Randomized controlled trial of oral glutathione supplementation on body stores of glutathione

Inhibitory Effects of Raw-Extract Centella asiatica (RECA) on Acetylcholinesterase, Inflammations, and Oxidative Stress Activities via In Vitro and In Vivo

Centella asiatica (C. asiatica) is one of the medicinal plants that has been reported to exert comprehensive neuroprotection in vitro and in vivo. In view of this, the present study was performed to investigate the effect of ethanolic extract of C. asiatica, designated as raw-extract of C. asiatica (RECA) in reducing the acetylcholinesterase (AChE), inflammations, and oxidative stress activities via both in vitro (SH-SY5Y and RAW 264.7 cells) and in vivo (Sprague Dawley rats). Quantitative high-performance liquid chromatography analysis reveals that RECA contains a significantly high proportion of glycosides than the aglycones with madecassoside as the highest component, followed by asiaticoside. Treatment of SH-SY5Y cells with RECA significantly reduced the AChE activity in a concentration-dependent manner with an IC₅₀ value of 31.09 ± 10.07 µg/mL. Furthermore, the anti-inflammatory and antioxidant effects of RECA were evaluated by lipopolysaccharides (LPS)-stimulated RAW 264.7 cells. Our results elucidated that treatment with RECA significantly suppressed the level of pro-inflammatory cytokine/mediators and oxidative stress released in a concentration-dependent manner. Interestingly, these patterns of inhibition were consistent as observed in the LPS-induced neuroinflammation Sprague Dawley rats’ model. The highest concentration used in the two models presented the most significant results. Herein, our findings strongly suggest that RECA may offer therapeutic potential for the treatment of Alzheimer’s disease through inhibiting the AChE, inflammation, and oxidative stress activities.

A Review of Dietary (Phyto)Nutrients for Glutathione Support

Glutathione is a tripeptide that plays a pivotal role in critical physiological processes resulting in effects relevant to diverse disease pathophysiology such as maintenance of redox balance, reduction of oxidative stress, enhancement of metabolic detoxification, and regulation of immune system function. The diverse roles of glutathione in physiology are relevant to a considerable body of evidence suggesting that glutathione status may be an important biomarker and treatment target in various chronic, age-related diseases. Yet, proper personalized balance in the individual is key as well as a better understanding of antioxidants and redox balance. Optimizing glutathione levels has been proposed as a strategy for health promotion and disease prevention, although clear, causal relationships between glutathione status and disease risk or treatment remain to be clarified. Nonetheless, human clinical research suggests that nutritional interventions, including amino acids, vitamins, minerals, phytochemicals, and foods can have important effects on circulating glutathione which may translate to clinical benefit. Importantly, genetic variation is a modifier of glutathione status and influences response to nutritional factors that impact glutathione levels. This narrative review explores clinical evidence for nutritional strategies that could be used to improve glutathione status.

Characteristics of Selected Antioxidative and Bioactive Compounds in Meat and Animal Origin Products

Meat and meat products have a high nutritional value. Besides major components, meat is rich in bioactive components, primarily taurine, l-carnitine, choline, alpha-lipoic acid, conjugated linoleic acid, glutathione, creatine, coenzyme Q10 and bioactive peptides. Many studies have reported their antioxidant and health-promoting properties connected with their lipid-lowering, antihypertensive, anti-inflammatory, immunomodulatory activity and protecting the organism against oxidative stress. The antioxidant activity of meat components results, among others, from the capability of scavenging reactive oxygen and nitrogen species, forming complexes with metal ions and protecting cells against damage. This review is focused to gather accurate information about meat components with antioxidant and biological activity.

Antioxidant supplementation during illness in dogs: effect on oxidative stress and outcome, an exploratory study

OBJECTIVES

To assess whether combination antioxidant supplementation for 30 days in systemically ill dogs alters antioxidant status, degree of lipid peroxidation, clinical score and survival.

MATERIALS AND METHODS

Forty client-owned systemically-ill hospitalised dogs were eligible for inclusion. Dogs were randomised to no supplementation (NS; n=19) or supplementation with N-acetylcysteine/S-adenosylmethionine/silybin and vitamin E (AS; n=20) for 30 days. Clinical score and oxidative biomarkers including glutathione, cysteine, vitamin E, selenium and urine isoprostanes/creatinine (F₂ -IsoPs/Cr) were determined on days 0 and 30. Glutathione, cysteine, vitamin E and urine F₂ -IsoPs/Cr were quantified by high-performance liquid chromatography, and selenium concentrations determined using atomic absorption spectroscopy.

RESULTS

Thirty-two dogs completed the study (NS, n=16; AS, n=16). Vitamin E concentrations were significantly greater in the supplemented compared to the non-supplemented group. No other markers of oxidative stress significantly changed with supplementation. There was no difference in Day 30 clinical scores or survival between the two groups.

CLINICAL SIGNIFICANCE

In this population of systemically-ill hospitalised dogs, combination antioxidant supplementation did not alter redox state or clinical outcome.

Hyperglycemia (high-glucose) decreases L-cysteine and glutathione levels in cultured monocytes and blood of Zucker diabetic rats

L-Cysteine (LC) is an essential precursor of GSH biosynthesis. GSH is a major physiological antioxidant, and its depletion increases oxidative stress. Diabetes is associated with lower blood levels of LC and GSH. The mechanisms leading to a decrease in LC in diabetes are not entirely known. This study reports a significant decrease in LC in human monocytes exposed to high glucose (HG) concentrations as well as in the blood of type 2 diabetic rats. Thus, a significant decrease in the level of LC in response to exposure to HG supports the assertion that uncontrolled hyperglycemia contributes to a reduction of blood levels of LC and GSH seen in diabetic patients. Increased requirement of LC to replace GSH needed to scavenge excess ROS generated by hyperglycemia can result in lower levels of LC and GSH. Animal and human studies report that LC supplementation improves GSH biosynthesis and is beneficial in lowering oxidative stress and insulin resistance. This suggests that hyperglycemia has a direct role in the impairment of LC and GSH homeostasis in diabetes.

Impact of Supplementary Amino Acids, Micronutrients, and Overall Diet on Glutathione Homeostasis

Glutathione (GSH) is a critical endogenous antioxidant found in all eukaryotic cells. Higher GSH concentrations protect against cellular damage, tissue degeneration, and disease progression in various models, so there is considerable interest in developing interventions that augment GSH biosynthesis. Oral GSH supplementation is not the most efficient option due to the enzymatic degradation of ingested GSH within the intestine by γ-glutamyltransferase, but supplementation of its component amino acids-cysteine, glycine, and glutamate-enhances tissue GSH synthesis. Furthermore, supplementation with some non-precursor amino acids and micronutrients appears to influence the redox status of GSH and related antioxidants, such as vitamins C and E, lowering systemic oxidative stress and slowing the rate of tissue deterioration. In this review, the effects of oral supplementation of amino acids and micronutrients on GSH metabolism are evaluated. And since specific dietary patterns and diets are being prescribed as first-line therapeutics for conditions such as hypertension and diabetes, the impact of overall diets on GSH homeostasis is also assessed.

Glutathione "Redox Homeostasis" and Its Relation to Cardiovascular Disease

More people die from cardiovascular diseases (CVD) than from any other cause. Cardiovascular complications are thought to arise from enhanced levels of free radicals causing impaired "redox homeostasis," which represents the interplay between oxidative stress (OS) and reductive stress (RS). In this review, we compile several experimental research findings that show sustained shifts towards OS will alter the homeostatic redox mechanism to cause cardiovascular complications, as well as findings that show a prolonged antioxidant state or RS can similarly lead to such cardiovascular complications. This experimental evidence is specifically focused on the role of glutathione, the most abundant antioxidant in the heart, in a redox homeostatic mechanism that has been shifted towards OS or RS. This may lead to impairment of cellular signaling mechanisms and elevated pools of proteotoxicity associated with cardiac dysfunction.

The absorptive effects of orobuccal non-liposomal nano-sized glutathione on blood glutathione parameters in healthy individuals: A pilot study

BACKGROUND

Glutathione is an endogenous antioxidant found in oxidized (GSSG) and reduced (GSH) forms. Glutathione depletion is indicative of oxidative stress and occurs in various pathological conditions and following extreme exercise activity. Raising blood glutathione concentration has potential to attenuate and prevent chronic disease and also to improve recovery from exercise. There are a number of challenges to achieving this through traditional dietary supplements, and thus there is a need to develop optimized delivery methods to improve blood glutathione status. This study evaluated the effect of a novel glutathione formulation on blood glutathione parameters in healthy individuals.

METHODS

15 (8 male) healthy individuals (25±5y old, 78.0±14.6kg) participated in a single-blinded randomized placebo-controlled crossover study, with a minimum one-week washout period between treatments. Participants were overnight fasted and administered 1mL of a non-liposomal nano-size glutathione solution (NLNG) containing 200mg of glutathione or 1mL of placebo lacking glutathione. The solution was held in the mouth for 90 seconds before the remainder was swallowed. Blood was collected at baseline, 5, 10, 30, 60 and 120 minutes post-treatment. Protein-bound plasma and erythrocyte lysate concentrations of GSH and GSSG were measured at all time points using previously validated procedures. Linear mixed effects models were used to compare differences between baseline and post-treatment glutathione concentrations between NLNG and placebo for each parameter.

RESULTS

There was a significant main effect for treatment type, such that increases in GSH concentration in erythrocyte lysate were greater following NLNG than placebo (p = 0.001). Similar significant main effects for treatment were also found for total (protein bound + erythrocyte lysate) GSH (p = 0.015) and GSSG (p = 0.037) concentration, as well as total blood glutathione pool (GSH+GSSG, p = 0.006).

DISCUSSION

NLNG increased multiple blood glutathione parameters compared to placebo. Future research should examine whether NLNG can attenuate oxidative stress.

Recent practical researches in the development of gluten-free breads

Wheat bread is consumed globally and has played a critical role in the story of civilization since the development of agriculture. While the aroma and flavor of this staple food continue to delight and satisfy most people, some individuals have a specific allergy to wheat or a genetic disposition to celiac disease. To improve the quality of life of these patients from a dietary standpoint, food-processing researchers have been seeking to develop high-quality gluten-free bread. As the quality of wheat breads depends largely on the viscoelastic properties of gluten, various ingredients have been employed to simulate its effects, such as hydrocolloids, transglutaminase, and proteases. Recent attempts have included the use of redox regulation as well as particle-stabilized foam. In this short review, we introduce the ongoing advancements in the development of gluten-free bread, by our laboratory as well as others, focusing mainly on rice-based breads. The social and scientific contexts of these efforts are also mentioned.

Antioxidant Defense Mechanisms in Erythrocytes and in the Central Nervous System

Differential antioxidant action is found upon comparison of organ/tissue systems in the human body. In erythrocytes (red blood cells), which transport oxygen and carbon dioxide through the circulatory system, the most important issue is to keep hemoglobin in a functional state that requires maintaining the haem group in ferrous (Fe²⁺) state. Conversion of oxidized Fe³⁺ back into Fe²⁺ in hemoglobin needs a special mechanism involving a tripeptide glutathione, glucose-6-phosphate dehydrogenase, and glucose and NADPH as suppliers of reducing power. Fava beans are probably a good resource to make the detox innate system more robust as the pro-oxidant molecules in this food likely induce the upregulation of members of such mechanisms. The central nervous system consumes more oxygen than the majority of human tissues, i.e., 20% of the body's total oxygen consumption and, therefore, it is exposed to a high level of oxidative stress. This fact, together with the progressive age-related decline in the efficiency of the antioxidant defense system, leads to neuronal death and disease. The innate mechanism operating in the central nervous system is not well known and seems different to that of the erythrocytes. The strategies of antioxidant intervention in brain will be reviewed here.

Protective effects of selenium and nano-selenium on bisphenol-induced reproductive toxicity in male rats

Bisphenol A (BPA) is a widespread compound associated with the manufacture of many consumer products. The BPA-induced reproductive toxicity was reported to be mainly attributed to oxidative stress. However, the role of antioxidants usage to decrease the injurious effects of BPA, on male reproductive functions, remains to unveil. The present research is established to evaluate the role of selenium (Se) and its nano form (NSe) as protective agents to alleviate BPA-induced testicular toxicity. Ninety mature albino male rats were assigned into six equal groups: negative control; orally BPA 150 mg/kg; Se 3 mg/kg; NSe 2 mg/kg; both BPA 150 mg/kg and Se 3 mg/kg; and BPA 150 mg/kg + NSe 2 mg/kg. The experiment lasted for 70 consecutive days, and then serum was collected for estimation of prostatic acid phosphatase. Testicular tissues were subjected to measurement of antioxidant status, lipid peroxidation, DNA damage, and expression of some apoptotic genes. Our results reported that BPA-induced marked testicular damage evidenced by significant elevations in serum prostatic acid phosphatase activity, malondialdehyde levels, a decrease in testicular catalase activity and reduced glutathione level. Moreover, marked DNA internucleosomal fragmentation pattern as well as upregulation of cyclooxygenase-2 and estrogen receptor-2 NSe genes were detected. Coadministration of Se and NSe attenuated the reproductive toxicity induced by BPA via improvement of the antioxidant activity, genetic changes, and restoration of testicular tissue nearly as control one. These results indicated that both Se and NSe forms could be used as reproductive protective agents against the detrimental effect induced by BPA. However, the NSe surpassed the selenium in modulating the DNA laddering, and the studied gene expression levels, and offered a potent reproductive protection.

Oral supplementation with liposomal glutathione elevates body stores of glutathione and markers of immune function

BACKGROUND/OBJECTIVES

Glutathione (GSH) is the most abundant endogenous antioxidant and a critical regulator of oxidative stress. Maintenance of optimal tissues for GSH levels may be an important strategy for the prevention of oxidative stress-related diseases. We investigated if oral administration of liposomal GSH is effective at enhancing GSH levels in vivo.

SUBJECTS/METHODS

A 1-month pilot clinical study of oral liposomal GSH administration at two doses (500 and 1000 mg of GSH per day) was conducted in healthy adults. GSH levels in whole blood, erythrocytes, plasma and peripheral blood mononuclear cells (PBMCs) were assessed in 12 subjects at the baseline and after 1, 2 and 4 weeks of GSH administration.

RESULTS

GSH levels were elevated after 1 week with maximum increases of 40% in whole blood, 25% in erythrocytes, 28% in plasma and 100% in PBMCs occurring after 2 weeks (P<0.05). GSH increases were accompanied by reductions in oxidative stress biomarkers, including decreases of 35% in plasma 8-isoprostane and 20% in oxidized:reduced GSH ratios (P<0.05). Enhancements in immune function markers were observed with liposomal GSH administration including Natural killer (NK) cell cytotoxicity, which was elevated by up to 400% by 2 weeks (P<0.05), and lymphocyte proliferation, which was elevated by up to 60% after 2 weeks (P<0.05). Overall, there were no differences observed between dose groups, but statistical power was limited due to the small sample size in this study.

CONCLUSIONS

Collectively, these preliminary findings support the effectiveness of daily liposomal GSH administration at elevating stores of GSH and impacting the immune function and levels of oxidative stress.

Protective effects of oral glutathione on fasting-induced intestinal atrophy through oxidative stress

AIM

To determine whether oral glutathione (GSH) administration can alleviate the effects of fasting-induced intestinal atrophy in the small intestinal mucosa.

METHODS

Rats were divided into eight groups. One group was fed ad libitum, another was fed ad libitum and received oral GSH, and six groups were administrated saline (SA) or GSH orally during fasting. Mucosal height, apoptosis, and cell proliferation in the jejunum were histologically evaluated. iNOS protein expression (by immunohistochemistry), nitrite levels (by high performance liquid chromatography, as a measure of NO production), 8-hydroxydeoxyguanosine formation (by ELISA, indicating ROS levels), glutathione/oxidized glutathione (GSH/GSSG) ratio (by enzymatic colorimetric detection), and γ-glutamyl transpeptidase (Ggt1) mRNA levels in the jejunum (by semi-quantitative RT-PCR) were also estimated.

RESULTS

Oral GSH administration was demonstrated to drastically reduce fasting-induced intestinal atrophy in the jejunum. In particular, jejunal mucosal height was enhanced in GSH-treated animals compared to SA-treated animals [527.2 ± 6.9 for 50 mg/kg GSH, 567.6 ± 5.4 for 500 mg/kg GSH vs 483.1 ± 4.9 (μm), P < 0.01 at 72 h]. This effect was consistent with decreasing changes in GSH-treated animals compared to SA-treated animals for iNOS protein staining [0.337 ± 0.016 for 50 mg/kg GSH, 0.317 ± 0.017 for 500 mg/kg GSH vs 0.430 ± 0.023 (area of staining part/area of tissue), P < 0.01 at 72 h] and NO [2.99 ± 0.29 for 50 mg/kg GSH, 2.88 ± 0.19 for 500 mg/kg GSH vs 5.34 ± 0.35 (nmol/g tissue), P < 0.01 at 72 h] and ROS [3.92 ± 0.46 for 50 mg/kg GSH, 4.58 ± 0.29 for 500 mg/kg GSH vs 6.42 ± 0.52 (8-OHdG pg/μg DNA), P < 0.01, P < 0.05 at 72 h, respectively] levels as apoptosis mediators in the jejunum. Furthermore, oral GSH administration attenuated cell proliferation decreases in the fasting jejunum [182.5 ± 1.9 for 500 mg/kg GSH vs 155.8 ± 3.4 (5-BrdU positive cells/10 crypts), P < 0.01 at 72 h]. Notably, both GSH concentration and Ggt1 mRNA expression in the jejunum were also attenuated in rats following oral administration of GSH during fasting as compared with fasting alone [0.45 ± 0.12 vs 0.97 ± 0.06 (nmol/mg tissue), P < 0.01; 1.01 ± 0.11 vs 2.79 ± 0.39 (Ggt1 mRNA/Gapdh mRNA), P < 0.01 for 500 mg/kg GSH at 48 h, respectively].

CONCLUSION

Oral GSH administration during fasting enhances jejunal regenerative potential to minimize intestinal mucosal atrophy by diminishing fasting-mediated ROS generation and enterocyte apoptosis and enhancing cell proliferation.

Mushrooms: A rich source of the antioxidants ergothioneine and glutathione

While mushrooms are the highest dietary source for the unique sulfur-containing antioxidant ergothioneine, little is known regarding levels of the major biological antioxidant glutathione. Thus, our objectives were to determine and compare levels of glutathione, as well as ergothioneine, in different species of mushrooms. Glutathione levels varied >20-fold (0.11-2.41mg/gdw) with some varieties having higher levels than reported for other foods. Ergothioneine levels also varied widely (0.15-7.27mg/gdw) and were highly correlated with those of glutathione (r=0.62, P<0.001). Both antioxidants were more concentrated in pileus than stipe tissues in selected mushrooms species. Agaricus bisporus harvested during the third cropping flush contained higher levels of ergothioneine and glutathione compared to the first flush, possibly as a response to increased oxidative stress. This study demonstrated that certain mushroom species are high in glutathione and ergothioneine and should be considered an excellent dietary source of these important antioxidants.

Suppression of nuclear factor erythroid‑2‑related factor 2‑mediated antioxidative defense in the lung injury induced by chronic exposure to methamphetamine in rats

The imbalance between oxidative stress and antioxidant defense is important in the pathogenesis of lung diseases. Nuclear factor erythroid‑2‑related factor 2 (Nrf2) is a key transcriptional factor that regulates the antioxidant response. The purpose of the present study was to investigate whether Nrf2‑mediated antioxidative defense is involved in methamphetamine (MA)‑induced lung injury in rats. Following establishment of chronic MA toxicity in rats, Doppler ultrasonic detection was used to measure the changes of physiological indexes, followed by hematoxylin and eosin staining, ELISA and western blot analysis. MA was demonstrated to increase the heart rate and peak blood flow velocity of pulmonary arterial valves and to decrease the survival rate of rats, and resulted in lung injury characterized by perivascular exudates, airspace edema, slight hemorrhage and inflammatory cell infiltration. MA significantly inhibited the expression of nuclear Nrf2 protein and its target genes (glutamate‑cysteine ligase catalytic subunit C and heme oxygenase‑1), and dose‑dependently reduced glutathione (GSH) levels and the ratio of GSH/oxidized glutathione, accompanied by increases in reactive oxygen species (ROS) levels in rat lungs. Linear regression analysis revealed that there was a positive correlation between lung ROS level and lung injury indexes. These findings suggested that chronic exposure to MA led to lung injury by suppression of Nrf2‑mediated antioxidative defense, suggesting that Nrf2 may be an important therapeutic target for MA‑induced chronic lung toxicity.

Fluoxetine protects against methamphetamine‑induced lung inflammation by suppressing oxidative stress through the SERT/p38 MAPK/Nrf2 pathway in rats

Methamphetamine (MA) abuse is a major public health and safety concern throughout the world and a growing burden on healthcare costs. The purpose of the present study was to investigate the protective effect of fluoxetine against MA‑induced chronic pulmonary inflammation and to evaluate the potential role of nuclear factor erythroid 2-related factor 2 (Nrf2)-mediated antioxidative stress. Wistar rats were divided into control, MA and two fluoxetine‑treated groups. Rats in the MA and the two fluoxetine‑treated groups were treated daily with intraperitoneal injection of 10 mg/kg MA twice daily. Rats in the two fluoxetine‑treated groups were injected intragastrically with fluoxetine (2 and 10 mg/kg) once daily, respectively. After 5 weeks, the rats were euthanized and hematoxylin and eosin staining, immunohistochemistry, western blot analysis and redox assay were performed. It was demonstrated that chronic exposure to MA can induce pulmonary inflammation in rats, with the symptoms of inflammatory cell infiltration, crowded lung parenchyma, thickened septum and a reduced number of alveolar sacs. Fluoxetine attenuated pulmonary inflammation and the expression of interleukin‑6 and tumor necrosis factor‑α in rat lungs. Fluoxetine inhibited MA‑induced increases in the expression levels of serotonin transporter (SERT) and p‑p38 mitogen‑activated protein kinase (MAPK), and reversed the MA‑induced decrease in nuclear Nrf2 and human heme oxygenase‑1 in lungs. Fluoxetine at 10 mg/kg significantly reversed the reduced glutathione (GSH) level, the ratio of GSH/oxidized glutathione, and the reactive oxygen species level in rat lungs from the MA group. These findings suggested that fluoxetine, a SERT inhibitor, has a protective effect against MA‑induced lung inflammation by suppressing oxidative stress through the SERT/p38 MAPK/Nrf2 pathway in rats.

Developing criteria for evaluation of geroprotectors as a key stage toward translation to the clinic

In the coming decades, a massive shift in the aging segment of the population will have major social and economic consequences around the world. One way to offset this increase is to expedite the development of geroprotectors, substances that slow aging, repair age‐associated damage and extend healthy lifespan, or healthspan. While over 200 geroprotectors are now reported in model organisms and some are in human use for specific disease indications, the path toward determining whether they affect aging in humans remains obscure. Translation to the clinic is hampered by multiple issues including absence of a common set of criteria to define, select, and classify these substances, given the complexity of the aging process and their enormous diversity in mechanism of action. Translational research efforts would benefit from the formation of a scientific consensus on the following: the definition of ‘geroprotector’, the selection criteria for geroprotectors, a comprehensive classification system, and an analytical model. Here, we review current approaches to selection and put forth our own suggested selection criteria. Standardizing selection of geroprotectors will streamline discovery and analysis of new candidates, saving time and cost involved in translation to clinic.

Efficacy of screening immune system function in at-risk newborns

This paper explores the introduction of a screening test to highlight impaired immune system status for newborn infants and its efficacy as a preventative clinical measure. Moreover, it is suggested that screening of the infantile immune system has the potential to highlight susceptibility to a range of infant and childhood diseases, bestowing an opportunity to introduce early intervention to reduce the incidence of these diseases. Development of the neonatal immune system is an important health issue, implicated in many childhood problems such as allergies, infection, and autoimmunity. The neonate has a limited immune system and ability to combat bacteria. Depleted levels of the tripeptide reduced glutathione (GSH) have been linked to numerous conditions and its intracellular level is acknowledged as an indicator of immune system function. Introduction of an immune system screening programme for infants is formally reviewed and assessed. Several benefits are reported in the treatment of impaired immune systems, a trial screening programme is proposed for at-risk infants to gather further evidence as to its efficacy. Infants at risk of impaired immune system function include cystic fibrosis, premature infants, and low birth weight infants. The interventions include breastfeeding, milk banks, and appropriate formula to support the immune system.