The systemic availability of oral glutathione

Effective Repeated Production of γ-glutamylcysteine, Essential For Intracellular Glutathione Production, Using Cellulose-immobilized Phytochelatin Synthase-like Enzyme NsPCS

γ-Glutamylcysteine (γ-EC) can increase intracellular glutathione (GSH) levels, which may prevent and alleviate age-related disorders and chronic diseases caused by oxidative damage. However, the commercial availability of γ-EC remains limited owing to its complex chemical synthesis from glutamate and cysteine. In this study, we have developed the method of the effective conversion of GSH to γ-EC to achieve the optimal reaction conditions for repeated batch production and potential application in industrial γ-EC production using the phytochelatin synthase-like enzyme NsPCS. For repeated batch conversion reactions, the optimal temperature was determined at 25 °C, where γ-EC showed good stability compared with that at 37 °C, leading to higher overall productivity. Cellulose sponges and microcrystalline cellulose (MCC) showed superior mechanical strength as immobilization carriers and greater stability and productivity than other materials. The total amounts of γ-EC obtained by NsPCS immobilized on the cellulose sponge and MCC were 305 mg and 291 mg, respectively, in a 5 mL reaction over five repeated batch reactions. These simple production processes are easily reproduced, and their high volumetric efficiency is promising for the industrial production of stable and low-cost γ-EC.

Safety assessment of S-Acetyl Glutathione for use in foods and dietary supplements

S-Acetyl Glutathione (SAG) is a glutathione precursor used as a food or dietary ingredient in a bioavailable form to restore or maintain circulating glutathione (GSH) levels. GSH is a potent defense compound against oxidative stress and a key determinant of many other physiological functions. The safety of SAG supplementation was assessed in an in vitro bacterial reverse mutation assay, an in vitro micronucleus test, an acute oral toxicity study, and a repeated dose (13 week) toxicity study. The in vitro assays did not reveal any genotoxic or mutagenic activity. No mortality or morbidity resulted from the acute oral toxicity study (LD50 > 2000 mg/kg). Administration of SAG over 13 weeks was well tolerated and did not result in any neurobehavioral alterations or effects on locomotor activity, ophthalmology, hematology, coagulation, blood biochemistry, urinalysis, thyroid hormones or the male reproductive system. Mild increases noted in liver, kidney and spleen weights were non-adverse and within historical control ranges, and no treatment-related gross or histopathology findings were observed in any organs. As a result, the NOAEL was determined to be 1500 mg/kg/day, the highest dose tested. Therefore, the results of these toxicological studies support the safe use of SAG in foods or dietary supplements.

Revealing the Transcriptional and Metabolic Characteristics of Sebocytes Based on the Donkey Cell Transcriptome Atlas

Worldwide, donkeys (Equus asinus) are valued for their meat and milk, and in China also for the medical value of their skin. Physiological characteristics are key to the donkey's adaptability, including their digestive, respiratory, and reproductive systems, which enable them to survive and work in a variety of environments. However, the understanding of donkey physiological characteristics at the cellular level remains poor. Thus, single-cell transcriptome sequencing is used to construct a detailed transcriptional atlas based on 20 tissues from the Dezhou donkey (in total 84 cell types and 275 050 high quality cells) to perform an in-depth investigation of molecular physiology. Cross-species and cross-tissue comparative analyses reveal SOX10 to be an evolutionally conserved regulon in oligodendrocytes and illuminate the distinctive transcriptional patterns of donkey sebocytes. Moreover, through multispecies skin metabolomics, highly abundant, species-specific metabolites in donkey skin are identified, such as arachidonic acid and gamma-glutamylcysteine, and the pivotal role of sebocytes in donkey skin metabolism is highlighted. In summary, this work offers new insights into the unique metabolic patterns of donkey skin and provides a valuable resource for the conservation of donkey germplasm and the advancement of selective breeding programs.

Minimizing Oxidative Stress in the Lens: Alternative Measures for Elevating Glutathione in the Lens to Protect against Cataract

Oxidative stress plays a major role in the formation of the cataract that is the result of advancing age, diabetes or which follows vitrectomy surgery. Glutathione (GSH) is the principal antioxidant in the lens, and so supplementation with GSH would seem like an intuitive strategy to counteract oxidative stress there. However, the delivery of glutathione to the lens is fraught with difficulties, including the limited bioavailability of GSH caused by its rapid degradation, anatomical barriers of the anterior eye that result in insufficient delivery of GSH to the lens, and intracellular barriers within the lens that limit delivery of GSH to its different regions. Hence, more attention should be focused on alternative methods by which to enhance GSH levels in the lens. In this review, we focus on the following three strategies, which utilize the natural molecular machinery of the lens to enhance GSH and/or antioxidant potential in its different regions: the NRF2 pathway, which regulates the transcription of genes involved in GSH homeostasis; the use of lipid permeable cysteine-based analogues to increase the availability of cysteine for GSH synthesis; and the upregulation of the lens's internal microcirculation system, which is a circulating current of Na+ ions that drives water transport in the lens and with it the potential delivery of cysteine or GSH. The first two strategies have the potential to restore GSH levels in the epithelium and cortex, while the ability to harness the lens's internal microcirculation system offers the exciting potential to deliver and elevate antioxidant levels in its nucleus. This is an important distinction, as the damage phenotypes for age-related (nuclear) and diabetic (cortical) cataract indicate that antioxidant delivery must be targeted to different regions of the lens in order to alleviate oxidative stress. Given our increasing aging and diabetic populations it has become increasingly important to consider how the natural machinery of the lens can be utilized to restore GSH levels in its different regions and to afford protection from cataract.

Oral administration of cysteine peptides attenuates UV-B-induced skin erythema and pigmentation in humans

The oral administration of antioxidants may suppress UV-B-induced skin damage. HITHION YH-15, the extract of Torula yeast (Cyberlindnera jadinii), is rich in cysteine-containing peptides such as reduced and oxidized glutathione (GSH and GSSG), γ-glutamylcysteine (γ-Glu-Cys), and cysteinylglycine (Cys-Gly). These four constituents are termed cysteine peptides. In this study, we investigated the protective effects of cysteine peptides against UV-B in a randomized, placebo-controlled, double-blind, parallel-group study. A total of 90 healthy males and females aged 30-59 years were enrolled and randomized into two groups of 45 individuals each (cysteine peptides (48 mg/day) and placebo). Changes in UV-B-induced erythema and pigmentation were compared between groups after 5 weeks of test food intake. The minimal erythema dose (MED) significantly increased (*p = 0.019) in the cysteine peptides group compared to that in the placebo group, indicating suppression of UV-B-induced erythema. ΔL* value significantly increased (***p < 0.0001) in the cysteine peptides group compared to that in the placebo, indicating pigmentation suppression. We demonstrated that oral administration of cysteine peptides suppresses UV-B-induced erythema and pigmentation through multiple mechanisms. Thus, cysteine peptides may find use as nutricosmetics for maintaining skin health and well-being.UMIN Clinical Trials Registry ID: UMIN 000050157.

Durian fruit pulp extract enhances intracellular glutathione levels, mitigating oxidative stress and inflammation for neuroprotection

Durian (Durio zibethinus L.) fruit pulp is a rich source of γ-glutamylcysteine (γ-EC), a direct precursor to the antioxidant glutathione (GSH). This study elucidated the in vitro neuroprotective potential of unripe durian fruit pulp extract (UDE) against H2O2-induced neurotoxicity in SH-SY5Y cells and neuroinflammation in lipopolysaccharide (LPS)-stimulated BV-2 cells. Treatments with γ-EC, GSH standards, or UDE exhibited no cytotoxicity in SH-SY5Y and BV-2 cells, except at high concentrations. A 4-h pretreatment with 100 µM γ-EC or UDE containing 100 µM γ-EC significantly increased SH-SY5Y cell viability post H2O2 induction. Moreover, a similar pretreatment reduced LPS-stimulated production of proinflammatory cytokines in BV-2 cells. The neuroprotective effect of UDE is primarily attributed to γ-EC provision and the promotion of GSH synthesis, which in turn elevates intracellular GSH levels and reduces proinflammatory cytokines. This study identifies γ-EC in UDE as a potential neuroprotective biomarker boosting intracellular GSH levels, providing insights into UDE's therapeutic potential.

Tough and Water-Resistant Bioelastomers with Active-Controllable Degradation Rates

Biodegradable electronic devices have gained significant traction in modern medical applications. These devices are generally desired to have a long enough working lifetime for stable operation and allow for active control over their degradation rates after usage. However, current biodegradable materials used as encapsulations or substrates for these devices are challenging to meet the two requirements due to the constraints of inadequate water resistance, poor mechanical properties, and passive degradation characteristics. Herein, we develop a novel biodegradable elastomer named POC-SS-Res by introducing disulfide linkage and resveratrol (Res) into poly(1,8-octanediol-co-citrate) (POC). Compared to POC, POC-SS-Res exhibits good water resistance and excellent mechanical properties in PBS, providing effective protection for devices. At the same time, POC-SS-Res offers the unique advantage of an active-controllable degradation rate, and its degradation products express low biotoxicity. Good biocompatibility of POC-SS-Res is also demonstrated. Bioelectronic components encapsulated with POC-SS-Res have an obvious prolongation of working lifetime in PBS compared to that encapsulated with POC, and its degradation rate can be actively controlled by the addition of glutathione (GSH).

Development of a mouse model expressing a bifunctional glutathione-synthesizing enzyme to study glutathione limitation in vivo

Glutathione (GSH) is a highly abundant tripeptide thiol that performs diverse protective and biosynthetic functions in cells. While changes in GSH availability are associated with inborn errors of metabolism, cancer, and neurodegenerative disorders, studying the limiting role of GSH in physiology and disease has been challenging due to its tight regulation. To address this, we generated cell and mouse models that express a bifunctional glutathione-synthesizing enzyme from Streptococcus thermophilus (GshF), which possesses both glutamate-cysteine ligase and glutathione synthase activities. GshF expression allows efficient production of GSH in the cytosol and mitochondria and prevents cell death in response to GSH depletion, but not ferroptosis induction, indicating that GSH is not a limiting factor under lipid peroxidation. CRISPR screens using engineered enzymes further revealed genes required for cell proliferation under cellular and mitochondrial GSH depletion. Among these, we identified the glutamate-cysteine ligase modifier subunit, GCLM, as a requirement for cellular sensitivity to buthionine sulfoximine, a glutathione synthesis inhibitor. Finally, GshF expression in mice is embryonically lethal but sustains postnatal viability when restricted to adulthood. Overall, our work identifies a conditional mouse model to investigate the limiting role of GSH in physiology and disease.

A mouse model to study glutathione limitation in vivo

Glutathione (GSH) is a highly abundant tripeptide thiol that performs diverse protective and biosynthetic functions in cells. While changes in GSH availability are linked to many diseases, including cancer and neurodegenerative disorders, determining the function of GSH in physiology and disease has been challenging due to its tight regulation. To address this, we generated cell and mouse models that express a bifunctional glutathione-synthesizing enzyme from Streptococcus Thermophilus (GshF). GshF expression allows efficient production of GSH in the cytosol and mitochondria and prevents cell death in response to GSH depletion, but not ferroptosis, indicating that GSH is not a limiting factor under lipid peroxidation. CRISPR screens using engineered enzymes revealed metabolic liabilities under compartmentalized GSH depletion. Finally, GshF expression in mice is embryonically lethal but sustains postnatal viability when restricted to adulthood. Overall, our work identifies a conditional mouse model to investigate the role of GSH availability in physiology and disease.

Orally administered Streptococcus thermophilus YIT 2001 is a vehicle for the delivery of glutathione, a reactive reduced thiol, to the intestine

AIMS

We aimed to analyze the behavior of cellular glutathione of Streptococcus thermophilus strain YIT 2001 (ST-1) in the gastrointestinal environment to understand how orally administered glutathione in ST-1 cells is delivered stably to the intestine in a reactive form, which is essential for its systemic bioavailability against lipid peroxidation.

METHODS AND RESULTS

Intracellular glutathione was labeled with L-cysteine-containing stable isotopes. ST-1 cells from fresh culture or lyophilized powder were treated with simulated gastric and intestinal juices for 60 min each. The release of intracellular glutathione in digestive juices was quantified via LC-MS/MS. Most of the cellular glutathione was retained in the gastric environment and released in response to exposure to the gastrointestinal environment. During digestion, the membrane permeability of propidium iodide increased significantly, especially when cells were exposed to cholate, without change in the cell wall state.

CONCLUSIONS

ST-1 cells act as vehicles to protect intracellular reactive components, such as glutathione, from digestive stress, and release them in the upper intestine owing to the disruption of membrane integrity induced by bile acid.

Acid-Resistant Near-Infrared II Ag2Se Quantum Dots for Gastrointestinal Imaging

With the development of near-infrared II (NIR-II) fluorescence imaging, Ag2Se quantum dots (QDs) have become promising label candidates due to their negligible toxicity and narrow band gap. Despite their potential for gastrointestinal (GI) imaging, the application of Ag2Se QDs still presents significant challenges due to issues such as fluorescence extinction or poor stability in the complex digestive microenvironment. Herein, we have proposed a novel approach to the continuous production of Se precursors using glutathione (GSH) as the reductant under acidic conditions, realizing the continuous growth of water-dispersible Ag2Se QDs. The Ag2Se QDs emitting at 600-1100 nm have been successfully synthesized. Meanwhile, the silver-rich surface of the synthesized NIR-II Ag2Se QDs has been passivated well with the dense GSH, resulting in exceptional colloidal stability and photostability and endowing them with acid resistance. As a result, the obtained NIR-II Ag2Se QDs have exhibited remarkable stability in gastric acid, thus enabling their utilization for long-term real-time monitoring of GI peristalsis via NIR-II fluorescence imaging. Moreover, in contrast to conventional barium meal-based X-ray imaging, NIR-II fluorescence imaging with as-prepared NIR-II Ag2Se QDs can offer clearer visualization of fine intestinal structures, with a width as small as 1.07 mm. The developed strategy has offered a new opportunity for the synthesis of acid-resistant nanocrystals, and the acid-resistant, low-toxicity, and biocompatible NIR-II Ag2Se QDs synthesized in this work show a great promise for GI imaging and diagnosis of GI diseases in vivo.

Citrate-Based Polyester Elastomer with Artificially Regulatable Degradation Rate on Demand

Citrate-based polymers are commonly used to create biodegradable implants. In an era of personalized medicine, it is highly desired that the degradation rates of citrate-based implants can be artificially regulated as required during clinical applications. Unfortunately, current citrate-based polymers only undergo passive degradation, which follows a specific degradation profile. This presents a considerable challenge for the use of citrate-based implants. To address this, a novel citrate-based polyester elastomer (POCSS) with artificially regulatable degradation rate is developed by incorporating disulfide bonds (S-S) into the backbone chains of the crosslinking network of poly(octamethylene citrate) (POC). This POCSS exhibits excellent and tunable mechanical properties, notable antibacterial properties, good biocompatibility, and low biotoxicity of its degradation products. The degradation rate of the POCSS can be regulated by breaking the S-S in its crosslinking network using glutathione (GSH). After a period of subcutaneous implantation of POCSS scaffolds in mice, the degradation rate eventually increased by 2.46 times through the subcutaneous administration of GSH. Notably, we observed no significant adverse effects on its surrounding tissues, the balance of the physiological environment, major organs, and the health status of the mice during degradation.

The kinetics of glutathione in the gastrointestinal tract of weaned piglets supplemented with different doses of dietary reduced glutathione

This study aimed to investigate the kinetics of dietary GSH in the gastrointestinal tract and the effect of GSH on the intestinal redox status of weaned piglets. Forty-eight piglets with an average age of 26 days and an average body weight of 7.7 kg were used in this study. The piglets were divided into three treatment groups including the control group with a basal diet (CON) and two GSH groups with a basal diet supplemented with 0.1% GSH (LGSH) and 1.0% GSH (HGSH), respectively. The basal diet did not contain any GSH. The experiment lasted for 14 days, with eight animals sampled from each group on d5 and 14. The parts of 0-5%, 5-75%, and 75-100% of the length of the small intestine were assigned to SI1, SI2, and SI3. The results showed that GSH almost completely disappeared from the digesta at SI2. However, no difference in the GSH level in mucosa, liver, and blood erythrocytes was found. The level of cysteine (CYS) in SI1 digesta was significantly higher in HGSH than CON and LGSH on d14, and similar findings were observed for cystine (CYSS) in SI3 digesta on d5. The CYSS level in HGSH was also significantly higher than LGSH in the stomach on d14, while no CYS or CYSS was detected in the stomach for control animals, indicating the breakdown of GSH to CYS already occurred in the stomach. Irrespective of the dietary treatment, the CYS level on d14 and the CYSS level on d5 and 14 were increased when moving more distally into the gastrointestinal tract. Furthermore, the mucosal CYS level was significantly increased at SI1 in the LGSH and HGSH group compared with CON on d5. Glutathione disulfide (GSSG) was recovered in the diets and digesta from the LGSH and HGSH group, which could demonstrate the auto-oxidation of GSH. It is, therefore, concluded that GSH supplementation could not increase the small intestinal mucosal GSH level of weaned piglets, and this could potentially relate to the kinetics of GSH in the digestive tract, where GSH seemed to be prone to the breakdown to CYS and CYSS and the auto-oxidation to GSSG.

Enhancing Supplemental Effects of Acute Natural Antioxidant Derived from Yeast Fermentation and Vitamin C on Sports Performance in Triathlon Athletes: A Randomized, Double-Blinded, Placebo-Controlled, Crossover Trial

This study investigated the acute effects of natural antioxidants, derived from yeast fermentation containing glutathione and dietary vitamin C supplementation, on metabolic function, skeletal muscle oxygenation, cardiac function, and antioxidant function during submaximal exercise in middle-aged triathlon athletes. Twelve participants (aged 49.42 ± 5.9 years) completed 90 min submaximal cycling trials corresponding to 70% maximal oxygen uptake with either vitamin C and glutathione (VitC+Glu), vitamin C (VitC), glutathione (Glu) supplementation, or placebo. Metabolic function (minute ventilation, oxygen uptake, carbon dioxide output [VCO2], respiratory exchange ratio [RER], oxygen pulse [O2pulse], carbohydrate oxidation, fat oxidation, and energy expenditure), skeletal muscle oxygenation (oxidized hemoglobin and myoglobin in skeletal muscle tissue, total hemoglobin and myoglobin in skeletal muscle tissue [tHb]), cardiac function (heart rate [HR], stroke volume [SV], cardiac output, end-diastolic volume, end-systolic volume, and ejection fraction), and antioxidant function parameters (blood lactate, superoxide dismutase, catalase, glutathione peroxidases, glutathione [GSH], diacron reactive oxygen metabolite [dROM], and biological antioxidant potential [BAP]) were measured during submaximal exercise and recovery. VCO2, RER, HR, blood lactate after exercise, and dROM were significantly lower, and O2pulse, tHb, and BAP were significantly higher for VitC+Glu than for the other trials (p < 0.05). In conclusion, combined vitamin C and glutathione supplementation was more effective in improving metabolic function, skeletal oxygenation, cardiac function, and antioxidant function during prolonged submaximal exercise in middle-aged triathletes.

An investigation on glutathione derived from spinach and red cabbage leaves and their effects of adding to meat patties

Plants that produce leaves have been cultivated by humans for thousands of years because of the benefits they provide in terms of food and other necessities. Because of their high nutritional value and key phyto-components like glutathione, Leaf producing vegetables (LPVs) are being studied for their potential uses and health benefits. As a result, the focus of this study was using efficient methods for isolating and identifying glutathione from spinach and red cabbage. Glutathione was extracted using three extraction solvents: water (100%), ethanol (100%), and a combination of ethanol and water (30% and 70%, respectively) by volume (v/v), while separation was accomplished using ultrafiltration equipment. In our investigation, the best extraction solvent was a mixture of ethanol and water at a ratio of 30:70% (v/v), which extracted 951 µg/g glutathione. The antioxidant activity of plant leaf extract was measured using DPPH, with butylated hydroxytoluene serving as a comparative standard. Identification and characterization of glutathione from plant leaf extracts were revealed by thin-layer chromatography (TLC), ultraviolet-visible (UV-Vis) spectrophotometry studies, Fourier transform infrared (FTIR) spectroscopy, and high-performance liquid chromatography (HPLC). In addition, the physical and chemical properties (pH, water holding capacity, extracted liquid volume, peroxide value, free fatty acids, and thiobarbituric acid) of meat patties prepared with three different concentrations of determined glutathione were tested for susceptibility to preservation during 10 days of refrigeration at 4 ± 1 °C. The findings of the current study provide vast prospects for subsequent research to researchers and scientists that the glutathione obtained from leaf extract has no toxicity that might be applied to developed functional foods and other food formulations. Because foods containing plant-derived glutathione improve health, biological function, and food spoilage. It may be utilized as high-quality antioxidants that are safe and non-toxic. Furthermore, glutathione preserves food quality and prevents oxidation.

Ferroptosis: A Novel Type of Cell Death in Male Reproduction

Ferroptosis, an iron-dependent type of regulated cell death, is triggered by the accumulation of lethal lipid peroxides. Due to its potential in exploring disease progression and highly targeted therapies, it is still a widely discussed topic nowadays. In recent studies, it was found that ferroptosis was induced when testicular tissue was exposed to some high-risk factors, such as cadmium (Cd), busulfan, and smoking accompanied by a variety of reproductive damage characteristics, including changes in the specific morphology and ferroptosis-related features. In this literature-based review, we summarize the related mechanisms of ferroptosis and elaborate upon its relationship network in the male reproductive system in terms of three significant events: the abnormal iron metabolism, dysregulation of the Cyst(e)ine/GSH/GPX4 axis, and lipid peroxidation. It is meaningful to deeply explore the relationship between ferroptosis and the male reproductive system, which may provide suggestions regarding pristine therapeutic targets and novel drugs.

Effects of glutathione on mitochondrial DNA and antioxidant enzyme activities in Drosophila melanogaster

The free radical theory in aging assumes that the accumulation of macromolecular damage induced by toxic reactive oxygen species plays a central role in the aging process. The intake of nutritional antioxidants can prevent this damage by neutralizing reactive oxygen derivatives. Glutathione (GSH; en-L-Glutamyl-L-cysteinyl glycine) is the lowest molecular weight thiol in the cells and as a cofactor of many enzymes and a potent antioxidant plays an important role in maintaining normal cell functions by destroying toxic oxygen radicals. In this study, the effects of GSH on SOD, GST and catalase enzymes and mtDNA damage were investigated at various time intervals by giving reduced glutathione to Drosophila. It was observed that 3-week GSH administration did not have a statistically significant effect on SOD and GST activities whereas GSH application decreased the catalase enzyme activities significantly. Although the decrease in antioxidant capacity with age was observed in SOD and catalase enzymes, such a situation was not observed in GST enzyme activities. There was no statistically significant difference between the control and GSH groups in mtDNA copy number values, while in the GSH group, oxidative mtDNA damage was high. These results may be due to the prooxidant effect of GSH at the dose used in this study.

Augmented Glutathione Absorption from Oral Mucosa and its Effect on Skin Pigmentation: A Clinical Review

Treatment of dark skin with glutathione has become popular due to its depigmenting properties and low toxicity. Glutathione has been used topically, orally and parenterally in the management of dark skin. There are no clear published guidelines for management of skin pigmentation despite some clinical trials of shorter duration and small sample sizes. We examined published scientific and patient data to generate guidance for the clinician for managing hyperpigmentation using glutathione by orobuccal route. Various aspects of glutathione bioavailability were examined when administered by oral routes. Absorption of glutathione from the gastrointestinal tract is poor. Some trials have favored administering high oral doses to achieve therapeutic effect. General consensus remains against treatment of hyperpigmentation with glutathione by the oral route. Clinical and experimental evidence supporting significant glutathione absorption from orobuccal mucosa was examined. The latter is superior to the oral route since glutathione passes directly into systemic circulation resulting in a much higher rate of absorption compared to that achieved by oral intake. High blood levels thus achieved have therapeutic value. Treatment of hyperpigmentation with glutathione by the orobuccal route using hydroxypropyl cellulose (HPC) film was reviewed to formulate clinical guidance from published data. A future randomized, double-blind, placebo-controlled trial should study treatment of hyperpigmentation with glutathione using oral dispersible HPC film, with longer-term follow-up and larger sample size. This paper will hopefully offer broad guidance for the clinician on use of glutathione for hyperpigmentation management, until outcomes of larger, longer duration trials become available.

Findings from a pilot open-label trial of N-acetylcysteine for the treatment of pediatric mania and hypomania

BACKGROUND

Pediatric bipolar disorder is a highly prevalent and morbid disorder and is considered a prevalent public health concern. Currently approved treatments often pose the risk of serious side effects. Therefore, this study assessed the efficacy and tolerability of N-acetylcysteine (NAC), in children and adolescents with bipolar spectrum disorder.

METHODS

We conducted a 12-week open-label trial of NAC for treatment of mania and hypomania in children and adolescents ages 5-17 with bipolar spectrum disorder including participants with full and subthreshold manic symptoms, accepting those with and without mixed states with co-occurring depression, and Young Mania Rating Scale scores ≥ 20 and < 40. Symptoms of mania and depression were assessed using the Young Mania Rating Scale (YMRS), Hamilton Depression Rating Scale (HDRS), Children's Depression Rating Scale (CDRS), and Clinical Global Impression (CGI) Severity (CGI-S) and Improvement (CGI-I) scales for mania and depression.

RESULTS

This study had a high drop-out rate with only 53% completing all 12 weeks. There was a significant reduction in YMRS, HDRS, and CDRS mean scores from baseline to endpoint. Of the 24 exposed participants, 54% had an anti-manic response measured by a reduction in YMRS ≥ 30% and 46% had a CGI-I mania score ≤ 2 at endpoint. Additionally, 62% of participants had an anti-depressive response measured by a reduction in HDRS ≥ 30%, 31% had an anti-depressive response measured by a reduction in CDRS ≥ 30%, and 38% had a CGI-I depression score ≤ 2 at endpoint.

CONCLUSIONS

These pilot open-label findings in a small sample provide preliminary data supporting the tolerability and safety of NAC in a pediatric population. The findings of this pilot scale study indicating improvement in mania and depression are promising, but require replication with a monotherapy randomized placebo controlled clinical trial and larger sample.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT02357290 . First Registration 06/02/2015.

Contributions and Limitations of Mitochondria-Targeted and Non-Targeted Antioxidants in the Treatment of Parkinsonism: an Updated Review

As conventional therapeutics can only treat the symptoms of Parkinson's disease (PD), major focus of research in recent times is to slow down or prevent the progression of neuronal degeneration in PD. Non-targeted antioxidants have been an integral part of the conventional therapeutics regimen; however, their importance have lessened over time because of their controversial outcomes in clinical PD trials. Inability to permeate and localize within the mitochondria remains the main drawback on the part of non-targeted antioxidants inspite of possessing free radical scavenging properties. In contrast, mitochondrial-targeted antioxidants (MTAs), a special class of compounds have emerged having high advantages over non-targeted antioxidants by virtue of efficient pharmacokinetics and better absorption rate with capability to localize many fold inside the mitochondrial matrix. Preclinical experimentations indicate that MTAs have the potential to act as better alternatives compared to conventional non-targeted antioxidants in treating PD; however, sufficient clinical trials have not been conducted to investigate the efficacies of MTAs in treating PD. Controversial clinical outcomes on the part of non-targeted antioxidants and lack of clinical trials involving MTAs have made it difficult to go ahead with a direct comparison and in turn have slowed down the progress of development of safer and better alternate strategies in treating PD. This review provides an insight on the roles MTAs and non-targeted antioxidants have played in the treatment of PD till date in preclinical and clinical settings and discusses about the limitations of mitochondria-targeted and non-targeted antioxidants that can be resolved for developing effective strategies in treating Parkinsonism.

Cysteine-Rich Whey Protein Isolate (CR-WPI) Ameliorates Erectile Dysfunction by Diminishing Oxidative Stress via DDAH/ADMA/NOS Pathway

Nitric oxide synthase- (NOS-) dependent endothelial dysfunction induced by oxidative stress (OS) is assumed to play a pivotal role in the pathogenesis and progression of diabetes mellitus-related erectile dysfunction (DMED). Cysteine-rich whey protein isolate (CR-WPI) is a widely used protein supplement and has been confirmed to reduce reactive oxygen species (ROS) by increasing cellular antioxidant glutathione (GSH). However, it is currently unknown whether CR-WPI elicits therapeutic effects in DMED. Here, we provide diabetic rats with CR-WPI to determine its effect on DMED and the underlying mechanisms. The results suggest that CR-WPI supplementation increased GSH biosynthesis and reduced ROS content and simultaneously upregulated the dimethylarginine dimethylaminohydrolase (DDAH)/asymmetrical dimethylarginine (ADMA)/nitric oxide synthase (NOS) metabolic pathway. Evaluation of intracavernous pressure (ICP) also showed an improvement of penile erectile function in CR-WPI-treated rats. The results of the vitro cell culture showed that glutathione pretreatment protected corpus cavernosum smooth muscle cells (CCSMC) from H₂O₂-induced apoptosis by decreasing Caspase 9 and Caspase 3 expressions. These results augur well for the potential therapeutic application of dietary CR-WPI supplementation for treating diabetic erectile dysfunction.

Olive polyphenols and bioavailable glutathione: Promising results in patients diagnosed with mild Alzheimer's disease

Introduction

Recent studies highlighted the role of olive polyphenols in disrupting the ordered structure of highly cytotoxic amyloid beta protofibrils and the efficacy of a derivatized form of glutathione to counteract neuronal oxidative stress affecting specific brain regions at early stages of Alzheimer's disease (AD) pathogenesis. We performed a randomized cross-over clinical trial to evaluate their potential benefits in mild AD.

Methods

Oleuropein and S-acetyl glutathione were administered as dietary supplement for 6 months to 18 patients diagnosed for probable mild AD according to International Working Group 2 criteria. Patients underwent an extensive cognitive and behavioral neuropsychological test battery at the beginning and end of the study to evaluate cognitive deterioration, memory, visuospatial abilities, attention, language, executive functions, and behavioral disorders. We compared patients receiving treatment to patients receiving no treatment.

Results

All the measured neurocognitive parameters stabilized or improved after the treatment in all patients.

Discussion

Dietary supplement with olive polyphenols and bioavailable glutathione could be useful for patients diagnosed with mild AD.

Protective effect of γ-glutamylcysteine against UVB radiation in NIH-3T3 cells

BACKGROUND

Ultraviolet (UV) radiation-induced oxidative stress is the main cause of photodamage to the skin. Glutathione (GSH) serves important physiological functions, including scavenging oxygen-free radicals and maintaining intracellular redox balance. γ-glutamylcysteine (γ-GC), as an immediate precursor of GSH and harboring antioxidant and anti-inflammatory properties, represents an unexplored option for skin photodamage treatment.

PURPOSE

The purpose of this study was to investigate whether γ-GC can reduce UVB-induced NIH-3T3 cell damage.

METHODS

The experimental groups were as follows: control, UVB radiation, UVB radiation after pretreatment with γ-GC. Cell counting kit-8 (CCK-8) assays were used to measure cell proliferation, flow cytometry, and immunoblotting to detect the apoptosis rate and apoptosis-associated proteins. The levels of Reactive Oxygen Species (ROS), Superoxide Dismutase (SOD), and GSH/GSSG (oxidized GSH) were measured to assess oxidative stress. Immunoblotting and immunofluorescence were used to detect DNA damage. The members of the MAPK signaling pathways were detected by immunoblotting.

RESULTS

UVB irradiation significantly reduced cell viability and destroyed the oxidative defense system. Pretreatment with γ-GC reduced UVB-induced cytotoxicity, restored the oxidation defense system, and inhibited activation of the MAPK pathway. It also reduced the apoptosis rate, downregulated the levels of cleaved caspase 3 and cleaved PARP. Furthermore, pretreatment with γ-GC reduced the accumulation of γH2AX after UVB radiation exposure, indicating that γ-GC could protect cells from DNA damage.

CONCLUSION

γ-GC protected NIH-3T3 from damage caused by UVB irradiation. The photoprotective effect of γ-GC is mediated via strengthening the endogenous antioxidant defense system, which prevents DNA damage and inhibits the activation of the MAPK pathway.

Ligaza γ-glutamylocysteiny – od molekularnych mechanizmów regulacji aktywności enzymatycznej do implikacji terapeutycznych

Glutation (γ-glutamylocysteinyloglicyna, GSH) jest najbardziej rozpowszechnionym tiolowym antyoksydantem wytwarzanym w cytozolu wszystkich komórek ssaków, który pełni ważną rolę ochronną przed stresem oksydacyjnym. GSH jest syntetyzowany de novo przez sekwencyjne działanie dwóch enzymów: ligazy γ-glutamylocysteiny (GCL) i syntetazy glutationowej (GS). GCL katalizuje pierwszy etap biosyntezy GSH, którego produktem jest γ-glutamylocysteina (γ-GC). GCL jest heterodimerycznym enzymem zbudowanym z podjednostki katalitycznej (GCLc) i modulatorowej (GCLm), kodowanych przez dwa różne geny. Podjednostki GCL podlegają złożonej regulacji zarówno na poziomie przed-, jak i potranslacyjnym. Zmiany w ekspresji i aktywności GCL mogą zaburzać poziom GSH i homeostazy redoks. Przyczyną wielu przewlekłych schorzeń związanych ze stresem oksydacyjnym jest upośledzenie aktywności katalitycznej GCL oraz spadek stężenia GSH. Badania przedkliniczne sugerują, że podawanie egzogennej γ-GC podwyższa wewnątrzkomórkowe GSH przez dostarczenie brakującego substratu i może wykazywać potencjał jako terapia uzupełniająca w chorobach związanych z deplecją GSH.

Nebulization of glutathione and N-Acetylcysteine as an adjuvant therapy for COVID-19 onset

Ever since its emergence, the highly transmissible and debilitating coronavirus disease spread at an incredibly fast rate, causing global devastation in a matter of months. SARS-CoV-2, the novel coronavirus responsible for COVID-19, infects hosts after binding to ACE2 receptors present on cells from many structures pertaining to the respiratory, cardiac, hematological, neurological, renal and gastrointestinal systems. COVID-19, however, appears to trigger a severe cytokine storm syndrome in pulmonary structures, resulting in oxidative stress, exacerbated inflammation and alveolar injury. Due to the recent nature of this disease no treatments have shown complete efficacy and safety. More recently, however, researchers have begun to direct some attention towards GSH and NAC. These natural antioxidants play an essential role in several biological processes in the body, especially the maintenance of the redox equilibrium. In fact, many diseases appear to be strongly related to severe oxidative stress and deficiency of endogenous GSH. The high ratios of ROS over GSH, in particular, appear to reflect severity of symptoms and prolonged hospitalization of COVID-19 patients. This imbalance interferes with the body's ability to detoxify the cellular microenvironment, fold proteins, replenish antioxidant levels, maintain healthy immune responses and even modulate apoptotic events. Oral administration of GSH and NAC is convenient and safe, but they are susceptible to degradation in the digestive tract. Considering this drawback, nebulization of GSH and NAC as an adjuvant therapy may therefore be a viable alternative for the management of the early stages of COVID-19.

Bifidobacterium dentium-derived y-glutamylcysteine suppresses ER-mediated goblet cell stress and reduces TNBS-driven colonic inflammation

Endoplasmic reticulum (ER) stress compromises the secretion of MUC2 from goblet cells and has been linked with inflammatory bowel disease (IBD). Although Bifidobacterium can beneficially modulate mucin production, little work has been done investigating the effects of Bifidobacterium on goblet cell ER stress. We hypothesized that secreted factors from Bifidobacterium dentium downregulate ER stress genes and modulates the unfolded protein response (UPR) to promote MUC2 secretion. We identified by mass spectrometry that B. dentium secretes the antioxidant γ-glutamylcysteine, which we speculate dampens ER stress-mediated ROS and minimizes ER stress phenotypes. B. dentium cell-free supernatant and γ-glutamylcysteine were taken up by human colonic T84 cells, increased glutathione levels, and reduced ROS generated by the ER-stressors thapsigargin and tunicamycin. Moreover, B. dentium supernatant and γ-glutamylcysteine were able to suppress NF-kB activation and IL-8 secretion. We found that B. dentium supernatant, γ-glutamylcysteine, and the positive control IL-10 attenuated the induction of UPR genes GRP78, CHOP, and sXBP1. To examine ER stress in vivo, we first examined mono-association of B. dentium in germ-free mice which increased MUC2 and IL-10 levels compared to germ-free controls. However, no changes were observed in ER stress-related genes, indicating that B. dentium can promote mucus secretion without inducing ER stress. In a TNBS-mediated ER stress model, we observed increased levels of UPR genes and pro-inflammatory cytokines in TNBS treated mice, which were reduced with addition of live B. dentium or γ-glutamylcysteine. We also observed increased colonic and serum levels of IL-10 in B. dentium- and γ-glutamylcysteine-treated mice compared to vehicle control. Immunostaining revealed retention of goblet cells and mucus secretion in both B. dentium- and γ-glutamylcysteine-treated animals. Collectively, these data demonstrate positive modulation of the UPR and MUC2 production by B. dentium-secreted compounds.

Improvement of cognitive performance by a nutraceutical formulation: Underlying mechanisms revealed by laboratory studies

Cognitive decline, decrease in neuronal function and neuronal loss that accompany normal aging and dementia are the result of multiple mechanisms, many of which involve oxidative stress. Herein, we review these various mechanisms and identify pharmacological and non-pharmacological approaches, including modification of diet, that may reduce the risk and progression of cognitive decline. The optimal degree of neuronal protection is derived by combinations of, rather than individual, compounds. Compounds that provide antioxidant protection are particularly effective at delaying or improving cognitive performance in the early stages of Mild Cognitive Impairment and Alzheimer's disease. Laboratory studies confirm alleviation of oxidative damage in brain tissue. Lifestyle modifications show a degree of efficacy and may augment pharmacological approaches. Unfortunately, oxidative damage and resultant accumulation of biomarkers of neuronal damage can precede cognitive decline by years to decades. This underscores the importance of optimization of dietary enrichment, antioxidant supplementation and other lifestyle modifications during aging even for individuals who are cognitively intact.

Potential anti-toxic effect of d-ribose-l-cysteine supplement on the reproductive functions of male rats administered cyclophosphamide

Objectives

This study aimed to access the protective effects of d-ribose-l-cysteine (DRLC) on cyclophosphamide (CPA) induced gonadal toxicity in male rats.

Methods

Forty-eight male Sprague-Dawley rats were divided into six groups of eight rats each. Group I the control, received distilled water (10 ml/kg), Group II received a single dose of CPA 100 mg/kg body weight intraperitoneally (i.p), Groups III and IV received a single dose of CPA at 100 mg/kg (i.p) and then were treated with DRLC at 200 mg/kg bodyweight (b.w) and 400 mg/kg b.w for 10 days, respectively. Rats in Groups V and VI received DRLC at 200 and 400 mg/kg b.w for 10 days, respectively. DRLC was administered orally.

Results

Results showed that CPA increased percentage of abnormal sperm cells and reduced body weight, sperm count, sperm motility, follicle-stimulating hormone (FSH), luteinizing hormone (LH) and testosterone levels (p<0.05). CPA also induced oxidative stress as indicated by the increased malondialdehyde (MDA) content and reduced activities of the oxidative enzymes measured (p<0.05). Liver enzymes were elevated while the blood cells production was decreased in the rats administered CPA. DRLC supplementation enhanced the antioxidant defence system as indicated in the reduced MDA levels and increased activities of the antioxidant enzymes when compared with CPA (p<0.05). Bodyweight, sperm count, sperm motility, FSH, and testosterone levels were increased in the CPA + DRLC II group compared with CPA (p<0.05).

Conclusions

The results of this present study showed that DRLC has a potential protective effect on CPA-induced gonadotoxicity.

A Review of Oral Therapies for the Treatment of Skin Hyperpigmentation

This review article examines evidence supporting the use of oral therapies in treating idiopathic, actinic, and metabolically induced skin hyperpigmentation. A thorough review of the literature regarding oral treatments for hyperpigmentation was systematically conducted through PubMed. Keywords used in the primary search include "Hyperpigmentation," "Melanosis" or "Melasma," "Lightening," "Oral," and "Therapeutics." The search was limited to the English language, and no timeframe restrictions were implemented. Numerous orally administered therapies have been proposed for the treatment of skin hyperpigmentation. There is an abundant body of literature demonstrating the efficacy of orally administered tranexamic acid, glutathione, isotretinoin, and proanthocyanidin. It is reasonable to expect that the most effective oral therapies will address known underlying causes of hyperpigmentation such as thyroid disease, diabetes, and hormonal imbalance. Improvement due to oral therapy of otherwise unresponsive skin hyperpigmentation or hyperpigmentation of unknown cause is less predictable. This review is limited by the strength of evidence contained within the available studies. Clinical studies investigating the treatments discussed within this article are limited in number, at times lack blinding in the study design, and are based on small sample sizes. Based on existing research, the most promising oral remedies for hyperpigmentation appear to be tranexamic acid, glutathione, isotretinoin, and proanthocyanidin. Additional studies to better establish safety and efficacy are necessary.

Deletion of the lactoperoxidase gene causes multisystem inflammation and tumors in mice

Strongly oxidative H₂O₂ is biologically important, but if uncontrolled, would lead to tissue injuries. Lactoperoxidase (LPO) catalyzes the redox reaction of reducing highly reactive H₂O₂ to H₂O while oxidizing thiocyanate (SCN^-) to relatively tissue-innocuous hypothiocyanite (OSCN^-). SCN^- is the only known natural, effective reducing-substrate of LPO; humans normally derive SCN^- solely from food. While its enzymatic mechanism is understood, the actual biological role of the LPO-SCN^- system in mammals remains unestablished. Our group previously showed that this system protected cultured human cells from H₂O₂-caused injuries, a basis for the hypothesis that general deficiency of such an antioxidative mechanism would lead to multisystem inflammation and tumors. To test this hypothesis, we globally deleted the Lpo gene in mice. The mutant mice exhibited inflammation and lesions in the cardiovascular, respiratory, digestive or excretory systems, neuropathology, and tumors, with high incidence. Thus, this understudied LPO-SCN^- system is an essential protective mechanism in vivo.

An Orally Bioavailable (Mice) Prodrug of Glutathione

L-Cysteine-glutathione mixed disulfide (CySSG), a prodrug of glutathione (GSH), was found to be orally bioavailable in mice, and protected mice against a toxic dose of acetaminophen. If oral bioavailability can also be demonstrated in humans, a wide range of applicability for CySSG can be envisioned.

Combination of topical and oral glutathione as a skin-whitening agent: a double-blind randomized controlled clinical trial

BACKGROUND

The antimelanogenesis effect of topical and oral glutathione has been shown in several in vitro and clinical studies. However, whether combination of topical and oral glutathione is superior to topical or oral monotherapy is unknown. This study aimed to compare the skin-whitening effect of topical and oral glutathione combination therapy against topical and oral monotherapy.

METHODS

This double-blind randomized controlled study was done on 46 participants who were divided into two equal groups. Each group received oral placebo and oral glutathione, respectively. All participants were also instructed to apply topical placebo and glutathione to each facial side, respectively. Colorimeter examination was done biweekly using mexameter and chromameter for 8 weeks. One-way ANOVA test was used to compare the results of all groups.

RESULTS

The combination group showed significantly lower melanin index (MI) and L* score to placebo (P < 0.05). The mean MI and L* score of the combination group were the highest of all groups. Statistical significance of difference in L* score was reached when the combination group was compared to the oral placebo and topical glutathione group (P < 0.05).

CONCLUSION

This study showed that topical and oral glutathione were effective skin-lightening agents. Furthermore, combination of topical and oral glutathione might be superior to monotherapy.

Polymerized Whey Protein Concentrate-Based Glutathione Delivery System: Physicochemical Characterization, Bioavailability and Sub-Chronic Toxicity Evaluation

Glutathione (GSH) is a powerful antioxidant, but its application is limited due to poor storage stability and low bioavailability. A novel nutrient encapsulation and delivery system, consisting of polymerized whey protein concentrate and GSH, was prepared and in vivo bioavailability, antioxidant capacity and toxicity were evaluated. Polymerized whey protein concentrate encapsulated GSH (PWPC-GSH) showed a diameter of roughly 1115 ± 7.07 nm (D50) and zeta potential of 30.37 ± 0.75 mV. Differential scanning calorimetry (DSC) confirmed that GSH was successfully dispersed in PWPC particles. In vivo pharmacokinetics study suggested that PWPC-GSH displayed 2.5-times and 2.6-fold enhancement in maximum concentration (Cmax) and area under the concentration-time curve (AUC) as compared to free GSH. Additionally, compared with plasma of mice gavage with free GSH, significantly increased antioxidant capacity of plasma in mice with PWPC-GSH was observed (p < 0.05). Sub-chronic toxicity evaluation indicated that no adverse toxicological reactions related to oral administration of PWPC-GSH were observed on male and female rats with a diet containing PWPC-GSH up to 4% (w/w). Data indicated that PWPC may be an effective carrier for GSH to improve bioavailability and antioxidant capacity.

Antioxidants other than vitamin C may be detected by glucose meters: Immediate relevance for patients with disorders targeted by antioxidant therapies

Owing to their ease of use, glucose meters are frequently used in research and medicine. However, little is known of whether other non-glucose molecules, besides vitamin C, interfere with glucometry. Therefore, we sought to determine whether other antioxidants might behave like vitamin C in causing falsely elevated blood glucose levels, potentially exposing patients to glycemic mismanagement by being administered harmful doses of glucose-lowering drugs. To determine whether various antioxidants can be detected by seven commercial glucose meters, human blood samples were spiked with various antioxidants ex vivo and their effect on the glucose results were assessed by Parkes error grid analysis. Several of the glucose meters demonstrated a positive bias in the glucose measurement of blood samples spiked with vitamin C, N-acetylcysteine, and glutathione. With the most interference-sensitive glucose meter, non-blood solutions of 1 mmol/L N-acetylcysteine, glutathione, cysteine, vitamin C, dihydrolipoate, and dithiothreitol mimicked the results seen on that glucose meter for 0.7, 1.0, 1.2, 2.6, 3.7 and 5.5 mmol/L glucose solutions, respectively. Glucose meter users should be alerted that some of these devices might produce spurious glucose results not only in patients on vitamin C therapy but also in those being administered other antioxidants. As discussed herein, the clinical relevance of the data is immediate in view of the current use of antioxidant therapies for disorders such as the metabolic syndrome, diabetes, cardiovascular diseases, and coronavirus disease 2019.

Antioxidant Therapeutics in Parkinson's Disease: Current Challenges and Opportunities

Oxidative stress is considered one of the pathological mechanisms that cause Parkinson’s disease (PD), which has led to the investigation of several antioxidants molecules as a potential therapeutic treatment against the disease. Although preclinical studies have demonstrated the efficacy of these compounds to maintain neuronal survival and activity in PD models, these results have not been reflected in clinical trials, antioxidants have not been able to act as disease modifiers in terms of clinical symptoms. Translational medicine currently faces the challenge of redesigning clinical trials to standardize criteria when testing molecules to reduce responses’ variability. Herein, we discuss current challenges and opportunities regarding several non-enzymatic antioxidants’ therapeutic molecules for PD patients’ potential treatment.

Sulfur-containing therapeutics in the treatment of Alzheimer's disease

Sulfur is widely existent in natural products and synthetic organic compounds as organosulfur, which are often associated with a multitude of biological activities. OBenzothiazole, in which benzene ring is fused to the 4,5-positions of the thiazolerganosulfur compounds continue to garner increasing amounts of attention in the field of medicinal chemistry, especially in the development of therapeutic agents for Alzheimer's disease (AD). AD is a fatal neurodegenerative disease and the primary cause of age-related dementia posing severe societal and economic burdens. Unfortunately, there is no cure for AD. A lot of research has been conducted on sulfur-containing compounds in the context of AD due to their innate antioxidant potential and some are currently being evaluated in clinical trials. In this review, we have described emerging trends in the field, particularly the concept of multi-targeting and formulation of disease-modifying strategies. SAR, pharmacological targets, in vitro/vivo ADMET, efficacy in AD animal models, and applications in clinical trials of such sulfur compounds have also been discussed. This article provides a comprehensive review of organosulfur-based AD therapeutic agents and provides insights into their future development.

CCRD based development of bromocriptine and glutathione nanoemulsion tailored ultrasonically for the combined anti-parkinson effect

Bromocriptine Mesylate (BRM) acts as a dopamine receptor agonist along with antioxidant effect and is utilized in the treatment of Parkinson's disease (PD). Glutathione (GSH) is a thiol- reducing agent having antioxidant properties in the brain. Replenishment of GSH inside the brain can play a major role in the management of PD. Both BRM and GSH suffer from low oral bioavailability and poor absorption. The objective of the present study was to develop BRM and GSH loaded nanoemulsion for the combined and synergistic effect delivered through the intranasal route for the better and effective management of PD. After extensive screening experiments, Capmul PG-8 NF was selected as oil, polyethylene glycol (PEG) 400 as a surfactant and propylene glycol as co-surfactant. Ultrasonication technique was employed for the fabrication of nanoemulsion. Central composite rotatable design (CCRD) was used to obtain the best formulation by optimization. Oil (%), S_mix (%), and sonication time (second) were chosen as independent variables for the optimization. Particle size, PDI, zeta potential, % transmittance, pH, refractive index, viscosity and conductivity of the optimized nanoemulsion were found to be 80.71 ± 2.75 nm, 0.217 ± 0.009, -12.60 ± 0.10 mV, 96.00 ± 3.05 %, 6.48 ± 0.28, 1.36 ± 0.03, 30.12 ± 0.10 mPas and 214.28 ± 2.79 μS/cm respectively. Surface morphology demonstrated that nanoemulsion possessed spherical and globular nature of the particle which showed 3.4 times and 1.5 times enhancement in drug permeation in the case of BRM and GSH respectively as compared to suspension. MTT assay done on neuro-2a cell lines revealed that nanoemulsion was safe for intranasal delivery. Behavioural studies were carried out to prove the efficacy of optimized nanoemulsion in PD using forced swimming test, locomotor activity test, catalepsy test, rota-rod test, and akinesia test in Wistar rats. The outcomes of the behavioural studies revealed that BRM and GSH loaded nanoemulsion treatment showed significant improvement in behavioural activities of PD (haloperidol-induced) rats after intranasal administration. This study concluded that BRM and GSH loaded nanoemulsion could be promising for the combined and synergistic anti-parkinson effect for the effective management of PD.

Dietary γ-Glutamylcysteine: Its Impact on Glutathione Status and Potential Health Outcomes

Glutathione (GSH) is a tripeptide that is readily synthesized intracellularly in humans and other mammals. More than a century of research suggests that GSH has numerous biological functions, including protection from the potential adverse events associated with reactive oxygen species (ROS) and related redox reactions that may induce oxidative stress, and that may be linked to innate detoxification processes. Normal tissue and plasma levels of GSH decline through the aging process and decrease during various disease states. While the health value of dietary GSH remains controversial, there is evidence that some metabolic intermediates, such as γ-glutamylcysteine (GGC) may function to preserve adequate GSH levels when the synthetic pathways decline in activity, and the innate antioxidant system is challenged. It is also important to recognize that among the thousands of protein-coding human genes and their respective polymorphisms, at least two genes (Gclc and Gclm) are directly involved with GSH synthesis via glutamate-cysteine ligase. This commentary examines the classic biochemistry, toxicology, safety, and clinical value of GSH and its intermediates that may be modulated by dietary supplementation.

pH-bioresponsive poly(ε-caprolactone)-based polymersome for effective drug delivery in cancer and protein glycoxidation prevention

Artificial nanostructures using polymers to produce polymeric vesicles are inspired by the many intricate structures found in living organisms. Polymersomes are a class of self-assembled vesicles known for their great stability and application in drug delivery. They can be tuned according to their intended use by changing their components and introducing activable block copolymers that transform these polymersomes into smart nanocarriers. In this study, we propose the synthesis of a poly (ethylene oxide)-poly (ε-caprolactone)-based polymersome (PEO-PCL) loaded with GSH as a pH-responsive drug delivery molecule for cancer and protein alteration inhibition. Initially, the nanocarrier was synthesized and characterized by DLS, TEM/SEM microscopy as well as gel permeation chromatography (GPC) and ¹H NMR. Their CMC formation, encapsulation efficiency, and pH responsiveness were analyzed. In addition, empty and GSH-loaded PEO-PCL polymersomes were tested for their toxicity and therapeutic effect on normal and cancer cells via an MTT test. Subsequently, protein alteration models (aggregation, glycation, and oxidation) were performed in vitro where the polymersomes were tested. Results showed that other than being non-toxic and able to highly encapsulate and release the GSH in response to acidic conditions, the nanocomposites do not hinder its content's ameliorative effects on cancer cells and protein alterations. This infers that polymeric nanocarriers can be a base for future smart biomedicine applications and theranostics.

Anethole Dithiolethione Increases Glutathione in Kidney by Inhibiting γ-Glutamyltranspeptidase: Biochemical Interpretation and Pharmacological Consequences

Aims

Anethole dithiolethione (ADT) is a marketed drug to treat xerostomia. Its mechanism of action is still unknown, but several preclinical studies indicate that it is able to increase intracellular glutathione (GSH) and protect against oxidative stress. Here, we investigated the molecular mechanisms behind these effects.

Results

Oral treatment of rats confirmed the GSH enhancing properties of ADT; among the different organs examined in this study, only the kidney showed a significant GSH increase that was already observed at low-dose treatments. The increase in GSH correlated with a decrease in γ-glutamyltranspeptidase (γ-GT) activity of the different tissues. In vitro and ex vivo experiments with tubular renal cells and isolated perfused rat kidney showed that the cellular uptake of intact GSH was correlated with the extracellular concentrations of GSH.

Conclusion

s. The prominent in vivopharmacological effect of ADT was a marked increase of GSH concentration in the kidney and a decrease of some systemic and renal biomarkers of oxidative stress. In particular, by inhibition of γ-GT activity, it decreased the production cysteinylglycine, a thiol that has prooxidant effects as the consequence of its autooxidation. The activity of ADT as GSH enhancer in both the circulation and the kidney was long-lasting. All these characteristics make ADT a promising drug to protect the kidney, and in particular proximal tubule cells, from xenobiotic-induced damage.

Ferroptosis in Acute Central Nervous System Injuries: The Future Direction?

Acute central nervous system (CNS) injuries, such as stroke, traumatic brain injury (TBI), and spinal cord injury (SCI) present a grave health care challenge worldwide due to high morbidity and mortality, as well as limited clinical therapeutic strategies. Established literature has shown that oxidative stress (OS), inflammation, excitotoxicity, and apoptosis play important roles in the pathophysiological processes of acute CNS injuries. Recently, there have been many studies on the topic of ferroptosis, a form of regulated cell death characterized by the accumulation of iron-dependent lipid peroxidation. Some studies have revealed an emerging connection between acute CNS injuries and ferroptosis. Ferroptosis, induced by the abnormal metabolism of lipids, glutathione (GSH), and iron, can accelerate acute CNS injuries. However, pharmaceutical agents, such as iron chelators, ferrostatin-1 (Fer-1), and liproxstatin-1 (Lip-1), can inhibit ferroptosis and may have neuroprotective effects after acute CNS injuries. However, the specific mechanisms underlying this connection has not yet been clearly elucidated. In this paper, we discuss the general mechanisms of ferroptosis and its role in stroke, TBI, and SCI. We also summarize ferroptosis-related drugs and highlight the potential therapeutic strategies in treating various acute CNS injuries. Additionally, this paper suggests a testable hypothesis that ferroptosis may be a novel direction for further research of acute CNS injuries by providing corresponding evidence.

Spotlight on Ferroptosis: Iron-Dependent Cell Death in Alzheimer's Disease

Alzheimer's disease is an emerging global epidemic that is becoming increasingly unsustainable. Most of the clinical trials have been centered around targeting β-amyloid and have met with limited success. There is a great impetus to identify alternative drug targets. Iron appears to be the common theme prevalent across neurodegenerative diseases. Iron has been shown to promote aggregation and pathogenicity of the characteristic aberrant proteins, β-amyloid, tau, α-synuclein, and TDP43, in these diseases. Further support for the involvement of iron in pathogenesis is provided by the recent discovery of a new form of cell death, ferroptosis. Arising from iron-dependent lipid peroxidation, ferroptosis is augmented in conditions of cysteine deficiency and glutathione peroxidase-4 inactivation. Here, we review clinical trials that provide the rationale for targeting ferroptosis to delay the pathogenesis of Alzheimer's disease (AD), potentially of relevance to other neurodegenerative diseases.

Vitamin D and N-Acetyl Cysteine Supplementation in Treatment-Resistant Depressive Disorder Patients: A General Review

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Major Depressive Disorder (MDD) is often a lifetime disabling mental illness as individuals with MDD might not benefit from standard-therapy, including both pharmacological and psychosocial interventions. Novel therapies are, therefore, required.

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It was shown by recent preclinical and clinical studies that the dysfunction of glutamatergic neurotransmission might be involved in the pathophysiology of MDD. Furthermore, neuroimmune alterations could have a significant role in the pathogenesis of MDD.

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Vitamin D is a neurosteroid hormone essential for several metabolic processes, immune responses, and for regulating neurotrophic-neuroprotective processes, neurotransmission and synaptic plasticity. Recent studies have also shown Vitamin D deficiency in patients with severe psychiatric disorders, including MDD.

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Lately, clinical studies have shown the neuroprotective action of N-acetyl cysteine (NAC) through the modulation of inflammatory pathways and via the modulation of synaptic release of glutamate in cortico-subcortical brain regions; the cysteine-glutamate antiporter.

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This paper reviews the therapeutic use of Vitamin D and NAC and among individuals with refractory MDD to the first- line pharmacological interventions, reviewing the clinical studies published in the last decade.

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A detailed summary of the current evidence in this area aims to better inform psychiatrists and general practitioners on the potential benefits of Vitamin D and NAC supplementation for this disorder.

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Nutraceutical supplementation with Vitamin D and NAC in treatment-resistant MDD patients may be important not only for improving depressive clinical manifestations but also for their safety and tolerability profile. This is of great interest, especially considering the need for treating special populations affected by MDD, such as youngsters and elders. Finally, the nutraceutical approach represents a good choice, considering its better compliance by the patients compared to traditional psychopharmacological treatment.

Oxidative stress, metabolic and mitochondrial abnormalities associated with autism spectrum disorder

Autism spectrum disorder is a neurodevelopmental disorder characterized by impaired development and by abnormal function in regards to social interaction, communication and restricted, repetitive behavior. It affects approximately 1% of the worldwide population. Like other psychiatric disorders the diagnosis is based on observation of, and interview with the patient and next of kin, and diagnostic tests. Many genes have been associated with autism, but only few highly penetrant. Some researchers have instead focused on oxidative stress, metabolic abnormalities and mitochondrial dysfunction as an explanation of the disorder. Currently no cure exists for the disorder, making these abnormalities interesting as they are possibly correctable with supplements or treatment. These various processes cannot be seen independently as they are influencing and interacting with each other. Furthermore many of the metabolic changes seen in autism have also been shown in other psychiatric disorders such as attention deficit hyperactivity disorder, schizophrenia and bipolar disorder along with often comorbid disorders like epilepsy and intellectual disability. As such some of these abnormalities are not specific, however, could indicate a similar mechanism for the development of these disorders, with symptomatology and severity varying according to the location and the amount of damage done to proteins, cells and DNA. Clinical studies trying to treat these abnormalities, have widely been successful in correcting the metabolic abnormalities seen, but only some studies have also shown bettering of autistic symptoms. Hopefully with increased knowledge of the pathophysiology of the disorder, future preventive measures or treatment can be developed.

Increased oxidative stress, inflammation, and glutamate: Potential preventive and therapeutic targets for hearing disorders

Hearing disorders constitute one of the major health concerns in the USA. Decades of basic and clinical studies have identified numerous ototoxic agents and investigated their modes of action on the inner ear, utilizing tissue culture as well as animal and human models. Current preventive and therapeutic approaches are considered unsatisfactory. Therefore, additional modalities should be developed. Many studies suggest that increased levels of oxidative stress, chronic inflammation, and glutamate play an important role in the initiation and progression of damage to the inner ear leading to hearing impairments. To prevent these cellular deficits, antioxidants, anti-inflammatory agents, and antagonists of glutamate receptor have been used individually or in combination with limited success. It is essential, therefore, to simultaneously enhance the levels of antioxidant enzymes by activating the Nrf2 (a nuclear transcriptional factor) pathway, dietary and endogenous antioxidant compounds, and B12-vitamins in order to reduce the levels of oxidative stress, chronic inflammation, and glutamate at the same time. This review presents evidence to show that increased levels of these cellular metabolites, biochemical or factors are involved in the pathogenesis of cochlea leading to hearing impairments. It presents scientific rationale for the use of a mixture of micronutrients that may decrease the levels of oxidative damage, chronic inflammation, and glutamate at the same time. The benefits for using oral administration of proposed micronutrient mixture in humans are presented. Animal and limited human studies indirectly suggest that orally administered micronutrients can accumulate in the inner ear. Therefore, this route of administration may be useful in prevention, and in combination with standard care, in improved management of hearing problems following exposure to well-recognized and studied ototoxic agents, such as noise, cisplatin, aminoglycoside antibiotics, and advanced age.

Egg white consumption increases GSH and lowers oxidative damage in 110-week-old geriatric mice hearts

The number of geriatrics with an advanced age is rising worldwide, with attendant cardiovascular disorders, characterized by elevated oxidative stress. Such oxidative stress is accelerated by an age-related loss of critical antioxidants like glutathione (GSH) and dietary solutions to combat this loss does not exist. While egg white is rich in sulphur amino acids (AAs), precursors for GSH biosynthesis, whether they can increase sulphur AA in vivo and augment GSH in the aged myocardium remain unclear. We hypothesized that egg white consumption increases GSH and reduces oxidative damage and inflammation in the geriatric heart. To this end, 101-102 week-old mice were given a AIN 76A diet supplemented with either 9% w/w egg white powder or casein for 8 weeks. Subsequent analysis revealed that egg white increased serum sulphur AA and cardiac GSH, while reducing the cysteine carrying transporter SNAT-2 and elevating glutamine transporter ASCT2 in the heart. Increased GSH was accompanied by elevated expression of GSH biosynthesis enzyme glutathione synthase as well as mitochondrial antioxidants like superoxide dismutase 2 and glutathione peroxidase 1 in egg white-fed hearts. These hearts also demonstrated lower oxidative damage of lipids (4-hydroxynonenal) and proteins [nitrotyrosine] with elevated anti-inflammatory IL-10 gene expression. These data demonstrate that even at the end of lifespan, egg whites remain effective in promoting serum sulphur AAs and preserve cardiac GSH with potent anti-oxidant and mild anti-inflammatory effects in the geriatric myocardium. We conclude that egg white intake may be an effective dietary strategy to attenuate oxidative damage in the senescent heart.

Sulforaphane: Its "Coming of Age" as a Clinically Relevant Nutraceutical in the Prevention and Treatment of Chronic Disease

A growing awareness of the mechanisms by which phytochemicals can influence upstream endogenous cellular defence processes has led to intensified research into their potential relevance in the prevention and treatment of disease. Pharmaceutical medicine has historically looked to plants as sources of the starting materials for drug development; however, the focus of nutraceutical medicine is to retain the plant bioactive in as close to its native state as possible. As a consequence, the potency of a nutraceutical concentrate or an extract may be lower than required for significant gene expression. The molecular structure of bioactive phytochemicals to a large extent determines the molecule's bioavailability. Polyphenols are abundant in dietary phytochemicals, and extensive in vitro research has established many of the signalling mechanisms involved in favourably modulating human biochemical pathways. Such pathways are associated with core processes such as redox modulation and immune modulation for infection control and for downregulating the synthesis of inflammatory cytokines. Although the relationship between oxidative stress and chronic disease continues to be affirmed, direct-acting antioxidants such as vitamins A, C, and E, beta-carotene, and others have not yielded the expected preventive or therapeutic responses, even though several large meta-analyses have sought to evaluate the potential benefit of such supplements. Because polyphenols exhibit poor bioavailability, few of their impressive in vitro findings have been replicated in vivo. SFN, an aliphatic isothiocyanate, emerges as a phytochemical with comparatively high bioavailability. A number of clinical trials have demonstrated its ability to produce favourable outcomes in conditions for which there are few satisfactory pharmaceutical solutions, foreshadowing the potential for SFN as a clinically relevant nutraceutical. Although myrosinase-inert broccoli sprout extracts are widely available, there now exist myrosinase-active broccoli sprout supplements that yield sufficient SFN to match the doses used in clinical trials.