Article

Suppression of influenza A virus nuclear antigen production and neuraminidase activity by a nutrient mixture containing ascorbic acid, green tea extract and amino acids

Authors:
  • Dr. Rath Health Foundation
  • Dr. Rath Health Foundation
  • Dr. Rath Health Foundation
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Abstract

Influenza, one of the oldest and most common infections, poses a serious health problem causing significant morbidity and mortality, and imposing substantial economic costs. The efficacy of current drugs is limited and improved therapies are needed. A unique nutrient mixture (NM), containing ascorbic acid, green tea extract, lysine, proline, N-acetyl cysteine, selenium among other micronutrients, has been shown to exert anti-carcinogenic and anti-atherogenic activity both in vitro and in vivo. Many of the constituents of NM have been shown to have an inhibitory effect on replication of influenza virus and HIV. This prompted us to study the effect of NM on influenza A virus multiplication in infected cells and neuraminidase activity (NA) in virus particles. Addition of NM to Vero or MDCK cells post infection resulted in dose-dependent inhibition of viral nucleoprotein (NP) production in infected cells. NM-mediated inhibition of viral NP was selective and not due to cytotoxicity towards host cells. This antiviral effect was enhanced by pretreatment of virus with the nutrient mixture. Individual components of NM, namely ascorbic acid and green tea extract, also blocked viral NP production, conferring enhanced inhibition when tested in combination. Incubation of cell-free virus with NM resulted in dose-dependent inhibition of associated NA enzyme activity. In conclusion, the nutrient mixture exerts an antiviral effect against influenza A virus by lowering viral protein production in infected cells and diminishing viral enzymatic activity in cell-free particles.

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... In in vitro cell culture systems, ascorbic acid has been shown to exhibit specific antiviral effects against influenza virus [40]. In the Vero cell line, it shows 50% inhibition of influenza viral proliferation at 100 and 250 mM at 24 h. ...
... In the Vero cell line, it shows 50% inhibition of influenza viral proliferation at 100 and 250 mM at 24 h. In the MDCK cell line, the specific antiviral effect of ascorbic acid is observed at higher doses (>200 mM) in a dose-dependent manner [40]. Ascorbic acid 3000 mM has been shown to inhibit the cell cycle of fibroblasts in an in vitro cell culture system at S phase with 100% inhibition of entry of those cells into G2 M phase, probably by down-modulating the genes essential for S-phase progression [41]. ...
... Influenza virus infection is known to produce matrix metalloprotease (MMP) in epithelial cells, which is thought to be a mechanism of spread of the virus [40]. Vero cells infected with influenza virus have been shown to produce substantial MMP-9 [56]. ...
Article
Occurrence of influenza pandemics is a worldwide phenomenon and a significant cause of mortality and morbidity throughout the globe. It is due to mutations in the influenza virus genetic material creating antigenic drift of pathogenic viral proteins resulting in emergence of new influenza virus strains. Therefore, the vaccines available for prevention of influenza offer no protection against influenza pandemics caused by new virus strains. Moreover, the existing drugs used to combat influenza may be ineffective to treat influenza pandemics due to the emergence of drug resistance in the pandemic virus strain. Therefore, a working strategy must be developed to combat influenza pandemics. In this review we have addressed this problem and reviewed the published studies on ascorbic acid in the common cold and influenza and laboratory studies on the effect of ascorbic acid on influenza virus. We have also correlated the clinical and laboratory studies and developed a hypothesis to prevent influenza pandemics.
... Studies have also found that EGCG has a significant inhibitory effect on the malignant growth and proliferation of a variety of cancer cells and can further induce tumor cells to undergo apoptosis [67,68]. In terms of being antiviral, EGCG displays potent inhibitory effects toward HIV, influenza A virus (IAV), hepatitis B virus (HBV), PRRSV, HCV, and porcine circovirus type 2 [69][70][71][72][73][74]. The latest study found that EGCG is also able to inhibit the replication of PEDV [75]. ...
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Coronaviruses, mainly including severe acute respiratory syndrome virus, severe acute respiratory syndrome coronavirus 2, Middle East respiratory syndrome virus, human coronavirus OC43, chicken infectious bronchitis virus, porcine infectious gastroenteritis virus, porcine epidemic diarrhea virus, and murine hepatitis virus, can cause severe diseases in humans and livestock. The severe acute respiratory syndrome coronavirus 2 is infecting millions of human beings with high morbidity and mortality worldwide, and the multiplicity of swine epidemic diarrhea coronavirus in swine suggests that coronaviruses seriously jeopardize the safety of public health and that therapeutic intervention is urgently needed. Currently, the most effective methods of prevention and control for coronaviruses are vaccine immunization and pharmacotherapy. However, the emergence of mutated viruses reduces the effectiveness of vaccines. In addition, vaccine developments often lag behind, making it difficult to put them into use early in the outbreak. Therefore, it is meaningful to screen safe, cheap, and broad-spectrum antiviral agents for coronaviruses. This review systematically summarizes the mechanisms and state of anti-human and porcine coronavirus drugs, in order to provide theoretical support for the development of anti-coronavirus drugs and other antivirals.
... Ascorbic acid significantly recovered the diminished mitochondrial membrane potential and decreased the gene expression of pro-inflammatory cytokines. [24,25] Ascorbic acid appears to have clinical benefits in patients with acute viral infections, including HCoV, based on several physiological properties that make it an attractive option to both prevent viral infections and treat the resulting severe illness through its immune-modulating property related to the increased production of α/β INFs and downregulating the production of pro-inflammatory cytokines. [26,27] A controlled trial found that ascorbic acid intake at a dose of 300 mg/day reduced the incidence of pneumonia and hospital stay compared to the control group, suggesting its possible beneficial role to ameliorate viral-induced oxidative injury and prevent influenza virus infection. ...
Article
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The use of supplementary medicines and antioxidant drugs is not restricted to just preventing deficiencies or inhibiting the production of free radicals. There are a plethora of indications that supplements and antioxidants may suffice for and they include viral infections. Hence, the importance of understanding the potential efficacy and activity of supplements and antioxidants in the management of viral infections, specifically the coronavirus disease, cannot be overemphasized. This article aims to explain what supplements and antioxidants are, their proven efficacy in the management/treatment of the existing viral infections, and the possibility of their usefulness in the management/treatment of coronavirus disease. The coronavirus pandemic affected almost 10 million people worldwide and has contributed to hundreds of thousands of deaths, while research is ongoing for the development of a vaccine and if possible, a cure, it is important to explore every available option including traditional medicines, antioxidants, and complementary and supplementary medicines. A comprehensive review of this study was achieved by evaluating recent existing literature on the activity of supplements and antioxidants against viral infections and the coronavirus disease. It was discovered that although Vitamins C and D, zinc, and elderberry have antiviral properties and may be effective in managing preexisting viral infections, their activity against COVID-19 is still unknown and speculative. Therefore, there are no recent guidelines provided for the treatment of COVID-19 that recommend dietary supplements and/or antioxidants as pharmacological interventions.
... The antiviral effect is not probably based on antioxidant potency, as the dehydroascorbic acid is more potent antiviral agent than ascorbic acid [71]. Supplementation of food by some natural products containing ascorbic acid leads to inhibitory effect on replication of influenza virus and isolated parts of the tested natural products including ascorbic acid and green tea extracts had similar antiviral effect [72]. Application of ascorbic acid and vitamin E and B supplements is recommended for pharmacological purposes. ...
Article
Full-text available
Ascorbic acid is a low molecular weight antioxidant well known as anti-scorbut acting vitamin C in humans, primates and guinea pigs. This review summarizes basic data about ascorbic acid in its physiological action point of view. It is divided into biochemistry of ascorbic acid synthesis, mechanism of antioxidant action and participation in anabolism, pharmacokinetics and excretion, exogenous ascorbic acid immunomodulatory effect and participation in infectious diseases, impact on irradiation and intoxication pathogenesis, and supplementary demands. The primary intention was to consider ascorbic acid not only as an antioxidant but also as a chemical compound affecting multiple pathways with a potential beneficial impact in many diseases and processes in human body.
... Ascorbic acid (19,Figure 4) scavenges superoxide anion [78]. Ascorbic acid inhibited the proliferation of influenza virus in cell cultures [79]. Dehydroascorbic acid, an oxidized form of ascorbic acid without reducing ability, showed much stronger antiviral activity than that of ascorbic acid, indicating that the antiviral activity of ascorbic acid is due to factors other than antioxidant mechanism [80]. ...
Article
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With the appearance of the novel influenza A (H1N1) virus 2009 strain we have experienced a new influenza pandemic and many patients have died from severe complications associated with this pandemic despite receiving intensive care. This suggests that a definitive medical treatment for severe influenza-associated complications has not yet been established. Many studies have shown that superoxide anion produced by macrophages infiltrated into the virus-infected organs is implicated in the development of severe influenza-associated complications. Selected antioxidants, such as pyrrolidine dithiocabamate, N-acetyl-L-cysteine, glutathione, nordihydroguaiaretic acid, thujaplicin, resveratrol, (+)-vitisin A, ambroxol, ascorbic acid, 5,7,4-trihydroxy-8-methoxyflavone, catechins, quercetin 3-rhamnoside, iso- quercetin and oligonol, inhibit the proliferation of influenza virus and scavenge superoxide anion. The combination of antioxidants with antiviral drugs synergistically reduces the lethal effects of influenza virus infections. These results suggest that an agent with antiviral and antioxidant activities could be a drug of choice for the treatment of patients with severe influenza-associated complications. This review article updates knowledge of antioxidant therapy as a potential approach to severe influenza-associated complications.
... It is shown that green tea catechins inhibited the activity of the endonuclease which might affect the propagation of the virus Fig. (3). The extract from green tea was shown to inhibit the neuraminidase activity thus reducing the production of nucleoprotein [101]. The polyphenols from green tea exhibited virucidal effect against three types of influenze viruses, H1N1 [Influenza A/Chile/1/83], H3N2 [A/Sydney/5/97] and influenze B/Yamagata/16/88 [102]. ...
Article
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Herbal products have gained considerable interest among the pharmaceutical companies and consumers due to the minimal side effects associated with them. The bioflavanoids present in these products are the key players in modulating their effects. Several therapeutic effects have been attributed to the bioflavanoids present in green tea and turmeric. Antimicrobial activity is one among the spectrum of activities they exhibit. Curcumin and catechins, the principle components of turmeric and green tea respectively have virucidal and virustatic actions. An antimicrobial composition consisting of extracts from green tea and turmeric have shown to be highly potent against various microbes, especially viruses. In the present review, we have discussed the patents and the antiviral effects of curcumin and catechins. The antimalarial effect of curcumin has also been discussed.
... One specific role of ROS is their ability to enhance the pathogenesis of infections, such as influenza 220,221 . It has been demonstrated that during times of influenza infection ROS may damage lung parenchyma cells, but that this injury may be ameliorated by anti-oxidant supplementation [222][223][224][225] . Current theories propose the mechanism behind this benefit is attenuation of ROS produced by the innate immune system, but this is not commonly accepted and is still highly debated. ...
... One specific role of ROS is their ability to enhance the pathogenesis of infections, such as influenza [9,10]. It has been demonstrated that during times of influenza infection ROS may damage lung parenchyma cells, but that this injury may be ameliorated by anti-oxidant supplementation [11][12][13][14]. Current theories propose the mechanism behind this benefit is attenuation of ROS produced by the innate immune system, but this is not commonly accepted and is still highly debated. ...
Article
Reactive oxygen species (ROS) are critical in a broad spectrum of cellular processes including signaling, tumor progression, and innate immunity. The essential nature of ROS signaling in the immune systems of Drosophila and zebrafish has been demonstrated; however, the role of ROS, if any, in mammalian adaptive immune system development and function remains unknown. This work provides the first clear demonstration that thymus-specific elevation of mitochondrial superoxide (O(2)(•-)) disrupts normal T cell development and impairs the function of the mammalian adaptive immune system. To assess the effect of elevated mitochondrial superoxide in the developing thymus, we used a T-cell-specific knockout of manganese superoxide dismutase (i.e., SOD2) and have thus established a murine model to examine the role of mitochondrial superoxide in T cell development. Conditional loss of SOD2 led to increased superoxide, apoptosis, and developmental defects in the T cell population, resulting in immunodeficiency and susceptibility to the influenza A virus H1N1. This phenotype was rescued with mitochondrially targeted superoxide-scavenging drugs. These findings demonstrate that loss of regulated levels of mitochondrial superoxide lead to aberrant T cell development and function, and further suggest that manipulations of mitochondrial superoxide levels may significantly alter clinical outcomes resulting from viral infection.
... AA is crucial in all demanding conditions such as immune-stimulating, anti-inflammatory, antiviral and antibacterial functions, which all are related to inflammatory procedures [28]. Another study represented that the nutrient combination containing lysine, proline, ascorbic acid, green tea extract, N-acetyl cysteine (NAC), selenium, and different micronutrients is an effective inhibitor of influenza A virus growth as examined in MDCK and Vero cell cultures [29]. Also, vitamin C has been used to treat hepatitis, encephalitis, influenza, SARS, and a few different viral sicknesses [30]. ...
Article
Full-text available
Background Influenza A virus (IAV) infection remains a serious public health threat. Due to drug resistance and side effects of the conventional antiviral drugs, repurposing the available natural compounds with high tolerability and fewer side effects has attracted researchers’ attention. The aim of this study was to screen in vitro anti-influenza activity of three anionic compounds ascorbate, acetate, and citrate. Methods The non-cytotoxic concentration of the compounds was determined by MTT assay and examined for the activity against IAV in simultaneous, pre-, and post-penetration combination treatments over 1 h incubation on Madin-Darby Canine Kidney (MDCK) cell line. The virus titer and viral load were determined using hemagglutination assay (HA) and qPCR, respectively. Few pro-inflammatory and anti-inflammatory cytokines were evaluated at RNA and protein levels by qPCR and ELISA, respectively. Results The non-cytotoxic concentrations of the ascorbate (200 mg/ml), acetate and citrate (both 3 mg/ml) reduced the viral titer by 6.5, 4.5, and 1.5 logs in the simultaneous combination treatment. The M protein gene copy number decreased significantly in simultaneous treatment ( P < 0.01). The expression of cytokines was also affected by the treatment of these compounds. Conclusions These anionic compounds could affect the influenza virus load, thereby reducing pro-inflammatory cytokines and increasing anti-inflammatory cytokines levels.
... In cell cultures, ascorbic acid suppresses the reproduction of the influenza virus [34]. At the same time, its reduced form, dehydroascorbic acid, which does not exhibit antioxidant properties, exhibits much higher antiviral activity compared to AA. ...
Article
Full-text available
Ascorbic acid (vitamin C, AA) is an essential nutrient of the human diet due to its participation on numerous regulatory and enzymatic processes. AA takes part in such vital physiological processes as hormone production, collagen synthesis, stimulation of the immune system, etc. In the present review the activities of AA are considered that provide its protective effect at influenza infection. This effect can be result of direct virus-inhibiting activity of AA as well as of anti-inflammatory and antioxidant properties. Oxidative stress during influenza infection leads to nonspecific damage of the pulmonary tissue and subsequent inflammation of the lungs. The antioxidant activity of AA results in alleviation of infection due to suppression of tissue damage as well as in inhibition of reactive oxygen species-mediated signal transduction and regulatory reactions. After oxidation by ROS, AA is converted to dehydroascorbic acid (DAA) and inhibits the key enzymes of NF-κB pathway, such as kinases IKKα and IKKβ. AA itself blocks the activity of another component of the NF-kB pathway, kinase IKKβ(SS/EE), whose activity is directed to the phosphorylation of the factor IκBα. As a result, activation of NF-κB and its transport to the nucleus does not occur. Thus, AA performs a dual function: first, it neutralizes free radicals, preventing them from activating NF-κB, and secondly, the product of its oxidation, DAA, further blocks the activation of this pathway. In addition, in some cases AA results in the decrease in the infectious activity of influenza virus that is not due to the antioxidant activity of AA, but to direct virus-inhibiting activity. Taken together, the presented data suggests that the use of drugs with antiviral and antioxidant activity, as a combination of individual drugs or, as in the case of AA, as a single drug with complex activity, for treatment of influenza has advantages over the etiotropic drug monotherapy scheme.
... collagen stability is also modulated by n-acetyl cysteine through the inhibition of metalloproteinase (MMP) activity (27) and tumor cell invasion (28). Selenium has been shown to interfere with the migration of endothelial cells through the extracellular matrix (ecM) (28), as well as to inhibit MMP expression and tumor invasion (29). in previous studies, we showed that nM not only inhibited virus-associated neuraminidase activity and viral nuclear antigen production (30), but also inhibited extracellular invasive parameters such as MMP-2 and -9 secretion and the invasion of influenza A virus in MDCK and Vero cells in vitro (31). ...
Article
Nutrients are known to display pharmacologic activity against viruses and to exert cooperative effects in cells. To study the influence of nutrient cooperation on HIV production in chronically infected T lymphocytes, we evaluated the individual and combined effects of nutrients on HIV-1 reverse transcriptase (RT) released into the culture supernatant. In unstimulated cells, low concentrations of single nutrients, namely ascorbic acid (AA), green tea polyphenols (GT) or lysine, did not significantly suppress HIV-1 RT production. However, when GT (25 µg/ml) and AA (32-64 µg/ml) were combined and applied to cells, extracellular RT was significantly reduced relative to the control. Combining GT (25 µg/ml) with lysine (25 µg/ml) also reduced the RT level to a greater extent (51% of control) than was observed wih lysine alone, and the addition of AA (16 µg/ml) to the combination further decreased RT to 17% of the control (p=0.06). Under the same assay conditions, the nucleoside analog azidothymidine did not significantly suppress HIV production at low to moderate concentrations (0.5-1.0 µg/ml), but did reduce the RT level to 40% of the control (p=0.02) at the highest dose tested (2 µg/ml). In unstimulated cells as well as in latently infected cells stimulated with mitogen (PMA or TNF-α), a nutrient mixture containing GT, AA and amino acids imparted significantly greater RT suppression than equivalent concentrations of key individual components. Nutrient effects on RT suppression were virus-specific and were not due to non-specific cellular toxicity. These results suggest that relatively non-toxic micronutrient combinations are more potent than single nutrients in suppressing virus production in chronically infected T cells, indicating that the constituent nutrients have a cooperative effect in HIV inhibition.
... Ascorbic acid significantly recovered the diminished mitochondrial membrane potential and decreased the gene expression of pro-inflammatory cytokines. [24,25] Ascorbic acid appears to have clinical benefits in patients with acute viral infections, including HCoV, based on several physiological properties that make it an attractive option to both prevent viral infections and treat the resulting severe illness through its immune-modulating property related to the increased production of α/β INFs and downregulating the production of pro-inflammatory cytokines. [26,27] A controlled trial found that ascorbic acid intake at a dose of 300 mg/day reduced the incidence of pneumonia and hospital stay compared to the control group, suggesting its possible beneficial role to ameliorate viral-induced oxidative injury and prevent influenza virus infection. ...
Article
Full-text available
The use of supplementary medicines and antioxidant drugs is not restricted to just preventing deficiencies or inhibiting the production of free radicals. There are a plethora of indications that supplements and antioxidants may suffice for and they include viral infections. Hence, the importance of understanding the potential efficacy and activity of supplements and antioxidants in the management of viral infections, specifically the coronavirus disease, cannot be overemphasized. This article aims to explain what supplements and antioxidants are, their proven efficacy in the management/treatment of the existing viral infections, and the possibility of their usefulness in the management/treatment of coronavirus disease. The coronavirus pandemic affected almost 10 million people worldwide and has contributed to hundreds of thousands of deaths, while research is ongoing for the development of a vaccine and if possible, a cure, it is important to explore every available option including traditional medicines, antioxidants, and complementary and supplementary medicines. A comprehensive review of this study was achieved by evaluating recent existing literature on the activity of supplements and antioxidants against viral infections and the coronavirus disease. It was discovered that although Vitamins C and D, zinc, and elderberry have antiviral properties and may be effective in managing preexisting viral infections, their activity against COVID-19 is still unknown and speculative. Therefore, there are no recent guidelines provided for the treatment of COVID-19 that recommend dietary supplements and/or antioxidants as pharmacological interventions.
... Furthermore, vitamin C, not in combination with antivirals, supressed viral replication of herpes simplex virus-1 (HSV-1), influenza type A virus, poliovirus type 1 and rhinovirus [16,17]. In another in vitro study, a nutrient mixture, including vitamin C, had a dose-dependent suppression effect on production of influenza viral nucleoproteins and neuraminidase activity [18]. Interestingly, exposure of chick embryo tracheal organ to vitamin C increased resistance of infection to coronavirus [19]. ...
Article
Full-text available
The mainstay of management of coronavirus disease 2019 (COVID-19) is mainly supportive as to date there is no effective antiviral treatment, apart from remdesivir which has been approved by Food and Drug administration (FDA) for treatment of COVID-19, or vaccine. Supplementation with micronutrients, such as vitamins and minerals, has gained an increasing interest as part of the supportive management of COVID-19. Vitamin C levels in serum and leukocytes are depleted during the acute stage of infection owing to increased metabolic demands. High-dose vitamin C supplement helps to normalise both serum and leukocytes vitamin C levels. Vitamin C has multiple pharmacological characteristics, antiviral, anti-oxidant, anti-inflammatory and immunomodulatory effects, which make it a potential therapeutic option in management of COVID-19. The use of high dose of intravenous vitamin C for management of COVID-19 in China and the United Stated has shown promising results. There were no reported adverse reactions with the short-term use of high dose of vitamin C. Given the fact that vitamin C is cheap, available and safe drug with beneficial effects in management of viral infections and critically ill patients reported in previous clinical trials, it is sensible to add it to COVID-19 management protocol particularly if the current ongoing clinical trials testing the effect of vitamin C in management of COVID-19 show positive results.
... It has been reported that high doses of ascorbic acid in viral infections clears superoxide anion, inhibits virus proliferation and decreases expression of viral antigens and cellular viral load. It has also been reported to have immunomodulatory characteristics, concentrate in leukocytes, lymphocytes and macrophages, heal chemotaxis, increase neutrophil phagocytic capacity and oxidative killing, support lymphocyte proliferation and function, significantly restore decreased mitochondrial membrane potential and decrease gene expression of pro-inflammatory cytokines [157,158] . It has been reported that ROS production increases for viral replication in BHV-1 infection and causes mitochondrial dysfunction in the cell [159] . ...
Article
Full-text available
The formation of reactive oxygen species is a physiological event in aerobic life. In case of infection, if the increased oxidant substances cannot be cleaned sufficiently by antioxidants, oxidative stress occurs. As a result, a number of pathological problems occur by damaging DNA, protein, carbohydrate and lipids. In biological systems, the balance between oxidants and antioxidants is important. In oxidative stress situations where the balance cannot be achieved sufficiently, support can be provided with the use of exogenous antioxidants. However, the molecular structure, route of administration and concentrations of these exogenous antioxidants are important. Otherwise, they may show a pro-oxidative effect. The present rewiev study makes a general overview of oxidative-nitrosative stress markers commonly used in infective clinical studies, antioxidant enzymes and parameters and antioxidant supplements.
... Fatty acid monoester derivatives of EGCG, especially those with long alkyl chains, exhibited a sharply increased antiviral effect against IAV compared to natural EGCG [57]. The inhibitory effects of different nutrient mixtures of natural EGCG on influenza virus have also been demonstrated by different investigators [58,81,82]. Some researchers contributed to clinical trials of EGCG as an IAV restriction factor [59]. ...
... It has antibacterial, antiviral, antioxidant, antiarthritic, antiangiogenic, anti-inflammatory and antitumor activities (Haqqi et al., 1999;Osada et al., 2001;Sartippour et al., 2002;Dona et al., 2003;Weber et al., 2003;Sudano Roccaro et al., 2004). Studies have shown that EGCG has antiviral activity against retroviruses, orthomyxoviruses and flaviviruses in vitro (Fassina et al., 2002;Yamaguchi et al., 2002;Jariwalla et al., 2007;Roomi et al., 2008;Calland et al., 2012;Chen et al., 2012;Fukazawa et al., 2012). However, inhibitory effects of EGCG on pseudorabies virus (PRV) have not yet been reported. ...
Article
Full-text available
A newly emerged pseudorabies virus (PRV) variant with enhanced pathogenicity has been identified in many PRV-vaccinated swine in China since 2011. The PRV variant has caused great economic cost to the swine industry, and measures for the effective prevention and treatment of this PRV variant are still lacking. (–)-Epigallocatechin-3-gallate (EGCG) exhibits antiviral activity against diverse viruses and thus in this study, we investigated the anti-PRV activity of EGCG in vitro and in vivo . EGCG significantly inhibited infectivity of PRV Ra and PRV XJ5 strains in PK15 B6 cells and Vero cells. The anti-PRV activity of EGCG was dose-dependent, and 50 μM EGCG could completely block viral infection at different multiplicities of infection. We next revealed that EGCG blocked PRV adsorption and entry to PK15 B6 cells in a dose-dependent manner, but inhibition of PRV entry by EGCG was not as efficient as its inhibition of PRV adsorption. PRV replication was suppressed in PK15 B6 cells treated with EGCG post-infection. However, EGCG did not affect PRV assembly and could promote PRV release. Furthermore, 40 mg/kg EGCG provided 100% protection in BALB/c mice challenged with PRV XJ5, when EGCG was administrated both pre- and post-challenge. These results revealed that EGCG exhibits antiviral activity against PRV mainly by inhibiting virus adsorption, entry and replication in vitro . Meanwhile, EGCG increased the survival of mice challenged with PRV. Therefore, EGCG might be a potential antiviral agent against PRV infection.
... Structurally and functionally, the properties of catechin are attributed to the presence or absence of a galloyl moiety and the number of hydroxyl groups on its B-ring. EGCG displays potent inhibitory effects toward human immunodeficiency virus, influenza virus, hepatitis virus, hepatitis B virus, porcine reproductive and respiratory syndrome virus and porcine circovirus type 2 (Fassina, et al., 2002;Yamaguchi, et al., 2002;Jariwalla, et al., 2007;Roomi, et al., 2008;Fukazawa, et al., 2012;Calland, et al., 2012;Chen, et al., 2012;Ge, et al., 2018;Li, et al., 2020). However, whether EGCG has an inhibitory effect on PEDV has not been reported. ...
Article
Full-text available
There are currently no licensed drugs against porcine epidemic diarrhea virus (PEDV), but vaccines are available. We identified a natural molecule, epigallocatechin-3-gallate (EGCG), the main polyphenol in green tea, which is effective against infection with PEDV. We used a variety of methods to test its effects on PEDV in Vero cells. Our experiments show that EGCG can effectively inhibit PEDV infections (with HLJBY and CV777 strains) at different time points in the infection using western blot analysis. We found that EGCG inhibited PEDV infection in a dose-dependent manner 24 h after the infection commenced using western blotting, plaque formation assays, immunofluorescence assays (IFAs), and quantitative reverse-transcriptase PCR (qRT-PCR). We discovered that EGCG treatment of Vero cells decreased PEDV attachment and entry into them by the same method analysis. Western blotting also showed that PEDV replication was inhibited by EGCG treatment. Whereas EGCG treatment was found to inhibit PEDV assembly, it had no effect on PEDV release. In summary, EGCG acts against PEDV infection by inhibiting PEDV attachment, entry, replication, and assembly.
... Moreover, many studies have identified AA as an immune-modulator affecting the proper function of several cell types included in innate and acquired immunity [104][105][106][107][108][109]. The clinical and biological importance of vitamin C is further confirmed by many studies reporting its adjuvant properties towards viral infections, such as herpes virus (HSV), influenza type 1, HIV, and rhinovirus [110][111][112][113], but also sepsis and inflammation [114][115][116][117]. In the context of the ongoing COVID-19 pandemic and while there is still no effective antiviral therapy, this antiviral hallmark has a new significance. ...
Article
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In recent years, there has been a growth in scientific interest in nutraceuticals, which are those nutrients in foods that have beneficial effects on health. Nutraceuticals can be extracted, used for food supplements, or added to foods. There has long been interest in the antiviral properties of nutraceuticals, which are especially topical in the context of the ongoing COVID-19 pandemic. Therefore, the purpose of this review is to evaluate the main nutraceuticals to which antiviral roles have been attributed (either by direct action on viruses or by modulating the immune system), with a focus on the pediatric population. Furthermore, the possible applications of these substances against SARS-CoV-2 will be considered.
... Fatty acid monoester derivatives of EGCG, especially those with long alkyl chains, exhibited a sharply increased antiviral effect against IAV compared to natural EGCG [57]. The inhibitory effects of different nutrient mixtures of natural EGCG on influenza virus have also been demonstrated by different investigators [58,81,82]. Some researchers contributed to clinical trials of EGCG as an IAV restriction factor [59]. ...
Article
Full-text available
Over the centuries, infectious diseases caused by viruses have seriously threatened human health globally. Viruses are responsible not only for acute infections but also many chronic infectious diseases. To prevent diseases caused by viruses, the discovery of effective antiviral drugs, in addition to vaccine development, is important. Green tea catechins (GTCs) are polyphenolic compounds from the leaves of Camellia sinensis. In recent decades, GTCs have been reported to provide various health benefits against numerous diseases. Studies have shown that GTCs, especially epigallocatechin-3-gallate (EGCG), have antiviral effects against diverse viruses. The aim of this review is to summarize the developments regarding the antiviral activities of GTCs, to discuss the mechanisms underlying these effects and to offer suggestions for future research directions and perspectives on the antiviral effects of EGCG.
... 25 Originally this finding suggested EA derivates interacted directly with specific virion proteins, but not HA or NA, and blocks the infection cycle at some stage. Nevertheless, the effect of certain amino acid derivates 36 and the efficacy of a blend composed by natural substances and amino acids as neuraminidase inhibitors have been reported, 37 suggesting the need for studies more focused on the activity of EA alone. ...
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Seasonal flu is caused by influenza infection, a virus that spreads easily in human population with periodical epidemic outbreaks. The high mutational rate of influenza viruses leads to the emergence of strains resistant to the current treatments. Due to that, scientific research is focusing on the development of new anti-influenza agents as alternative or complementary treatments. Olive tree ( Olea europaea L.) has been a source of ancestral remedies due to its antimicrobial activity. Thus, the aim of this study was to test the anti-influenza activity of a standardized olive leaf extract rich in elenolic acid (EA), Isenolic ® , compared with oseltamivir. Isenolic ® extract was characterized by High Performance Liquid Chromatography (HPLC)-Mass Spectrometry and its content in EA was determined by HPLC. Cytotoxicity, viral neuraminidase inhibitor activity and cell viability protection against influenza infection of Isenolic ® were tested in vitro using sialic acid overexpressing Madin-Darby Canine Kidney cells. Isenolic ® formulations showed a 4% and 8% dry basis. Oseltamivir and Isenolic ® extracts showed anti-influenza activity. The 8% Isenolic ® formulation showed a dose-dependent neuraminidase inhibitor activity higher than the 4% formulation, and preserved cell viability under viral infection. Thus, Isenolic ® become a promising natural alternative to existing influenza treatments.
... Based on this study and our earlier findings [18,19,27], this combination of plant-derived compounds and micronutrients may constitute a new anti-SARS-CoV-2 strategy by simultaneously affecting multiple aspects of viral life cycle, including viral entry and replication. This strategy was also implemented in our earlier studies, including those of human influenza H1N1, bird flu H1N5, and others, which were based on selecting natural components that simultaneously affect key pathology mechanisms across a wide spectrum of infective agents [28][29][30][31]. ...
Article
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Despite vaccine availability, the global spread of COVID-19 continues, largely facilitated by emerging SARS-CoV-2 mutations. Our earlier research documented that a specific combination of plant-derived compounds can inhibit SARS-CoV-2 binding to its ACE2 receptor and controlling key cellular mechanisms of viral infectivity. In this study, we evaluated the efficacy of a defined mixture of plant extracts and micronutrients against original SARS-CoV-2 and its Alpha, Beta, Gamma, Delta, Kappa, and Mu variants. The composition containing vitamin C, N-acetylcysteine, resveratrol, theaflavin, curcumin, quercetin, naringenin, baicalin, and broccoli extract demonstrated a highest efficacy by inhibiting the receptor-binding domain (RBD) binding of SARS-CoV-2 to its cellular ACE2 receptor by 90%. In vitro exposure of test pseudo-typed variants to this formula for 1 h before or simultaneously administrated to human pulmonary cells resulted in up to 60% inhibition in their cellular entry. Additionally, this composition significantly inhibited other cellular mechanisms of viral infectivity, including the activity of viral RdRp, furin, and cathepsin L. These findings demonstrate the efficacy of natural compounds against SARS-CoV-2 including its mutated forms through pleiotropic mechanisms. Our results imply that simultaneous inhibition of multiple mechanisms of viral infection of host cells could be an effective strategy to prevent SARS-CoV-2 infection.
... This suppression effect was dose-dependent. 191 Furthermore, it was found that 1-2 g/day of vitamin C inhibits VRTIs. 138 Thus, a high dose of vitamin C may be a therapeutic agent for improving oxidative stress and inflammation caused by coronavirus infection, preventing virus replication, improving the antiviral immune system and adrenal function. ...
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... Green tea infusion is a well-known beverage, popular for its health benefits [1][2][3][4][5][6][7][8]. Several studies have shown that green tea displays potent antioxidant activity, which has sparked several studies about its effects to diseases involving free radicals such as cancer, cardiovascular diseases and neurodegenerative diseases [3, [9][10][11][12][13][14][15][16][17]. There are four types of catechins found in green tea: (-)-epicatechin (EC), (-)-epicatechin-3-gallate (ECG), (-)-epigallocatechin (EGC) and (-)-epigallocatechin-3-gallate (EGCG) (Fig. 1). ...
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We have studied the action of ascorbate (vitamin C) on human immunodeficiency virus type 1 (HIV-1), the etiological agent clinically associated with AIDS. We report the suppression of virus production and cell fusion in HIV-infected T-lymphocytic cell lines grown in the presence of nontoxic concentrations of ascorbate. In chronically infected cells expressing HIV at peak levels, ascorbate reduced the levels of extracellular reverse transcriptase (RT) activity (by greater than 99%) and of p24 antigen (by 90%) in the culture supernatant. Under similar conditions, no detectable inhibitory effects on cell viability, host metabolic activity, and protein synthesis were observed. In freshly infected CD4+ cells, ascorbate inhibited the formation of giant-cell syncytia (by approximately 93%). Exposure of cell-free virus to ascorbate at 37 degrees C for 1 day had no effect on its RT activity or syncytium-forming ability. Prolonged exposure of virus (37 degrees C for 4 days) in the presence of ascorbate (100-150 micrograms/ml) resulted in the drop by a factor of 3-14 in RT activity as compared to a reduction by a factor of 25-172 in extracellular RT released from chronically infected cells. These results indicate that ascorbate mediates an anti-HIV effect by diminishing viral protein production in infected cells and RT stability in extracellular virions.
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(-)Epigallocatechin gallate (EGCg) and theaflavin digallate (TF3) (1-10 microM) inhibited the infectivity of both influenza A virus and influenza B virus in Madin-Darby canine kidney (MDCK) cells in vitro. Study by electron microscope revealed that EGCg and TF3 (1 mM) agglutinated influenza viruses as well as did antibody, and that they prevented the viruses from adsorbing to MDCK cells. EGCg and TF3 more weakly inhibited adsorption of the viruses to MDCK cells. EGCg and TF3 (1-16 microM) also inhibited haemagglutination by influenza viruses. These findings suggest that tea polyphenols bind to the haemagglutinin of influenza virus, inhibit its adsorption to MDCK cells, and thus block its infectivity.
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Many studies describe the protective role of vitamin C (ascorbic acid) against cancer development and in treatment of established cancer. The present study investigated whether ascorbic acid demonstrates a therapeutic benefit for prostate cancer. Androgen-independent (DU145) and androgen-dependent (LNCaP) human prostate cancer cell lines were both treated in vitro with vitamin C (0-10 mM). Cell counts, cell viability, and thymidine incorporation into DNA were determined. Treatment of DU145 and LNCaP cells with vitamin C resulted in a dose- and time-dependent decrease in cell viability and thymidine incorporation into DNA. Vitamin C induced these changes through the production of hydrogen peroxide; addition of catalase (100-300 units/ml), an enzyme that degrades hydrogen peroxide, inhibited the effects of ascorbic acid. Superoxide dismutase, an enzyme that dismutates superoxide and generates hydrogen peroxide, did not prevent decreases in cell number and DNA synthesis, suggesting further the involvement of hydrogen peroxide in vitamin C-induced changes. These results clearly indicate that reactive oxygen species (ROS) are involved in vitamin C-induced cell damage. However, that singlet oxygen scavengers such as sodium azide and hydroquinone and hydroxyl radical scavengers such as D-mannitol and DL-alpha-tocopherol did not counteract the effects of ascorbic acid on thymidine incorporation suggests that vitamin C-induced changes do not occur through the generation of these ROS. Vitamin C inhibits cell division and growth through production of hydrogen peroxide, which damages the cells probably through an as yet unidentified free radical(s) generation/mechanism. Our results also suggest that ascorbic acid is a potent anticancer agent for prostate cancer cells.
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We investigated the effect of influenza A/Beijing/353/89 (H3N2) virus infection on the expression of type IV collagenase in two different types of epithelial cell. Depending on the cell line infected, the viral infection caused changes in the expression of type IV collagenase. The expression of matrix metalloproteinase-9 (MMP-9; 92 kDa) but not of matrix metalloproteinase-2 (MMP-2; 72 kDa) was stimulated in Vero cells. In MDCK cells, the MMP-2 production increased with the virus infection. According to the enzymatic activity revealed with zymography, the MMP-9 promoter activity rose by a factor of over 1788 in influenza A virus-infected Vero cells but not in MDCK cells. The tissue inhibitor of metalloproteinase, TIMP-1, had increased slightly (2.3-fold) in Vero cells 48 hours after the infection, but in MDCK cells, influenza A virus had no effect on the TIMP-1 expression. In conclusion, the MMP-9 and -2 expression by influenza A virus infection are modulated at transcriptional level, depending on the epithelial cell line.
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Selenium, an essential biological trace element, has been shown to reduce and prevent the incidence of cancer. Our previous studies have shown that selenite is involved in the chemoprevention of cancer and induction of apoptosis of cancer cells. In this study, we demonstrate that selenite also inhibits the invasion of tumor cells. Cancer cell invasion requires coordinated processes, such as changes in cell-cell and cell-matrix adhesion, degradation of the extracellular matrix, and cell migration. We found that selenite inhibited invasion of HT1080 human fibrosarcoma cells. Adhesion of HT1080 cells to the collagen matrix was also inhibited by treatment with selenite, but cell-cell interaction and cell motility were not affected by selenite. Moreover, selenite reduced expression of matrix metalloproteinase-2 and -9 and urokinase-type plasminogen activator, which are involved in matrix degradation, but increased a tissue inhibitor of metalloproteinase-1. This inhibitory effect of selenite on the protease expressions was mediated by the suppression of transcription factors, NF-κB and AP-1. However, selenate showed no remarkable effect on all the steps of cancer cell invasion.
Article
MMPs play a crucial role in the process of cancer invasion and metastasis. The influence of NAC on invasion and MMP-9 production of human bladder cancer cell line T24 was investigated using an in vitro invasion assay, gelatin zymography, Western and Northern blot analyses and RT-PCR assays. TPA increased the number of invading T24 cells through reconstituted basement membrane more than 10-fold compared to basal condition. NAC inhibited TPA-enhanced invasion dose-dependently. TPA increased the MMP-9 production by T24 cells without altering expression of TIMP-1 gene, while NAC suppressed TPA-enhanced production of MMP-9. Neither TPA nor NAC altered TIMP-1 mRNA level in T24 cells. In vitro experiments demonstrated that MMP-9 was directly inhibited by NAC but was not influenced by TPA. NAC limits invasion of T24 human bladder cancer cells by inhibiting the MMP-9 production in addition to a direct inhibition of MMP-9 activity.
Article
Epigallocatechin-3-gallate (EGCG), one of the components of green tea, has been suggested to have antiviral activity. To determine the effects of EGCG on HIV infection, peripheral blood lymphocytes were incubated with either LAI/IIIB or Bal HIV strains and increasing concentrations of EGCG. EGCG strongly inhibited the replication of both virus strains as determined by reverse transcriptase and p24 assays on the cell supernatants.
Article
It has been previously reported that green-tea extract (GTE) inhibits the growth of influenza virus by preventing its adsorption. In this study, we further investigated whether GTE exerts an additional inhibitory effect on the acidification of intracellular compartments such as endosomes and lysosomes (referred to as ELS) and thereby inhibits the growth of influenza A and B viruses in Madin-Darby canine kidney cells. The vital fluorescence microscopic study showed that GTE inhibited acidification of ELS in a concentration-dependent manner. Moreover, the growth of influenza A and B viruses was equally inhibited when the cells were treated with GTE within as early as 5 to 15 min after infection, depending on the virus strains. The fact that (-)epigallocatechin (EGC), one of major catechin molecules in GTE, exerts the inhibitory effects on the acidification of ELS and virus growth in a manner similar to that of GTE strongly suggests that EGC is one of the active components in the extract.
Article
Reactive oxygen intermediates (ROI) and cytokines, particularly tumor necrosis factor (TNF) have been implicated in the pathogenesis of influenza. Using a murine model of influenza, we have studied the levels of TNF, interleukin 6 (IL-6) and of superoxide-generating xanthine oxidase (XO). Mice infected intranasally with influenza virus APR/8 had high levels of XO, TNF and IL-6 in the broncoalveolar lavage, as early as 3 d after infection. XO was elevated also in serum and lung tissue. Administration of the antioxidant N-acetylcysteine (NAC,1 g/kg per day, orally) significantly decreased the mortality in infected mice, indicating a role for RO1 in the lethality associated with influenza infection.
Article
Oxidative stress is implicated in the pathogenesis of pulmonary damage during viral infections. In a previous study we observed a significant improvement of survival of influenza-infected mice with NAC, 1g/kg divided in two daily administrations, for 8 days including a pretreatment on day 1 before infection. In order to test NAC in a more realistic model, we studied the effect of combined treatment with NAC and the antiviral drug, ribavirin. Since in the present work we wanted to test a possible synergistic effect by combination of NAC and ribavirin, we used a different NAC's treatment regimen (1 g/kg, once a day for 4 days) that, alone, did not significantly protect mice from death. Mice (12 per group) infected intranasally with a lethal dose of influenza A virus APR/8. NAC was given as a single daily dose of 1000 mg/kg starting from 4 h after infection and until day 4 after infection, in association with ribavirin (100 mg/kg, i.p.). End-point evaluation was 14-day survival. With this schedule survival in infected mice was 17%, it was not significantly changed by NAC (25%). Survival increased to 58% with ribavirin and to 92% (n=12) with a combined treatment with ribavirin and NAC. This suggest that antioxidant therapy can increase survival by either improving the defenses against virus or by protecting from the pathogenesis of lung inflammation.
Article
Influenza virus causes one of the most prevalent infections in humans. In a typical year, 10-20% of the population in the United States are infected by influenza virus, resulting in up to 40,000 deaths. Current vaccines can prevent illness in approximately 70-80% of healthy individuals under age 65, but the protection rate is much lower in those most susceptible to infection, namely infants, the elderly, and immunocompromised individuals. Although four antiviral drugs have been approved in the United States for treatment and/or prophylaxis of influenza, their use is limited because of concerns about side effects, compliance, and the possible emergence of resistant virus. We found that short interfering RNAs (siRNAs) specific for conserved regions of the influenza virus genome are potent inhibitors of influenza virus replication in both cell lines and embryonated chicken eggs. In this review, we discuss the potential value of siRNAs for preventing and treating influenza virus infections in humans and the challenges that have to be overcome to realize their potential.
Article
Michael P.Clark, Mark W.Ledeboer, IoanaDavies, Randal A.Byrn, Steven M.Jones, EmanuelePerola, AliceTsai, MarcJacobs, KwameNti-Addae, Upul K.Bandarage, Michael J.Boyd, Randy S.Bethiel, John J.Court, HongboDeng, John P.Duffy, Warren A.Dorsch, Luc J.Farmer, HuaiGao, WenxinGu, KatrinaJackson, Dylan H.Jacobs, Joseph M.Kennedy, BrianLedford, JianglinLiang, FrançoisMaltais, MarkMurcko, TianshengWang, M. WoodsWannamaker, Hamilton B.Bennett, Joshua R.Leeman, ColleenMcNeil, William P.Taylor, ChristineMemmott, MinJiang, ReneRijnbrand, ChristopherBral, UrsulaGermann, AzinNezami, YuegangZhang, Francesco G.Salituro, Youssef L.Bennani, Paul S.Charifson. (2014) Discovery of a Novel, First-in-Class, Orally Bioavailable Azaindole Inhibitor (VX-787) of Influenza PB2. Journal of Medicinal Chemistry 57, 6668-6678 CrossRef
Article
RNA interference (RNAi) is a sequence-specific gene-silencing mechanism that has been proposed to function as a defence mechanism of eukaryotic cells against viruses and transposons. RNAi was first observed in plants in the form of a mysterious immune response to viral pathogens. But RNAi is more than just a response to exogenous genetic material. Small RNAs termed microRNA (miRNA) regulate cellular gene expression programs to control diverse steps in cell development and physiology. The discovery that exogenously delivered short interfering RNA (siRNA) can trigger RNAi in mammalian cells has made it into a powerful technique for generating genetic knock-outs. It also raises the possibility to use RNAi technology as a therapeutic tool against pathogenic viruses. Indeed, inhibition of virus replication has been reported for several human pathogens including human immunodeficiency virus, the hepatitis B and C viruses and influenza virus. We reviewed the field of antiviral RNAi research in 2003 (Haasnoot et al. 2003), but many new studies have recently been published. In this review, we present a complete listing of all antiviral strategies published up to and including December 2004. The latest developments in the RNAi field and their antiviral application are described.
Article
Certain drastic behavioral modifications by arterial wall smooth muscle cells (SMC) have been considered key steps in the formation of atherosclerotic lesions: massive migration of SMC from the media to the intima layer of the vessel, dedifferentiation of SMC to proliferating phenotype, and increased secretion of inflammatory cytokines as a response to inflammatory stimuli. We investigated the anti-atherogenic effects of naturally occurring compounds (ascorbic acid, green tea extract, lysine, proline, arginine, and N-acetyl cysteine) using the model of cultured aortic SMC. Cell growth was measured by DNA synthesis, cell invasiveness was measured through Matrigel, matrix metalloproteinase-2 (MMP-2) secretion was measured by zymography, and SMC secretion of monocyte chemoattractant protein-1 (MCP-1) and interleukin-6 (IL-6) was measured by immunochemistry. Fetal bovine serum-stimulated SMC growth was inhibited by the nutrient mixture (NM) with 85% inhibition at 100 microg/mL. A corresponding concentration of epigallocatechin gallate (EGCG; 15 microM), the most active tea phenolic, produced a significant effect but one lower than NM. NM inhibited aortic SMC Matrigel invasion in a dose-dependent manner and significantly decreased MMP-2 expression. Stimulation of SMC with tumor necrosis factor-alpha significantly increased production and secretion of such mediators of inflammation as IL-6 and MCP-1; addition of 100 microg/mL NM inhibited secretion of MCP-1 and IL-6 by 65% and 47%, respectively. These data suggest that the NM of ascorbic acid, tea phenolics, and selected amino acids has potential in blocking the development of atherosclerotic lesions by inhibiting atherogenic responses of vascular SMC to pathologic stimuli and warrants in vivo studies.
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Health Benefits and Applications, Marcel Dekker
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Evaluation of the efficacy of Epican Forte against avian flu virus
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Cu(II) inhibition of the proton translocation machinery of the influenza A virus by gentian violet (GV) and GV-dyed cotton cloth, and bacteriological activities of these agents
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Effect of vitamin C on prostate cancer cells in vitro: effect on cell number, viability and DNA synthesis
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Serum markers of the liver, heart, and kidney and lipid profile and histopathology in ODS rats treated with nutrient synergy
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