The synergetic cytocidal effect of ascorbic acid and mitomycin C on Ehrlich as-cites tumor cells in culture was studied. The chain scission of DNA by Cu(Ⅱ)mitomycin C/ascorbic acid system,and the chemical kinetics of...The synergetic cytocidal effect of ascorbic acid and mitomycin C on Ehrlich as-cites tumor cells in culture was studied. The chain scission of DNA by Cu(Ⅱ)mitomycin C/ascorbic acid system,and the chemical kinetics of the Cu(Ⅱ) catalyzed aerobic oxidation of ascorbic acid in the presence of mitomycin C were also discussed. Experimental results showed that ascorbic acid and mitomycin C were synergetic in destroying Ehrlich ascites tumor cells.The effect is related to the breaking action of the Cu(Ⅱ)mitomycin C/ascorbic acid system on the DNA chain, and to the quantity of the system produced ·OH, and the speed of production which are both directly proportional to the concentration of ascorbic aci.These results imply that the ·OH produced in the aerobic oxidation of ascorbic acid,and·OH induced scission of DNA chain, are important factors to he synergetic cytocidal effect of ascorbic acid and mitomycin C on Ehrlich ascites tumor cells.展开更多
Objective:To evaluate the alteration of chemical behavior of L-ascorbic acid(vitamin C) with metal ion(nickel) at different pH solutions in vitro.Methods:Spectra of pure aqueous solution of L-ascorbic acid(E mark) com...Objective:To evaluate the alteration of chemical behavior of L-ascorbic acid(vitamin C) with metal ion(nickel) at different pH solutions in vitro.Methods:Spectra of pure aqueous solution of L-ascorbic acid(E mark) compound and NiSO_4(H_2O)(sigma USA) were evaluated by UV visible spectrophotometer.Spectral analysis of L-ascorbic acid and nickel at various pH(2.0, 7.0,7.4 and 8.6) at room temperature of 29℃ was recorded.In this special analysis,combined solution of L-ascorbic acid and nickel sulfate at different pH was also recorded.Results:The result revealed that λ_(max)(peak wavelength of spectra) of L-ascorbic acid at pH 2.0 was 289.0 run whereas at neutral pH 7.0,λ_(max) was 29S.4 run.In alkaline pH 8.6,λ_(max) was 295.4 nm and at pH 7.4 the λ_(max) of L-ascorbic acid remained the same as 295.4 nm.Nickel solution at acidic pH 2.0 was 394.5 nm,whereas at neutral pH 7.0 and pH 7.4 were the same as 394.5 nm.But at alkaline pH 8.6,λ_(max) value of nickel sulfate became 392.0 nm.The combined solution of L-ascorbic acid and nickel sulfate(6 mg/mL each) at pH 2.0 showed 292.5 nm and 392.5 nm,respectively whereas at pH 7.0,L-ascorbic acid showed 296.5 nm and nickel sulfate showed 391.5 nm.At pH 7.4,L-ascorbic acid showed 297.0 nm and nickel sulfate showed 394.0 nm in the combined solution whereas at pH 8.6(alkaline) L-ascorbic acid and nickel sulfate were showing 297.0 and 393.5 nm,respectively. Conclusions:Results clearly indicate an altered chemical behavior of L-ascorbic acid either alone or in combination with nickel sulfate in vitro at different pH.Perhaps oxidation of L-ascorbic acid to L-dehydro ascorbic acid via the free radical(HSc*) generation from the reaction of H,ASc + Ni(Ⅱ) is the cause of such alteration of λ_(max),value of L-ascorbic acid in the presence of metal nickel.展开更多
Sepsis and septic shock remain a major cause of morbidity and mortality among patients admitted in the intensive care unit.Diabetes is a major risk factor for the development of sepsis.The global mortality of sepsis r...Sepsis and septic shock remain a major cause of morbidity and mortality among patients admitted in the intensive care unit.Diabetes is a major risk factor for the development of sepsis.The global mortality of sepsis remains high,despite significant interventions and guidelines.It has been known for decades that patients with sepsis have reduced levels of antioxidants,most notably vitamin C.Furthermore,experimental data has demonstrated multiple beneficial effects of vitamin C in sepsis.In addition,corticosteroids and thiamine may have synergistic biological effects together with vitamin C.Preliminary data suggests that therapy with hydrocortisone,ascorbic acid and thiamine improves the outcome of patients with sepsis with the potential to save millions of lives.However,this intervention has met with much resistance and has not been widely adopted.Ultimately,we await the final jury verdict on this simple,safe and cheap intervention.展开更多
AIM: To study the role of gastric mucosal ascorbic acid(AA) in the progression of acute gastric mucosal lesions induced by compound 48/80 (C48/80), a mast cell degranulator, in rats.METHODS: C48/80 (0.75 mg/kg) was in...AIM: To study the role of gastric mucosal ascorbic acid(AA) in the progression of acute gastric mucosal lesions induced by compound 48/80 (C48/80), a mast cell degranulator, in rats.METHODS: C48/80 (0.75 mg/kg) was intraperitoneally injected to fasted Wistar rats. Oral administration of AA (10, 50 or 100 mg/kg) was performed 0.5 h after C48/80treatment. Determinations for gastric mucosal lesion severity and blood flow, and assays for gastric mucosal total AA, reduced AA, oxidized AA, vitamin E, thiobarbituric acid reactive substances (TBARS), adherent mucus, nitrite/nitrate (NOx), non-protein SH (NPSH), and myeloperoxidase(MPO), and serum total AA, reduced AA, oxidized AA,and NOx were conducted 0.5 and 3 h after C48/80treatment.RESULTS: Gastric mucosal lesions occurred 0.5 h after C48/80 treatment and progressed at 3 h. Gastric mucosal blood flow decreased 0.5 h after C48/80 treatment but the decrease was recovered at 3 h. Gastric mucosal total AA, reduced AA, vitamin E, and adherent mucus concentrations decreased 3 h after C48/80 treatment.Gastric mucosal oxidized AA concentration remained unchanged after C48/80 treatment. Gastric mucosal NPSH concentration decreased 0.5 h after C48/80 treatment,but the decrease was recovered at 3 h. Gastric mucosal TBARS concentration and MPO activity increased 0.5 h after C48/80 treatment and further increased at 3 h.Serum total AA and reduced AA concentrations increased 0.5 h after C48/80 treatment and further increased at 3 h, while serum oxidized AA concentration increased at 0.5 h. Serum and gastric mucosal NOx concentrations increased 3 h after C48/80 treatment. AA administration to C48/80-treated rats at 0.5 h after the treatment prevented the gastric mucosal lesion progression and the changes in gastric mucosal total AA, reduced AA, vitamin E, adherent mucus, NOx, and TBARS concentrations and MPO activity and serum NOx concentration found at 3 h after the treatment dose-dependently. The AA administration to C48/80-treated rats caused further increases in serum total AA and reduced AA concentrations at 3 h after the treatment dose-dependently.CONCLUSION: Gastric mucosal AA plays a critical role in the progression of C48/80-induced acute gastric mucosal lesions in rats.展开更多
Diabetic ketoacidosis(DKA) is life-threatening acute metabolic complication of diabetes mellitus(DM) that is characterized by acidosis, ketosis, and hyperglycemia, currently affecting mostly patients under 30 years of...Diabetic ketoacidosis(DKA) is life-threatening acute metabolic complication of diabetes mellitus(DM) that is characterized by acidosis, ketosis, and hyperglycemia, currently affecting mostly patients under 30 years of age with diabetes mellitus type 1. In both, DM and DKA, a pro-inflammatory state exists. This clinical entity occurs as a result of hyperglycemia-induced disturbances, resulting in an increased oxidative metabolism. For the latter reason, the use of vitamin C seems promising in DKA due to its antioxidant role in reducing the superoxide radicals that are consequence of the oxidative stress. This can decrease the proinflammatory state and avoids complications. Vitamin C, or also known as ascorbic acid, has been widely used in several illnesses, such as common cold, tissue healing, fertility, atherosclerosis, cancer prevention, immunity restoration, neuro-degenerative disease and also has been suggested to decrease the risk of DM, and this reason is giving place to believe that vitamin C can have an important role in treating diabetic complications such as DKA. In order to counteract these oxidative disturbances in DKA patients, we analyzed the current data regarding vitamin C and evaluate its role in any type treatment of this complication in the near future.展开更多
The cardiovascular effects of vitamin C (VitC) could be mediated by epoxyeicosatrienoic acids (EETs). We aimed to study the mechanism of VitC-dependent microsomal formation of cis- and trans-EETs and the regulation of...The cardiovascular effects of vitamin C (VitC) could be mediated by epoxyeicosatrienoic acids (EETs). We aimed to study the mechanism of VitC-dependent microsomal formation of cis- and trans-EETs and the regulation of EET levels in rat isolated perfused kidneys and in vivo. VitC biphasically stimulated rat kidney microsomal cis- and trans-EET formation in a ratio of 1:2, involving the participation of lipid hydroperoxides (LOOHs), Fe2+ , and cytochrome P450 (CYP). Levels of LOOHs correlated with microsomal EET production. LOOH stimulation of CYP isoforms resulted in preferred trans- over cis-EET formation from arachidonic acid and was associated with the cleavage of LOOHs, which indicated a CYP peroxy-genase activity. EETs contributed to VitC-induced vasodilator responses in rat isolated perfused kidneys. VitC (1 mg/ml) given in the drinking water for 9 days doubled rat urinary EET excretion, increased plasma levels of EETs, mostly trans-EETs, by 40%, and reduced plasma levels of 20-hydroxyeicosatetraenoic acid. Depletion of VitC in brain cortex and kidney tissues by more than 20- and 50-fold, respectively, in gulonolactone oxidase-knockout mice was associated with mild increases in tissue EETs. These data suggest that LOOHs are a determinant factor for EET formation in vivo in which VitC exerts a key regulatory effect. VitC-activated CYP peroxygenase activity may represent a CYP interaction with lipoxygenases and cyclooxygenases to mediate the cardiovascular effects of VitC via formation of EETs.展开更多
In this review,we summarize the involvement of vitamin C in mental disorders by presenting available evidence on its pharmacological effects in animal models as well as in clinical studies.Vitamin C,especially its red...In this review,we summarize the involvement of vitamin C in mental disorders by presenting available evidence on its pharmacological effects in animal models as well as in clinical studies.Vitamin C,especially its reduced form,has gained interest for its multiple functions in various tissues and organs,including central nervous system(CNS).Vitamin C protects the neuron against oxidative stress,alleviates inflammation,regulates the neurotransmission,affects neuronal development and controls epigenetic function.All of these processes are closely associated with psychopathology.In the past few decades,scientists have revealed that the deficiency of vitamin C may lead to motor deficit,cognitive impairment and aberrant behaviors,whereas supplement of vitamin C has a potential preventive and therapeutic effect on mental illness,such as major depressive disorder(MDD),schizophrenia,anxiety and Alzheimer's disease(AD).Although several studies support a possible role of vitamin C against mental disorders,more researches are essential to accelerate the knowledge and investigate the mechanism in this field.展开更多
Ascorbic acid(vitamin C) elicits pleiotropic effects in thebody. Among its functions, it serves as a potent antioxidant, a co-factor in collagen and catecholamine synthesis, and a modulator of immune cell biology. Fur...Ascorbic acid(vitamin C) elicits pleiotropic effects in thebody. Among its functions, it serves as a potent antioxidant, a co-factor in collagen and catecholamine synthesis, and a modulator of immune cell biology. Furthermore, an increasing body of evidence suggests that highdose vitamin C administration improves hemodynamics, end-organ function, and may improve survival in critically ill patients. This article reviews studies that evaluate vitamin C in pre-clinical models and clinical trials with respect to its therapeutic potential.展开更多
Eight types of spongy sheet were prepared by freeze-drying aqueous solutions of hyaluronic acid (HA) and poly(γ-glutamic acid) (PGA) with or without bioactive components including vitamin C derivative (VC), glucosylc...Eight types of spongy sheet were prepared by freeze-drying aqueous solutions of hyaluronic acid (HA) and poly(γ-glutamic acid) (PGA) with or without bioactive components including vitamin C derivative (VC), glucosylceramide (GC), and epidermal growth factor (EGF). Spongy sheets were categorized into the following groups: Group I (HA/PGA), Group II (HA/PGA + VC), Group III (HA/PGA + GC), Group IV (HA/PGA + VC, GC), Group V (HA/PGA + EGF), Group VI (HA/PGA + VC, EGF), Group VII (HA/PGA + GC, EGF), and Group VIII (HA/PGA + VC, GC, EGF). In the first experiment, we examined fibroblast proliferation in conditioned medium that had been prepared by immersing each spongy sheet in a conventional culture medium. EGF-incorporating spongy sheets (Groups V-VIII) enhanced fibroblast proliferation more than EGF-free spongy sheets (Groups I-IV). In the second experiment, cytokine production by fibroblasts was evaluated using a wound surface model. This involved elevation of fibroblasts-incorporating collagen gel sheets to the air-liquid interface, on which a spongy sheet (Groups I, IV, V and VIII) was placed and cultured for 1 week. EGF-incorporating spongy sheets (Groups V and VIII) enhanced the production of vascular endothelial growth factor (VEGF) and hepatocyte growth factor (HGF) by fibroblasts more than EGF-free spongy sheets (Groups I and IV). The effect of these four types of spongy sheet on wounds was investigated in animal experiments. Chemical peel was performed by contacting 50% trichloroacetic acid (TCA) on the dorsal region of mice, after which a spongy sheet was placed, and the wound condition was then observed in a two-week period. Angiogenesis was facilitated to a greater degree in Group VIII compared with Groups I, IV and V. This finding indicates that Group VIII spongy sheet is a promising aid for skin recovery after chemical peel.展开更多
Sepsis and septic shock are common diagnoses for patients requiring intensive care unit admission and associated with high morbidity and mortality.In addition to aggressive fluid resuscitation and antibiotic therapy,s...Sepsis and septic shock are common diagnoses for patients requiring intensive care unit admission and associated with high morbidity and mortality.In addition to aggressive fluid resuscitation and antibiotic therapy,several other drugs have been tried as adjuvant therapies to reduce the inflammatory response and improve outcomes.Vitamin C has been shown to have several biological actions,including anti-inflammatory and immunomodulatory effects,which may prove beneficial in sepsis management.Initial trials showed improved patient outcomes when high dose vitamin C was used in combination with thiamine and hydrocortisone.These results,along with relative safety of high-dose(supra-physiological)vitamin C,encouraged physicians across the globe to add vitamin C as an adjuvant therapy in the management of sepsis.However,subsequent largescale randomised control trials could not replicate these results,leaving the world divided regarding the role of vitamin C in sepsis management.Here,we discuss the rationale,safety profile,and the current clinical evidence for the use of highdose vitamin C in the management of sepsis and septic shock.展开更多
The purpose of this paper was to identify content changes in the main nutritional indicators of three common leafy vegetables, and to provide a theoretical basis for the protection of leafy vegetables from acid rain. ...The purpose of this paper was to identify content changes in the main nutritional indicators of three common leafy vegetables, and to provide a theoretical basis for the protection of leafy vegetables from acid rain. The experiment investigated the effects of simulated acid rain on four main nutritional indicators, including soluble sugar, total free amino acid, soluble protein and vitamin C during the application of simulated acid rain(SAR) in pakchoi(Brassica rapa chinensis), rape(Brassica campestris L.) and lettuce(Lactuca sativa Linn. var. ramosa Hort). The vegetables were respectively exposed to SAR of pH=7.0, 5.6, 5.0, 4.0, 3.0 and a control level of pH=6.5. The concentrations of the four main nutritional indicators were determined at harvest. The results show that nutritional quality of the three leafy vegetable species decreased with the declining of pH values of SAR. The higher the acidity of SAR was, the more significant the inhibitions were. Nutritional quality of lettuce was the most affected by simulated acid rain, followed by pakchoi and rape. The change range of soluble protein content was higher than those of the other three indicators’ contents, which indicates that soluble protein is most sensitive to simulated acid rain.展开更多
This review provides information determining how much vitamin C to take, including analysis of the recent findings, which demonstrate advantages and problems with higher daily doses. The Daily Value for vitamin C was ...This review provides information determining how much vitamin C to take, including analysis of the recent findings, which demonstrate advantages and problems with higher daily doses. The Daily Value for vitamin C was raised to 90 mg for men in 2000, and Upper Limit of 2,000 mg per day was established as being safe. This followed a study of urinary excretion of vitamin C (AA) that demonstrated 500 mg twice a day provides levels sufficient to cause continuous urinary excretion in humans. That is the lowest oral dosage evaluated that significantly saturates blood plasma. A later study endorsed 200 mg from dietary sources for the RDA. Even though plasma concentration of AA is then significantly lower, at 200 mg daily certain white blood cells are saturated with AA. Recently many studies have indicated the benefit of high levels of AA to maintain the brain, bones, and heart, reduce damage from stroke, brain trauma, and cataracts, and lower the risk of cancer metastasis and colds. Pro-oxidant activity has been found only for i.v. adminstration, where high concentrations appear effective destroying tumor cells while not harming normal cells. This review evaluates recent research and finds it consistent with the hypothesis that people, especially older people and soldiers in combat environments, are likely to benefit if they maintain the saturating level of AA by taking 500mg supplements twice a day.展开更多
Herein, the iodometric titration and HPLC-RP methods were compared for the determination of vitamin C in vitamin and mineral supplements. The methods were validated in terms of linearity, limits of detection (LOD), li...Herein, the iodometric titration and HPLC-RP methods were compared for the determination of vitamin C in vitamin and mineral supplements. The methods were validated in terms of linearity, limits of detection (LOD), limits of quantification (LOQ), precision, and recovery by using vitamin standards and a reference material SRM 3280 (multivitamin/multimineral tablets) obtained from the National Institute of Standards and Technology (NIST). A total of 22 samples of vitamin supplements, randomly acquired in local markets of Sao Paulo (Brazil) were evaluated for content of vitamin C by these two methodologies. The precision expressed as RSD was lower than 5% for both methods. LOD was 3.6 μg/mL for HPLC and 1.0 mg for titration, while LOQ were 12.0 μg/mL and 3.0 mg for HPLC and titration, respectively. Percent recoveries (%) of spiked samples ranged from 98.7 to 100.5 for HPLC and from 98 to 104 for titration. The contents of vitamin C in SRM 3280 (Certified value = 42.2 ± 3.7 mg/g) were 40.2 and 42.1 mg/g when determined by HPLC and titration respectively. Statistically, there was no difference in the analysed vitamin C content for half of the samples, irrespective of the method applied. HPLC was more sensitive, but the titrimetric method was faster and consumed less reagent. Although both methods were accurate in determining the vitamin C content in SRM 3280, the matrix constituents of some vitamin supplements may have interfered with the analysis.展开更多
The aim of this study was to examine whether vitamin C reduced mortality when adjutant therapy of patients with septic shock and severe sepsis compared with placebo by meta-analysis. Eligible trials were identified fr...The aim of this study was to examine whether vitamin C reduced mortality when adjutant therapy of patients with septic shock and severe sepsis compared with placebo by meta-analysis. Eligible trials were identified from Pubmed, Embase, Ovid, and the Cochrane database. Four randomized controlled trials (RCT) and two retrospective studies were published between 2000 and 2017 met the inclusion criteria and suitable for meta-analysis. The data were analyzed with randomized-effects or fixed-effects models using Review Manager Version 5.3. Four randomized studies with a total of 109 participants were suitable for meta-analysis. The heterogeneity was assessed by calculating the Q and I2 methods. A random-effects approach instead of a fixed-effects analysis was undertaken if I2 > 50%. Adjuvant vitamin C did not associate with a reduction in mortality as compared with placebo, it is occurred similarly in both RCT studies and retrospective studies. However, high doses of vitamin C (>50 mg/kg/day) significant reduced the mortality rate of severe sepsis patients. And administration of high doses of vitamin C to therapy severe sepsis did not significantly reduce the ICU length of stay. The results suggested a trend toward reducing mortality in severe sepsis and septic shock patients’ adjuvant with vitamin C. Further multicenter large randomized controlled trials are necessary to determine the potential benefits of vitamin C in patients with severe sepsis and septic shock.展开更多
Severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)has emerged as one of the most dreadful viruses the mankind has witnessed.It has caused worldwide havoc and wrecked human life.In our quest to find therapeuti...Severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)has emerged as one of the most dreadful viruses the mankind has witnessed.It has caused worldwide havoc and wrecked human life.In our quest to find therapeutic options to counter this threat,several drugs have been tried,with varying success.Certain agents like corticosteroids,some anti-virals and immunosuppressive drugs have been found useful in improving clinical outcomes.Vitamin C,a water-soluble vitamin with good safety profile,has been tried to reduce progression and improve outcomes of patients with coronavirus disease 2019(COVID-19).Because of its anti-oxidant and immunomodulatory properties,the role of vitamin C has expanded well beyond the management of scurvy and it is increasingly been employed in the treatment of critically ill patients with sepsis,septic shock,acute pancreatitis and even cancer.However,in spite of many case series,observational studies and even randomised control trials,the role of vitamin C remains ambiguous.In this review,we will be discussing the scientific rationale and the current clinical evidence for using high dose vitamin C in the management of COVID-19 patients.展开更多
文摘The synergetic cytocidal effect of ascorbic acid and mitomycin C on Ehrlich as-cites tumor cells in culture was studied. The chain scission of DNA by Cu(Ⅱ)mitomycin C/ascorbic acid system,and the chemical kinetics of the Cu(Ⅱ) catalyzed aerobic oxidation of ascorbic acid in the presence of mitomycin C were also discussed. Experimental results showed that ascorbic acid and mitomycin C were synergetic in destroying Ehrlich ascites tumor cells.The effect is related to the breaking action of the Cu(Ⅱ)mitomycin C/ascorbic acid system on the DNA chain, and to the quantity of the system produced ·OH, and the speed of production which are both directly proportional to the concentration of ascorbic aci.These results imply that the ·OH produced in the aerobic oxidation of ascorbic acid,and·OH induced scission of DNA chain, are important factors to he synergetic cytocidal effect of ascorbic acid and mitomycin C on Ehrlich ascites tumor cells.
基金financially supported by Defence Institute ofPhysiology and Allied Sciences,Government of India,New Delhi[grant No.TC/292/TASK-116(KDS)/DIPAS/2006]
文摘Objective:To evaluate the alteration of chemical behavior of L-ascorbic acid(vitamin C) with metal ion(nickel) at different pH solutions in vitro.Methods:Spectra of pure aqueous solution of L-ascorbic acid(E mark) compound and NiSO_4(H_2O)(sigma USA) were evaluated by UV visible spectrophotometer.Spectral analysis of L-ascorbic acid and nickel at various pH(2.0, 7.0,7.4 and 8.6) at room temperature of 29℃ was recorded.In this special analysis,combined solution of L-ascorbic acid and nickel sulfate at different pH was also recorded.Results:The result revealed that λ_(max)(peak wavelength of spectra) of L-ascorbic acid at pH 2.0 was 289.0 run whereas at neutral pH 7.0,λ_(max) was 29S.4 run.In alkaline pH 8.6,λ_(max) was 295.4 nm and at pH 7.4 the λ_(max) of L-ascorbic acid remained the same as 295.4 nm.Nickel solution at acidic pH 2.0 was 394.5 nm,whereas at neutral pH 7.0 and pH 7.4 were the same as 394.5 nm.But at alkaline pH 8.6,λ_(max) value of nickel sulfate became 392.0 nm.The combined solution of L-ascorbic acid and nickel sulfate(6 mg/mL each) at pH 2.0 showed 292.5 nm and 392.5 nm,respectively whereas at pH 7.0,L-ascorbic acid showed 296.5 nm and nickel sulfate showed 391.5 nm.At pH 7.4,L-ascorbic acid showed 297.0 nm and nickel sulfate showed 394.0 nm in the combined solution whereas at pH 8.6(alkaline) L-ascorbic acid and nickel sulfate were showing 297.0 and 393.5 nm,respectively. Conclusions:Results clearly indicate an altered chemical behavior of L-ascorbic acid either alone or in combination with nickel sulfate in vitro at different pH.Perhaps oxidation of L-ascorbic acid to L-dehydro ascorbic acid via the free radical(HSc*) generation from the reaction of H,ASc + Ni(Ⅱ) is the cause of such alteration of λ_(max),value of L-ascorbic acid in the presence of metal nickel.
文摘Sepsis and septic shock remain a major cause of morbidity and mortality among patients admitted in the intensive care unit.Diabetes is a major risk factor for the development of sepsis.The global mortality of sepsis remains high,despite significant interventions and guidelines.It has been known for decades that patients with sepsis have reduced levels of antioxidants,most notably vitamin C.Furthermore,experimental data has demonstrated multiple beneficial effects of vitamin C in sepsis.In addition,corticosteroids and thiamine may have synergistic biological effects together with vitamin C.Preliminary data suggests that therapy with hydrocortisone,ascorbic acid and thiamine improves the outcome of patients with sepsis with the potential to save millions of lives.However,this intervention has met with much resistance and has not been widely adopted.Ultimately,we await the final jury verdict on this simple,safe and cheap intervention.
文摘AIM: To study the role of gastric mucosal ascorbic acid(AA) in the progression of acute gastric mucosal lesions induced by compound 48/80 (C48/80), a mast cell degranulator, in rats.METHODS: C48/80 (0.75 mg/kg) was intraperitoneally injected to fasted Wistar rats. Oral administration of AA (10, 50 or 100 mg/kg) was performed 0.5 h after C48/80treatment. Determinations for gastric mucosal lesion severity and blood flow, and assays for gastric mucosal total AA, reduced AA, oxidized AA, vitamin E, thiobarbituric acid reactive substances (TBARS), adherent mucus, nitrite/nitrate (NOx), non-protein SH (NPSH), and myeloperoxidase(MPO), and serum total AA, reduced AA, oxidized AA,and NOx were conducted 0.5 and 3 h after C48/80treatment.RESULTS: Gastric mucosal lesions occurred 0.5 h after C48/80 treatment and progressed at 3 h. Gastric mucosal blood flow decreased 0.5 h after C48/80 treatment but the decrease was recovered at 3 h. Gastric mucosal total AA, reduced AA, vitamin E, and adherent mucus concentrations decreased 3 h after C48/80 treatment.Gastric mucosal oxidized AA concentration remained unchanged after C48/80 treatment. Gastric mucosal NPSH concentration decreased 0.5 h after C48/80 treatment,but the decrease was recovered at 3 h. Gastric mucosal TBARS concentration and MPO activity increased 0.5 h after C48/80 treatment and further increased at 3 h.Serum total AA and reduced AA concentrations increased 0.5 h after C48/80 treatment and further increased at 3 h, while serum oxidized AA concentration increased at 0.5 h. Serum and gastric mucosal NOx concentrations increased 3 h after C48/80 treatment. AA administration to C48/80-treated rats at 0.5 h after the treatment prevented the gastric mucosal lesion progression and the changes in gastric mucosal total AA, reduced AA, vitamin E, adherent mucus, NOx, and TBARS concentrations and MPO activity and serum NOx concentration found at 3 h after the treatment dose-dependently. The AA administration to C48/80-treated rats caused further increases in serum total AA and reduced AA concentrations at 3 h after the treatment dose-dependently.CONCLUSION: Gastric mucosal AA plays a critical role in the progression of C48/80-induced acute gastric mucosal lesions in rats.
文摘Diabetic ketoacidosis(DKA) is life-threatening acute metabolic complication of diabetes mellitus(DM) that is characterized by acidosis, ketosis, and hyperglycemia, currently affecting mostly patients under 30 years of age with diabetes mellitus type 1. In both, DM and DKA, a pro-inflammatory state exists. This clinical entity occurs as a result of hyperglycemia-induced disturbances, resulting in an increased oxidative metabolism. For the latter reason, the use of vitamin C seems promising in DKA due to its antioxidant role in reducing the superoxide radicals that are consequence of the oxidative stress. This can decrease the proinflammatory state and avoids complications. Vitamin C, or also known as ascorbic acid, has been widely used in several illnesses, such as common cold, tissue healing, fertility, atherosclerosis, cancer prevention, immunity restoration, neuro-degenerative disease and also has been suggested to decrease the risk of DM, and this reason is giving place to believe that vitamin C can have an important role in treating diabetic complications such as DKA. In order to counteract these oxidative disturbances in DKA patients, we analyzed the current data regarding vitamin C and evaluate its role in any type treatment of this complication in the near future.
文摘The cardiovascular effects of vitamin C (VitC) could be mediated by epoxyeicosatrienoic acids (EETs). We aimed to study the mechanism of VitC-dependent microsomal formation of cis- and trans-EETs and the regulation of EET levels in rat isolated perfused kidneys and in vivo. VitC biphasically stimulated rat kidney microsomal cis- and trans-EET formation in a ratio of 1:2, involving the participation of lipid hydroperoxides (LOOHs), Fe2+ , and cytochrome P450 (CYP). Levels of LOOHs correlated with microsomal EET production. LOOH stimulation of CYP isoforms resulted in preferred trans- over cis-EET formation from arachidonic acid and was associated with the cleavage of LOOHs, which indicated a CYP peroxy-genase activity. EETs contributed to VitC-induced vasodilator responses in rat isolated perfused kidneys. VitC (1 mg/ml) given in the drinking water for 9 days doubled rat urinary EET excretion, increased plasma levels of EETs, mostly trans-EETs, by 40%, and reduced plasma levels of 20-hydroxyeicosatetraenoic acid. Depletion of VitC in brain cortex and kidney tissues by more than 20- and 50-fold, respectively, in gulonolactone oxidase-knockout mice was associated with mild increases in tissue EETs. These data suggest that LOOHs are a determinant factor for EET formation in vivo in which VitC exerts a key regulatory effect. VitC-activated CYP peroxygenase activity may represent a CYP interaction with lipoxygenases and cyclooxygenases to mediate the cardiovascular effects of VitC via formation of EETs.
基金supported by grants from the Foundation for Innovative Research Groups of NSFC(No.81721005)National Natural Science Foundation of China(No.81773712,and No.81473198)+1 种基金the National Basic Research Program of China(973 Program,No.2014CB744601)Program for Changjiang Scholars and Innovative Research Team in University(PCSIRT No.13016)
文摘In this review,we summarize the involvement of vitamin C in mental disorders by presenting available evidence on its pharmacological effects in animal models as well as in clinical studies.Vitamin C,especially its reduced form,has gained interest for its multiple functions in various tissues and organs,including central nervous system(CNS).Vitamin C protects the neuron against oxidative stress,alleviates inflammation,regulates the neurotransmission,affects neuronal development and controls epigenetic function.All of these processes are closely associated with psychopathology.In the past few decades,scientists have revealed that the deficiency of vitamin C may lead to motor deficit,cognitive impairment and aberrant behaviors,whereas supplement of vitamin C has a potential preventive and therapeutic effect on mental illness,such as major depressive disorder(MDD),schizophrenia,anxiety and Alzheimer's disease(AD).Although several studies support a possible role of vitamin C against mental disorders,more researches are essential to accelerate the knowledge and investigate the mechanism in this field.
文摘Ascorbic acid(vitamin C) elicits pleiotropic effects in thebody. Among its functions, it serves as a potent antioxidant, a co-factor in collagen and catecholamine synthesis, and a modulator of immune cell biology. Furthermore, an increasing body of evidence suggests that highdose vitamin C administration improves hemodynamics, end-organ function, and may improve survival in critically ill patients. This article reviews studies that evaluate vitamin C in pre-clinical models and clinical trials with respect to its therapeutic potential.
文摘Eight types of spongy sheet were prepared by freeze-drying aqueous solutions of hyaluronic acid (HA) and poly(γ-glutamic acid) (PGA) with or without bioactive components including vitamin C derivative (VC), glucosylceramide (GC), and epidermal growth factor (EGF). Spongy sheets were categorized into the following groups: Group I (HA/PGA), Group II (HA/PGA + VC), Group III (HA/PGA + GC), Group IV (HA/PGA + VC, GC), Group V (HA/PGA + EGF), Group VI (HA/PGA + VC, EGF), Group VII (HA/PGA + GC, EGF), and Group VIII (HA/PGA + VC, GC, EGF). In the first experiment, we examined fibroblast proliferation in conditioned medium that had been prepared by immersing each spongy sheet in a conventional culture medium. EGF-incorporating spongy sheets (Groups V-VIII) enhanced fibroblast proliferation more than EGF-free spongy sheets (Groups I-IV). In the second experiment, cytokine production by fibroblasts was evaluated using a wound surface model. This involved elevation of fibroblasts-incorporating collagen gel sheets to the air-liquid interface, on which a spongy sheet (Groups I, IV, V and VIII) was placed and cultured for 1 week. EGF-incorporating spongy sheets (Groups V and VIII) enhanced the production of vascular endothelial growth factor (VEGF) and hepatocyte growth factor (HGF) by fibroblasts more than EGF-free spongy sheets (Groups I and IV). The effect of these four types of spongy sheet on wounds was investigated in animal experiments. Chemical peel was performed by contacting 50% trichloroacetic acid (TCA) on the dorsal region of mice, after which a spongy sheet was placed, and the wound condition was then observed in a two-week period. Angiogenesis was facilitated to a greater degree in Group VIII compared with Groups I, IV and V. This finding indicates that Group VIII spongy sheet is a promising aid for skin recovery after chemical peel.
文摘Sepsis and septic shock are common diagnoses for patients requiring intensive care unit admission and associated with high morbidity and mortality.In addition to aggressive fluid resuscitation and antibiotic therapy,several other drugs have been tried as adjuvant therapies to reduce the inflammatory response and improve outcomes.Vitamin C has been shown to have several biological actions,including anti-inflammatory and immunomodulatory effects,which may prove beneficial in sepsis management.Initial trials showed improved patient outcomes when high dose vitamin C was used in combination with thiamine and hydrocortisone.These results,along with relative safety of high-dose(supra-physiological)vitamin C,encouraged physicians across the globe to add vitamin C as an adjuvant therapy in the management of sepsis.However,subsequent largescale randomised control trials could not replicate these results,leaving the world divided regarding the role of vitamin C in sepsis management.Here,we discuss the rationale,safety profile,and the current clinical evidence for the use of highdose vitamin C in the management of sepsis and septic shock.
基金Supported by the National Basic Research Program of China(No.2005CB422207)
文摘The purpose of this paper was to identify content changes in the main nutritional indicators of three common leafy vegetables, and to provide a theoretical basis for the protection of leafy vegetables from acid rain. The experiment investigated the effects of simulated acid rain on four main nutritional indicators, including soluble sugar, total free amino acid, soluble protein and vitamin C during the application of simulated acid rain(SAR) in pakchoi(Brassica rapa chinensis), rape(Brassica campestris L.) and lettuce(Lactuca sativa Linn. var. ramosa Hort). The vegetables were respectively exposed to SAR of pH=7.0, 5.6, 5.0, 4.0, 3.0 and a control level of pH=6.5. The concentrations of the four main nutritional indicators were determined at harvest. The results show that nutritional quality of the three leafy vegetable species decreased with the declining of pH values of SAR. The higher the acidity of SAR was, the more significant the inhibitions were. Nutritional quality of lettuce was the most affected by simulated acid rain, followed by pakchoi and rape. The change range of soluble protein content was higher than those of the other three indicators’ contents, which indicates that soluble protein is most sensitive to simulated acid rain.
文摘This review provides information determining how much vitamin C to take, including analysis of the recent findings, which demonstrate advantages and problems with higher daily doses. The Daily Value for vitamin C was raised to 90 mg for men in 2000, and Upper Limit of 2,000 mg per day was established as being safe. This followed a study of urinary excretion of vitamin C (AA) that demonstrated 500 mg twice a day provides levels sufficient to cause continuous urinary excretion in humans. That is the lowest oral dosage evaluated that significantly saturates blood plasma. A later study endorsed 200 mg from dietary sources for the RDA. Even though plasma concentration of AA is then significantly lower, at 200 mg daily certain white blood cells are saturated with AA. Recently many studies have indicated the benefit of high levels of AA to maintain the brain, bones, and heart, reduce damage from stroke, brain trauma, and cataracts, and lower the risk of cancer metastasis and colds. Pro-oxidant activity has been found only for i.v. adminstration, where high concentrations appear effective destroying tumor cells while not harming normal cells. This review evaluates recent research and finds it consistent with the hypothesis that people, especially older people and soldiers in combat environments, are likely to benefit if they maintain the saturating level of AA by taking 500mg supplements twice a day.
文摘Herein, the iodometric titration and HPLC-RP methods were compared for the determination of vitamin C in vitamin and mineral supplements. The methods were validated in terms of linearity, limits of detection (LOD), limits of quantification (LOQ), precision, and recovery by using vitamin standards and a reference material SRM 3280 (multivitamin/multimineral tablets) obtained from the National Institute of Standards and Technology (NIST). A total of 22 samples of vitamin supplements, randomly acquired in local markets of Sao Paulo (Brazil) were evaluated for content of vitamin C by these two methodologies. The precision expressed as RSD was lower than 5% for both methods. LOD was 3.6 μg/mL for HPLC and 1.0 mg for titration, while LOQ were 12.0 μg/mL and 3.0 mg for HPLC and titration, respectively. Percent recoveries (%) of spiked samples ranged from 98.7 to 100.5 for HPLC and from 98 to 104 for titration. The contents of vitamin C in SRM 3280 (Certified value = 42.2 ± 3.7 mg/g) were 40.2 and 42.1 mg/g when determined by HPLC and titration respectively. Statistically, there was no difference in the analysed vitamin C content for half of the samples, irrespective of the method applied. HPLC was more sensitive, but the titrimetric method was faster and consumed less reagent. Although both methods were accurate in determining the vitamin C content in SRM 3280, the matrix constituents of some vitamin supplements may have interfered with the analysis.
文摘The aim of this study was to examine whether vitamin C reduced mortality when adjutant therapy of patients with septic shock and severe sepsis compared with placebo by meta-analysis. Eligible trials were identified from Pubmed, Embase, Ovid, and the Cochrane database. Four randomized controlled trials (RCT) and two retrospective studies were published between 2000 and 2017 met the inclusion criteria and suitable for meta-analysis. The data were analyzed with randomized-effects or fixed-effects models using Review Manager Version 5.3. Four randomized studies with a total of 109 participants were suitable for meta-analysis. The heterogeneity was assessed by calculating the Q and I2 methods. A random-effects approach instead of a fixed-effects analysis was undertaken if I2 > 50%. Adjuvant vitamin C did not associate with a reduction in mortality as compared with placebo, it is occurred similarly in both RCT studies and retrospective studies. However, high doses of vitamin C (>50 mg/kg/day) significant reduced the mortality rate of severe sepsis patients. And administration of high doses of vitamin C to therapy severe sepsis did not significantly reduce the ICU length of stay. The results suggested a trend toward reducing mortality in severe sepsis and septic shock patients’ adjuvant with vitamin C. Further multicenter large randomized controlled trials are necessary to determine the potential benefits of vitamin C in patients with severe sepsis and septic shock.
文摘Severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)has emerged as one of the most dreadful viruses the mankind has witnessed.It has caused worldwide havoc and wrecked human life.In our quest to find therapeutic options to counter this threat,several drugs have been tried,with varying success.Certain agents like corticosteroids,some anti-virals and immunosuppressive drugs have been found useful in improving clinical outcomes.Vitamin C,a water-soluble vitamin with good safety profile,has been tried to reduce progression and improve outcomes of patients with coronavirus disease 2019(COVID-19).Because of its anti-oxidant and immunomodulatory properties,the role of vitamin C has expanded well beyond the management of scurvy and it is increasingly been employed in the treatment of critically ill patients with sepsis,septic shock,acute pancreatitis and even cancer.However,in spite of many case series,observational studies and even randomised control trials,the role of vitamin C remains ambiguous.In this review,we will be discussing the scientific rationale and the current clinical evidence for using high dose vitamin C in the management of COVID-19 patients.