Differential inhibition of human erythrocyte acetylcholinesterase by polyphenols epigallocatechin-3-gallate and resveratrol. Relevance of the membrane-bound form.

The activity of acetylcholinesterase (AChE) from human erythrocytes was tested in the presence of the phenolic compounds resveratrol and epigallocatechin-3-gallate (EGCG). Even though the stilbene barely changed this enzymatic activity, EGCG did inhibit AChE. Importantly, it preferentially acted on the membrane-bound enzyme rather than on its soluble form. Actually, it was shown that this flavonoid may bind to the red blood cell membrane surface, which may improve the interaction between EGCG and AChE. Therefore, caution should be taken when screening AChE inhibitors. In fact, testing compounds with the soluble form of the enzyme may underestimate the activity of some of these potential inhibitors, hence it would be advisable not to use them as a sole model system for screening. Moreover, erythrocyte AChE is proposed as a good model for these enzymatic assays. © 2016 BioFactors, 43(1):73-81, 2017.

Influence of kaempferol, a flavonoid compound, on membrane-bound ATPases in streptozotocin-induced diabetic rats.

CONTEXT: Kaempferol is a flavonoid found in many edible plants (e.g. tea, cabbage, beans, tomato, strawberries, and grapes) and in plants or botanical products commonly used in traditional medicine. Numerous preclinical studies have shown that kaempferol have a wide range of pharmacological activities, including antioxidant, anti-inflammatory, anticancer, cardioprotective, neuroprotective, and antidiabetic activities. OBJECTIVE: The present study investigates the effect of kaempferol on membrane-bound ATPases in erythrocytes and in liver, kidney, and heart of streptozotocin (STZ)-induced diabetic rats. MATERIALS AND METHODS: Diabetes was induced into adult male albino rats of the Wistar strain, by intraperitoneal administration of STZ (40 mg/kg body weight (BW)). Kaempferol (100 mg/kg BW) or glibenclamide (600 µg/kg BW) was administered orally once daily for 45 d to normal and STZ-induced diabetic rats. The effects of kaempferol on membrane-bound ATPases (total ATPase, Na(+)/K(+)-ATPase, Ca(2+)-ATPase, and Mg(2+)-ATPase) activity in erythrocytes and in liver, kidney, and heart were determined. RESULTS: In our study, diabetic rats had significantly (p < 0.05) decreased activities of total ATPases, Na(+)/K(+)-ATPase, Ca(2+)-ATPase, and Mg(2+)-ATPase in erythrocytes and tissues. Oral administration of kaempferol (100 mg/kg BW) or glibenclamide (600 µg/kg BW) for a period of 45 d resulted in significant (p < 0.05) reversal of these enzymes' activities to near normal in erythrocytes and tissues when compared with diabetic control rats. DISCUSSION AND CONCLUSION: Thus, obtained results indicate that administration of kaempferol has the potential to restore deranged activity of membrane-bound ATPases in STZ-induced diabetic rats. Further detailed investigation is necessary to discover kaempferol's action mechanism.

Antioxidative effect of rice bran oil and medium chain fatty acid rich rice bran oil in arsenite induced oxidative stress in rats.

The present study was adopted to evaluate the antioxidant efficacy of medium chain fatty acid (caprylic, capric and lauric) rich rice bran oils in comparison to rice bran oil in terms of altered biochemical parameters of oxidative stress following sodium arsenite treatment in rats. Animals were divided into ten groups; five normal groups and five arsenite treated groups. Results showed that activities of antioxidant enzymes in liver, brain and erythrocyte membrane increased with the administration of rice bran oil and MCFA rich rice bran oils both in normal and arsenite treated cases. Lipid peroxidation increased with the administration of sodium arsenite, but again administration of rice bran oil and MCFA rich rice bran oils decreased the lipid peroxidation. Caprylic acid rich rice bran oil showed the best ameliorative effects.

Ameliorative effect of diallyl trisulphide on arsenic-induced oxidative stress in rat erythrocytes and DNA damage in lymphocytes.

BACKGROUND: Arsenic (As) is a naturally occurring semimetallic element that is classified as a toxicant and a human carcinogen. Diallyl trisulphide (DATS), an organosulphur compound, is an antioxidative substance that is extracted from garlic (Allium sativum). Erythrocytes are very expedient models to understand the susceptibility of membrane to oxidative damage induced by different xenobiotic compounds. Arsenic has been reported to induce oxidative stress to erythrocytes due to lipid peroxidation and alteration in defence mechanism as erythrocytes are the first target that arsenic compounds attack in the body after systemic absorption. In the light of this fact, the purpose of this study is to characterise the ameliorative effect of DATS on arsenic-induced oxidative stress in rat erythrocytes. METHODS: Experimental rats were randomly divided into four groups and treated orally for 28 days: control, As [5 mg/kg body weight (BW)] treated, As+DATS (80 mg/kg BW) treated, DATS (80 mg/kg BW) treated and As+vitamin C (100 mg/kg BW) treated. Oxidative stress in erythrocytes was recorded by estimating plasma marker enzymes, plasma and erythrocyte membrane oxidative stress markers, erythrocyte membrane antioxidant enzymes and non-antioxidant enzymes, etc. RESULTS: Oral administration of arsenic at 5 mg/kg BW per day elevated the levels of plasma marker enzymes, namely, aspartate transaminase (AST), alanine transaminase (ALT), acid phosphatase (ACP), alkaline phosphatase (ALP), lactate dehydrogenase (LDH), and γ-glutamyl transferase (γGT) (U/L) with significantly increased lipid peroxidation markers such as thiobarbituric acid reactive substances (TBARS), malondialdehyde (MDA), lipid hydroperoxides (LH), conjugated dienes (CD), and protein carbonyl (PC) contents were also elevated in As-treated rat plasma and erythrocytes. The levels of non-enzymatic antioxidants (reduced glutathione, vitamins C and E) and enzymatic antioxidants such as superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione S-transferase (GST), glutathione reductase (GR), and glucose-6-phosphate dehydrogenase (G6PD) were also decreased in As-treated rats. The toxic effect of As significantly decreased the activities of membrane-bound ATPases (Na+/K+-ATPase, Mg2+-ATPase, and Ca2+-ATPase), with a significant increase in% tail DNA of rat lymphocytes measured by means of a single-cell gel electrophoresis assay. Administration of DATS for 28 days significantly reduced the levels of plasma markers. The levels of TBARS, MDA, LH, CD, and PC were significantly decreased and there was a significant increase in ATPase activities and non-enzymatic and enzymatic antioxidants on treatment with DATS in a dose-related manner. CONCLUSIONS: All these changes were supported by reduction of DNA damage in lymphocytes with DATS treatment. DATS at a dose of 80 mg/kg BW was found to be most effective and the results revealed the same. The results of the study showed that DATS shows a protective effect against As-induced oxidative stress in rat erythrocytes and lymphocytes.

[Clinical-biochemical and immunological parameters in the diagnosis and treatment of chronic pyelonephritis on the background of intercurrent diseases].

Studies have shown that complicated chronic pyelonephritis in the active phase is characterized by structural and functional instability cytomembranes and decreased immunological resistance of the patient man. Supplement standard antibiotic treatment with ozone therapy antioxidant immunomodulation drug thus received immunobiochemical study.

Effect of viologen-phosphorus dendrimers on acetylcholinesterase and butyrylcholinesterase activities.

The inhibition of acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) is the first step in checking whether new compounds can be considered as drugs for treating neurodegenerative diseases. The effect of viologen-phosphorus dendrimers on AChE and BChE activities was studied. The results show that the effects on the cholinesterase activities depend on dendrimer type and size. Viologen dendrimers can interact with the enzymes in two ways: they can bind either to a peripheral site of the enzyme or to amino acids located near the active site, inhibiting catalysis by both cholinesterases. All tested non-toxic viologen-phosphorus dendrimers inhibited the activities of both cholinesterases, showing their potential as new drugs for treating neurodegenerative diseases.

Acetylcholinesterase from human erythrocytes membrane: a screen for evaluating the activity of some traditional plant extracts.

The extraction of plant constituents is essential to isolate biologically active compounds and understanding their role in disease prevention, treatment and in knowing their toxic effects as well. However, meager information is available about the properties and biological activities of phytochemicals derived from certain plants found in Allahabad and adjoining areas. Keeping this information in view, we prepared aqueous extracts and determined their biochemical properties including their impact on the activity of human RBC's acetylcholinesterase (AChE). The UV­Visible spectrophotometric profiles of the aqueous extracts of different parts of the four plant species viz. Calotropis procera, Datura metal, Cannabis sativa, Argemone mexicana and Thevitia peruviana displayed two major peaks at 302 and 336 nm corresponding to the presence of different flavonoids in these preparations. These extracts indicated presence of protein in the range of 1.12 to 19.25mg/g wet weight of the plant tissues. The impact of different phytochemicals present in these extracts was studied on the activity of AChE isolated from human erythrocytes (RBCs). The extracts derived from Argemone mexicana and Datura metal exhibited strong AChE inhibitory potential, whereas others did not show significant inhibition even at higher concentrations. The results indicate that human RBC's can be used as a potential biomarker towards evaluation of the efficacy and toxic potential of varied plant extracts.

GC/MS analysis of three Amaryllidaceae species and their cholinesterase activity.

Alzheimer's disease (AD), characterized by the death of nerve cells in the cerebral cortex, is the most common subtype of dementia. Despite the exponential growth in the number of AD patients, acetylcholinesterase (AChE) inhibitors are currently used to treat AD. Plants of the Amaryllidaceae family are known to synthesize a particular type of bioactive compounds, named Amaryllidaceae alkaloids, which have shown AChE inhibitory activity. Alkaloid extracts of three species of Amaryllidaceae were studied with respect to their acetylcholinesterase and butyrylcholinesterase inhibitory activity and alkaloid patterns. Eleven alkaloids were identified by GC/MS. Significant cholinesterase inhibitory activity was demonstrated by the alkaloid extract of N. undulata (IC50,(HuAChE) = 14.3 +/- 1.2 microg/mL; IC50,(HuBuChE) = 33.9 +/- 1.9 microg/mL).

Zinc absorption and zinc status are reduced after Roux-en-Y gastric bypass: a randomized study using 2 supplements.

BACKGROUND: Micronutrient deficiencies are common in patients undergoing gastric bypass. The effect of this type of surgery on zinc absorption and zinc status is not well known. OBJECTIVE: The objective was to evaluate the effects of Roux-en-Y gastric bypass (RYGBP) on zinc status and zinc absorption at different stages after surgery. We hypothesized that zinc status would be significantly impaired after surgery and that this impairment would be less severe in subjects receiving increased supplemental zinc. We also hypothesized that zinc absorption would be lower after surgery. DESIGN: Anthropometric and body-composition variables and dietary and biochemical indexes of zinc status and zinc absorption were determined in 67 severe and morbidly obese women [mean (±SD) age: 36.9 ± 9.8 y; BMI (in kg/m(2)): 45.2 ± 4.7] who underwent RYGBP. The subjects were randomly assigned to 1 of 2 vitamin-mineral supplementation groups. Measurements were made before and 6, 12, and 18 mo after surgery. Fifty-six subjects completed the 18-mo follow-up. RESULTS: Mean plasma zinc, erythrocyte membrane alkaline phosphatase activity, and the size of the rapidly exchangeable zinc pool decreased after RYGBP. Percentage zinc absorption decreased significantly from 32.3% to 13.6% at 6 mo after RYGBP and to 21% at 18 mo after surgery. No effect of supplement type was observed. CONCLUSIONS: Zinc status is impaired after RYGBP, despite the finding that dietary plus supplemental zinc doubled recommended zinc intakes in healthy persons. Zinc absorption capacity is significantly reduced soon after RYGBP, with no major changes until 18 mo after surgery.

Biochemical and morphological perturbations in rat erythrocytes exposed to ethion: protective effect of vitamin E.

Erythrocyte membranes are an excellent model system to study interaction of pro-oxidants with membranes. The aim of the present study is to examine the effect of vitamin E on ethion-induced biochemical and morphological alterations in erythrocytes. Ethion was administered to the rats orally at a daily dose of 2.7 mg/kg body weight for a period of 7, 14, 21 and 28 days. The results from the present study show that administration of ethion resulted in oxidative damage to erythrocyte membranes as evident by increased lipid peroxidation and decreased phospholipid content. This was accompanied by decrease in membrane cholesterol levels. In addition, ethion exposure inhibited the activities of membrane bound enzymes; Na+ K+ ATPase and Mg2+ATPase. Scanning electron micrographs of erythrocytes from animals exposed to ethion revealed morphological changes. Supplementation of vitamin E (50 mg/kg body weight) to ethion exposed animals ameliorated the ethion-induced oxidative stress, restored membrane lipid composition and activity of membrane bound enzymes along with erythrocyte shape. The results clearly demonstrate that ethion-induced damage involves increase in oxidative stress that results in alterations in erythrocyte membrane structure and function. Furthermore, supplementation with vitamin E reversed ethion induced alterations suggesting its beneficial role in individuals exposed to ethion.

Modulatory action of α-tocopherol on erythrocyte membrane adenosine triphosphatase against radiation damage in oral cancer.

To investigate the possible effects of α-tocopherol on erythrocyte membrane adenosine triphosphatases against radiation damage in oral cancer patients. Adenosine triphosphatase activities were analysed in oral cancer patients before and after radiotherapy (at a dosage of 6000 cGY in five fractions per week for a period of six weeks) and after supplemented with α-tocopherol (400 IU per day for entire period of radiotherapy). The membrane bound enzymes such as Na(+)/K(+)-ATPase, Ca(2+)-ATPase, Mg(2+)-ATPase and some trace elements were altered in oral cancer patients before and after radiotherapy. Supplemented with α-tocopherol modulates the erythrocyte membrane which is damaged by radiotherapy which suggests that α-tocopherol protects the erythrocyte membrane from radiation damage in oral cancer patients.

If vitamins could kill: massive hemolysis following naturopathic vitamin infusion.

INTRODUCTION: Hemolysis from naturopathic remedies remains poorly reported in the medical literature, although it is most commonly noted in the patients with glucose 6-phosphate dehydrogenase (G6PD) deficiency. We report a case of massive intravascular hemolysis following the infusion of a naturopathic preparation that contains vitamins. CASE REPORT: A 47-year-old African-American man presented to the hospital with 3 days of fever, dyspnea, emesis, dark urine, and progressive confusion. His symptoms began 1 day following an infusion of a vitamin complex. His physical examination was significant for lethargy and scleral icterus. Initial laboratory studies were notable for anemia (hemoglobin, 3.3 g/dL and hematocrit, 11%), brisk reticulocytosis (33%), acute renal insufficiency (creatinine, 2.8 mg/dL), and indirect hyperbilirubinemia (total bilirubin, 4.4 mg/dL). His peripheral smear demonstrated "blister cells," erythrocytes that have been left devoid of precipitated hemoglobin by the spleen, which are commonly seen in patients with G6PD deficiency. His physician revealed that the infusion contained vitamins B and D complex, free amino acids, magnesium, and taurine. The patient clinically improved and was discharged to home. G6PD concentration was significantly reduced to 4.7 U/g Hb upon recovery. DISCUSSION: Life-threatening intravascular hemolysis may occur following a naturopathic vitamin infusion and may identify previously unknown G6PD deficiency. Since most properly formulated naturopathic treatments have few toxic ingredients, the possibilities of improper formulation, toxic diluents, or contaminants should be considered. Inadequate regulatory oversight of naturopathic remedies has the potential to allow serious toxicity especially in genetically predisposed individuals.

In vitro reactivation of sarin-inhibited human acetylcholinesterase (AChE) by bis-pyridinium oximes connected by xylene linkers.

A series of bis-pyridinium oximes connected by xylene linkers were synthesized and their in vitro reactivation potential was evaluated against human acetylcholinesterase (hAChE) inhibited by nerve agent sarin and the data were compared with 2-PAM and obidoxime. Among the synthesized compounds, N,N'-p-xylene-bis-[(2,2'-hydroxyiminomethyl)pyridinium] dibromide (3c) was found to be the most potent reactivator for hAChE inhibited by sarin. The oxime 3c exhibited 45% regeneration of inhibited hAChE, in comparison to 34% and 24% regeneration by 2-PAM and obidoxime, respectively, at a concentration of 10(-3) M within 10 min. The higher reactivation efficacies of these oximes were attributed to their acid dissociation constants (pKa). The pKa values of all the oximes were determined spectrophotometrically and correlated with their observed reactivation potential. This method involving the in vitro reactivation of inhibited hAChE may be useful for the screening of new oximes as reactivators.

Influence of Helicteres isora administration for diabetes mellitus: Its effect on erythrocyte membrane and antioxidant status.

In this study the effect of Helicteres isora L. on erythrocyte membrane bound enzymes and antioxidants activity in plasma and erythrocytes of streptozotocin (STZ) induced diabetic model was investigated. The aqueous bark extract of H. isora was administered orally for 30 days to control and STZ induced diabetic rats. The effect of bark extract on glucose, insulin, haemoglobin, glycosylated haemoglobin, TBARS, hydroperoxide, superoxide dismutase (SOD), catalase (CAT), glutathione peroxide (GPx), glutathione-S-transferase (GST), vitamins C and E, reduced glutathione (GSH) and membrane bound enzymes were studied. The levels of glucose, glycosylated haemoglobin, TBARS, hydroperoxide, and vitamin E were increased significantly whereas the level of insulin, haemoglobin, as well as antioxidants, membrane bound total ATPase, Na(+)/K(+)-ATPase, Ca(2+)-ATPase and Mg(2+)-ATPase were decreased significantly in STZ diabetic rats. Administration of bark extract to diabetic rats showed a decrease in the levels of glucose, glycosylated haemoglobin, lipid peroxidation markers and vitamin E. In addition the levels of insulin, haemoglobin, enzymatic antioxidants, vitamin C, and GSH and the activities of membrane bound enzymes also were increased in H. isora treated diabetic rats. The present study indicates that the H. isora possesses a significant favourable effect on erythrocyte membrane bound enzymes and antioxidants defense system in addition to its antidiabetic effect.

[Study the effect of antioxidant vitamin E, vitamin C and beta-carotene supplement on erythrocyte functions in elderly person].

OBJECTIVE: To study the effect of antioxidant vitamin E (VE), vitamin C (VC) combined with different doses of beta-carotene (beta-C) supplementation on erythrocyte functions in the elderly person. METHODS: 300 elderly person at the age from 60 to 75years old were randomized into 5 groups: from group 1 to group 4 were supplemented with (VC 300 + VE 200) mg/d and different doses of beta-C (16.7, 8.4, 5.6 and 0.0 mg/d, respectively), and control group 5 were supplemented with VE 5 mg/d. The trial lasted for 16 weeks. H2O2-caused hemolytic of erythrocytes was measured spectrometricalyl. ATPase activities in erythrocyte membrane were detected by colorimetric analysis. The fluidity of erythrocyte membrane was evaluated by fluorescence polarization (rho) and microviscosity (eta). All the data was analyzed with SPSS12.0. RESULTS: H2O2-caused hemolysis of erythrocyte was decreased significantly from group 1 to group 4 after the trial compared with before the trial (P < 0.01), they also had significant difference in compared with group 5 after the trial (P < 0.01). ATPase activities in erythrocyte membrane were more higher in group 1 than those of group 5 after the trial( P < 0.05). Moreover, rho and eta values were lower from 1 to 4 groups after the trial than itself before the trial (P < 0.01). CONCLUSION; Antioxidant VE, VC combined with different doses of beta-C supplementation could improve the function of erythrocyte in the elderly subjects.

The in vivo and in vitro effects of L-carnitine supplementation on the erythrocyte membrane acetylcholinesterase, Na+, K+-ATPase and Mg2+-ATPase activities in basketball players.

BACKGROUND: We investigated whether the activities of erythrocyte membrane acetylcholinesterase (AChE), Na+, K+-ATPase and Mg2+-ATPase are modulated in basketball players pre- vs. post-forced training with or without L-carnitine (L-C) supplementation. METHODS: Blood was obtained from 10 male players pre-game (group A) and post-game (group B) and after 1 month L-C supplementation (2 g/24 h orally) pre-training (group C) and post-training (group D). Lactate, pyruvate and total antioxidant status (TAS) were measured with commercial kits, catecholamines with HPLC and the enzyme activities spectrophotometrically. RESULTS: Lactate, pyruvate, AChE, Na+, K+-ATPase and catecholamines were increased (p<0.001) and TAS was decreased (p<0.001) in group B. In contrast, TAS remained unaltered and the all enzyme activities were reduced (p<0.001) in group D at the same time of study. Mg2+-ATPase activity remained unchanged. In vitro incubation of the modulated AChE and Na+, K+-ATPase with L-C (25 microM) from group B and group D resulted in a non-significant reduction of the enzymes in group B and complete restoration of their activities in group D. CONCLUSIONS: The increase of AChE and Na+, K+-ATPase activities may be due to the elevation of catecholamines in group B. Carnitine utilization by the muscles during training may result in a reduction of the enzyme activities (group D). The latter is supported by the recovery of the enzyme activities after incubation of the membranes from group D with L-C.

Influence of tetrahydrocurcumin on erythrocyte membrane bound enzymes and antioxidant status in experimental type 2 diabetic rats.

Curcuma longa (Zingiberaceae) has been used traditionally as antidiabetic and has been proven scientifically to possess high antioxidant activity and anticancer properties. The active components of Curcuma longa such as curcumin and tetrahydrocurcumin (THC), a major colourless metabolite of curcumin also possesses antidiabetic, antiinflammatory and antioxidant activity. In the present study the effect of THC and curcumin on erythrocyte membrane bound enzymes and antioxidants activity in streptozotocin (STZ) and nicotinamide induced type 2 diabetic model was investigated. Oral administration of THC at 80 mg/kg body weight to diabetic rats for 45 days. The effect of THC and curcumin on glucose, insulin, haemoglobin, glycosylated haemoglobin, thiobarbituric acid reactive substances (TBARS), superoxide dismutase (SOD), catalase (CAT), glutathione peroxide (Gpx), glutathione-S-transferase (GST), reduced glutathione (GSH) and membrane bound enzymes were studied. The effect of THC was compared with curcumin. The levels of blood glucose, glycosylated haemoglobin, erythrocyte TBARS, were increased significantly whereas the level of plasma insulin and haemoglobin, erythrocyte antioxidants (SOD, CAT, GPx, GST and GSH), membrane bound total ATPase, Na(+)/K(+)-ATPase, Ca(2+)-ATPase, Mg(2+)-ATPase were decreased significantly in diabetic rats. Administration of THC and curcumin to diabetic rats showed decreased level of blood glucose, glycosylated haemoglobin and erythrocyte TBARS. In addition the levels of plasma insulin, haemoglobin, erythrocyte antioxidants and the activities of membrane bound enzymes also were increased in THC and curcumin treated diabetic rats. These biochemical observations were supplemented by histopathological examination of pancreas section. The present study indicates that the THC possesses a significant beneficial effect on erythrocyte membrane bound enzymes and antioxidants defense in addition to its antidiabetic effect.

L-cysteine supplementation prevents exercise-induced alterations in human erythrocyte membrane acetylcholinesterase and Na+,K+-ATPase activities.

BACKGROUND: L-Cysteine (L-Cys) is implicated in the reduction of free radical production. The aim of this study was to investigate whether L-Cys supplementation prevents modulation of the activities of erythrocyte membrane acetylcholinesterase (AChE), Na(+),K(+)-ATPase and Mg(2+)-ATPase induced by free radicals in basketball players during training. METHODS: Blood was obtained from 10 basketball male players before (group A) and after a game (group B) and after 1 week of L-Cys (0.5 g/24 h orally) supplementation before (group C) and after training (group D). Lactate, pyruvate and total antioxidant status (TAS) were measured using commercial kits and the enzyme activities were determined spectrophotometrically. RESULTS: Both lactate and pyruvate levels remarkably increased after exercise. In contrast, TAS levels significantly decreased in group B, increased in group C and then declined (group D), reaching those of group A. AChE activity was statistically increased post-exercise (3.98+/-0.04 Delta OD/min x mg protein) compared with pre-training (2.90+/-0.05 Delta OD/min x mg protein, p<0.01). Na(+),K(+)-ATPase activity was also higher post-exercise (1.27+/-0.05 micromol Pi/h x mg protein) than that pre-exercise (0.58+/-0.04 micromol Pi/h x mg protein, p<0.001). When the players were supplemented with L-Cys, both AChE and Na(+),K(+)-ATPase activities remained unaltered post-exercise. Mg(2+)-ATPase activities were unchanged in all groups studied. CONCLUSIONS: L-Cys supplementation may protect the enzyme activities studied against stimulation induced by free radical production during training in athletes by ameliorating their total antioxidant capacity.

An in vivo and in vitro study of erythrocyte membrane acetylcholinesterase, (Na+, K+)-ATPase and Mg2+-ATPase activities in basketball players on alpha-tocopherol supplementation. The role of L-carnitine.

BACKGROUND & AIMS: Vitamin E (alpha-tocopherol, alpha-Te) and carnitine reduce lipid peroxidation. THE AIM WAS TO: To investigate the erythrocyte membrane acetylcholinesterase (AChE), Na+, K+-ATPase and Mg2+-ATPase activities in basketball players with or without alpha-Te supplementation, before and after training. In vitro, we aimed to find out any additional effect of L-carnitine (L-C) on the modulated enzyme activities. SUBJECTS AND METHODS: Blood was obtained from 10 players before (group A), after exercise (group B) and after 1 month on alpha-Te (200 mg/24 h orally) supplementation before (group C) and after the game (group D). Lactate, pyruvate, muscle enzyme activities and total antioxidant status (TAS) were measured with commercial kits. Catecholamines and alpha-Te were determined with HPLC methods and membrane enzyme activities spectrophotometrically. RESULTS: Lactate, pyruvate, muscle enzymes and catecholamine levels were increased (P<0.001) in all groups after training. Alpha-Te levels and Mg2+-ATPase activity remained unaltered before and after exercise. TAS was decreased in the groups after the game. AChE activity was increased in group B (P<0.01) and decreased in group D (P<0.01). After the exercise, Na+, K+-ATPase activity was increased in group B and remained unaltered in group D. In vitro incubation of membranes from group D with L-C resulted in a partially restoration of the membrane AChE activity, whereas Na+, K+-ATPase and Mg2+-ATPase activities were found unchanged. CONCLUSIONS: Alpha-Te supplementation in basketball players results in an increase of TAS and AChE activity, whereas the other enzyme activities were found unchanged. L-C addition may restore AChE activity, which was modulated by training in players on alpha-Te.

Synthesis and evaluation of in vitro antioxidant capacities of some benzimidazole derivatives.

New, except 1d, melatonin analogue benzimidazole derivatives were synthesized and characterized in the present study. The potential role of melatonin as an antioxidant by scavenging and detoxifying ROS raised the possibility that compounds that are analogous to melatonin can also be used for their antioxidant properties. Therefore the antioxidant effects of the newly synthesized compounds were investigated in vitro by means of their inhibitory effect on hydrogen peroxide-induced erythrocyte membrane lipid peroxidation (EMLP) and on various erythrocyte antioxidant enzymes viz. superoxide dismutase (SOD), catalase (CAT) and glucose-6-phosphate dehydrogenase (G6PD). The synthesized benzimidazole derivatives showed remarkable antioxidant activity in vitro in the H2O2-induced EMLP system. Furthermore their effects on various antioxidant enzymes are discussed and evaluated from the perspective of structure- activity relationships.