Effect of Garlic Extract on the Erythrocyte as a Simple Model Cell.

Garlic is known to have diverse effects on mammalian cells, being cytotoxic, especially to cancer cells, but also protect against oxidative stress. Mammalian erythrocyte is a simple cell devoid of intracellular organelles, protein synthesis ability, and most signaling pathways. Therefore, examination of the effects of garlic on erythrocytes allows for revealing primary events in the cellular action of garlic extract. In this study, human erythrocytes or erythrocyte membranes were exposed to garlic extract at various dilutions. Hemoglobin oxidation to methemoglobin, increased binding of hemoglobin to the membrane, and formation of Heinz bodies were observed. Garlic extract depleted acid-soluble thiols, especially glutathione, and induced a prooxidative shift in the cellular glutathione redox potential. The extract increased the osmotic fragility of erythrocytes, induced hemolysis, and inhibited hemolysis in isotonic ammonium chloride, indicative of decreased membrane permeability for Cl- and increased the membrane fluidity. Fluorescent probes indicated an increased level of reactive oxygen species and induction of lipid peroxidation, but these results should be interpreted with care since the extract alone induced oxidation of the probes (dichlorodihydrofluorescein diacetate and BODIPY C11). These results demonstrate that garlic extract induces oxidative changes in the erythrocyte, first of all, thiol and hemoglobin oxidation.

Developmental changes in the levels and redox potentials of main hemolymph thiols/disulfides in the Jamaican field cricket Gryllus assimilis.

Main thiols and disulfides were determined in the hemolymph of the Jamaican field cricket Gryllus assimilis at various developmental stages. On the basis of these data, redox potentials of the glutathione, cysteine and homocysteine redox systems were calculated. The concentrations of all thiols studied decreased during development (at a stage of 6 molts) with respect to young crickets, and increased again in adult insects. Redox potentials of the glutathione and cysteine systems increased from values of -131.0±5.6 mV and -86.9±17.1 mV, respectively in young crickets to -58.0±3.6 mV and -36.1±4.2 mV, respectively, at the stage of 6 molts and decreased to values of -110.4±24.8 mV and -66.3±12.2 mV, respectively, in adult insects. Redox potentials of the glutathione and cysteine systems in the hemolymph of young and adult insects were similar to those reported for human plasma.

Oxidative modifications of blood serum proteins in myasthenia gravis.

Myasthenia gravis (MG) is an autoimmune disease caused by production of antibodies against acetylcholine receptors of the neuromuscular junction (Ab). The aim of this study was to ascertain if oxidative stress accompanies MG by estimation of the several independent parameters of oxidative damage, mainly the levels of oxidative modifications of blood serum proteins. The group studied consisted of 50 MG patients (28 females and 22 males), 24 with ocular MG (OMG) and 26 with generalized MG (GMG), of mean age of 66.7 (30-81)years (y), mean disease duration of 9.5 (0.5-34)y, mean level of Ab of 8.9 (0.1-85)nmol/ml, and 25 age-matched healthy controls. MG patients were stratified into groups according to disease duration (<5y or >5y), Ab level (low, <3 or high, >3nmol/l) as well as symptoms (GMG or OMG). Glycophore fluorescence was increased in OMGa. Dityrosine was increased in both types of MGc, in patients ill <5b and >5cy, with lowc and highc levels of Ab. N-formylkynurenine was increased in OMGa and GMGb, in both disease duration groupsa, in the group of low Aba. Kynurenine was increased in the group with high Aba. Tryptophan fluorescence was decreased in OMGb and GMGc, in patients ill for <5b and >5ay, with lowa and highc Ab. Serum thiol group concentration were decreased in GMGc, in patients ill for >5yb. AOPP level was elevated in OMGa, in patients ill for >5ya with high Aba. Protein carbonyls were increased in both OMGc and GMGc, in patients ill for >5ay, with lowb and highb Ab. FRAP and ABTS• scavenging by fast antioxidants were unchanged, but ABTS• scavenging by slow antioxidants was lower in OMGb and GMGc, in patients ill for >5cy, in patients with lowc and highb Ab (ap<0.05, bp<0.01, cp<0.001). These results demonstrate systemic oxidative stress in MG, suggesting therapeutic use of antioxidants.

Nutritional supplement attenuates selected oxidative stress markers in pediatric patients with cystic fibrosis.

Our aim was to test the hypothesis that nutritional supplement (AquADEKs; Axcan Scandipharm Inc., Birmingham, Ala, USA) with various pharmaceutical forms of such as chewable tablets, capsules, and liquid administered daily for 12 weeks would reduce oxidative stress and enhance antioxidant status in pediatric patients with cystic fibrosis (CF). A total of 50 patients with CF and 21 healthy children were included in the study. Patients were divided into 4 groups: group A received supplementation with vitamins A (3 mg daily), E (200 mg daily), and D(3) (20 µg daily); group B was supplemented with AquADEKs chewable tablets; group C received the recommended amount of AquADEKs capsules; and group D was supplemented with AquADEKs liquid. The level of oxidative stress was determined by the analysis of activities of enzymes neutralizing reactive oxygen species and by the estimated markers of intensity of free radical processes. There was no difference in the activity of erythrocyte catalase, hydroperoxides level, and sulfhydryl group content in blood plasma between patients with CF and healthy children. The plasma total antioxidant status was decreased in all CF groups compared with the control. The supplementation with either AquADEKs chewable tablets or capsules normalized the malondialdehyde level in plasma. AquADEKs in various pharmaceutical forms normalized the sulfhydryl group content of erythrocytes. The superoxide dismutase activity was increased to near control level in the patients supplemented with either AquADEKs chewable tablets or liquid as compared with the group supplemented with vitamins or with AquADEKs capsules. In conclusion, AquADEKs attenuates selected oxidative stress markers in pediatric patients with CF.

Influence of desloratadine on selected oxidative stress markers in patients between 3 and 10 years of age with allergic perennial rhinitis.

The objective of this study was to evaluate the selected oxidative stress parameters in 50 (35 males, 15 females) pediatric patients aged from 3 to 10 years diagnosed with perennial allergic rhinitis before and after the two-month treatment with desloratadine at the dose of 5 mg/day and in 11 healthy individuals. Oxidative stress was determined by the analysis of the reactive oxygen species neutralizing enzyme activity in erythrocytes superoxide dismutase and catalase, the estimation of free radical processes intensity: content of malondialdehyde in erythrocytes and the level of plasma hydroperoxides as well as by quantification of the plasma total antioxidant status. Changes in the studied parameters in untreated perennial allergic rhinitis patients indicate increased oxidative stress. The treatment with desloratadine normalized the superoxide dismutase and catalase activity as well as the malondialdehyde formation. The plasma hydroperoxides level in treated patients with perennial allergic rhinitis is reduced as compared with untreated subjects, although still higher than in the control. Desloratadine caused an increase in the total antioxidant status level, but it was not statistically significant. It can be concluded that oxidative stress is implicated in the pathogenesis of perennial allergic rhinitis. The results demonstrate that desloratadine exerts antioxidant effects in vivo.

Protective effect of desloratadine against oxidative stress in human erythrocytes in vitro.

Desloratadine (DCL) is a non-sedating antihistamine approved for the treatment of allergic rhinitis or chronic idiopathic urticaria. The objective of this study was to evaluate the potential protective effect of DCL against oxidative stress in human erythrocytes in vitro. Human erythrocytes were oxidized by a water-soluble radical generators-2,2' azobis (2-amidinopropane) hydrochloride (AAPH; 20, 50mM) or tert-butyl hydroperoxide (TBHP; 0.5mM) and the protective effects of DCL (2, 5, 7, 10 and 26µM) on selected oxidative stress markers were investigated. Erythrocytes were divided into aliquots. The first aliquot was incubated for 2h at 37°C with AAPH or TBHP. The other test aliquots were preincubated with selected concentrations of DCL for 30min and followed by AAPH or TBHP incubation for 2h. Malondialdehyde (MDA) content, catalase (CAT) and superoxide dismutase (SOD) activities, as well as hemolysis percentage (H) were measured in all erythrocyte samples. The influence of solvent (0.5% ethanol) on the parameters studied was also checked. Pretreatment with DCL (7, 10, 26µM) could prevent TBHP-induced increase in MDA formation in a concentration-dependent manner. DCL has no influence on CAT activity and it significantly enhanced SOD activity compared to AAPH treatment samples at 7, 10, 26µM. DCL (26µM) also reduced the hemolytic effect on erythrocytes when compared to the erythrocytes exposed to oxidants only. These results suggest a beneficial effect of DCL as an antioxidant, which might be an additional explanation of its therapeutic action.

Effect of selected antioxidants in beta-cyfluthrin-induced oxidative stress in human erythrocytes in vitro.

beta-Cyfluthrin is one of the most widely used type II pyrethroid in agriculture. The aim of this study was to examine (1) the possibility of beta-cyfluthrin to induce oxidative stress in human erythrocytes in vitro and its effect on catalase (CAT) and superoxide dismutase (SOD) activities as well as (2) the role of melatonin (MEL; 2mM), its precursor--N-acetylserotonin (NAS; 1mM), quercetin (Q; 80 microM) and rutin (R; 80 microM) in alleviating the cytotoxic effects of beta-cyfluthrin. Erythrocytes were divided into portions. The first portion was incubated for 4h at 37 degrees C with different concentrations (0, 43, 215, 1075 ppm) of beta-cyfluthrin. The other portions were preincubated with selected antioxidant, respectively for 30 min and followed by beta-cyfluthrin incubation for 4h. Malondialdehyde (MDA) concentrations, CAT and SOD activities, as well as haemolysis percentage (H) were measured in all treatment portions of erythrocytes. It could be concluded that the in vitro toxicity of beta-cyfluthrin may be associated with oxidative stress. Significant reduction in the activities of CAT was observed at all beta-cyfluthrin concentrations, while SOD activities were significantly decreased only in erythrocytes incubated with the highest beta-cyfluthrin concentration. SOD activity of the non-pretreated erythrocytes exposed to the lowest dose of beta-cyfluthrin was significantly greater when compared to comparably beta-cyfluthrin-exposed antioxidant pretreated cells. The highest concentration of beta-cyfluthrin has caused over 35% haemolysis, and the lowest concentration about 15%. MEL pretreatment had no effect on H and MDA induction by beta-cyfluthrin. NAS, Q and R reduced H and MDA level, but could not prevent induction of these parameters. Compared to other antioxidants NAS appeared to maintain better the CAT activity at control levels for all doses of beta-cyfluthrin. Pretreatment with Q was found to protect against the decrease in SOD activity induced by beta-cyfluthrin.