrocytes, which results in extensive membrane damage and lowers the antioxidant response.

Crocin protects human erythrocytes from nitrite-induced methemoglobin formation and oxidative damage.

Sodium nitrite (NaNO2 ) is a common contaminant of drinking water and food and feed chain. Nitrite induces oxidative damage in humans and animals. In this work, we studied the protective effect of crocin, the active constituent of Crocus sativus (saffron), on NaNO2 -induced oxidative damage in human erythrocytes. Changes in oxidative stress parameters following NaNO2 incubation of erythrocytes in presence and absence of crocin were determined. It was found that crocin pre-treatment significantly attenuated NaNO2 -induced oxidative damage of proteins, lipids, and plasma membrane. Crocin reduced the level of methemoglobin, the primary acute effect of nitrite intoxication. It also improved the antioxidant capacity of cells and NaNO2 -induced morphological changes in erythrocytes. Crocin is thus a potent protective agent against nitrite-induced cytotoxicity.

Protective effect of Scutellaria species on AAPH-induced oxidative damage in human erythrocyte.

Scutellaria baicalensis is a well-known plant in traditional Chinese medicine. Recently, several Scutellaria species with therapeutic potential have been recognized worldwide. Scutellaria colebrookiana and Scutellaria violacea, native to the Western Ghats of India, are reported to possess free radical scavenging efficacy. At present, the protective effect of these Scutellaria spp. against 2,2' azobis (2-amidinopropane) hydrochloride (AAPH)-induced oxidative damage in human erythrocytes has been analyzed. Oxidative stress in erythrocyte was induced by AAPH. The inhibition of hemolysis, membrane lipid peroxidation, and protein damage by chloroform extracts of Scutellaria spp. was assessed biochemically. Phytochemicals of the extracts were analyzed by Fourier transform infrared spectrophotometer (FTIR). Approximately 95% of erythrocytes were lysed by AAPH over 3 h of incubation. Significant reduction in hemolysis was observed by the extracts, and the IC50 values were 18.3 and 23.5 μg/mL for S. colebrookiana and S. violacea, respectively. Both the extracts were found to inhibit AAPH-induced lipid peroxidation in ghost membrane with IC50 92±2.8 and 70±5.6 μg/mL. In the analysis of the membrane proteins using sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), the AAPH-induced degradation of actin was found reduced by both the extracts. The FTIR spectrum revealed the presence of polyphenols, carboxylic acids, alkanes, and aromatic compounds in extracts. In quantitative analysis, the total polyphenolic content estimated was 380±0.23 and 203.7±1.4 mg of gallic acid equivalent per gram extract of S. colebrookiana and S. violacea. Results indicate that S. colebrookiana and S. violacea are capable of protecting erythrocytes from oxidative damage. This cytoprotective effect of the extract is possibly by its antioxidant property.

Protective Effect of Alkaloids from Amaranthus Viridis Linn. Against Hydrogen Peroxide Induced Oxidative Damage in Human Erythrocytes (RBC)

Plants are rich in antioxidants which play an essential role in disease prevention. Amaranthus viridis linn. Is a common medicinal plant, spread throughout the world is used in traditional ayurvedic medicine. The present study was aimed to examine the protective effect of partially purified alkaloids (PPA) from Amaranthus viridis against hydrogen peroxide induced oxidative damage in human erythrocytes in vitro conditons.

Radical scavenging activities of Tyr-, Trp-, Cys- and Met-Gly and their protective effects against AAPH-induced oxidative damage in human erythrocytes

Radical scavenging activities of Tyr-, Trp-, Cys- and Met-Gly and their protective effects against AAPH-induced oxidative damage in erythrocytes were evaluated in this study. This damage includes hemolysis, oxidation of hemoglobin, formation of MDA and the depletion of glutathione (GSH) and catalase (CAT). Results showed that Tyr- and Trp-Gly could quench the radicals effectively in ABTS and ORAC assays with TE (Trolox equivalent) values of more than 1.0μmol TE/μmol, followed by Cys- and Met-Gly. All these dipeptides could protect erythrocytes against AAPH-induced hemolysis in a dose-dependent manner. They could also significantly (p<0.05) retard the oxidation of hemoglobin and depletion of GSH in erythrocytes. The protective effects of these dipeptides decreased in the following order: Trp-Gly>Tyr-Gly>Met-Gly>Cys-Gly, which were consistent with their peroxyl radical scavenging activities. It suggested that these dipeptides might protect erythrocytes against AAPH-induced oxidative damage, mainly by acting as the direct radical scavengers.

Protection against oxidative damage in human erythrocytes and preliminary photosafety assessment of Punica granatum seed oil nanoemulsions entrapping polyphenol-rich ethyl acetate fraction

The main purpose of the present study is to evaluate the ability of nanoemulsion entrapping pomegranate peel polyphenol-rich ethyl acetate fraction (EAF) prepared from pomegranate seed oil and medium chain triglyceride to protect human erythrocyte membrane from oxidative damage and to assess preliminary in vitro photosafety. In order to evaluate the phototoxic effect of nanoemulsions, human red blood cells (RBCs) are used as a biological model and the rate of haemolysis and photohaemolysis (5Jcm−2 UVA) is assessed in vitro. The level of protection against oxidative damage caused by the peroxyl radical generator AAPH in human RBCs as well as its effects on bilayer membrane characteristics such as fluidity, protein profile and RBCs morphology are determined. EAF-loaded nanoemulsions do not promote haemolysis or photohaemolysis. Anisotropy measurements show that nanoemulsions significantly retrain the increase in membrane fluidity caused by AAPH. SDS-PAGE analysis reveals that AAPH induced degradation of membrane proteins, but that nanoemulsions reduce the extension of degradation. Scanning electron microscopy examinations corroborate the interaction between AAPH, nanoemulsions and the RBC membrane bilayer. Our work demonstrates that Punica granatum nanoemulsions are photosafe and protect RBCs against oxidative damage and possible disturbance of the lipid bilayer of biomembranes. Moreover it suggests that these nanoemulsions could be promising new topical products to reduce the effects of sunlight on skin.