Antioxidant Effect Of Ascorbic Acid Research Articles

Design, Synthesis, Evaluation, and Molecular Docking Study of Ascorbic Acid Dual-Coated Omeprazole Pellets and the Antioxidative Effect of Ascorbic Acid on Omeprazole-Induced Renal Injury in an Animal Model.

The present study was carried out to investigate the antioxidant effect of ascorbic acid on omeprazole (O.P.)-induced acute kidney infection (AKI). Design of experiment (DoE) was employed to fabricate formulations (P1-P8) by the extrusion spheronization technique, and they were evaluated using various analytical techniques. P1-P8 formulations have % drug loading ranging from 56.34 ± 1.10 to 98.67 ± 1.05%, encapsulation efficiency from 70.98 ± 0.96 to 98.67 ± 1.05%, percentage drug release varying from 36.56 ± 1.34 to 93.45 ± 1.45%, Hausner's ratio ranging from 1.026 ± 0.05 to 1.065 ± 0.02%, and Carr's index varying from 2.3 ± 0.07 to 6.1 ± 0.06 g/mL. The optimized formulation (P6) was dual-coated with Eudragit L-100 (5% w/v) and ascorbic acid (2% w/v). A smooth uniform morphology was found after coating, and particle size nonsignificantly changed from 85.31 ± 77.43 to 101.99 ± 65.56 μm. IR spectra showed omeprazole characteristic peaks confirming drug loading, and peaks at 1747.40 and 1611.51 cm-1 confirmed ascorbic acid and Eudragit L-100 coating. X-ray diffraction (XRD) analysis confirmed the crystalline nature, and thermal degradation studies until 500 °C demonstrated increased stability after coating. Cytotoxicity analysis with 97% cell viability revealed the nontoxic behavior of pellets. In vitro dissolution studies of coated pellets showed <20% drug release at pH 1.2 and 99.54% at pH 6.8. Animal studies showed that pure omeprazole showed a nonsignificant decrease in weight, urine output, and fecal output compared to rodents on ascorbic acid pellets. Increased uric acid and creatinine levels in the group on pure omeprazole indicated AKI. Histopathological studies of renal cells also supported these results. The integration of experimental pellet formulation with molecular docking simulations has unveiled the potential of ascorbic acid and omeprazole as highly promising therapeutic agents for addressing oxidative stress and inflammation.

Intravenous Ascorbic Acid for the Prevention of Postreperfusion Syndrome in Orthotopic Liver Transplantation: Protocol for a Randomized Controlled Trial.

Liver transplantation is the last therapeutic option for patients with end-stage liver disease. Postreperfusion syndrome (PRS), defined as a fall in mean arterial pressure of more than 30% within the first 5 minutes after reperfusion of at least 1 minute, can occur in liver transplantation as a deep hemodynamic instability with associated hyperfibrinolysis immediately after reperfusion of the new graft. Its incidence has remained unchanged since it was first described in 1987. PRS is related to ischemia-reperfusion (I/R) injury, whose pathophysiology involves the release of several mediators from both the donor and the recipient. The antioxidant effect of ascorbic acid has been studied in resuscitating patients with septic shock and burns. Even today, there are publications with conflicting results, and there is a need for further studies to confirm or rule out the usefulness of this drug in this group of patients. The addition of ascorbic acid to preservation solutions used in solid organ transplantation is under investigation to harness its antioxidant effect and mitigate I/R injury. Since PRS could be considered a manifestation of I/R injury, we believe that the possible beneficial effect of ascorbic acid on the occurrence of PRS should be investigated. The aim of this randomized controlled trial is to assess the benefits of ascorbic acid over saline in the development of PRS in adult liver transplantation. We plan to conduct a single-center randomized controlled trial at the Hospital Universitario Ramón y Cajal in Spain. A total of 70 participants aged 18 years or older undergoing liver transplantation will be randomized to receive either ascorbic acid or saline. The primary outcome will be the difference between groups in the incidence of PRS. The randomized controlled trial will be conducted under conditions of respect for fundamental human rights and ethical principles governing biomedical research involving human participants and in accordance with the international recommendations contained in the Declaration of Helsinki and its subsequent revisions. The enrollment process began in 2020. A total of 35 patients have been recruited so far. Data cleaning and analysis are expected to occur in the first months of 2024. Results are expected around the middle of 2024. We believe that this study could be particularly relevant because it will be the first to analyze the clinical effect of ascorbic acid in liver transplantation. Moreover, we believe that this study fills an important gap in the knowledge of the potential benefits of ascorbic acid in the field of liver transplantation, particularly in relation to PRS. European Union Drug Regulating Authorities Clinical Trials Database 2020-000123-39; https://tinyurl.com/2cfzddw8; ClinicalTrials.gov NCT05754242; https://tinyurl.com/346vw7sm. DERR1-10.2196/50091.

Comparative antioxidant effect of ascorbic acid and rosemary extract

The aim of the work was to study an effect of ascorbic acid and the extract of rosemary on fat oxidation, color characteristics, pH and moisture binding capacity of minced pork during cold storage. The antioxidants were introduced into minced pork in an amount of 0.05%. After addition of the antioxidant, minced meat was packed in the modified atmosphere with the high oxygen content and stored at a temperature of 4 ± 2 ºС for 15 days. The indicators of the hydrolytic (acid value) and oxidative (peroxide value and thiobarbituric acid value) spoilage, color characteristics, pH and moisture binding capacity (MBC) were determined during the whole storage period (0, 5, 8, 12, 15 days). An increase in the acid value was recorded in all minced meat samples during storage without a significant difference between the control and experimental samples. Addition of the antioxidants led to a decrease in the peroxide value after 12 days of minced meat storage. Malonaldehyde began to accumulate in the control and the sample with ascorbic acid on the 8th day of storage and in the sample with the rosemary extract on the 12th day. The results obtained point to inhibition of fat oxidation in the minced meat samples with the antioxidants. Addition of the antioxidants facilitated an increase in redness compared to the control. Contrary to the rosemary extract, addition of ascorbic acid led to a decrease in pH and MBC of minced meat. Therefore, the use of the rosemary extract exerted more effective action of minced pork stability during storage compared to the same dose of ascorbic acid.

Продукция активных форм кислорода при действии ультрафиолетового-В излучения на клетки дрожжей

The present investigation is devoted to the study of the effect of ultraviolet-B (UV-B) radiation on the survival and production of reactive oxygen species in yeast cells. It has been determined that under the action of UV-B radiation on cells, depending on its dose, the rate of oxidation of the dye 2',7'-dichlorodihydrofluorescein diacetate (H2DCF•DA) increases and a high intensity of DCF fluorescence is observed. When cells are modified with ascorbic acid before irradiation, the rate of H2DCF oxidation and the intensity of DCF fluorescence decreases. The survival rate of modified cells is increased. Ascorbic acid reduces the amount of ROS in the suspension of irradiated cells. At high doses (4.5-10 erg/mm2) of irradiation, the antioxidant effect of ascorbic acid in yeast cells is negligible. The concentration of 2-4 dinitrophenol (DNF) 10-7 M was determined as a protector, in which the substance potentially contributes to the manifestation of the effect of "soft uncoupling" in cells and, under the influence of UV-B radiation on yeast cells, helps to reduce the production of reactive oxygen species and an increase in survival. High concentrations (10–3M–10–5 M) of DNP adversely affect the survival of yeast cells and ROS production. So, it can be concluded that under the action of UV-B rays on yeast cells, antioxidants can possibly participate in the regulation of redox homeostasis.

CO-oximetry measurements and antioxidant effects of ascorbic acid and methylene blue in equine methemoglobinemic blood.

To determine the effects of time after sampling on CO-oximetry measurements of equine blood samples and the effects of adding ascorbic acid (AscAc) and methylene blue (MetBlue) to samples with methemoglobinemia. Experimental study. University teaching hospital. Thirty healthy adult horses assigned to 5 groups. Repeated CO-oximetry determinations were performed on venous (n=6) and arterial blood samples (n=7) stored at 0°C for 48hours. Methemoglobinemia was induced in vitro in 17 additional blood samples. Six were used as untreated controls, 6 had AscAc added, and 5 had MetBlue added. Total hemoglobin, oxyhemoglobin, carboxyhemoglobin, methemoglobin (MetHb), and oxygen saturation of hemoglobin (SO2 ) were measured. Oxyhemoglobin and SO2 increased from 69.8%±10.2% and 90%±3% to 82.8%±7.9% and 99%±3%, respectively, after 8hours in venous blood (mean±SD, P<0.001). There was an effect of treatment (P=0.032) and of time (interaction P=0.003) on MetHb% in methemoglobinemic samples. The difference in absolute MetHb% from time 0 was as follows: 7.0% (interquartile range [IQR] = 21.2), -0.2% (IQR=3.5), and -4.4% (IQR=5.2) at 48hours in control, AscAc, and MetBlue groups, respectively (P<0.05). There was no effect of time on MetHb% in the AscAc group (23% [IQR = 52.6] at time 0 to 23.2% [IQR = 56.9] after 48h). Storage of blood in ice water to determine O2 Hb and SO2 using a CO-oximeter should not exceed 4hours. Measurement of MetHb% could be delayed by up to 48hours if AscAc is added to the sample. MetBlue significantly decreased MetHb% over time. The limitations of this study include the fact that the antioxidant effects of AscAc and MetBlue were evaluated in vitro and not in vivo. Further studies are needed to evaluate different storage temperatures and syringe types.

Antioxidant effect of ascorbic acid against cisplatin-induced nephrotoxicity and P-glycoprotein expression in rats

Cisplatin (CDDP) is a highly potent anticancer drug that is widely used in the treatment of several cancers. CDDP-induced nephrotoxicity (CIN) is one of the most significant adverse effects, and oxidative stress is thought to be one of the mechanisms underlying CIN. Although there are some studies available on the variability in transporter expression in the kidney after a single CDDP dose, none have reported the change in renal transporter expression after multiple CDDP dose administrations. P-glycoprotein (P-gp), a transporter, is reported to be induced by oxidative stress. Ascorbic acid is a vitamin with antioxidant potential and therefore, may regulate the expression of P-gp transporter and affect CIN. In the present study, our aim was to assess the variability in expression of several renal transporters after multiple CDDP dose administrations and the antioxidant effect of ascorbic acid against transporter expression and CIN. Multiple doses of CDDP affected markers of kidney injury and antioxidants in the kidneys. Also, the expression of P-gp, breast cancer resistance protein, and multidrug resistance-associated protein 4 was upregulated by CDDP. Using a normal kidney cell line, we demonstrated that ascorbic acid attenuated CDDP-induced cytotoxicity due to its high superoxide scavenging ability. CDDP and ascorbic acid were injected into rats once a week for three weeks, and it was observed that co-administration of ascorbic acid attenuated CIN and regulated antioxidant marker. In addition, ascorbic acid reduced P-gp expression, which was upregulated by CDDP. In conclusion, ascorbic acid may attenuate CIN and reverse P-gp-mediated changes in drug pharmacokinetics.

Ascorbic Acid Supplementation Improves Skeletal Muscle Growth in Pacu (Piaractus mesopotamicus) Juveniles: In Vivo and In Vitro Studies.

In fish, fasting leads to loss of muscle mass. This condition triggers oxidative stress, and therefore, antioxidants can be an alternative to muscle recovery. We investigated the effects of antioxidant ascorbic acid (AA) on the morphology, antioxidant enzyme activity, and gene expression in the skeletal muscle of pacu (Piaractus mesopotamicus) following fasting, using in vitro and in vivo strategies. Isolated muscle cells of the pacu were subjected to 72 h of nutrient restriction, followed by 24 h of incubation with nutrients or nutrients and AA (200 µM). Fish were fasted for 15 days, followed by 6 h and 15 and 30 days of refeeding with 100, 200, and 400 mg/kg of AA supplementation. AA addition increased cell diameter and the expression of anabolic and cell proliferation genes in vitro. In vivo, 400 mg/kg of AA increased anabolic and proliferative genes expression at 6 h of refeeding, the fiber diameter and the expression of genes related to cell proliferation at 15 days, and the expression of catabolic and oxidative metabolism genes at 30 days. Catalase activity remained low in the higher supplementation group. In conclusion, AA directly affected the isolated muscle cells, and the higher AA supplementation positively influenced muscle growth after fasting.

Evaluation of the anti-oxidant effect of ascorbic acid on apoptosis and proliferation of germinal epithelium cells of rat testis following malathion-induced toxicity.

Objective(s):The aim of this study was to determine the protective role of ascorbic acid on apoptosis and proliferation of spermatogonia and primary spermatocyte cells after malathion administration as an organophosphate pesticide in rat testis.Materials and Methods:Thirty male Wistar rats were randomly divided into five groups of 6 rats each, including control (no intervention), sham (normal saline 0.09%), malathion (50 mg/kg), malathion plus ascorbic acid (50 mg/kg and 200 mg/kg, respectively), and ascorbic acid (200 mg/kg) groups. Malathion and ascorbic acid were administrated via intraperitoneal injection once per day and seven times per week. After 6 weeks, animals were sacrificed, and testis tissue was used for evaluation of apoptosis and proliferation of germinal epithelium cells using the TUNEL and PCNA staining techniques. Results:The results of TUNEL staining showed that the numbers of apoptotic cells in spermatogonia and primary spermatocyte cells were significantly increased in the malathion 50 mg/kg group vs control group (P<0.001). Co-administration of malathion 50 mg/kg and ascorbic acid 200 mg/kg significantly decreased the apoptotic cells in both cell types in comparison with malathion 50 mg/kg group (P<0.001). The results of PCNA staining revealed that the proliferation of these cells was significantly decreased in malathion 50 mg/kg group vs control group (P<0.001), and malathion 50 mg/kg plus ascorbic acid 200 mg/kg administration increased the proliferation of cells compared with malathion 50 mg/kg group (P<0.001).Conclusion:The results provide evidence that ascorbic acid showed preventive effects on malathion-induced toxicity in male rat testis.

An Overview of the Antioxidant Effects of Ascorbic Acid and Alpha Lipoic Acid (in Liposomal Forms) as Adjuvant in Cancer Treatment.

Antioxidants are known to minimize oxidative stress by interacting with free radicals produced as a result of cell aerobic reactions. Oxidative stress has long been linked to many diseases, especially tumours. Therefore, antioxidants play a crucial role in the prevention or management of free radical-related diseases. However, most of these antioxidants have anticancer effects only if taken in large doses. Others show inadequate bioavailability due to their instability in the blood or having a hydrophilic nature that limits their permeation through the cell membrane. Therefore, entrapping antioxidants in liposomes may overcome these drawbacks as liposomes have the capability to accommodate both hydrophilic and hydrophobic compounds with a considerable stability. Additionally, liposomes have the capability to accumulate at the cancer tissue passively, due to their small sizes, with enhanced drug delivery. Additionally, liposomes can be engineered with targeting moieties to increase the delivery of chemotherapeutic agents to specific tumour cells with decreased accumulation in healthy tissues. Therefore, combined use of liposomes and antioxidants, with or without chemotherapeutic agents, is an attractive strategy to combat varies tumours. This mini review focuses on the liposomal delivery of selected antioxidants, namely ascorbic acid (AA) and alpha-lipoic acid (ALA). The contribution of these nanocarriers in enhancing the antioxidant effect of AA and ALA and consequently their anticancer potentials will be demonstrated.

Cytoprotective Effect of Ascorbic Acid and Rutin against Oxidative Changes in the Proteome of Skin Fibroblasts Cultured in a Three-Dimensional System.

The combination of ascorbic acid and rutin, commonly used in oral preparations for their antioxidant and anti-inflammatory properties, can also be used to protect skin cells from the effects of UV radiation in sunlight. Here, we tested the potential protective effect of ascorbic acid and rutin used together in UVB-irradiated human skin fibroblasts, and assessed the proteomic profile of these cells, grown in a three-dimensional (3D) system. Proteomic findings revealed a combined effect of ascorbic acid and rutin in UV-irradiated fibroblasts against overexpression of pro-inflammatory signaling proteins and DNA reorganization/expression. These effects were not observed when cells were treated with either compounds alone. The antioxidant effects of ascorbic acid and rutin also prevented protein modifications by lipid peroxidation products. Further, ascorbic acid stimulated rutin-protein adduct formation, which supports intra/extracellular signaling and the Nrf2/ARE antioxidant pathway, contributing to the protective effects against UV-induced oxidative stress. The combined effect of ascorbic acid and rutin suggests that this combination of compounds is potentially effective against skin damage caused by UV radiation.

Impact of storage, leukofiltration, and ascorbic acid fortification on red cell-derived microparticles in stored packed red blood cells: A flow cytometric and procoagulant study

INTRODUCTION: During blood storage, red blood cells (RBCs) undergo changes termed “storage lesion” including shape modification and microparticles (MPs) production, as well as oxidative injury to lipids and proteins. OBJECTIVE: We studied the impact of storage on RBCs by quantification of red cell MPs and their potential procoagulant activity (PCA). The antioxidant effect of ascorbic acid (AA) was assessed, as a proposed additive, to improve stored RBC quality. METHODS: Forty randomly selected packed red cell units (filtered and nonfiltered) were sampled weekly over 35 days of storage. Flow cytometric and coagulation tests were performed on MPs isolated from erythrocyte concentrates. RBCs were either in citrate phosphate dextrose adenine-1 (CPDA1) only (standard storage) or CPDA1 with AA (Vitamin C) in three concentrations. RESULTS: Red cell MPs progressively increased over 35 days of storage. Filtration efficiently reduced the production of MPs (P < 0.001). PCA increased significantly on storage assessed by the shortened coagulation time (P < 0.001). A strong inverse correlation between coagulation time and Annexin V positive MPs was found, (r = −0.723, P < 0.001), and the dual-positive population. This highlights the strong correlation between the functional assay (PCA) and the direct quantitative assay (flow cytometry). The red cells fortified with AA demonstrated a reduction in the accumulation of RBC MPs by almost 50% compared to standard storage in CPDA-1 alone in an evident dose-dependent manner. CONCLUSION: We concluded that MPs increase on storage with increased PCA. AA reduced MPs production which can be possible additive for further research in the future

Effect of antioxidant ascorbic acid on in vitro maturation of Caprine oocytes under normal and elevated temperatures

The aim of the present study was to assess the effect of ascorbic acid on in vitro maturation of caprine oocytes under normal and elevated temperatures. Goat ovaries were collected at slaughter and both A and B grade cumulus-oocyte-complexes (COCs) were aspirated out and were matured in vitro under normal (38.5°C) and elevated temperatures (41°C). On the basis of cumulus expansion and nuclear maturation, the maturation competencewere compared with and without ascorbic acid supplementation (100 µM). Heat stress significantly (P£ 0.01) reduced cumulus expansion, maturation rate and lowered metaphase stage II of nuclear maturation. Ascorbic acid improved developmental competence of oocytes during heat stress (41 °C) and ascorbic acid supplemented COCs demonstrated significantly (P£ 0.05) higher maturation rates when compared to non-supplemented groups.

Antioxidant Effect of Ascorbic Acid (Vit.C) in Different Concentration against Harmful Effect of Toxic Heavy Metal (Lead Acetate) in Rats

Ascorbic acid (Vit.C) is one of the most potent antioxidants that interacts directly with the oxidizing radicals and protects the cells from reactive oxygen species. There is a need to increase the daily intake of Vit.C. The present study was aimed to evaluate the potential protective effects of different concentration of Vit.C against oxidative stress of lead acetate toxicity (Pb) in rats. Fifty albino male rats with average body weight 180 gm were classified into five equal groups (10 each); control group received tap water only, Pb group received 0.2% lead acetate /kg,b.w and the other three groups received 500, 1000 and 1500 mg Vit. C, along with 0.2%lead acetate /kg.bw, respectively. Doses were orally administered daily for two months.The results showed that Pb affected significantly on the hematological parameters, which decreased red blood cell count (RBC) by 28.9%, hemoglobin(HB) by 28.2%, hematocrit (Htc) by 26.4%and platelets(Plt) by 25,1% than control group ;while white blood cell count (WBC) increased significantly by 35.9% than control group. But Vit.C enhanced hematological parameters in the present of lead acetate at all concentrations than lead group, and the best effect was found with high concentration (1500mg),where it increased RBC count by 27.5%,Hb by 44.7%,Htc by 30.2%and Plt by 45%,while WBC count was decreased by 29%.Pb caused significant increase in total lipid by 53.7%, triglyceride (TG) by 43.6%, cholesterol (CHO) by 50%, low density lipoprotein (LDL)by 76% and very low density lipoprotein(VLDL) by 43.8% than control group, while Vit.C significantly decrease the total lipid by 26.1%, TG by 20.5%,CHO by 21.3%.LDL by 50%, and VLDL by 2o.5% at high concentration of Vit C(1500mg),it also increased HDL significantly by 57.5% than lead group. Pb administration increased nitric oxide (NO) by 53.9% and thiobarbaturic acid reactive substances(TBARS) by 53.3% in plasma compared to the control group, while it significantly decreased glutathione (GSH) by 50% and total antioxidants capacity (TAC) by 57.9%.Pb also increased NO and TBARS and decreased GSH and TAC in liver, kidneys and brain. Vit.C had benefits effect as antioxidant activity, the best effect noticed in the highest concentration of Vit.C (1500 mg).It caused significant decrease in NO by 23.4% and TBARS by 25.5%.But also caused significant increase in GSH by 60% and TAC by 100% in plasma than lead group. Vit C also decreased NO and TBARS and increased GSH and TAC in organs than lead groupIt can be concluded that Vit.C is capable of alleviating the harmful effects of Pb and highly recommended increasing the daily intake of Vit. C either from food rich in ascorbic acid or from supplementation.

Ascorbic acid supplementation improves skeletal muscle oxidative stress and insulin sensitivity in people with type 2 diabetes: Findings of a randomized controlled study

Aim/hypothesisSkeletal muscle insulin resistance and oxidative stress are characteristic metabolic disturbances in people with type 2 diabetes. Studies in insulin resistant rodents show an improvement in skeletal muscle insulin sensitivity and oxidative stress following antioxidant supplementation. We therefore investigated the potential ameliorative effects of antioxidant ascorbic acid (AA) supplementation on skeletal muscle insulin sensitivity and oxidative stress in people with type 2 diabetes. MethodsParticipants with stable glucose control commenced a randomized cross-over study involving four months of AA (2×500mg/day) or placebo supplementation. Insulin sensitivity was assessed using a hyperinsulinaemic, euglycaemic clamp coupled with infusion of 6,6-D2 glucose. Muscle biopsies were measured for AA concentration and oxidative stress markers that included basal measures (2′,7′-dichlorofluorescin [DCFH] oxidation, ratio of reduced-to-oxidized glutathione [GSH/GSSG] and F2-Isoprostanes) and insulin-stimulated measures (DCFH oxidation). Antioxidant concentrations, citrate synthase activity and protein abundances of sodium-dependent vitamin C transporter 2 (SVCT2), total Akt and phosphorylated Akt (ser473) were also measured in muscle samples. ResultsAA supplementation significantly increased insulin-mediated glucose disposal (delta rate of glucose disappearance; ∆Rd) (p=0.009), peripheral insulin-sensitivity index (p=0.046), skeletal muscle AA concentration (p=0.017) and muscle SVCT2 protein expression (p=0.008); but significantly decreased skeletal muscle DCFH oxidation during hyperinsulinaemia (p=0.007) when compared with placebo. Total superoxide dismutase activity was also lower following AA supplementation when compared with placebo (p=0.006). Basal oxidative stress markers, citrate synthase activity, endogenous glucose production, HbA1C and muscle Akt expression were not significantly altered by AA supplementation. Conclusions/interpretationIn summary, oral AA supplementation ameliorates skeletal muscle oxidative stress during hyperinsulinaemia and improves insulin-mediated glucose disposal in people with type 2 diabetes. Findings implicate AA supplementation as a potentially inexpensive, convenient, and effective adjunct therapy in the treatment of insulin resistance in people with type 2 diabetes.

Ascorbic acid modulates doxorubicin and cyclophosphamide-induced cytogenetic damages in Sarcoma 180 cells

Cancer is a public health global problem. Cyclophosphamide (CPA) and Doxorubicin (DOX) are used in chemotherapy, especially by generating reactive oxygen species. The clinical use of ascorbic acid during chemotherapy also raises several controversies due to its antagonistic effects on antineoplastic agent. In this sense, this study aims to evaluate the effects of ascorbic acid (2 µg/mL) on the modulation of cytogenetic damage induced by CPA (20 µg/mL) and DOX (2 µg/ mL), as well as their interaction (AC protocol) on Sarcoma 180 tumor cells. Cytogenetic damage classified as apoptosis, necrosis, micronuclei, buds and nucleoplasmic bridges were linked to the CytokinesisBlock Micronucleus Assay application. CPA and DOX induce significant (p<0.05) increases in apoptosis, necrosis and micronuclei in the cell types tested. The damage on Sarcoma 180 cells was modulated by ascorbic acid with percentage modulation in more than 70% of CPA relative to apoptosis and micronuclei, and 32% to necrosis. The damage of DOX has been modulated by 70% to apoptosis, 40% to necrosis, rather than micronuclei, whereas, in AC protocol, modulations were observed by 52% to apoptosis and 32% and 40% to necrosis and micronuclei, respectively. There was no significance in relation to the nuclear buds and nucleoplasmic bridges. In addition, ascorbic acid did not show any effect. These results are other studies, which indicate hazards to chemotherapy effectiveness due to the antioxidant effects of ascorbic acid in the modulation of oxidative stress to promote major cytogenetic damage that is important to tumor regression.

Effects of Ascorbic Acid in Controlling Lethal Browning in &amp;lt;i&amp;gt;in Vitro&amp;lt;/i&amp;gt; Culture of &amp;lt;i&amp;gt;Brahylaena huillensis&amp;lt;/i&amp;gt; Using Nodal Segments

Brachylaena huillensis (Asteraceae) is a threatened resourceful timber tree species. B. huillensis regenerates only through seeds. However, the seeds have poor germination rate and are also not obtainable. Developing tissue culture techniques for B. huillensis will permit the application of biotechnology to its propagation and provide alternative method for its regeneration. The current study was conducted to investigate the effect of antioxidant ascorbic acid in controlling lethal browning caused by oxidized phenols in in vitro culture of Brachylaena huillensis using nodal segments. The treatments included four levels of ascorbic acid (0, 50, 100, 150, 200, & 250 mg/litre) supplied into basal woody plant medium supplemented with Benzylaminopurine (BAP). The results of the current study revealed that production of phenolic compounds of explants was significantly controlled by incorporating higher levels of ascorbic acid into the medium. The best control was achieved by supplying 200-250 mg/litre of ascorbic acid in the woody plant medium supplemented with BAP.

Positive modulation of the α9α10 nicotinic cholinergic receptor by ascorbic acid

The activation of α9α10 nicotinic cholinergic receptors (nAChRs) present at the synapse between efferent olivocochlear fibres and cochlear hair cells can prevent acoustic trauma. Hence, pharmacological potentiators of these receptors could be useful therapeutically. In this work, we characterize ascorbic acid as a positive modulator of recombinant α9α10 nAChRs. ACh-evoked responses were analysed under two-electrode voltage-clamp recordings in Xenopus laevis oocytes injected with α9 and α10 cRNAs. Ascorbic acid potentiated ACh responses in X. laevis oocytes expressing α9α10 (but not α4β2 or α7) nAChRs, in a concentration-dependent manner, with an effective concentration range of 1-30 mM. The compound did not affect the receptor's current-voltage profile nor its apparent affinity for ACh, but it significantly enhanced the maximal evoked currents (percentage of ACh maximal response, 240 ± 20%). This effect was specific for the L form of reduced ascorbic acid. Substitution of the extracellular cysteine residues present in loop C of the ACh binding site did not affect the potentiation. Ascorbic acid turned into a partial agonist of α9α10 nAChRs bearing a point mutation at the pore domain of the channel (TM2 V13'T mutant). A positive allosteric mechanism of action rather than an antioxidant effect of ascorbic acid is proposed. The present work describes one of the few agents that activates or potentiates α9α10 nAChRs and leads to new avenues for designing drugs with potential therapeutic use in inner ear disorders.

Correlations between Endothelial Functions and ROS Detection in Diabetic Microvascular Wall:Early and Late Ascorbic Acid Supplementation

The correlation between endothelial function and reactive oxygen species detecting from diabetic microvascular wall and the antioxidant effect of ascorbic acid (AA) during early and late phases of diabetic induction were determined. Male Spraque-Dawley rats were divided into four groups: control, diabetes rats (DM, using iv.injection of 55 mg/kg BW streptozotocin, (STZ)), and two groups of DM rats treated with AA (1 g/L, (STZ)) starting on day 2 (DM + AAday2) and week 6th (DM + AA6wk). On 12th week after STZ injection, the findings showed that in DM group, Ach (10−5 M)-induced vasodilatation was decreased, while the number of leukocyte adhesion was increased significantly (P < 0.01). Interestingly, these abnormalities induced by DM could be protected or improved in both AA-treated groups, DM + AAday2 and DM + AA6wk. By using dihydrorhodamine 123, our findings also indicated that the existing of ROS productions on diabetic arteriolar and venular walls were different significantly (ROSarteriole = 165.89 ± 24.59 and ROSvenule = 172.26 ± 34.70) (P < 0.05). Moreover by using BH4 inhibitor to induce increase in arteriolar ROS, the results also confirmed that AA could improve endothelial function with closed correlation to its potential to reduce vascular ROS content.

Synergetic and antagonistic role of natural antioxidant in the autoxidation of soybean oil

The antioxidant effects of ascorbic acid (vitamin C), α-tocopherol (vitamin E), 2,6-di -t-butyl-4-cresol (BHT) and 4-hydroxy-2,2,6,6-tetramethyl-piperidine-N-oxyl (abbr. N-oxyl = 4-hydroxy-TEMPO) on the autoxidation of soybean oil (SBO) were evaluated at 140 °C in four different concentrations (at 1.0, 0.7, 0.5, and 0.3 wt% of SBO). Ascorbic acid and α-tocopherol showed lower active oxygen concentration at the range of 0.5–0.7 wt% concentrations than that at 1.0 wt%. However, on the contrary, 2,6-di- t-butyl-4-cresol and N-oxyl showed higher effect with increasing concentration. In 1.0 wt% antioxidant concentration, the inhibiting effect showed in the following order, 2,6-di- t-butyl-4-cresol > α-tocopherol > N-oxyl > ascorbic acid and in lower concentration of 0.5 wt%, the order was inverted as follows: ascorbic acid > α-tocopherol > 2,6-di- t-butyl-4-cresol > N-oxyl. The inversion of the order at lower concentration could be attributed to the synergetic and antagonistic effect arousing from hydrogen bonding. The composition of oxidized triglyceride was investigated by means of LC/ESI-MS/MS spectroscopy.

Retinol potentiates the inhibitory effect of ascorbic acid on uric acid assay

The interference of ascorbic acid in the determination of plasma uric acid concentrations, by decreasing the formation of chromophore in Trinder's reaction, is well known. By contrast, the effects of other antioxidant vitamins, such as retinol and alpha-tocopherol have not been investigated. Knowledge of the analytical interaction of these antioxidants in the uric acid assay would be useful. The effect of a mix of vitamins (Cernevit) on uric acid analysis in a patient hospitalized in a neurological intensive care unit was observed. The effects of the different antioxidant components of the mixture (retinol, alpha-tocopherol and ascorbic acid) on the concentration of uric acid from a pool of plasma were also tested. Among the different combinations of vitamins tested, only retinol potentiated the antioxidant effect of ascorbic acid. The most marked effect was observed with 80 IU/mL of retinol and 5.7 mmol/L of ascorbic acid. We demonstrate for the first time the synergistic interference of ascorbic acid and retinol on the measurement of uric acid in plasma. We established that ascorbic acid interference is potentiated by regeneration of reduced ascorbic acid by retinol. Such interference must be kept in mind to avoid misinterpreting low plasma uric acid concentrations in patients in whom this analyte is critical.