Electrochemical sensor based on Ni-exchanged natural zeolite/carbon black hybrid nanocomposite for determination of vitamin B6.

The utilization of environmentally friendly nanoporous natural zeolite exchanged with Ni2+ ions (NiZ) and conductive carbon black (CB) in the fabrication of a novel and selective voltammetric sensor of vitamin B6 (VB6) is presented. The used clinoptilolite-rich zeolite material and CB were characterized in terms of morphology and textural properties. The superior properties of Ni-zeolite/carbon black modified glassy carbon electrode (NiZCB-GCE), arising from the synergistic effect of combining the unique features of zeolite and conductive carbon black, were confirmed by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) measurements. In the determination of VB6 with the use of differential pulse voltammetry (DPV), the optimization of the pH value of supporting electrolyte and instrumental parameters, as well as the interference study were performed. Under optimized conditions, the oxidation peak current at the potential +0.72 V vs. Ag | AgCl | 3 M KCl reference electrode was linear to the VB6 concentration in the range 0.050 to 1.0 mg L-1 (0.30-5.9 µmol L-1) (R = 0.9993). The calculated limit of detection (LOD, S/N = 3), equal to 15 µg L-1 (0.09 µmol L-1), was much better compared to chemically modified electrodes with other carbon-based materials. The RSD for 0.5 mg L-1 was in the range 2.5-5.4% (n = 4). The developed NiZCB-GCE was successfully applied to the determination of VB6 in commercially available multivitamin dietary supplements, food, and water samples. The obtained recoveries ranged from 95 to 106%.

Effect of low-temperature storage on the content of folate, vitamin B6 , ascorbic acid, chlorogenic acid, tyrosine, and phenylalanine in potatoes.

BACKGROUND: Changes in the metabolite composition of potato tubers during low-temperature storage can affect their nutritional value, susceptibility to bruising, and processing qualities. Here, we measured changes in the amounts of folate, vitamin B6 , and vitamin C, and the blackspot pigment precursors chlorogenic acid and tyrosine, as well as phenylalanine, in five potato varieties stored at 7.8 °C for 8 months in 2015 and 2016. RESULTS: Folate content increased in all varieties in both years during low-temperature storage, with statistically significant changes occurring in six out of eight conditions. Increase rates ranged from 11% to 141%. Vitamin B6 content increased in all varieties during the storage period, but changes were statistically significant in only two out of eight conditions. Increase rates ranged from 5% to 24%. Ascorbic acid content decreased in all varieties in both years during the storage period. Decrease rates ranged from 16% to 78%, and were statistically significant in seven out of eight conditions. For chlorogenic acid, no consistent trend was observed. Changes varied between -14% and +14%, but none was statistically significant. Tyrosine content increased in all varieties in both years, except in Sage Russet in 2015. Increase rates ranged from 19% to 238% and were statistically significant in three out of seven conditions. Changes in phenylalanine content were very similar to those observed for tyrosine, with increases up to 272% in Teton Russet. CONCLUSIONS: These results show that storage at low temperature substantially affects tuber nutritional quality and biochemical bruising potential. © 2019 Society of Chemical Industry.

Comparison of GC-MS and MEKC methods for caffeine determination in preworkout supplements.

In this study, GC-MS- and MEKC-based methods for determination of caffeine (CAF) in preworkout supplements were developed and validated. The proposed protocols utilized minimal sample preparation (simple dilution and syringe filtration). The developed methods achieved satisfactory validation parameters, i.e. good linearity (R2 > 0.9988 and R2 > 0.9985 for GC-MS- and MEKC-based method, respectively), satisfactory intra- and interaccuracy (within 92.6-100.7% for method utilizing GC-MS and 92.1-110.3% for protocol based on MEKC) and precision (CV < 15.9% and CV < 6.3% for GC-MS- and MEKC-based method, respectively) and recovery (within 100.1-100.8% for method utilizing GC-MS and 101.5-106.2% for protocol based on MEKC). The LOD was 0.03 and 3 µg/mL for method utilizing GC-MS and MEKC, respectively. The CAF concentrations determined by GC-MS- and MEKC-based methods were found to be in the range of 8.53-11.23 and 8.20-11.61 µg/mL, respectively. Taking into consideration information on the labels, the investigated supplements were found to contain from 110.0 to 167.3% of the declared CAF content, which confirmed the literature reports on incompatibility of the declared product compositions with real ones. Nevertheless, the consumption of examined supplements as recommended by producers did not lead to exceeding the CAF safe limit of 400 mg per day. Additionally, the MEKC-based method allowed for detection and identification of vitamin B3 and B6 in all of the investigated supplement samples, which demonstrated that MEKC-based protocols may be an appropriate assays for simultaneous determination of CAF and vitamins.

Overexpression of PDX-II gene in potato (Solanum tuberosum L.) leads to the enhanced accumulation of vitamin B6 in tuber tissues and tolerance to abiotic stresses.

Vitamin B6 is a vital metabolite required for living organisms as a cofactor in several metabolic biochemical reactions and recognized as a potent antioxidant molecule which modulates the expression of the proteins responsible for the scavenging of cellular reactive oxygen species. It is well established that the microorganisms and plants can synthesize the B6 de novo, therefore, all the animals including humans must acquire it from the plant dietary resources. However, the bioavailability of the vitamin in the edible portions of the commonly consumed plants is insufficient to meet the daily recommended doses. Genetic engineering techniques have proven successful in increasing the vitamin B6 content in the model plants. Present study describe the development of transgenic potato (Solanum tuberosum L. cv. Kufri chipsona) overexpressing key vitamin B6 pathway gene, the PDXII (NCBI database Ref. ID- NM_125447.2) isolated from Arabidopsis thaliana under the control of CaMV 35S constitutive promoter. The stable integration and expression of transgene in the transgenic lines were confirmed by PCR, Southern blot and RT-PCR analysis. Transgenic tubers exhibited considerably improved vitamin B6 accumulation (up to 107-150%) in comparison to the untransformed controls potato. This increase in vitamin B6 was also correlated with the increased mRNA expression of PDXII gene. The prominent increase in the B6 content of transgenic potato was also associated with the capability to survive under abiotic stresses, therefore, the transgenic lines were able to withstand various abiotic stresses imposed by salinity (NaCl) or methyl viologen (MV). We thus demonstrated that overexpression of PDXII gene under the control of a constitutive promoter enhanced the accumulation of the vitamin B6 which also augmented the tolerance under various abiotic stresses in potato (Solanum tuberosum L.).

A novel electroanalytical approach to the measurement of B vitamins in food supplements based on screen-printed carbon sensors.

This paper describes the development of a novel electrochemical assay for the measurement of water-soluble vitamins in food and pharmaceutical products. The optimum conditions for the determination of vitamin B1 (thiamine), B2 (riboflavin) and B6 (pyridoxine) in phosphate buffer were established using cyclic voltammetry in conjunction with screen printed carbon electrodes (SPCEs). The optimum current response for all three vitamins was achieved in 0.1M phosphate buffer pH 11 using an initial potential of -1.0V. Using square wave voltammetry, the linear ranges for thiamine, riboflavin, and pyridoxine were found to be: 15-110µg/ml, 0.1-20µg/ml, and 2-80µg/ml respectively. The application of the method to a commercial food product yielded a recovery of 95.78% for riboflavin, with a coefficient of variation (CV) of 3.38% (n = 5). The method was also applied to a multi-vitamin supplement for the simultaneous determination of thiamine, riboflavin and pyridoxine. In both cases only simple dilution with buffer followed by centrifugation was required prior to analysis. The resulting square wave voltammetric signals were completely resolved with Ep values of -0.7V, +0.2V, and +0.6V respectively. The recoveries determined for the vitamin B complex in a commercial supplement product were found to be 110%, 114%, and 112% respectively (CV = 7.14%, 6.28%. 5.66% respectively, n = 5).

Gluten-Free Flours from Different Raw Materials as the Source of Vitamin B1, B2, B3 and B6.

Gluten-free (GF) products are those with a natural absence or acceptable level (<20 mg/kg) of gluten. They should be a part of a diet for people with gluten-related disorders, like celiac disease. Recently the popularity of a gluten-free diet (GFD) has risen extremely, because a lot of healthy individuals exclude gluten from their menus. According to the literature data on nutritional deficiencies in the GFD, this trend seems to be risky. This paper describes the nutritional value of 14 flours from different GF raw materials from the aspect of B-group vitamin content (B1, B2, B3, B6). Vitamins were determined using high performance liquid chromatography after enzymatic and acid hydrolysis of the samples. The vitamin contents significantly differed in the analysed flours. The content (in 100 g of the product) of vitamin B1 ranged from 0.01 mg (amaranth flour) to 0.60 mg (teff flour), vitamin B2 from 0.03 mg (GF flour with oats) to 0.22 mg (buckwheat flour), vitamin B3 from below 0.01 mg (amaranth flour) to 6.02 mg (millet flour), and vitamin B6 from 0.03 mg (acorn flour) to 0.69 mg (amaranth flour). The content of vitamins in the analysed GF flours was also compared to gluten-containing flours. Obtained results indicate that flours from teff, millet, chestnut, buckwheat, and amaranth are better sources of certain B-group vitamins than flours from corn, rice, and some flours with gluten.

SID tryptophan levels and B6 vitamin supplementation do not change blood parameters, organ weights, carcass traits, and meat quality of barrows (70-100kg).

This study evaluated the effects of standardized ileal digestible (SID) tryptophan and B6 on blood parameters, organ weights, carcass traits, and longissimus lumborum quality of barrows (70-100kg). Sixty-four crossbred barrows averaging 70.77±2.07kg were distributed in a 4×2 factorial with four SID tryptophan levels (0.130, 0.155, 0.180, and 0.205%) and two B6 levels (1 and 5mg/kg) in eight replicates of one animal each. The meat lightness degree answered linearly (P=0.015) to SID tryptophan levels and the shear force answered quadratically (P=0.050), with estimates of a higher value (31.67N) at 0.163% SID tryptophan. Although B6 showed positive effects (P<0.05) on hot and cold carcass yields and pH24, it resulted in a negative effect (P<0.05) on ham weight and yield, and increased the drip loss and cooking fluid. The dietary SID tryptophan requirement for barrows (70-100kg) was not higher than 0.130% (4.07g/day) and did not change due to B6.

B-Vitamin Levels in Human Milk among Different Lactation Stages and Areas in China.

To determine the contents of B-vitamins in human milk in China, we analyzed 1778 human milk samples from the sample bank of the National High Technique R & D Program (863 Projects) which was a cross-sectional survey and covered 6419 human milk samples from healthy lactating mothers who were at different stages of lactation (0-330 days postpartum) in 11 provinces of China. The contents of free forms of six B-vitamins in these human milk samples were analyzed by using UPLC-MS/MS. The median concentrations of free form of 6 B-vitamins in colostrums, transitional milk, 15-180 d mature milk and 181-330 d mature milk were respectively as follows: thiamin 5.0 µg/L, 6.7 µg/L, 21.1 µg/L and 40.7 µg/L; riboflavin 29.3 µg/L, 40.6 µg/L, 33.6 µg/L and 29.6 µg/L; niacin 470.7 µg/L, 661.3 µg/L, 687.0 µg/L and 571.3 µg/L; vitamin B-6 4.6 µg/L, 16.1 µg/L, 62.7 µg/L and 80.7 µg/L; flavin adenine dinucleotide (FAD) 808.7 µg/L, 1162.8 µg/L, 1023.9 µg/L and 1057.2 µg/L; pantothenic acid 1770.9 µg/L, 2626.8 µg/L, 2213.0 µg/L and 1895.5 µg/L. The contents of 6 B-vitamins varied significantly among the different lactation stages and different areas (coastal area vs inland area, rural area vs urban area). The present study indicated that the concentrations of B-vitamins in colostrum were generally much lower than those in transitional milk and mature milk. Further studies are warranted for their roles and significance on B-vitamins in colostrum in nutrition and metabolism of neonates.

A novel spectral resolution and simultaneous determination of multicomponent mixture of Vitamins B1, B6, B12, Benfotiamine and Diclofenac in tablets and capsules by derivative and MCR-ALS.

A novel method was developed for spectral resolution and further determination of five-component mixture including Vitamin B complex (B1, B6, B12 and Benfotiamine) along with the commonly co-formulated Diclofenac. The method is simple, sensitive, precise and could efficiently determine the five components by a complementary application of two different techniques. The first is univariate second derivative method that was successfully applied for determination of Vitamin B12. The second is Multivariate Curve Resolution using the Alternating Least Squares method (MCR-ALS) by which an efficient resolution and quantitation of the quaternary spectrally overlapped Vitamin B1, Vitamin B6, Benfotiamine and Diclofenac sodium were achieved. The effect of different constraints was studied and the correlation between the true spectra and the estimated spectral profiles were found to be 0.9998, 0.9983, 0.9993 and 0.9933 for B1, B6, Benfotiamine and Diclofenac, respectively. All components were successfully determined in tablets and capsules and the results were compared to HPLC methods and they were found to be statistically non-significant.

A randomised controlled trial of a preconceptional dietary intervention in women undergoing IVF treatment (PREPARE trial).

BACKGROUND: In vitro fertilisation (IVF) treatment provides an opportunity to study early developmental responses to periconceptional dietary interventions. Retrospective studies have suggested links between preconception diet and fertility, and more recently, a "Mediterranean" diet has been reported to increase pregnancy rates by up to 40%. In addition, a prospective study examining increased intake of omega-3 polyunsaturated fats demonstrated a quickened rate of embryo development after IVF. However, up to now, few prospective randomised controlled trials have investigated the impact of periconceptional dietary interventions on fertility outcomes. METHODS AND DESIGN: The study is a randomised controlled trial of a dietary intervention consisting of olive oil for cooking, an olive oil based spread, and a daily supplement drink enriched with Vitamin D (10 microgram daily) and marine omega-3 fatty acids (2 g daily) for 6 weeks preconception versus a control diet of sunflower seed oil for cooking, a sunflower oil based spread, and a daily supplement drink without added Vitamin D or marine omega-3 fatty acids. Couples undergoing IVF will be randomised to either the intervention or control group (55 in each arm). The primary endpoint is embryo developmental competency in vitro, measured by validated morphokinetic markers. Secondary outcomes will include the effect of the dietary intervention on the nutritional content of the intrauterine environment. DISCUSSION: This approach will enable rigorous examination of the impact of the dietary intervention on early embryo development, together with the influence of the peri-implantation intra-uterine nutritional environment. TRIAL REGISTRATION: ISRCTN50956936.

Presence and stability of B complex vitamins in bee pollen using different storage conditions.

This study has the objective of evaluating the stability of B complex vitamins and its vitamers, for a period of 1year of storage. The pollen samples were stored under room temperature (with and without light) and frozen. The vitamins were quantified by HPLC with fluorescence detection. All proposed vitamins were found in the samples and the dehydration process did not interfere in vitamin content. The variations were (dry basis): 0.59-1.09mg/100g (B(1)); 1.73-2.56 (B(2)); 6.43-15.34 (PP) and 0.33-0.68 (B(6)). After 1year of storage, it can be stated that vitamin B(1) concentration remained constant, while for the others, the concentration loss was dependent on time rather than on storage conditions. All samples were considered vitamin B(2) sources. The influence of the storage time in the concentrations of vitamin B(6) and PP was explained mathematically, through linear regression equations of multivariate analysis.

B vitamins in breast milk: relative importance of maternal status and intake, and effects on infant status and function.

Infants should be exclusively breastfed for the first 6 mo of life. However, maternal deficiency of some micronutrients, conveniently classified as Group I micronutrients during lactation, can result in low concentrations in breast milk and subsequent infant deficiency preventable by improving maternal status. This article uses thiamin, riboflavin, vitamin B-6, vitamin B-12, and choline as examples and reviews the evidence for risk of inadequate intakes by infants in the first 6 mo of life. Folate, a Group II micronutrient, is included for comparison. Information is presented on forms and concentrations in human milk, analytical methods, the basis of current recommended intakes for infants and lactating women, and effects of maternal supplementation. From reports of maternal and/or infant deficiency, concentrations in milk were noted as well as any consequences for infant function. These milk values were used to estimate the percent of recommended daily intake that infants fed by a deficient mother could obtain from her milk. Estimates were 60% for thiamin, 53% for riboflavin, 80% for vitamin B-6, 16% for vitamin B-12, and 56% for choline. Lack of data limits the accuracy and generalizability of these conclusions, but the overall picture that emerges is consistent across nutrients and points to an urgent need to improve the information available on breast milk quality.

Effects of dietary vitamin B6 supplementation on fillet fatty acid composition and fatty acid metabolism of rainbow trout fed vegetable oil based diets.

Fish oil replacement in aquaculture feeds results in major modifications to the fatty acid makeup of cultured fish. Therefore, in vivo fatty acid biosynthesis has been a topic of considerable research interest. Evidence suggests that pyridoxine (vitamin B(6)) plays a role in fatty acid metabolism, and in particular, the biosynthesis of LC-PUFA has been demonstrated in mammals. However, there is little information on the effects of dietary pyridoxine availability in fish fed diets lacking LC-PUFA. This study demonstrates a relationship between dietary pyridoxine supplementation and fatty acid metabolism in rainbow trout. In particular, the dietary pyridoxine level was shown to modulate and positively stimulate the activity of the fatty acid elongase and Δ-6 and Δ-5 desaturase enzymes, deduced by the whole-body fatty acid balance method. This activity was insufficient to compensate for a diet lacking in LC-PUFA but does highlight potential strategies to maximize this activity in cultured fish, especially when fish oil is replaced with vegetable oils.

Using a portable ion mobility spectrometer to screen dietary supplements for sibutramine.

In response to recent incidents of undeclared sibutramine, an appetite suppressant found in dietary supplements, we developed a method to detect sibutramine using hand-held ion mobility spectrometers with an analysis time of 15 s. Ion mobility spectrometry is a high-throughput and sensitive technique that has been used for illicit drug, explosive, volatile organic compound and chemical warfare detection. We evaluated a hand-held ion mobility spectrometer as a tool for the analysis of supplement extracts containing sibutramine. The overall instrumental limit of detection of five portable ion mobility spectrometers was 2 ng of sibutramine HCl. When sample extractions containing 30 ng/µl or greater of sibutramine were analyzed, saturation of the ionization chamber of the spectrometer occurred and the instrument required more than three cleaning cycles to remove the drug. Hence, supplement samples suspected of containing sibutramine should be prepared at concentrations of 2-20 ng/µl. To obtain this target concentration range for products containing unknown amounts of sibutramine, we provided a simple sample preparation procedure, allowing the U.S. Food and Drug Administration or other agencies to screen products using the portable ion mobility spectrometer.

Determination of individual vitamin B(6) compounds based on enzymatic conversion to 4-pyridoxolactone.

A determination method for individual natural vitamin B(6) compounds was developed. The vitamin B(6) compounds were specifically converted into 4-pyridoxolactone (PAL), a highly fluorescent compound, through a combination of enzymatic reactions and HCl-hydrolysis. PAL was then determined by HPLC. Pyridoxal was completely oxidized to PAL with pyridoxal 4-dehydrogenase (PLDH). Pyridoxine and pyridoxamine were totally converted into PAL through a coupling reaction involving pyridoxine 4-oxidase and PLDH, and one involving pyridoxamine-pyruvate aminotransferase and PLDH, respectively. The 5'-phosphate forms and pyridoxine-beta-glucoside were hydrolyzed with HCl, and then determined as their free forms. Pyridoxine 5'-phosphate and pyridoxine-beta-glucoside were not separately determined here. Three food samples were analyzed by this method.

Vitamin B6 status, deficiency and its consequences--an overview.

BACKGROUND: Vitamin B6 is thought to be a most versatile coenzyme that participates in more than 100 biochemical reactions. It is involved in amino acid and homocysteine metabolism, glucose and lipid metabolism, neurotransmitter production and DNA/RNA synthesis. Vitamin B6 can also be a modulator of gene expression. Nowadays, clinically evident vitamin B6 deficiency is not a common disorder, at least in the general population. Nevertheless, a subclinical, undiagnosed deficiency may be present in some subjects, particularly in the elderly. OBJECTIVE: This review gives a complete overview over the metabolism and interactions of vitamin B6. Further, we show which complications and deficiency symptoms can occur due to a lack of vitamin B6 and possibilities for public health and supplemental interventions. METHODS: The database Medline (www.ncvi.nlm.nih.gov) was searched for terms like "vitamin B6", "pyridoxal", "cancer", "homocysteine", etc. For a complete understanding, we included studies with early findings from the forties as well as recent results from 2006. These studies were summarised and compared in different chapters. RESULTS AND CONCLUSION: In fact, it has been proposed that suboptimal vitamin B6 status is associated with certain diseases that particularly afflict the elderly population: impaired cognitive function, Alzheimer's disease, cardiovascular disease, and different types of cancer. Some of these problems may be related to the elevated homocysteine concentrations associated to vitamin B6 deficiency, but there is also evidence for other mechanisms independent of homocysteine by which a suboptimal vitamin B6 status could increase the risk for these chronic diseases.

Effect of vitamin supplements on some aspects of performance, vitamin status, and semen quality in boars.

The aim of the present study was to determine the effects of dietary supplements of vitamins on vitamin status, libido, and semen characteristics in young boars under normal and intensive semen collection. Sixty Landrace, Yorkshire, and Duroc boars were allocated randomly from 6 to 10 mo of age to one of the following diets: 1) basal diet (industry level) for minerals and vitamins (Control, n = 15); 2) basal diet supplemented with vitamin C (ASC, n = 15); 3) basal diet supplemented with fat-soluble vitamins (FSV, n = 15); and 4) basal diet supplemented with water-soluble vitamins (WSV, n = 15). After puberty (approximately 12 mo of age), semen was collected at a regular frequency (three times every 2 wk) for 5 wk. Thereafter, all boars were intensively collected (daily during 2 wk). A recovery period (semen collection three times every 2 wk) followed and lasted for 10 wk. Sperm quality (percentage of motile cells and percentage of morphologically normal cells) and quantity (sperm concentration, semen volume, and total sperm number) were recorded as well as direct and hormone related measurements of boar libido. Blood and seminal plasma samples were taken to monitor vitamin status. High concentrations of B6 (P < 0.05) and folic acid (P < 0.05) were observed in the blood plasma of WSV boars, whereas greater concentrations of vitamin E (P < 0.01) were obtained in FSV boars. In the seminal plasma, folic acid concentrations tended to be greater in WSV boars (P < 0.08). During the intensive collection period, there was a tendency (P < 0.06) for semen production to be greater in WSV boars, the effect being less pronounced (P < 0.10) in FSV boars. During the recovery period, the percentage of motile sperm cells was greater in WSV boars (P < 0.03) and, to a lesser extent, in FSV boars (P < 0.10) compared with Control boars. Sperm morphology and libido were not affected by treatments. These results indicate that the transfer of vitamins from blood to seminal plasma is limited and the dietary supplements of water-soluble and fat-soluble vitamins may increase semen production during intensive semen collection.

Preconception folate and vitamin B(6) status and clinical spontaneous abortion in Chinese women.

OBJECTIVE: To assess the association between preconception homocysteine and B vitamin status and risk of clinical spontaneous abortion in women from Anqing, China. METHODS: All women were aged 21-34 years, had never smoked, and were primigravid. Patients (n = 49) were women with a clinically recognized pregnancy who experienced a fetal death before 100 days' gestation. Controls (n = 409) were women who maintained a pregnancy that ended in a live birth. Homocysteine, folate, and vitamins B(6) and B(12) concentrations were measured in plasma obtained before conception. RESULTS: Mean vitamin B(6) concentration was lower in patients than in controls (34.0 versus 37.9 nmol/L, P =.04). In addition, the risk of spontaneous abortion tended to increase with decreasing plasma vitamin B(6) and folate concentration (P for trend =.06 and.07, respectively), although the significance of these trends was further reduced in logistic models that included age, body mass index, and both vitamins. The risk of spontaneous abortion was four-fold higher among women with suboptimal plasma concentrations of both folate and vitamin B(6) (folate less than or equal to 8.4 nmol/L and vitamin B(6) less than or equal to 49 nmol/L) than in those with higher plasma concentrations of both vitamins (odds ratio 4.1, 95% confidence interval 1.2, 14.4). Homocysteine and vitamin B(12) status were not associated with spontaneous abortion risk. CONCLUSION: Suboptimal preconception folate and vitamin B(6) status, especially when they occur together, may increase the risk of clinical spontaneous abortion. Additional prospective studies are needed to confirm these findings and to determine whether antenatal B vitamin supplementation reduces spontaneous abortion risk.