Serum Ascorbic Acid Research Articles

Carbon cloth surface engineering for simultaneous detection of ascorbic acid, dopamine, and uric acid in fetal bovine serum

Carbon cloth (CC) was electrochemically activated using three electrochemical methods in different electrolytes. The gases released during the activation process etched the surface of the CC, thereby increasing its surface area of the activated CC (FCC). Moreover, functional groups such as oxygen-containing groups and N-doping have been introduced. The quantity and type of functional groups introduced during the activation process were related to the anions in the solution. FCC electrodes were used to construct electrochemical sensors for the simultaneous determination of ascorbic acid (AA), dopamine (DA), and uric acid (UA). The PFCC electrode activated by advanced cyclic voltammetry in (NH4)2HPO4 showed linear ranges for AA, DA, and UA concentrations of 0.1 to 2.1 mM, 0.5 to 11 µM, and 0.5 to 11 µM, respectively. The detection limits are 72.93, 0.22, and 0.42 µM, respectively. The good flexibility the PFCC electrode made it suitable for the preparation of flexible sensors. The simultaneous determination of AA, DA, and UA in fetal bovine serum showed a reliable recovery ratio. This study provides a simple and green approach for activating carbon cloth and constructing flexible electrochemical sensors with the potential to simultaneously detect AA, DA, and UA.

Water-soluble vitamins stability by robust liquid chromatography-mass spectrometry.

The measurement of water-soluble vitamins is essential to diagnose and monitor various vitamin deficiencies. Establishing stability limits for these vitamins is crucial to ensure accurate laboratory testing. This study aimed to assess the stability of commonly measured water-soluble vitamins under different storage conditions to improve the accuracy of water-soluble vitamin measurement. The stabilities of thiamine, riboflavin, nicotinamide, pantothenic acid, pyridoxic acid and pyridoxal, biotin, 5-methyltetrahydrofolic acid (5-MTHF), and ascorbic acid were measured using liquid chromatography-tandem mass spectrometry. We investigated three pre-analytical factors: the effect of different temperatures and time durations on serum stability, variation between serum and plasma samples, and the impact of transferring samples to an ice bath before serum separation. We evaluated stability based on differences from the baseline. Thiamine, pyridoxal, and ascorbic acid in serum exhibited instability at room temperature and 2-8℃. Riboflavin and 5-MTHF in serum were only stable for up to 48 and 72 h at 2-8℃. However, when stored at -20℃, all water-soluble vitamins remained stable for up to 72 h, whereas at -80℃, stability was maintained for up to 7 days. All vitamins in whole blood, except nicotinamide, were stable for up to 2-4 h when stored in an ice bath. Water-soluble vitamins, such as thiamine, riboflavin, pyridoxal, and ascorbic acid, are unstable at room temperature and 2-8℃. All vitamins were stable for up to 7 days and stored at -80℃. The ice bath improved the stability of whole blood samples before centrifugation. Thus, laboratories should ensure appropriate storage conditions to maintain pre-analytical quality for vitamin measurements.

Mn‐functionalized ZIF‐67 for Sensitive Colorimetric Detection of Artemisinin and Ascorbic Acid

AbstractArtemisinin (Art) is the first‐choice medicine for treating malaria. It also shows good therapeutic effects in antibacterial and antitumor treatment. Therefore, a simple and efficient method for detecting Art is of great significance. Mn‐functionalized ZIF‐67 (Mn@ZIF‐67) hybrid materials were synthesized using a post‐synthesis modification method. Due to the introduction of Mn2+, Mn@ZIF‐67 possesses higher peroxidase/oxidase like dual‐mimic enzymes activity than ZIF‐67, which can catalyze Art and generate peroxyl radicals. Based on this fact, Mn@ZIF‐67 was used to detect Art in the presence of TMB. A good linear relationship between absorption intensities at 652 nm and Art concentrations was obtained in the range of 0–22 μM with a detection limit of 200 nM. Ascorbic acid (AA), due to its reducibility, can inhibit peroxidase/oxidase mimetics activity of Mn@ZIF‐67 and the blue Mn@ZIF‐67‐TMB solution fades gradually with the addition of AA. Mn@ZIF‐67‐TMB acting as a colorimetric sensor, AA can be sensitively detected ranging from 0–30 μM, and the detection limit is 50 nM. Coexisting substances don't interfere with the detection of Art or AA. This sensing platform provides a highly sensitive and selective colorimetric method for monitoring AA and Art in serum, thereby demonstrating remarkable practicality.

Content of ascorbic acid in different skin phototypes in children with vitiligo

Aim. To evaluate the blood level of ascorbic acid in children with vitiligo according to skin phototype.Material and Methods. Blood ascorbic acid levels were analysed in children of different ages (6-15 years) with different types of vitiligo, depending on skin phototype. Patients were divided into two groups according to the degree and localisation of the vitiligo lesions: with non-segmental (n=116) and with segmental (n=134) vitiligo. The area of distribution of the dermatosis and its stage of development were calculated using the VIMAN and VIDA indices, respectively. Serum ascorbic acid levels were determined by liquid chromatography-mass spectrometry. Patients were classified by phototype according to T. Fitzpatrick’s classification.Results and discussion. Among the children with vitiligo studied, skin phototypes II, III and IV were identified, with a predominance of phototype III over the others. Their percentages differed in the two groups studied. In non-segmental vitiligo, there were more children with a light phototype and fewer with a dark phototype compared to the group of children with segmental vitiligo. Ascorbic acid levels were significantly reduced in children with vitiligo compared to a group of healthy children. The most pronounced decrease was observed in the group with non-segmental vitiligo in the 7-9 year age group. In both groups of patients, there was a tendency for ascorbic acid levels to decrease with age.Conclusion. The data obtained indicate that children with vitiligo have lower ascorbic acid levels than healthy children. The tendency to decrease increases with age, especially in patients with a dark phototype. This fact indicates the need to correct vitamin C levels in the body of children with vitiligo.

Effect of lactose on the in vitro development of sheep secondary follicles

Considering that follicular development is an energy-dependent process, supplementation of the culture medium with energy substrates, such as lactose, would improve follicle viability and growth. Thus, the aim of this study was to evaluate the effect of lactose on morphology, development, glutathione (GSH) concentration, mitochondrial activity, DNA fragmentation, and meiotic resumption of oocytes from sheep secondary follicles cultured in vitro. Secondary follicles were isolated from the cortex of ovine ovaries and cultured individually for 18 days in α-MEM supplemented with bovine serum albumin (BSA), insulin, glutamine, hypoxanthine, transferrin, selenium and ascorbic acid (control medium: α-MEM+) or in α-MEM+ plus different concentrations of lactose (0.025, 0.05 and 0.1 M). After culture, some of the oocytes were subjected to TUNEL assay and in vitro maturation (IVM). Follicular morphology, glutathione (GSH) concentration and mitochondrial activity were evaluated at the end of the culture. At the day 18, the percentage of morphologically normal follicles was greater (P<0.05) in the treatment of 0.025 M lactose (92.5 %) compared to the control group (75.55 %). In addition, GSH concentrations increased (P<0.05) in treatment containing 0.025 M lactose compared to the other treatments. Furthermore, oocytes cultured in 0.025 M lactose had greater (P<0.05) mitochondrial activity levels than in α-MEM+ and 0.1 M lactose. The group α-MEM+ presented a increase of TUNEL-positive oocytes (35.09 %) compared to 0.025 lactose (9.09 %). The percentage of meiotic resumption was greater (P<0.05) in oocytes from secondary follicles cultured in 0.025 M lactose (54.5 %) than in α-MEM+ (45.5 %). In conclusion, 0.025 M lactose improved survival, GSH and active mitochondria levels and meiotic resumption of oocytes from in vitro cultured secondary follicles. Supplementation of the culture medium of preantral follicles with lactose can gradually provide energy to follicular cells, potentially enhancing the production of viable oocytes for biotechniques such as IVM and in vitro fertilization.

A dual-signal optical sensing platform of CDs-MnO2 NS composites for facile detection of ascorbic acid based on a combination of Tyndall effect scattering and fluorescence.

A dual-signal optical sensing platform was successfully developed for the determination of ascorbic acid (AA) based on blue fluorescent carbon dots (CDs) and manganese dioxide nanosheets (MnO2 NSs) with strong Tyndall effect (TE) scattering and fluorescence quenching capabilities. In this nanosystem, CDs-MnO2 NS composites were employed as probes to evaluate the AA concentration. Owing to the strong reduction, the presence of the target AA could reduce the MnO2 NSs to Mn2+ and induce the degradation of the MnO2 NSs, resulting in a significant decrease in the TE scattering intensity of the MnO2 NSs and the fluorescence recovery of the CDs. Therefore, a novel optical sensor based on TE scattering and fluorescence dual detectors was developed for the sensitive determination of AA. Under optimized conditions, the limits of detection (LODs) of the two modes were 113 and 3 nM, respectively. Furthermore, the dual-signal optical sensing platform was successfully applied for the detection of AA in human serum.

Higher serum ascorbic acid levels are associated with lower depression prevalence in US adults: a case-control study.

Recent studies have shown that a higher intake of ascorbic acid was associated with a lower prevalence of depression. Nevertheless, the recall bias was common in dietary surveys in these studies, and it was ignored that there were differences in the absorption and utilization of ascorbic acid in the body. Hence, we aim to investigate the association between serum ascorbic acid levels and the prevalence of depression in US adults. A total of 3,404 participants from the 2017-2018 National Health and Nutrition Examination Survey (NHANES) that underwent measurement of the Patient Health Questionnaire-9 (PHQ-9) scores and serum levels of ascorbic acid. Propensity Score Matching (PSM) successfully established a case-control study, comprising 299 participants diagnosed with depression and 1,107 as controls. We used binary logistic regression to estimate odds ratios (ORs) and 95% confidence intervals (CIs) to explore associated risk factors for depression. Restricted cubic splines (RCS) were used to show the nonlinear relationship between serum ascorbic acid levels and the prevalence of depression. The prevalence of depression was approximately 8.8%, with a median serum ascorbic acid level of 49.9 (36.0, 67.0) μmol/L. Results revealed that the serum ascorbic acid levels of depressed patients were significantly lower than those of non-depressed individuals (42.97 VS 52.97 μmol/L). The baseline data indicated that as serum ascorbic acid levels increased from Quartile 1 (Q1) to Quartile 4 (Q4), the depression prevalence decreased from 12.0 to 5.4% (p < 0.05). The results of the chi-square test after PSM showed that serum ascorbic acid was still statistically significant (p < 0.001) with the prevalence of depression. Forest plot showed that compared with the Q1 of serum ascorbic acid level, the OR and 95%CI of depression prevalence in Q4 was 0.42 (0.30 ~ 0.61), and the adjusted OR and 95%CI of depressive prevalence was 0.49 (0.33 ~ 0.73). RCS models showed an L-shaped nonlinear relationship (P for nonlinearity <0.05) between serum ascorbic acid and depression. Our results suggested that higher serum ascorbic acid levels are associated with a reduced prevalence of depression.

A clinic-pathological research explored the significance of ascorbic acid and iron levels in serum and saliva in premalignant disorder patients at Kanpur, Uttar Pradesh.

Oral submucous fibrosis (OSMF), or OSMF, is a well-known, potentially premalignant condition of the oral cavity. Monitoring OSMF widespread effects necessitate interventions in at-risk individuals, ideally before the disease becomes aggressive. Ascorbic acid and iron, for instance, are significant micronutrients in the pathogenesis of OSMF. This study aimed to investigate the significance of ascorbic acid and iron levels in serum and saliva in patients with premalignant disorder (OSMF) and to correlate variations in ascorbic acid and iron levels with histopathological grading. The present study was conducted on 195 patients over a period of 10 months. These patients were divided into two groups, Group I (n = 88, Control), Group II (n = 107, clinically diagnosed and histopathologically confirmed cases of OSMF). Serum and salivary ascorbic acid were analyzed by the dintrophenyl hydrazine method, whereas serum and salivary iron were analyzed by the dipyridyl method. Paired t-test and Fisher test were used to compare between the mean and to find the level of significance P value. The serum and salivary ascorbic acid levels consistently decreased with the progression of histopathological grading of OSMF. Serum and salivary iron levels were also decreased in OSMF patients, and it came as significant. Excess collagen synthesis during OSMF may have been promoted with ascorbic acid and iron. As a reason, serum and salivary monitoring may be significant in detecting and diagnosing OSMF early on.

Spectrum-resolved photoelectrochemical molecularly imprinted sensors for simultaneous determination of ascorbic acid and uric acid in a differential mode

Herein, a spectrum-resolved differential strategy was proposed to enhance further the selectivity of photoelectrochemical (PEC) sensors, demonstrated by the simultaneous determinations of ascorbic acid (AA) and uric acid (UA). Molecularly imprinted polymer (MIP) membranes for AA (MIPAA) and UA (MIPUA) were fabricated on the surface of TiO2 nanotubes via electropolymerization, using pyrrole as functional monomer, AA and UA as templates, respectively. It was shown that the increase in absorbance from AA or UA within the MIP membranes resulted in an intense decrease in the photocurrent of the PEC sensors. In the spectrum-resolved differential mode, ΔRIAA= (IAA/IAA0−IUA/IUA0)310 and ΔRIUA= (IUA0/IUA −IAA0/IAA)275 were used in the simultaneous determinations of AA and UA, respectively. Where IAA, IAA0, IUA and IUA0 are the photocurrents of MIPAA and MIPUA in sample and blank, the subscripts of 275 and 310 stand for the excitation wavelength (nm), respectively. The interference levels in the differential mode were reduced by one order of magnitude compared with the normal MIP mode. The spectrum-resolved differential PEC MIP sensors were used in the simultaneous determination of AA and UA in serum and urine samples, with the detection limits of 0.019 and 0.036 μM, respectively.

Effect of the acidified extract of Moringa oleifera leaves as a supplement in the in vitro culture medium of sheep preantral follicles

This study was conducted to evaluate the effects of the acidified extract of M. oleifera leaves as a supplement into the base medium for in vitro culture of sheep isolated secondary follicles. Follicles were isolated and cultured for 12 days in α-MEM+(supplemented with bovine serum albumin, insulin, glutamine, hypoxanthine, transferrin, selenium, and ascorbic acid) with or without 0.1; 0.2 or 0.4 mg/ml of the acidified extract of M. oleifera. Follicle morphology, antral cavity formation, follicular and oocyte diameter, glutathione (GSH) concentration, mitochondrial activity and meiotic resumption were evaluated. After 12 days of culture, there was no significant difference among treatments in relation to follicular morphology, antral cavity formation, diameter and mitochondrial activity. Nevertheless, oocytes from follicles cultured in α-MEM+ showed greater GSH concentration than media containing M. oleifera extract. Furthermore, the concentration of 0.4 mg/ml M. oleifera extract significantly increased the percentage of fully grown oocyte (≥ 110 µm) when compared to the other treatments. In conclusion, the concentration of 0.4 mg/ml M. oleifera extract as a supplement of the culture medium, maintained the survival, and increased the percentage of fully grown oocytes.

Predictive model for vitamin C levels in hyperinsulinemic individuals based on age, sex, waist circumference, low-density lipoprotein, and immune-associated serum proteins

Vitamin C (ascorbic acid) is an important water-soluble antioxidant associated with decreased oxidative stress in type 2 diabetes (T2D) patients. A previous targeted plasma proteomic study has indicated that ascorbic acid is associated with markers of the immune system in healthy subjects. However, the association between the levels of ascorbic acid and blood biomarkers in subjects at risk of developing T2D is still unknown. Serum ascorbic acid was measured by ultra-performance liquid chromatography and serum proteins were quantified by untargeted liquid-chromatography mass spectrometry in 25 hyperinsulinemia subjects that were randomly assigned a high dairy intake diet or an adequate dairy intake diet for 6 weeks, then crossed-over after a 6-week washout period. Spearman correlation followed by gene ontology analyses were performed to identify biological pathways associated with ascorbic acid. Finally, machine learning analysis was performed to obtain a specific serum protein signature that could predict ascorbic acid levels. After adjustments for waist circumference, LDL, HDL, fasting insulin, fasting blood glucose, age, gender, and dairy intake; serum ascorbic acid correlated positively with different aspects of the immune system. Machine learning analysis indicated that a signature composed of 21 features that included 17 proteins (mainly from the immune system), age, sex, waist circumference, and LDL could predict serum ascorbic acid levels in hyperinsulinemia subjects. In conclusion, the result reveals a correlation as well as modulation between serum ascorbic acid levels and proteins that play vital roles in regulating different aspects of the immune response in individuals at risk of T2D. The development of a predictive signature for ascorbic acid will further help the assessment of ascorbic acid status in clinical settings.

Dual-spot ratiometric microfluidic paper-based analytical device for accuracy and precision improvement

Instrumental and environmental fluctuations are common sources of error in smartphone-based optical detection, significantly affecting the accuracy of analytical measurements. In this regard, spotting the sample and reference simultaneously and in close proximity compensates for the fluctuations. This “dual-spot” design is similar to the double-beam technique used in spectrophotometry, which reduces fluctuations in the results. The underlying hypothesis is that any instrumental and/or environmental factors influencing the color intensity in the detection zones will similarly impact the color intensity in the control zone under the same conditions. To test our design, a ratiometric microfluidic paper-based analytical device (μPAD), functionalized with a mixture of green-emissive carbon dots (CDs) and red-emissive ethidium bromide, was developed for the selective detection of ascorbic acid (AA). The green emission of the CDs is quenched by both AA and Fe3+; NaF was thus loaded onto the 3D connector as a masking agent to remove the interference effect of the Fe3+ ions. The color variations were monitored under a UV lamp, using a smartphone to capture the images, and the RGB intensities were processed using the Color Grab application. The proposed double-spot method greatly enhanced the analytical precision and accuracy of the device. A linear working range from 0 to 125 μM was obtained, and the limit of detection was 2.71 μM. The μPAD was successfully used for the detection of AA in human serum, with recoveries from 87.27 to 98.52 %.

N,Si co-doped GQDs: Facile green preparation and application in visual identifying dihydroxybenzene isomers and selective quantification of catechol, hydroquinone and antioxidants

A green economical procedure for preparing N,Si co-doped graphene quantum dots (N,Si-GQDs) using waste toners and ethylene diamine was reported, which not only minimizes waste and promotes recycling but also offers an alternative method for producing N,Si-GQDs. At a pH of 8.5, hydroquinone and catechol underwent oxidation in the presence of air, resulting in the formation of diquinones, specifically p-phenyldiquinone and o-phenyldiquinone. Resorcinol, on the other hand, was converted into monoquinone. The interaction between diquinones and N,Si-GQDs caused a linear fluorescence quenching effect when catechol and hydroquinone were present. However, this effect was minimal in the case of resorcinol. Furthermore, the antioxidants glutathione (GSH) and ascorbic acid (AA) were observed to disrupt the redox equilibrium of catechol and o-phenyldiquinone, leading to the activation of fluorescence. Conversely, hydroquinone and p-phenyldiquinone, due to the highly stable and symmetrical structure of p-phenyldiquinone, did not exhibit this fluorescence activation. Based on the described “Off-On” sensor system, it was possible to visually identify dihydroxybenzene isomers and selectively quantify catechol and hydroquinone in environmental samples, as well as GSH and AA in human serum. The method detection limits were 0.93, 1.35, 2.34, and 1.37 μM for catechol, hydroquinone, GSH, and AA, respectively. In conclusion, the presented procedure offers several advantages, including environmental friendliness, cost-effectiveness, and a means of recycling waste toners. It also demonstrates the successful synthesis of N,Si-GQDs, as well as the potential for their application in the “Off-On” sensor system for the detection and quantification of various analytes.

Carbon Nitride-Based Heterojunction Photoelectrodes with Modulable Charge-Transfer Pathways toward Selective Biosensing.

Photoelectrochemical (PEC) sensing enables the rapid, accurate, and highly sensitive detection of biologically important chemicals. However, achieving high selectivity without external biological elements remains a challenge because the PEC reactions inherently have poor selectivity. Herein, we report a strategy to address this problem by regulating the charge-transfer pathways using polymeric carbon nitride (pCN)-based heterojunction photoelectrodes. Interestingly, because of redox reactions at different semiconductor/electrolyte interfaces with specific charge-transfer pathways, each analyte demonstrated a unique combination of photocurrent-change polarity. Based on this principle, a pCN-based PEC sensor for the highly selective sensing of ascorbic acid in serum against typical interferences, such as dopamine, glutathione, epinephrine, and citric acid was successfully developed. This study sheds light on a general PEC sensing strategy with high selectivity without biorecognition units by engineering charge-transfer pathways in heterojunctions on photoelectrodes.

Dual-functional cellulase-mediated gold nanoclusters for ascorbic acid detection and fluorescence bacterial imaging.

Protein-protected metal nanomaterials are becoming the most promising fluorescent nanomaterials for biosensing, bioimaging, and therapeutic applications due to their obvious fluorescent molecular properties, favorable biocompatibility and excellent physicochemical properties. Herein, we pioneeringly prepared a cellulase protected fluorescent gold nanoclusters (Cel-Au NCs) exhibiting red fluorescence under the excitation wavelength of 560nm via a facile and green one-step method. Based on the fluorescence turn-off mechanism, the Cel-Au NCs were used as a biosensor for specificity determination of ascorbic acid (AA) at the emission of 680nm, which exhibited satisfactory linearity over the range of 10-400µM and the detection limit of 2.5µM. Further, the actual sample application of the Au NCs was successfully established by evaluating AA in serum with good recoveries of 98.76%-104.83%. Additionally, the bacteria, including gram-positive bacteria (Bacillus subtilis and Staphylococcus aureus) and gram-negative bacteria (Escherichia coli), were obviously stained by Cel-Au NCs with strong red emission. Thereby, as dual-functional nanoclusters, the prepared Cel-Au NCs have been proven to be an excellent fluorescent bioprobe for the detection of AA and bacterial labeling in medical diagnosis and human health maintenance.

Cu-MOF nanosheets modified nickel foam: A versatile platform for highly sensitive electrochemical detection of transferrin in simulated human blood serum

Transferrin (TRF) is a type of glycoprotein present in blood plasma that plays a vital role in facilitating the absorption, storage, and movement of iron(III) ions within the circulatory system of multiple vertebrates. Herein, we report one-pot solvothermal synthesis of Copper Metal-Organic Framework nanosheets modified nickel foam (Cu-MOF/NF) for electrochemical detection of transferrin (TRF) in simulated human blood serum. The crystal structure of the Cu-MOF nanosheets was determined through X-ray diffraction (XRD), while Raman spectroscopy and Fourier-transform infrared spectroscopy (FTIR) analysis were employed to investigate the vibrational modes and the presence of surface OH groups, respectively. The nanosheet morphology of the Cu-MOF was observed and characterized using scanning electron microscopy (SEM) micrographs.The as-fabricated Cu-MOF/NF exhibits a sensitivity of 1.36 mA/x (x = mg.mL−1cm−2) for a linear range of concentrations from 1 mg mL−1 – 100 mg mL−1 with a low limit of detection (LOD) of 0.81 mg mL−1. The sensor exhibited good selectivity for TRF, even in the presence of interfering ions such as bovine serum albumin, ascorbic acid, uric acid, and urea, with concentrations 100-fold higher than TRF. The porous nickel foam with high conductivity, offers numerous active sites and pathways for ion transport, as well as pathways for electron transport during electrochemical catalytic reactions. This performance of the sensor is attributed to Cu 2+/Cu+ redox couple at the octahedral sites of the Cu-MOF facilitating the electro-oxidation of TRF and charge-carrier delocalization during the catalytic reaction. The as-fabricated sensor is successful in the determination of trace level TRF concentration the human blood serum with excellent recovery percentages of 108.33% This proves Cu-MOF/NF as a promising platform for various electrochemical analytical applications.

Ascorbic acid is associated with favourable hormonal profiles among infertile males.

Infertility affects about 16% of North American couples, with the male factor contributing to ∼30% of cases. Reproductive hormones play an integral role in regulating the reproductive system and consequently, fertility. Oxidative stress reduces testosterone synthesis, and reduction in oxidative stress can improve hormone profiles. Ascorbic acid is a potent antioxidant that accounts for up to 65% of seminal antioxidant activity; however, its effects on reproductive hormones in humans are unknown. The objective was to determine the association between serum ascorbic acid concentrations and male reproductive hormones. We conducted a cross-sectional study involving infertile males (n = 302) recruited from Mount Sinai Hospital, Toronto. Serum was analyzed for ascorbic acid, luteinizing hormone (LH), follicular stimulating hormone (FSH), total testosterone (TT), prolactin and estradiol. Statistical analyses included Spearman's rank correlations, linear regressions, logistic regressions, simple slope and Johnson-Neyman procedures. After adjusting for covariates, ascorbic acid was inversely associated with LH (P = 0.01). Ascorbic acid was positively associated with TT only among males over the age of 41.6 years (P = 0.01). Our findings show that ascorbic acid is associated with higher testosterone levels and improved androgenic status in infertile males, and some of the effects appear to be age dependent.

Low Overpotential Amperometric Sensor Using Yb2O3.CuO@rGO Nanocomposite for Sensitive Detection of Ascorbic Acid in Real Samples.

The ultimate objective of this research work is to design a sensitive and selective electrochemical sensor for the efficient detection of ascorbic acid (AA), a vital antioxidant found in blood serum that may serve as a biomarker for oxidative stress. To achieve this, we utilized a novel Yb2O3.CuO@rGO nanocomposite (NC) as the active material to modify the glassy carbon working electrode (GCE). The structural properties and morphological characteristics of the Yb2O3.CuO@rGO NC were investigated using various techniques to ensure their suitability for the sensor. The resulting sensor electrode was able to detect a broad range of AA concentrations (0.5-1571 µM) in neutral phosphate buffer solution, with a high sensitivity of 0.4341 µAµM-1cm-2 and a reasonable detection limit of 0.062 µM. The sensor's great sensitivity and selectivity allowed it to accurately determine the levels of AA in human blood serum and commercial vitamin C tablets. It demonstrated high levels of reproducibility, repeatability, and stability, making it a reliable and robust sensor for the measurement of AA at low overpotential. Overall, the Yb2O3.CuO@rGO/GCE sensor showed great potential in detecting AA from real samples.

TO EVALUATE THE SERUM ASCORBIC ACID LEVELS IN FRESH MYOCARDIAL INFRACTION PATIENTS AND TO COMPARE THEM WITH NORMAL HEALTHY INDIVIDUALS

Objective: Decreased serum magnesium and ascorbic acid has been associated with increased risk of myocardial infarction (MI). The present study was planned to evaluate the status of ascorbic acid in patients suffering from MI and to compare them with normal healthy individuals. Methods: This retrospective study was conducted in the Department of Biochemistry in collaboration with the Department of Medicine, Government Medical College, Guru Nanak Dev Hospital, Amritsar. Fifty patients already diagnosed with MI, attending medicine OPD and IPD. Fifty healthy individuals with ages and sex-matched from the same population served as controls. Plasma acorbic acid levels and lipid profiles were also estimated. Result: In our study, we observed that the difference between the plasma ascorbic acid levels of normal individuals and the patient of MI was statistically highly significant (p&lt;0.001). It was also seen that the maximum number of subjects was found the age of 51–70 years in MI patients. Conclusion: Decreased plasma ascorbic acid levels may be one of the causes of MI, so its supplementation may delay MI and its complications.

Associations Between Dietary Vitamin C, Serum Ascorbic Acid, and GSTT1 Genotype and Premenstrual Symptoms

Objective Premenstrual symptoms are a cyclically occurring combination of adverse psychological and somatic symptoms that impact the quality of life for most females of childbearing age. Growing evidence suggests that diet may attenuate premenstrual symptoms; however, the relationship between vitamin C and premenstrual symptoms remains unclear. The aim of the research was to determine the association between different measures of vitamin C status and premenstrual symptoms. Method Females (n = 555) aged 20 to 29 years from the Toronto Nutrigenomics and Health Study completed a General Health and Lifestyle Questionnaire, capturing 15 premenstrual symptoms. Dietary intake was measured using a 196-item Toronto-modified Harvard food frequency questionnaire. Serum ascorbic acid concentrations were measured, and participants were categorized into deficient (<11 µmol/L), suboptimal (11–28 µmol/L), and adequate (>28 µmol/L) ascorbic acid levels. DNA was genotyped for the GSTT1 (Ins/Del) polymorphism. Using logistic regression, odds of experiencing premenstrual symptoms were compared between vitamin C intake levels above and below the recommended daily allowance (75 mg/d) between ascorbic acid levels and between GSTT1 genotypes. Results Increased vitamin C intake was associated with premenstrual appetite changes (OR, 1.65; 95% CI, 1.01–2.68). Compared to deficient ascorbic acid levels, suboptimal levels were associated with premenstrual appetite changes (OR, 2.59; 95% CI, 1.02–6.58) and bloating/swelling (OR, 3.00; 95% CI, 1.09–8.22). Adequate serum ascorbic acid levels were not associated with premenstrual appetite changes (OR, 1.69; 95% CI, 0.73–3.94) or bloating/swelling (OR, 1.92; 95% CI, 0.79–4.67). Those with the GSTT1 functional variant (Ins*Ins) had an increased risk of premenstrual bloating/swelling (OR, 1.96; 95% CI, 1.10–3.48); however, the interaction between vitamin C intake and GSTT1 was not significant for any premenstrual symptoms. Conclusions Our findings suggest that indicators of higher vitamin C status are associated with increased premenstrual appetite changes and bloating/swelling. The observed associations with GSTT1 genotype suggest that these observations are not likely due to reverse causation.