Nutritional approaches to combat oxidative stress in Alzheimer's disease

Alzheimer's disease (AD) brains are characterized by extensive oxidative stress. Additionally, large depositions of amyloid beta-peptide (Abeta) are observed, and many researchers opine that Abeta is central to the pathogenesis of AD. Our laboratory combined these two observations in a comprehensive model for neurodegeneration in AD brains centered around Abeta-induced oxidative stress. Given the oxidative stress in AD and its potentially important role in neurodegeneration, considerable research has been conducted on the use of antioxidants to slow or reverse the pathology and course of AD. One source of antioxidants is the diet. This review examines the literature of the effects of endogenous and exogenous, nutritionally-derived antioxidants in relation to AD. In particular, studies of glutathione and other SH-containing antioxidants, vitamins, and polyphenolic compounds and their use in AD and modulation of Abeta-induced oxidative stress and neurotoxicity are reviewed.     

A literature review on beneficial role of vitamins and trace elements: Evidence from published clinical studies

COVID-19 is a kind of SARS-CoV-2 viral infectious pneumonia. This research aims to perform a bibliometric analysis of the published studies of vitamins and trace elements in the Scopus database with a special focus on COVID-19 disease. To achieve the goal of the study, network and density visualizations were used to introduce an overall picture of the published literature. Following the bibliometric analysis, we discuss the potential benefits of vitamins and trace elements on immune system function and COVID-19, supporting the discussion with evidence from published clinical studies. The previous studies show that D and A vitamins demonstrated a higher potential benefit, while Selenium, Copper, and Zinc were found to have favorable effects on immune modulation in viral respiratory infections among trace elements. The principles of nutrition from the findings of this research could be useful in preventing and treating COVID-19.     

Physiological levels of tea catechins increase cellular lipid antioxidant activity of vitamin C and vitamin E in human intestinal caco-2 cells

Oxidative stress has been linked to the development of various chronic diseases. Vegetables and fruits, which contain polyphenols, were shown to have protective effects. (-)-Epigallocatechin-3-gallate (EGCG), a polyphenol abundant in tea, has been shown to have antioxidant activities in cell-free conditions and this study focused on the effect of cellular EGCG. Using an intestinal cell model to examine the oxidative stress induced by hydroxyl radicals, we report here that physiological concentrations (0.1-1 microM) of EGCG have dose- and incubation duration-dependent cell-associated lipid antioxidant activity (measuring malondialdehyde production). Vitamin E and vitamin C at 10-40 microM also showed cell-associated lipid antioxidant activities under shorter incubation durations. When EGCG was included in the incubation with vitamin E or C, more antioxidant activities were consistently observed than when vitamins were added alone. Catechin (widely present in fruits and vegetables) at 1 microM also significantly increased the antioxidant activity of vitamins E and C. Previous studies examining cell-associated activity of EGCG mainly focused on the 10-100 microM concentration range. Our results suggest that although the physiological level (0.1-1 microM) of dietary catechins is much lower than that of vitamins, they further contribute to the total antioxidant capacity even in the presence of vitamins.     

Protecting antioxidative effects of vitamins E and C in experimental physical stress

Like every redox-active compound vitamin E may exert pro-oxidative and antioxidative effects depending on the reaction partners present. In this work we evaluated the intensity of oxidative stress produced by a physical exercise through swimming as well as of protecting action of antioxidant vitamins E and C. Antioxidant systems include antioxidant enzymes: superoxide-dismutase (SOD), catalase (CAT), glutathion peroxidase (GSH-Px), as well as of components with an antioxidant action of the reduced glutathion type (GSH) and vitamins E and C. We determine the activities of these enzymes in the erythrocytes and heart homogenate. Our results points out a protective effect against oxidative stress produced by swimming in animals treated with vitamins E and C, which are expressed through the diminution of the malondialdehyde (MDA) quantity both in erythrocytes and in the heart, and through the conservation of GSH content in both products. CAT and GSH-Px activities decrease while that of SOD increases on both tissues, but with different intensities in accordance with the variation of protection degree performed by the vitamin couple on these tissues. The obtained data underline the necessity of intensifying the means of endogenous antiradical defence with exogenous antioxidant vitamins C and E. This study highlights the need of a proper vitamin supplement in organism under stress.     

Protective antioxidant effect of vitamins C and E in streptozotocin induced diabetic rats

We have investigated the protective effect of vitamin C and E together supplementation on oxidative stress and antioxidant enzyme activities in the liver of streptozotocin-induced diabetic rats, unsupplemented diabetic and control rats. We also determined the levels of both the vitamins and oxidative stress in plasma. Vitamin supplementation in diabetic rats lowered plasma and liver lipid peroxidation, normalised plasma vitamin C levels and raised vitamin E above normal levels. In liver, the activity of glutathione peroxidase was raised significantly and that of glutathione-S-transferase was normalised by vitamin supplementation in diabetic rats. The levels of lipid peroxidation products in plasma and liver of vitamin-supplemented diabetic rats and activities of antioxidant enzymes in liver suggest that these vitamins reduce lipid peroxidation by quenching free radicals.     

Benefiting others and self: Production of vitamins in plants

Vitamins maintain growth and development in humans, animals, and plants. Because plants serve as essential producers of vitamins, increasing the vitamin contents in plants has become a goal of crop breeding worldwide. Here, we begin with a summary of the functions of vitamins. We then review the achievements to date in elucidating the molecular mechanisms underlying how vitamins are synthesized, transported, and regulated in plants. We also stress the exploration of variation in vitamins by the use of forward genetic approaches, such as quantitative trait locus mapping and genome-wide association studies. Overall, we conclude that exploring the diversity of vitamins could provide new insights into plant metabolism and crop breeding.     

Taurine as a universal carrier of lipid soluble vitamins: a hypothesis

Summary. In the literature taurine is characterized as a non-specific growth or blood clotting factor, an antioxidant, a membrane protector, or a regulator of calcium ion homeostasis, just as vitamins A, D, E, F, and K are similarly characterized. On the basis of recent finding concerning the relationship between taurine and the aldehyde of vitamin A-retinal (Petrosian and Haroutounian, 1988, 1998; Petrosian et al., 1996), as well as on the basis of data from the literature, we now suggest a hypothesis that taurine promotes the bioavailability of the lipid soluble vitamins A, D, E, K, and F, probably by forming different types of water soluble, easily hydrolyzable complexes. It is quite possible that the ability of taurine to convert lipids and lipid soluble substances into a water soluble state is the key to understanding the unusually wide diversity of biological phenomena associated with taurine. This form of delivery may be an additional, secondary mechanism for the transport of lipid soluble vitamins, which was probably acquired early in evolution, and remains extremely important for mammals and humans directly after birth for a variety of physiological functions such as: vision in normal and in emergency situations, rapid blood clotting, sperm eruption, and situations requiring a prompt consumption of lipid soluble vitamins characteristic of excitable systems. Clearly, the role of taurine in the physiology of the water insoluble vitamins remains an enigma and is worthy of further investigations. Received December 23, 1999; Accepted December 28, 1999     

Interaction of vitamin C and vitamin E during free radical stress in plasma: An ESR study

To study the interaction of the antioxidant vitamins C and E in a biological system, we used electron spin resonance (ESR) spectroscopy to make serial measurement of ascorbate tocopheroxyl free radicals in plasma subjected to continuous free radical-mediated oxidative stress. Upon initiation of a continuous oxidative stress, we observed an immediate increase in the concentration of ascorbate radical, which reached a peak, and then steadily declined. Only after the virtual disappearance of the ascorbate radical did we observe the appearance of the tocopheroxyl radical. These data are consistent with the hypothesis that ascorbate is the terminal small-molecule antioxidant in biological systems. This is the first experimental demonstration that the predicted thermodynamic hierarchy of ascorbate, -tocopherol, and their free radicals holds in a biological system containing endogenous levels of these antioxidant vitamins.     

Vitamins C and E prevent AZT-induced leukopenia and loss of cellularity in bone marrow. Studies in mice

A major limitation in the use of AZT for AIDS treatment is the occurrence of side effects, such as leukopenia. The effects of antioxidant vitamins C and E on AZT-induced leukopenia were investigated in mice. Mice were divided into four groups: (1) controls; (2) AZT-treated; (3) treated with AZT plus vitamins C and E; and (4) pre-treated with vitamins and then treated with AZT plus vitamins. Our results demonstrate that AZT causes leukopenia in mice, which was abrogated by administration of vitamins C and E in the pre-treated group. These vitamins prevented the decrease in cellular content induced by AZT in bone marrow and diminished peroxide levels in myeloid precursors in bone marrow. AZT also caused an increase in plasma malondialdehyde and blood oxidized glutathione levels, which was prevented by the administration of antioxidant vitamins. In conclusion, oxidative stress is involved in AZT-induced leukopenia which may be prevented by antioxidant treatment.     

Vitamins C and E prevent AZT-induced leukopenia and loss of cellularity in bone marrow. Studies in mice

A major limitation in the use of AZT for AIDS treatment is the occurrence of side effects, such as leukopenia. The effects of antioxidant vitamins C and E on AZT-induced leukopenia were investigated in mice. Mice were divided into four groups: (1) controls; (2) AZT-treated; (3) treated with AZT plus vitamins C and E; and (4) pre-treated with vitamins and then treated with AZT plus vitamins. Our results demonstrate that AZT causes leukopenia in mice, which was abrogated by administration of vitamins C and E in the pre-treated group. These vitamins prevented the decrease in cellular content induced by AZT in bone marrow and diminished peroxide levels in myeloid precursors in bone marrow. AZT also caused an increase in plasma malondialdehyde and blood oxidized glutathione levels, which was prevented by the administration of antioxidant vitamins. In conclusion, oxidative stress is involved in AZT-induced leukopenia which may be prevented by antioxidant treatment.     

Antioxidants prevent memory deficits provoked by chronic variable stress in rats

Learning and memory deficits occur in depression and other stress related disorders. Although the pathogenesis of cognitive impairment after stress has not been fully elucidated, factors such as oxidative stress and neurotrophins are thought to play possible roles. Here we investigated the effect of treatment with vitamin E (40 mg/kg) and vitamin C (100 mg/kg) on the effects elicited by chronic variable stress on rat performance in Morris water maze. Brain-derived neurotrophic factor (BDNF) immunocontent was also evaluated in hippocampus of rats. Sixty-day old Wistar rats were submitted to different stressors for 40 days (stressed group). Half of stressed group received administration of vitamins once a day, during the period of stress. Chronically stressed rats presented a marked decrease in reference memory in the water maze task as well as a reduced efficiency to find the platform in the working memory task. Rats treated with vitamins E and C had part of the above effects prevented, suggesting the participation of oxidative stress in such effects. The BDNF levels were not altered in hippocampus of stressed group when compared to controls. Our findings lend support to a novel therapeutic strategy, associated with these vitamins, to the cognitive dysfunction observed in depression and other stress related diseases.     

Vitamins C and E improve rat embryonic antioxidant defense mechanism in diabetic culture medium.

BACKGROUND: Diabetes teratogenicity seems to be related to embryonic oxidative stress and the extent of the embryonic damage can apparently be reduced by antioxidants. We have studied the mechanism by which antioxidants, such as vitamins C and E, reduce diabetes-induced embryonic damage. We therefore compared the antioxidant capacity of 10.5-day-old rat embryos and their yolk sacs cultured for 28h in diabetic culture medium with or without vitamins C and E. METHODS: The embryos were cultured in 90% rat serum to which 2mg/ml glucose, 2mg/ml beta hydroxy butyrate (BHOB) and 10 microg/ml of acetoacetate were added. Rat embryos were also cultured in a diabetic medium with 25 microg/ml of vitamin E and 50 microg/ml of vitamin C. Control embryos were cultured in normal rat serum with or without vitamins C and E. RESULTS: Decreased activity of Cu/Zn superoxide dismutase (SOD) and of catalase (CAT) in the "diabetic" embryos and their yolk sacs, and reduced concentrations of low molecular weight antioxidant (LMWA) were found. Under these conditions we also found a decrease in vitamin C and vitamin E concentrations in the embryos, as measured by HPLC. In situ hybridization for SOD mRNA showed a marked reduction of SOD mRNA in the brain, spinal cord, heart and liver of embryos cultured in diabetic medium in comparison to controls. Following the addition of vitamins C and E to the diabetic culture medium, SOD and CAT activity, the concentrations of LMWA, the levels of vitamin C and E and the expression of SOD mRNA in the embryos and yolk sacs returned to normal. CONCLUSIONS: Diabetic metabolic factors seem to have a direct effect on embryonic SOD gene and perhaps genes of other antioxidant enzymes, reducing embryonic endogenous antioxidant defense mechanism. This in turn may cause a depletion of the LMWA, such as vitamins C and E. The addition of these vitamins normalizes the embryonic antioxidant defense mechanism, reducing the damage caused by the diabetic environment.     

Purple non-sulphur bacteria and plant production: benefits for fertilization,stress resistance and the environment

Purple non-sulphur bacteria (PNSB) are phototrophic microorganisms, which increasingly gain attention in plant production due to their ability to produce and accumulate high-value compounds that are beneficial for plant growth. Remarkable features of PNSB include the accumulation of polyphosphate, the production of pigments and vitamins and the production of plant growth-promoting substances (PGPSs). Scattered case studies on the application of PNSB for plant cultivation have been reported for decades, yet a comprehensive overview is lacking. This review highlights the potential of using PNSB in plant production, with emphasis on three key performance indicators (KPIs): fertilization, resistance to stress (biotic and abiotic) and environmental benefits. PNSB have the potential to enhance plant growth performance, increase the yield and quality of edible plant biomass, boost the resistance to environmental stresses, bioremediate heavy metals and mitigate greenhouse gas emissions. Here, the mechanisms responsible for these attributes are discussed. A distinction is made between the use of living and dead PNSB cells, where critical interpretation of existing literature revealed the better performance of living cells. Finally, this review presents research gaps that remain yet to be elucidated and proposes a roadmap for future research and implementation paving the way for a more sustainable crop production.     

Antioxidants attenuate myocyte apoptosis and improve cardiac function in CHF: association with changes in MAPK pathways

Antioxidant vitamins reduce cardiac oxidative stress and cardiomyocyte apoptosis produced by exogenous norepinephrine (NE) and attenuate cardiac dysfunction in animals with pacing-induced congestive heart failure (CHF). This study was carried out to determine whether the mitogen-activated protein kinase (MAPK) signal transduction pathways are involved in oxidative stress-induced myocyte apoptosis. Rabbits with rapid pacing-induced CHF and sham operation were randomized to receive either a combination of antioxidant vitamins (beta-carotene, ascorbic acid, and alpha-tocopherol), alpha-tocopherol alone, or placebo for 8 wk. Compared with sham-operated animals, CHF animals exhibited increased oxidative stress as evidenced by decreased myocardial reduced-to-oxidized glutathione (GSH/GSSG) ratio (27 +/- 7 vs. 143 +/- 24, P < 0.05), myocyte apoptosis (77 +/- 18 vs. 17 +/- 4 apoptotic nuclei/10,000 cardiomyocytes, P < 0.05), increased total and phosphorylated c-Jun NH2-terminal protein kinase (p-JNK; 1.95 +/- 0.14 vs. 1.04 +/- 0.04 arbitrary units, P < 0.05) and phosphorylated p38 kinase (p-p38), and decreased phosphorylated extracellular signal-regulated kinase (p-ERK). Administration of antioxidant vitamins and alpha-tocopherol attenuated oxidative stress, myocyte apoptosis, and cardiac dysfunction, with reversal of the changes of total JNK, p-JNK, and p-ERK in CHF. Furthermore, because NE infusion produced changes of JNK, p-p38, and p-ERK similar to those in CHF, we conclude that NE may play an important role in the production of oxidative stress, MAPK activation, and myocyte apoptosis in CHF.     

Vitamin requirements for development of eight-cell hamster embryos to hatching blastocysts in vitro

We have shown in previous studies that development of 8-cell hamster embryos to hatching and hatched blastocysts in vitro is stimulated by the addition to the culture medium of a group of 11 water-soluble vitamins and growth factors from Ham's F10 medium. In the present study, the requirement for each of these vitamins for blastocyst hatching was examined by using a chemically defined protein-free medium. Eight-cell hamster embryos were cultured for 3 days either in medium with all 11 vitamins or in media with a single vitamin omitted at a time or in medium without any vitamins. The only vitamins whose omission caused a significant decrease in blastocyst hatching at any stage were inositol, pantothenate, and choline, with the omission of inositol having the most severe effect. This finding was confirmed in a subsequent experiment in which the addition of these 3 vitamins stimulated the same degree of hatching as all 11 vitamins.     

Modulation of restraint stress induced oxidative changes in rats by antioxidant vitamins

In the present study we examined immobilization stress-induced antioxidant defense changes in rat plasma and also observed the antioxidant effects of pre and post vitamins A, E and C administration (15 mg/Kg of body weight) individually and in combination (vit E + C) on these alterations.Following immobilization stress the circulating activities of superoxide dismutase, catalase and glutathione-S-transferase were decreased, while the level of thiobarbituric acid reactive substances (TBARS) was increased as compared to non-stressed control rats.Post treatment with individual vitamins A, E and C (after exposure to stress) resulted in a less marked alteration of plasma TBARS levels and activities of SOD, GST and catalase as compared to pre vitamin stress or stress alone treatments. Both pre and post vitamin treatments were effective in preventing stress induced derangement of free radical metabolism with a relative dominance by latter. The combined treatment with vitamin E and C did not show any additive antioxidant effect on restraint stress induced altered free radical metabolism, rather a predominant effect similar to vitamin E alone was observed. The prevention of oxidative stress generated in response to restraint stress by the vitamins can be summarized as: vitamin (E + C) i.e. vit E > vit C > vit A, thus combined vitamin (E + C) treatment though showed maximum preventive effect, but was similar to vitamin E treatment alone, in terms of the circulating activities of SOD, GST, catalase and TBARS levels.     

水溶性维生素在植物体内的合成

由于植物基因组的快速发展,研究者借助酵母和细菌等微生物的相关信息,使大多数水溶性维生素在植物体内的生物合成途径得以在分子水平上阐明.本文就近年来植物水溶性维生素的生物合成途径、合成场所等研究进展进行了概述,并就植物和微生物水溶性维生素合成途径的关系进行了比较.     

A systematic review of the role of vitamin insufficiencies and supplementation in COPD

Background

Pulmonary inflammation, oxidants-antioxidants imbalance, as well as innate and adaptive immunity have been proposed as playing a key role in the development of COPD. The role of vitamins, as assessed either by food frequency questionnaires or measured in serum levels, have been reported to improve pulmonary function, reduce exacerbations and improve symptoms. Vitamin supplements have therefore been proposed to be a potentially useful additive to COPD therapy.

Methods

A systematic literature review was performed on the association of vitamins and COPD. The role of vitamin supplements in COPD was then evaluated.

Conclusions

The results of this review showed that various vitamins (vitamin C, D, E, A, beta and alpha carotene) are associated with improvement in features of COPD such as symptoms, exacerbations and pulmonary function. High vitamin intake would probably reduce the annual decline of FEV1. There were no studies that showed benefit from vitamin supplementation in improved symptoms, decreased hospitalization or pulmonary function.     

AZT induces oxidative damage to cardiac mitochondria: protective effect of vitamins C and E

AZT (zidovudine) is a potent inhibitor of HIV replication and a major antiretroviral drug used for AIDS treatment. A major limitation in the use of AZT is the occurrence of severe side effects. The aim of this work was to test whether AZT causes oxidative damage to heart mitochondria and whether this can be prevented by supranutritional doses of antioxidant vitamins. An experimental animal model was used in which mice were treated with AZT for 35 days (10 mg/kg/day) in drinking water. Animals treated with antioxidant vitamins were fed the same diet as controls but supplemented with vitamins C (ascorbic acid, 10 g/ kg diet) and E (alpha-dl-tocopherol, 0.6 g/kg diet) for 65 days before sacrifice. This resulted in a daily intake of 1250 mg/kg/day (vitamin C) and 75 mg/kg/day (vitamin E). Cardiac mitochondrial DNA (mtDNA) of mice treated with AZT had over 120% more oxo-dG (8-oxo-7,8-dihydro-2'-deoxyguanosine, which is a biomarker of oxidative damage to DNA) in their mitochondrial DNA than untreated controls. AZT treatment also caused an increase in mitochondrial lipid peroxidation and an oxidation of mitochondrial glutathione. Dietary supplementation with supranutritional doses of the antioxidant vitamins C and E protected against these signs of mitochondrial oxidative stress. The oxidative effects of AZT are probably due to an increase in production of reactive oxygen species by mitochondria of AZT-treated animals, raising the possibility that oxidative stress may play an important role in the cardiotoxicity of AZT.     

Gestation linked radical oxygen species fluxes and vitamins and trace mineral deficiencies in the ruminant

In mammals, radical oxygen species (ROS) are essential factors of cell replication, differentiation and growth (oxidative signal), notably during gestation, but are also potentially damaging agents. In Women, ROS play a role in remodeling of uterine tissues, implantation of the embryo, settlement of the villi and development of blood vessels characteristic of gestation. The body stores of vitamins and minerals of gestating females are used to keep ROS fluxes at a level corresponding to oxidative signals and to prevent an imbalance between their production and scavenging (oxidative stress), which would be detrimental to the mother and fetus. There is some evidence that, although based on different regulatory mechanisms, most of the effects of ROS reported in humans also occur in pregnant ruminant females, some of which have been actually reported. Many vitamins and trace elements have dual effects in the organism of mammals: (a) they are involved in the control of metabolic pathways or/and gene expression, (b) but most of the time they also display ROS trapping activity or their deficiencies induce high rates of ROS production. Deficiencies induce different disorders of gestation and can be induced by different kinds of stress. An example is given, corresponding to the decreased contents of cobalt of forages, when exposed to sustained heavy rains, so that the supply of vitamins B12 to the organism of the ruminant that grazes them is reduced and failure of gestation is induced. Outdoor exposure of ruminants to adverse climatic conditions by itself can increase the vitamin and trace element requirements. Adaptation of production systems taking into account these interactions between gestation and sources of stress or change of the quality of feeding stuffs as well as further developments of knowledge in that field is necessary to promote sustainable agricultural practices.