A nutritional supplement formula for influenza A (H5N1) infection in humans

Structural Insights into Plasticity and Discovery of Flavonoid Allosteric Inhibitors of Flavivirus NS2B–NS3 Protease

Flaviviruses are among the most critical pathogens in tropical regions; they cause various severe diseases in developing countries but are not restricted to these countries. The development of antiviral therapeutics is crucial for managing flavivirus outbreaks. Ten proteins are encoded in the flavivirus RNA. The N2B–NS3pro protein complex plays a fundamental role in flavivirus replication and is a promising drug target; however, no flavivirus protease inhibitors have progressed to the preclinical stage. This study analyzed the structural models and plasticity of the NS2B–NS3pro protein complex of five medically important non-dengue flaviviruses (West Nile, Rocio, Ilhéus, yellow fever, and Saint Louis encephalitis). The flavonoids amentoflavone, tetrahydrorobustaflavone, and quercetin were selected for their exceptional binding energies as potential inhibitors of the NS2B–NS3pro protein complex. AutoDock Vina results ranged from −7.0 kcal/mol to −11.5 kcal/mol and the compounds preferentially acted non-competitively. Additionally, the first structural model for the NS2B–NS3pro protein complex was proposed for Ilhéus and Rocio viruses. The NS2B–NS3pro protease is an attractive molecular target for drug development. The three identified natural flavonoids showed great inhibitory potential against the viral species. Nevertheless, further in silico and in vitro studies are required to obtain more information regarding NS2B–NS3pro inhibition by these flavonoids and their therapeutic potential.

Modulating Neurological Complications of Emerging Infectious Diseases: Mechanistic Approaches to Candidate Phytochemicals

Growing studies are revealing the critical manifestations of influenza, dengue virus (DENV) infection, Zika virus (ZIKV) disease, and Ebola virus disease (EVD) as emerging infectious diseases. However, their corresponding mechanisms of major complications headed for neuronal dysfunction are not entirely understood. From the mechanistic point of view, inflammatory/oxidative mediators are activated during emerging infectious diseases towards less cell migration, neurogenesis impairment, and neuronal death. Accordingly, the virus life cycle and associated enzymes, as well as host receptors, cytokine storm, and multiple signaling mediators, are the leading players of emerging infectious diseases. Consequently, chemokines, interleukins, interferons, carbohydrate molecules, toll-like receptors (TLRs), and tyrosine kinases are leading orchestrates of peripheral and central complications which are in near interconnections. Some of the resulting neuronal manifestations have attracted much attention, including inflammatory polyneuropathy, encephalopathy, meningitis, myelitis, stroke, Guillain-Barré syndrome (GBS), radiculomyelitis, meningoencephalitis, memory loss, headaches, cranial nerve abnormalities, tremor, and seizure. The complex pathophysiological mechanism behind the aforementioned complications urges the need for finding multi-target agents with higher efficacy and lower side effects. In recent decades, the natural kingdom has been highlighted as promising neuroprotective natural products in modulating several dysregulated signaling pathways/mediators. The present study provides neuronal manifestations of some emerging infectious diseases and underlying pathophysiological mechanisms. Besides, a mechanistic-based strategy is developed to introduce candidate natural products as promising multi-target agents in combating major dysregulated pathways towards neuroprotection in influenza, DENV infection, ZIKV disease, and EVD.

Quercetin as a Natural Therapeutic Candidate for the Treatment of Influenza Virus

The medical burden caused by respiratory manifestations of influenza virus (IV) outbreak as an infectious respiratory disease is so great that governments in both developed and developing countries have allocated significant national budget toward the development of strategies for prevention, control, and treatment of this infection, which is seemingly common and treatable, but can be deadly. Frequent mutations in its genome structure often result in resistance to standard medications. Thus, new generations of treatments are critical to combat this ever-evolving infection. Plant materials and active compounds have been tested for many years, including, more recently, active compounds like flavonoids. Quercetin is a compound belonging to the flavonols class and has shown therapeutic effects against influenza virus. The focus of this review includes viral pathogenesis as well as the application of quercetin and its derivatives as a complementary therapy in controlling influenza and its related symptoms based on the targets. We also touch on the potential of this class of compounds for treatment of SARS-COV-2, the cause of new pandemic.

Antioxidants benefits in hepatitis C infection in the new DAAs era

Some of the evidence on whether antioxidant supplements are effective in treatment of liver diseases is contradictory. Here we perform a descriptive analysis of the available data in vivo and in vitro of the possible antiviral action and controversy of several antioxidant molecules against HCV.

Redox control in the pathophysiology of influenza virus infection

Triggered in response to external and internal ligands in cells and animals, redox homeostasis is transmitted via signal molecules involved in defense redox mechanisms through networks of cell proliferation, differentiation, intracellular detoxification, bacterial infection, and immune reactions. Cellular oxidation is not necessarily harmful per se, but its effects depend on the balance between the peroxidation and antioxidation cascades, which can vary according to the stimulus and serve to maintain oxygen homeostasis. The reactive oxygen species (ROS) that are generated during influenza virus (IV) infection have critical effects on both the virus and host cells. In this review, we outline the link between viral infection and redox control using IV infection as an example. We discuss the current state of knowledge on the molecular relationship between cellular oxidation mediated by ROS accumulation and the diversity of IV infection. We also summarize the potential anti-IV agents available currently that act by targeting redox biology/pathophysiology.

Metabolic host response and therapeutic approaches to influenza infection

Based on available metabolomic studies, influenza infection affects a variety of cellular metabolic pathways to ensure an optimal environment for its replication and production of viral particles. Following infection, glucose uptake and aerobic glycolysis increase in infected cells continually, which results in higher glucose consumption. The pentose phosphate shunt, as another glucose-consuming pathway, is enhanced by influenza infection to help produce more nucleotides, especially ATP. Regarding lipid species, following infection, levels of triglycerides, phospholipids, and several lipid derivatives undergo perturbations, some of which are associated with inflammatory responses. Also, mitochondrial fatty acid β-oxidation decreases significantly simultaneously with an increase in biosynthesis of fatty acids and membrane lipids. Moreover, essential amino acids are demonstrated to decline in infected tissues due to the production of large amounts of viral and cellular proteins. Immune responses against influenza infection, on the other hand, could significantly affect metabolic pathways. Mainly, interferon (IFN) production following viral infection affects cell function via alteration in amino acid synthesis, membrane composition, and lipid metabolism. Understanding metabolic alterations required for influenza virus replication has revealed novel therapeutic methods based on targeted inhibition of these cellular metabolic pathways.

Exercise in Glucose-6-Phosphate Dehydrogenase Deficiency: Harmful or Harmless? A Narrative Review

Objectives

Glucose-6-phosphate dehydrogenase (G6PD) deficiency, theoretically, renders red blood cells (RBC) susceptible to oxidative stress. G6PD deficiency has also been found in other types of cells than RBC, such as leukocytes and myocytes, where an inefficient protection against oxidative stress may occur too. Glutathione (GSH), a significant antioxidant molecule, levels are lower in G6PD individuals, and theoretically, the probability of oxidative stress and haemolysis due to exercise in individuals with G6PD deficiency is increased, whereas dietary supplementation with antioxidants may have beneficial effects on various aspects of this enzymopathy.

Methods

A search of the available literature was conducted using the keywords glucose-6-phosphate dehydrogenase (G6PD), deficiency, disease, exercise, muscle, antioxidant, vitamin, supplement, and supplementation. The search was limited to publications in English, conducted on humans, and published until August 2018. After screening, only relevant articles were included.

Results

There is little evidence indicating that G6PD deficiency can cause perturbations in redox status, haemolysis, and clinical symptoms such as fatigability and myoglobinuria, especially after intense exercise, compared to individuals with normal enzyme levels.

Conclusions

Exercise could be used by G6PD-deficient individuals as a tool to improve their quality of life. However, there is a lack of training studies, and assessment of the effects of regular and systematic exercise in G6PD-deficient individuals is warranted. Finally, since GSH levels are lower in G6PD deficiency, it would be interesting to examine the effects of antioxidant or cysteine donor supplements on redox status after exercise in these individuals.

Screening of melatonin, α-tocopherol, folic acid, acetyl-L-carnitine and resveratrol for anti-dengue 2 virus activity

OBJECTIVE

Infections with the mosquito transmitted dengue virus (DENV) are a significant public health burden in many parts of the world. Despite the introduction of a commercial vaccine in some parts of the world, the majority of the populations at risk of infection remain unprotected against this disease, and there is currently no treatment for DENV infection. Natural compounds offer the prospect of cheap and sustainable therapeutics to reduce the disease burden during infection, and thus potentially alleviate the risk of more severe disease. This study evaluated the potential anti-DENV 2 activity of five natural compounds namely melatonin, α-tocopherol, folic acid, acetyl-L-carnitine and resveratrol in two different cell lines.

RESULTS

Screening of the compounds showed that one compound (acetyl-L-carnitine) showed no effect on DENV infection, three compounds (melatonin, α-tocopherol and folic acid) slightly increased levels of infection, while the 5th compound, resveratrol, showed some limited anti-DENV activity, with resveratrol reducing virus output with an EC₅₀ of less than 25 μM. These results suggest that some commonly taken natural compounds may have beneficial effects on DENV infection, but that others may potentially add to the disease burden.

Regioselective IBX-Mediated Synthesis of Coumarin Derivatives with Antioxidant and Anti-influenza Activities

Different catechol and pyrogallol derivatives have been synthesized by oxidation of coumarins with 2-iodoxybenzoic acid (IBX) in DMSO at 25 °C. A high regioselectivity was observed in accordance with the stability order of the incipient carbocation or radical benzylic-like intermediate. The oxidation was also effective in water under heterogeneous conditions by using IBX supported on polystyrene. The new derivatives showed improved antioxidant effects in the DPPH test and inhibitory activity against the influenza A/PR8/H1N1 virus. These data represent a new entry for highly oxidized coumarins showing an antiviral activity possibly based on the control of the intracellular redox value.

The role of oxidative stress in influenza virus infection

Virus-induced oxidative stress plays an important role in the regulation of the host immune system. In this review, we provide backgrounds of the pathogenic mechanism of oxidative stress induced by influenza virus and the specific oxidant-sensitive pathways, and highlight that antioxidant is one of the effective strategies against influenza virus infection.

Intracellular redox state as target for anti-influenza therapy: are antioxidants always effective?

Influenza virus infections represent a big issue for public health since effective treatments are still lacking. In particular, the emergence of strains resistant to drugs limits the effectiveness of anti-influenza agents. For this reason, many efforts have been dedicated to the identification of new therapeutic strategies aimed at targeting the virus-host cell interactions. Oxidative stress is a characteristic of some viral infections including influenza. Because antioxidants defend cells from damage caused by reactive oxygen species induced by different stimuli including pathogens, they represent interesting molecules to fight infectious diseases. However, most of the available studies have found that these would-be panaceas could actually exacerbate the diseases they claim to prevent, and have thus revealed "the dark side" of these molecules. This review article discusses the latest opportunities and drawbacks of the antioxidants used in anti-influenza therapy and new perspectives.

Changes in glucose-6-phosphate dehydrogenase expression results in altered behavior of HBV-associated liver cancer cells

Hepatocellular carcinoma (HCC) is regarded as a major global health care issue, and chronic hepatitis B virus (HBV) infection is considered to be involved in pathogenesis of HCC. To increase knowledge of HCC pathogenesis, as well as discover potential novel molecules for anti-cancer therapy, mass spectrometry and isobaric tag for relative and absolute quantitation (iTARQ) were employed. The differences between nine HBV-related HCC and adjacent non-HCC tissue specimens were studied. In total, 222 proteins were analyzed for differential expression in the two types of samples. Among these proteins, several were further confirmed by immunohistochemical, immunoblotting, and real-time RT-PCR analysis. RNA interference induced downregulation of glucose-6-phosphate dehydrogenase (G6PD) and decreased HBV replication by fivefold by the IFN pathway. Decreased G6PD expression resulted in decreased hepatoma cell migration and invasion in cell culture. In summary, the investigation provides new information on pathogenesis of HBV infection and suggests G6PD as a novel anti-HCC target. G6PD suppression may contribute to treatment strategies for inhibiting tumor progression.

Glutathione: new roles in redox signaling for an old antioxidant

The physiological roles played by the tripeptide glutathione have greatly advanced over the past decades superimposing the research on free radicals, oxidative stress and, more recently, redox signaling. In particular, GSH is involved in nutrient metabolism, antioxidant defense, and regulation of cellular metabolic functions ranging from gene expression, DNA and protein synthesis to signal transduction, cell proliferation and apoptosis. This review will be focused on the role of GSH in cell signaling by analysing the more recent advancements about its capability to modulate nitroxidative stress, autophagy, and viral infection.

Current work and future possibilities for the management of severe influenza: using immunomodulatory agents that target the host response

In this article, we argue the case that the excessive inflammatory response seen in severe influenza contributes to severe illness and death by disabling oxidative phosphorylation in mitochondria, leading to reduced cellular levels of ATP. When the mitochondrial permeability transition is induced, cells cannot die by apoptosis in the face of reduced ATP levels, because apoptosis depends upon ATP availability, and so cells undergo necrosis. Cellular necrosis causes release of proinflammatory molecules such as high mobility group box 1 protein and mitochondrial DNA, and these could contribute to the prolongation of inflammation during severe influenza. With these concepts in mind, we discuss how immunomodulatory agents that prevent cellular necrosis (by restoring mitochondrial function) and limit inflammation are promising influenza treatments.

Selenium and glutamine supplements: where are we heading? A critical care perspective

PURPOSE OF REVIEW

There is considerable interest in glutamine and selenium in critical care as both offer the potential to enhance host defences, through different but complimentary mechanisms and may reduce subsequent infections and mortality. The SIGNET trial (randomized controlled factorial trial) is the largest, critical care study of both supplements. The data have been presented publicly, but the data are not published or available for review and will therefore not be discussed fully in this update. In the present review I will explore the recently available (past 1-2 years) published literature.

RECENT FINDINGS

The current literature demonstrates that there are currently insufficient data to enable confident recommendations on the optimal route, timing, duration and dosage of each of these nutritional supplements. The pending results of SIGNET, the largest critical care trial of parenteral nutrition supplemented by glutamine and or selenium promises to clarify some of the current ambiguities and inform future practice.

SUMMARY

To be able to confidently establish or refute the hypothesis that either glutamine or selenium alone or in combination improves outcome in critical care requires a well designed prospective randomized controlled trial. To design such a trial we require the optimal dose and duration of the nutritional supplement (balancing efficacy and toxicity, ease of administration and cost) and then conduct an adequately powered trial. Such a trial is still lacking for these two agents. There are some supportive data for selenium but the case is less strong for parenteral glutamine and weakest for enteral glutamine.

Effect of rutin on warfarin anticoagulation and pharmacokinetics of warfarin enantiomers in rats

Objectives

The effects of the flavonoid rutin on the anticoagulant activity of oral warfarin and the protein binding and pharmacokinetics of its enantiomers were investigated in rats.

Methods

A single dose of racemic warfarin, 1.5 mg/kg, was administered orally to rats either alone or on day 5 of an 8-day oral regimen of rutin, 1 g/kg daily.

Results

Rutin reduced the anticoagulant effect of racemic warfarin, evident as a 31% reduction in the area under the prothrombin complex activty–time curve (P < 0.05).

Key findings

Rutin had no apparent effect on pre-treatment baseline blood coagulation. It enhanced the in-vitro serum protein binding of S- and R-warfarin (reflected by 40% and 26% reductions in unbound fraction, respectively), and thus restricted distribution by 33 and 21%, respectively. Treatment with rutin significantly decreased the elimination half-life of S-warfarin by 37% as a result of the 69% increase in unbound clearance of the S-enantiomer. This effect was attributed to a significant 77% increase in the unbound formation clearance of the overall oxidative and reductive metabolites, and an increase in the unbound renal clearance of the more potent S-enantiomer of warfarin.

Conclusions

Concurrent rutin administration is likely to reduce the anticoagulant effect of racemic warfarin, reflecting a significant decrease in the elimination half-life of the more potent S-enantiomer.

Clinical management of pandemic 2009 influenza A(H1N1) infection

Antiviral therapy and vaccination are important strategies for controlling pandemic 2009 influenza A(H1N1) but efficacy depends on the timing of administration and is often limited by supply shortage. Patients with dyspnea, tachypnea, evidence of hypoxemia, and pulmonary infiltrates on chest radiograph should be hospitalized. Patients with severe illness or underlying medical conditions that increase the risk of more severe disease should be treated with oseltamivir or zanamivir as soon as possible, without waiting for the results of laboratory tests. Lung-protective ventilation strategy with a low tidal volume and adequate pressure, in addition to a conservative fluid management approach, is recommended when treating adult patients with ARDS. Extracorporeal membrane oxygenation has emerged as an important rescue therapy for critically ill patients. Use of systemic steroids was associated with delayed viral clearance in severe acute respiratory syndrome and H3N2 infection. Low-dose corticosteroids may be considered in the treatment of refractory septic shock. Passive immunotherapy in the form of convalescent plasma or hyperimmune globulin may be explored as rescue therapy. More data are needed to explore the potential role of IV gamma globulin and other drugs with immunomodulating properties, such as statins, gemfibrozil, and N-acetyl-cysteine. Health-care workers must apply strict standard and droplet precautions when dealing with suspected and confirmed case and upgrade to airborne precautions when performing aerosol-generating procedures. Nonpharmacologic measures, such as early case isolation, household quarantine, school/workplace closure, good community hygiene, and restrictions on travel are useful measures in controlling an influenza pandemic at its early phase.

The essential toxin: the changing perception of selenium in environmental sciences

During the last decades, the perception of selenium has undergone substantial changes. While its toxic effects were recognized causing hair and hoof loss in animals during the 1930s, its essential role in microbial, animal and human metabolism has been recognized later, i.e. with the discovery of selenium deficiency causing "white muscle disease" in feedstock in the 1950s. Nowadays, the positive effect of systematic selenium supplementation is discussed in manifold topics such as cancer or diabetes prevention and avian influenza susceptibility. Treatment of selenium containing waste streams poses a notable challenge to environmental engineers, and to date no ultimate solution has been found for e.g. the selenium contamination in agricultural areas of the western USA. For the future, selenium contamination carries an imminent danger, if the increasing energy demand is covered by fossil fuel combustion, which will lead to major selenium emission and toxicity. This review presents current knowledge of selenium's role in environmental sciences and outlines potentially feasible treatment options targeting a variety of selenium contaminated waste streams.

Advances in saponin-based adjuvants

Saponins are natural glycosides of steroid or triterpene which exhibited many different biological and pharmacological activities. Notably, saponins can also activate the mammalian immune system, which have led to significant interest in their potential as vaccine adjuvants. The most widely used saponin-based adjuvants are Quil A and its derivatives QS-21, isolated from the bark of Quillaja saponaria Molina, which have been evaluated in numerous clinical trials. Their unique capacity to stimulate both the Th1 immune response and the production of cytotoxic T-lymphocytes (CTLs) against exogenous antigens makes them ideal for use in subunit vaccines and vaccines directed against intracellular pathogens as well as for therapeutic cancer vaccines. However, Quillaja saponins have serious drawbacks such as high toxicity, undesirable haemolytic effect and instability in aqueous phase, which limits their use as adjuvant in vaccination. It has driven much research for saponin-based adjuvant from other kinds of natural products. This review will summarize the current advances concerning adjuvant effects of different kinds of saponins. The structure-activity relationship of saponin adjuvants will also be discussed in the light of recent findings. It is hoped that the information collated here will provide the reader with information regarding the adjuvant potential applications of saponins and stimulate further research into these compounds.

Glucose-6-phosphate dehydrogenase deficiency enhances human coronavirus 229E infection

The host cellular environment is a key determinant of pathogen infectivity. Viral gene expression and viral particle production of glucose-6-phosphate dehydrogenase (G6PD)–deficient and G6PD-knockdown cells were much higher than their counterparts when human coronavirus (HCoV) 229E was applied at 0.1 multiplicity of infection. These phenomena were correlated with increased oxidant production. Accordingly, ectopic expression of G6PD in G6PD-deficient cells or addition of antioxidant (such as α-lipoic acid) to G6PD-knockdown cells attenuated the increased susceptibility to HCoV 229E infection. All experimental data indicated that oxidative stress in host cells is an important factor in HCoV 229E infectivity

Response of selenium status indicators to supplementation of healthy North American men with high-selenium yeast

The essential nutrient selenium is required in microgram amounts [recommended dietary allowance (RDA) = 55 microg/day, 699 nmol/day] and has a narrow margin of safety (upper tolerable intake limit = 400 microg/day, 5 micromol/day). We conducted a randomized placebo-controlled study of high-selenium yeast, the form used in most supplements (300 microg/day, 3.8 micromol/day), administered to 42 free-living healthy men for 48 weeks. Dietary intakes of selenium, macronutrients, and micronutrients were not different between groups and did not change during the study. Supplementation more than doubled urinary selenium excretion from 69 to 160 microg/day (876 to 2,032 nmol/day). Urinary excretion was correlated with recent selenium intake estimated from 3-day diet records: urinary selenium excretion = 42 microg/day (533 nmol/day) + 0.132 x dietary selenium intake, p < 0.001. Dietary selenium intake was not significantly correlated with the other indicators of selenium status, presumably because urinary selenium excretion reflected recent intake, and tissue selenium was homeostatically controlled. After 48 weeks of supplementation, plasma selenium was increased 60% from 142 to 228 microg/l (1.8 to 2.9 micromol/l), and erythrocyte selenium was approximately doubled from 261 to 524 microg/l (3.3 to 6.6 micromol/l). Selenium concentrations increased more modestly in hair (56%) and platelets (42%). Platelets were the only blood component in which glutathione peroxidase activity was significantly related to selenium content. Selenium levels decreased rapidly after the end of supplementation, and there were no significant differences in selenium status indicators between groups by week 96. The absorption, distribution, and excretion of selenium from high-Se yeast were similar to selenium in foods.