Determination of Vitamin B3 Vitamer (Nicotinamide) and Vitamin B6 Vitamers in Human Hair Using LC-MS/MS

Water-soluble B vitamins participate in numerous crucial metabolic reactions and are critical for maintaining our health. Vitamin B deficiencies cause many different types of diseases, such as dementia, anaemia, cardiovascular disease, neural tube defects, Crohn’s disease, celiac disease, and HIV. Vitamin B3 deficiency is linked to pellagra and cancer, while niacin (or nicotinic acid) lowers low-density lipoprotein (LDL) and triglycerides in the blood and increases high-density lipoprotein (HDL). A highly sensitive and robust liquid chromatography–tandem mass spectroscopy (LC/MS-MS) method was developed to detect and quantify a vitamin B3 vitamer (nicotinamide) and vitamin B6 vitamers (pyridoxial 5′-phosphate (PLP), pyridoxal hydrochloride (PL), pyridoxamine dihydrochloride (PM), pridoxamine-5′-phosphate (PMP), and pyridoxine hydrochloride (PN)) in human hair samples of the UAE population. Forty students’ volunteers took part in the study and donated their hair samples. The analytes were extracted and then separated using a reversed-phase Poroshell EC-C18 column, eluted using two mobile phases, and quantified using LC/MS-MS system. The method was validated in human hair using parameters such as linearity, intra- and inter-day accuracy, and precision and recovery. The method was then used to detect vitamin B3 and B6 vitamers in the human hair samples. Of all the vitamin B3 and B6 vitamers tested, only nicotinamide was detected and quantified in human hair. Of the 40 samples analysed, 12 were in the range 100–200 pg/mg, 15 in the range 200–500 pg/mg, 9 in the range of 500–4000 pg/mg. The LC/MS-MS method is effective, sensitive, and robust for the detection of vitamin B3 and its vitamer nicotinamide in human hair samples. This developed hair test can be used in clinical examination to complement blood and urine tests for the long-term deficiency, detection, and quantification of nicotinamide.

Latent fingerprint residue detection method using Sagnac Fourier transform imaging spectroscopy

We propose a new method to detect latent fingerprints and their residues based on Sagnac ultraviolet Fourier transform imaging spectroscopy. The three-dimensional data cube including two-dimensional images and spectrum dimensions can be obtained by the new hyperspectral imaging technique. The method to inhibit the redundancy from the spectra-image data is also presented, which includes the self-adaptive differential filtering, the apodization algorithm, and a fast Fourier transform method. The whole process is also discussed in detail. Not only the latent fingerprint but also its residues' distribution are provided in experimental results, and the proposed method is demonstrated.

Rice plastidial NAD-dependent malate dehydrogenase 1 negatively regulates salt stress response by reducing the vitamin B6 content

Salinity is an important environmental factor that adversely impacts crop growth and productivity. Malate dehydrogenases (MDHs) catalyse the reversible interconversion of malate and oxaloacetate using NAD(H)/NADP(H) as a cofactor and regulate plant development and abiotic stress tolerance. Vitamin B6 functions as an essential cofactor in enzymatic reactions involved in numerous cellular processes. However, the role of plastidial MDH in rice (Oryza sativa) in salt stress response by altering vitamin B6 content remains unknown. In this study, we identified a new loss-of-function osmdh1 mutant displaying salt stress-tolerant phenotype. The OsMDH1 was expressed in different tissues of rice plants including leaf, leaf sheath, panicle, glume, bud, root and stem and was induced in the presence of NaCl. Transient expression of OsMDH1-GFP in rice protoplasts showed that OsMDH1 localizes to chloroplast. Transgenic rice plants overexpressing OsMDH1 (OsMDH1OX) displayed a salt stress-sensitive phenotype. Liquid chromatography-mass spectrometry (LC-MS) metabolic profiling revealed that the amount of pyridoxine was significantly reduced in OsMDH1OX lines compared with the NIP plants. Moreover, the pyridoxine content was higher in the osmdh1 mutant and lower in OsMDH1OX plants than in the NIP plants under the salt stress, indicating that OsMDH1 negatively regulates salt stress-induced pyridoxine accumulation. Furthermore, genome-wide RNA-sequencing (RNA-seq) analysis indicated that ectopic expression of OsMDH1 altered the expression level of genes encoding key enzymes of the vitamin B6 biosynthesis pathway, possibly reducing the level of pyridoxine. Together, our results establish a novel, negative regulatory role of OsMDH1 in salt stress tolerance by affecting vitamin B6 content of rice tissues.

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.

Spectroelectrochemical elucidation of B vitamins present in multivitamin complexes by EC-SERS

Raman spectroelectrochemistry based on electrochemical surface-enhanced Raman scattering (EC-SERS) effect is an interesting alternative to overcome the lack of sensitivity of normal Raman spectroscopy. Electrochemical activation of metallic screen-printed electrodes (SPEs) leads to the reproducible generation of nanostructures with excellent SERS properties. In that way, gold SPEs circumvent the traditional reproducibility limitation and produce the enhancement of the Raman intensity to favor the detection of low concentrations. Furthermore, fingerprint features of Raman spectroscopy make possible the dynamic spectroelectrochemical analysis of B vitamins. The accuracy assignments of Raman bands associated with B1, B2, B3, B6 and B12 vitamins present in multivitamin complexes provides valuable information, allowing us not only the detection of B vitamin present in mixtures, but also to understand the interaction between vitamins and metallic SERS surfaces.

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.).

Do dietary patterns determine levels of vitamin B6, folate, and vitamin B12 intake and corresponding biomarkers in European adolescents? The Healthy Lifestyle in Europe by Nutrition in Adolescence (HELENA) study

OBJECTIVES

To determine dietary patterns (DPs) and explain the highest variance of vitamin B6, folate, and B12 intake and related concentrations among European adolescents.

METHODS

A total of 2173 adolescents who participated in the Healthy Lifestyle in Europe by Nutrition in Adolescence study met the eligibility criteria for the vitamin B intake analysis (46% boys) and 586 adolescents for the biomarkers analysis (47% boys). Two non-consecutive, 24-h, dietary recalls were used to assess the mean intakes. Concentrations were measured by chromatography and immunoassay testing. A reduced rank regression was applied to elucidate the combined effect of food intake of vitamin B and related concentrations.

RESULTS

The identified DPs (one per vitamin B intake and biomarker and by sex) explained a variability between 34.2% and 23.7% of the vitamin B intake and between 17.2% and 7% of the biomarkers. In the reduced rank regression models, fish, eggs, cheese, whole milk and buttermilk intakes were loaded positively for vitamin B intake in both sexes; however, soft drinks and chocolate were loaded negatively. For the biomarkers, a higher variability was observed in the patterns in terms of food loads such as alcoholic drinks, sugars, and soft drinks. Some food items were loaded differently between intakes and biomarkers such as fish products, which was loaded positively for intakes but negatively for plasma folate in girls.

CONCLUSIONS

The identified DPs explained up to 34.2% and 17.2% of the variability of the vitamin B intake and plasma concentrations, respectively, in European adolescents. Further studies are needed to elucidate the factors that determine such patterns.

Maternal Exposure to Nitrogen Dioxide, Intake of Methyl Nutrients, and Congenital Heart Defects in Offspring

Nutrients that regulate methylation processes may modify susceptibility to the effects of air pollutants. Data from the National Birth Defects Prevention Study (United States, 1997-2006) were used to estimate associations between maternal exposure to nitrogen dioxide (NO2), dietary intake of methyl nutrients, and the odds of congenital heart defects in offspring. NO2 concentrations, a marker of traffic-related air pollution, averaged across postconception weeks 2-8, were assigned to 6,160 nondiabetic mothers of cases and controls using inverse distance-squared weighting of air monitors within 50 km of maternal residences. Intakes of choline, folate, methionine, and vitamins B6 and B12 were assessed using a food frequency questionnaire. Hierarchical regression models, which accounted for similarities across defects, were constructed, and relative excess risks due to interaction were calculated. Relative to women with the lowest NO2 exposure and high methionine intake, women with the highest NO2 exposure and lowest methionine intake had the greatest odds of offspring with a perimembranous ventricular septal defect (odds ratio = 3.23, 95% confidence interval: 1.74, 6.01; relative excess risk due to interaction = 2.15, 95% confidence interval: 0.39, 3.92). Considerable departure from additivity was not observed for other defects. These results provide modest evidence of interaction between nutrition and NO2 exposure during pregnancy.

Blood lead, cadmium and mercury in relation to homocysteine and C-reactive protein in women of reproductive age: a panel study

BACKGROUND

To examine the relationship between cadmium, lead, and mercury concentrations with high-sensitivity C-reactive protein (hs-CRP) and homocysteine in women.

METHODS

Metals were measured at enrollment in whole blood. Homocysteine and hs-CRP were measured in one (N = 9) or two (N = 250) menstrual cycles up to 3 and 8 times per cycle, respectively. Linear mixed models with inverse probability of exposure weights to account for time varying confounding were used and models were stratified by dietary and serum vitamin status (dietary: vitamin B₆, B₁₂, folate; serum: folate).

RESULTS

Geometric mean (95% confidence interval (CI)) concentrations for cadmium, lead, and mercury were 0.29 (0.26-0.31) μg/L, 0.91 (0.86-0.96) μg/dL, and 1.05 (0.93-1.18) μg/L, respectively. Lead was associated with increased homocysteine (0.08; 95% CI: 0.01, 0.15) and this persisted among those in the lower three quartiles of consumption of vitamin B₆, B₁₂, folate, and serum folate but was not significant among those in the upper quartile. No associations were observed between metals and hs-CRP.

CONCLUSIONS

Blood lead was associated with increased homocysteine in a cohort of healthy, premenopausal women but these associations did not persist among those consuming ≥75th percentile of essential micronutrients. Cadmium, lead, and mercury were not associated with hs-CRP concentrations.

Simultaneous Determination of Total Vitamins B1, B2, B3, and B6 in Infant Formula and Related Nutritionals by Enzymatic Digestion and LC-MS/MS: Single-Laboratory Validation, First Action 2015.14

This method provides simultaneous determination of total vitamins B1, B2, B3, and B6 in infant formula and related nutritionals (adult and infant). The method was given First Action for vitamins B1, B2, and B6, but not B3, during the AOAC Annual Meeting in September 2015. The method uses acid phosphatase to dephosphorylate the phosphorylated vitamin forms. It then measures thiamine (vitamin B1); riboflavin (vitamin B2); nicotinamide and nicotinic acid (vitamin B3); and pyridoxine, pyridoxal, and pyridoxamine (vitamin B6) from digested sample extract by liquid chromatography-tandem mass spectrometry. A single-laboratory validation was performed on 14 matrixes provided by the AOAC Stakeholder Panel on Infant Formula and Adult Nutritionals (SPIFAN) to demonstrate method effectiveness. The method met requirements of the AOAC SPIFAN Standard Method Performance Requirement for each of the three vitamins, including average over-spike recovery of 99.6 ± 3.5%, average repeatability of 1.5 ± 0.8% relative standard deviation, and average intermediate precision of 3.9 ± 1.3% relative standard deviation.

The influence of genetic and environmental factors on plasma homocysteine concentrations in a population at high risk for coronary artery disease

Background: Elevated plasma total homocysteine (tHcy) predisposes to vascular disease and results from interactions between genetic and nutritional factors. MTHFR C677T increases tHcy in association with low folate. CBS 844ins68 lowers tHcy and negates the raising effect of MTHFR C677T in healthy subjects, but it is unclear if this is the case in subjects at high risk of vascular disease. This study examines the effect on plasma tHcy of interactions between these polymorphisms in an at-risk group.

Methods: Blood samples were collected from 376 subjects at increased risk of coronary artery disease. Plasma tHcy and vitamin B6 were measured by HPLC and red cell folate and serum vitamin B12 were measured by immuno-luminometric assay. MTHFR C677T and CBS 844ins68 status was established by standard PCR techniques.

Results: MTHFR TT predisposed to hyperhomocysteinaemia; this was increased in the presence of low folate ( P<0.05) and vitamin B12 ( P<0.01). An inverse relationship was found between tHcy and folate ( r= -0.42, P<0.0001), vitamin B12 ( r= -0.26, P<0.0005) and vitamin B6 ( r= -0.25, P<0.01). There was no interaction between plasma tHcy, vitamins or MTHFR C677T and CBS 844ins68.

Discussion: In this population at high risk of coronary artery disease, plasma tHcy was determined by vitamin status. This was exacerbated by the MTHFR C677T mutation. CBS 844ins68 did not influence tHcy and did not negate the tHcy-raising effect of MTHFR C677T.

An aqueous friendly chemosensor derived from vitamin B₆ cofactor for colorimetric sensing of Cu²⁺ and fluorescent turn-off sensing of Fe³⁺

Chemosensor L derived from vitamin B6 cofactor pyridoxal-5-phosphate was investigated for the selective detection of Cu(2+) and Fe(3+) in aqueous medium. Sensor L formed a 1:1 complex with Cu(2+) and displays a perceptible color change from colorless to yellow brown with the appearance of a new charge transfer band at ~450 nm. In contrast, the fluorescence of L was quenched selectively in the presence of Fe(3+) without any interference from other metal ions including Cu(2+).

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.

Lower concentrations of B-vitamin subgroups in the serum and amniotic fluid correlate to cleft lip and palate appearance in the offspring of A/WySn mice

PURPOSE

The pathogenesis and prevention of cleft lip and palate (CL/P) have been studied mainly in clinical and animal experiments. A prophylactic poly-B-vitamin substitution during the first months of pregnancy has provided the most encouraging results for the prevention of CL/P recurrence in families at risk. In vitro studies of the palatal organ in an A/WySn mouse model have confirmed the positive influence of B-vitamins on palatal development. The present animal study was performed to analyze different B-vitamin concentrations in the serum and amniotic fluid of A/WySn mice according to the appearance of CL/P in their offspring.

MATERIAL AND METHODS

Concentrations of different B-vitamins (B1, B2, B3, B5, B6, and folic acid) in serum and amniotic fluid were analyzed by high-performance liquid chromatographic detection. Immunohistochemical staining against thiamin-1 receptor was performed on histologic midface sections of A/WySn fetuses with (n = 12) and without (n = 14) CL/P.

RESULTS

Vitamin B5 (P < .001) and folic acid (P < .004) concentrations in the amniotic fluid of dams with CL/P were significantly lower than in dams without CL/P. Serum concentrations of folic acid (P = .5) and B5 (P = .4) showed no difference between the 2 groups. Dams with CL/P had significantly lower thiamine concentrations in serum (P = .01) and amniotic fluid (P < .001). Histologic midface sections presented high thiamin-1 receptor expression in the palatal shelf of fetuses with CL/P.

CONCLUSION

A decreased use or uptake of some B-vitamin subgroups (B1, B5, and folic acid) in amniotic fluid and serum (vitamin B1) was correlated to an increased cleft appearance in A/WySn mice. The high thiamin-1 receptor expression in the palatal tissue of mouse fetuses with CL/P may be caused by a decreased availability of vitamin B1.

High-performance column liquid chromatographic method for the simultaneous determination of buclizine, tryptophan, pyridoxine, and cyanocobalamin in tablets and oral suspension

An HPLC method was developed and validated for the simultaneous determination of buclizine, tryptophan, pyridoxine, and cyanocobalamin in pharmaceutical formulations. The chromatographic separation was carried out on an RP-C18 column using a mobile phase gradient of methanol, 0.015 M phosphate buffer (pH 3.0), and 0.03 M phosphoric acid at a flow rate of 1.0 mL/min and UV detection at 230, 280, and 360 nm, respectively, for buclizine, tryptophan, pyridoxine, and cyanocobalamin. The method validation yielded good results with respect to linearity (r>0.999), specificity, precision, accuracy, and robustness. The RSD values for intraday and interday precision were below 1.82 and 0.63%, respectively, and recoveries ranged from 98.11 to 101.95%. The method was successfully applied for the QC analysis of buclizine, tryptophan, pyridoxine, and cyanocobalamin in tablets and oral suspension.

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.

Determination of vitamin B6 by means of differential spectrophotometry in pharmaceutical preparations in the presence of magnesium compounds

The content of pyridoxine hydrochloride in two-component pharmaceutical preparations containing various magnesium compounds was examined. The UV differentiation spectrophotometry was devised and compared with the reference method of high performance liquid chromatography (HPLC). The analysis of the absorbance spectra (A) and its first (D1) and second (D2) derivatives made it possible to establish the appropriate analytical wavelengths (A: 290 nm; D1: 302 nm; D2: 308 nm). It was proved that spectrum differentiation significantly corrects errors resulting from overlapping background especially when the magnesium hydroaspartate, lactate or magnesium lactogluconate is present together with vitamin B6.

Genotype and environment effects on the contents of vitamins B1, B2, B3, and B6 in wheat grain

The total contents of thiamine (vitamin B1), riboflavin (B2), and pyridoxine (B6) and the bioavailable forms of niacin (B3) were determined on wholemeal flours of 24 winter wheat varieties grown on four sites (United Kingdom, Poland, France, and Hungary) in 2007 and of two spring varieties grown on the same sites with the exception of Poland. The contents of vitamins B1 (5.53-13.55 μg/g dw), B2 (0.77-1.40 μg/g dw), and B6 (1.27-2.97 μg/g dw) were within the ranges reported previously, while the content of bioavailable vitamin B3 (0.16-1.74 μg/g dw) was about 10-15% of the total contents of vitamin B3 reported in previous studies. Strong correlations were observed between the contents of vitamins B1, B3, and B6, and partitioning of the variance in the contents of these three B vitamins showed that between 48 and 70% was accounted for by the environment. By contrast, the content of vitamin B2 was not correlated with the contents of other B vitamins, and 73% of the variance was ascribed to the error term, which suggests that this trait may be influenced by genotype × environment interactions. Whereas the contents of vitamins B1, B3, and B6 were correlated positively with the mean temperature from heading to harvest (r > 0.8), the content of vitamin B2 was positively correlated with precipitation during the 3 months prior to heading. These results are discussed in relation to the development of new wheat varieties with enhanced health benefits.

Study to evaluate the impact of heat treatment on water soluble vitamins in milk

OBJECTIVES

To evaluate the effect of domestic boiling practice on the contents of water soluble vitamins of loose milk and quantitative comparison of these vitamins in Ultra High Temperature (UHT) treated packaged milk with that of boiled loose milk.

METHODS

Loose milk samples were collected from various localities of Karachi city (Pakistan). These samples were boiled in simulated household conditions for 5, 10 and 15 minutes. Ultra High Temperature (UHT) treated packaged milk samples of various brands were obtained from the local market. The aliquots were analyzed for water-soluble vitamins using High Performance Liquid Chromatography (HPLC) technique. The mean values and standard deviations for data were computed and compared as well as level of variations were also determined.

RESULTS

Conventional boiling caused destruction of water soluble vitamins in milk i.e. vitamin 81 content in fresh milk decreased from 0.037 mg/100 g to 0.027 mg/100 g after 15 min boiling, whereas vitamin B2 from 0.115 to 0.084 mg/100 g, vitamin B3 0.062 to 0.044 mg/100 g, vitamin B6 0.025 to 0.019 mg/100 g and folic acid 3.38 to 2.40 microg/100 g. This accounted for a post-boiling decrease of about 27, 27, 29, 24 and 36% in vitamins B1, B2, B3, B6 and folic acid respectively. The values for vitamins B1, B2, B3, B6 and folic acid determined in boiled milk were significantly lower than UHT treated packaged milk samples by 25.9, 75.0, 54.5, 63.16 and 38.1% respectively.

CONCLUSION

Conventional boiling caused drastic reduction in vitamin levels of loose milk samples. In comparison to this, UHT milk retained high levels of water soluble B-vitamins. Thus it could be envisaged that UHT treated milk provides better water soluble vitamins' nourishment than conventionally boiled milk (JPMA 60:909; 2010).

Development and validation of PCR, PLS, and TLC densitometric methods for the simultaneous determination of vitamins B(1), B(6) AND B(12) in pharmaceutical formulations

This work represents the simultaneous determination of thiamine hydrochloride (B(1)), pyridoxine hydrochloride (B(6)) and cyanocobalamine (B(12)) by two different methods namely spectrophotometry multivariate calibration and densitometry. The spectrophotometric numerical method depends on the use of spectrophotometric data coupled to PLS and PCR multivariate calibration methods for the simultaneous determination of (B(1)) and (B(6)) in the presence of (B(12)) in laboratory prepared mixtures and commercial tablets. A calibration set was prepared, where the three vitamins were modeled using a full factorial 23 with three center points experimental design. This calibration set was used to build the PLS and PCR models. The models were validated by testing their predictive ability on a validation set where low RMSEP, RSEP % were obtained for both models. Figures of merit were determined using the net analyte signal concept. The proposed models were applied successfully to simultaneous determination of B1 and B6 in presence of a low concentration of B12 in pharmaceutical dosage forms that contain simple excipients. The TLC densitometric method was based on the use of a developing system of chloroform: ethanol: water: acetic acid solution (2: 8: 2: 0.5 v/v) to separate the three vitamins. The separated spots were scanned at 242nm, 291nm and 360nm for B(1), B(6) and B(12) respectively. The proposed method was applied successfully to simultaneous determination of the three vitamins in their pure powder form in the range 0.1-1.5 (µg/spot), 0.5-3.5 (µg/spot), 0.1-1.5 (µg/spot) for B(1), B(6), and B(12) respectively and in their pharmaceutical formulations.

Survey of vitamin B(6) content in commercial presentations of table olives

For nutritional purposes, a survey of the vitamin B(6) levels from a variety of commercial presentations of table olives was carried out, taking into account the three main processing types (Spanish-style, directly brined, and ripe olives). The analysis was performed by HPLC, following the official French method for vitamin B(6) determination in foodstuffs. In-house validation data for two commercial table olives showed that the method precision was good (coefficient of variation <6%) and recovery was quantitative (104% on average). There was a wide range of values for vitamin B(6) in table olives (0-69.3 microg/100 g edible portion). The highest mean content was found in directly brined olives (33.9 microg/100 g edible portion) followed by Spanish-style (14.4 microg/100 g) and ripe olives (4.3 microg/100 g). On average, samples of the Gordal and Carrasqueña cultivars showed the highest vitamin B(6) content in the case of Spanish-style olives, but in directly brined olives as well as in ripe olives the effect of cultivar was not statistically significant (p < 0.05).

Vitamin B6 status assessment in relation to dietary intake in high school students aged 16-18 years

The vitamin B6 status of high school students and its relationship with dietary intake were investigated in this cross-sectional study by face-to-face interview. A total of 157 healthy students aged 16-18 years (eighty-three boys and seventy-four girls) were randomly recruited from two out of nineteen senior high schools in Tainan, Taiwan. Vitamin B6 intakes were calculated from three 24-h dietary records. Direct and indirect vitamin B6 status indicators were measured in plasma, erythrocytes and urine. The anthropometric data, being similar to those of the first Nutrition and Health Survey in Taiwan (1993-1996), showed the normal growth and development of these students. All students except one girl (28.7 nmol/l) had plasma pyridoxal-5'-phosphate (PLP) levels >35 nmol/l, indicating an adequate vitamin B6 status. The mean dietary vitamin B6 intakes of boys and girls were 1.04 (sd 0.29) and 0.96 (sd 0.27) mg/d, respectively. Vitamin B6 status indicators, including plasma PLP, erythrocyte alanine aminotransferase activity coefficient (EALT-AC), aspartate aminotransferase activity coefficient (EAST-AC) and urinary 4-pyridoxic acid (4-PA), were correlated with vitamin B6 intake. Students with adequate values of plasma PLP (>35 nmol/l), EALT-AC ( < 1.25), EAST-AC ( < 1.8) and urinary 4-PA (>3.0 micromol/d) had median intakes of 1.08 and 1.01 mg/d, respectively, for boys and girls. This study suggests that vitamin B6 requirements for boys and girls aged 16-18 years were approximately 1.1 and 1.0 mg/d, respectively.

Photo-induced processes in vitamin B6 compounds

In this work, we applied multi-wavelength stopped-flow spectroscopy (MSFS) to study the chemical equilibria between tautomeric or hydrated forms of various vitamin B6 compounds and the Schiff base formed by epsilon-aminocaproic acid (= 6-aminohexanoic acid) with pyridoxal 5'-phosphate at 25 degrees and variable pH. Since some of these compounds are photosensitive, we analyzed the possible occurrence of any secondary photo-induced processes under the conditions of irradiation in the MSFS equipment (continuous irradiation with light from a 75-W Xe lamp spanning the wavelength range of 200-700 nm). To determine the tautomeric composition of these compounds, the electronic absorption spectra were analyzed by means of log-normal curves. Continuous irradiation of pyridoxamine and pyridoxal 5'-phosphate over the wavelength range of 200-700 nm displaces the chemical equilibrium between the tautomeric or hydrated forms of these compounds. However, the Schiff base of epsilon-aminocaproic acid with pyridoxal 5'-phosphate is insensitive to the radiation used. The photo-induced processes detected in pyridoxamine and pyridoxal 5'-phosphate should be taken into account in examining vitamers by MSFS. In fact, these additional processes should be considered in studying the mechanism of action of vitamin B6-dependent enzymes by the MSFS technique, whenever some free vitamer may be present in solution.

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.

[Distribution and relationships concentration of vitamins B6 and B12 in different parts of Atlantic salmons]

Fish constitute a major part of animal protein consumption in many countries of the world. Seafood are important source of a variety of nutrients, including vitamins B6 and B12. The concentration of vitamins B and B12 was determined in atlantic salmons obtained from commercial sources using a high-performance liquid chromatography (HPLC). In our study significant correlations (p<0.05, p<0.01 and p<0.001) for the concentration of vitamin B6 and cyanocobalamin between analyzed parts of atlantic salmons were observed.

[The real-time FOCSDT detection method and conditions for dissolution test of metronidazole and vitamin B6 tablets]

A method to monitor the dissolution rate of drug on-line fiber optic chemical sensor dissolution test(FOCSDT) was studied. Bifurcated optical fiber was used to connect the light source and detector, and the common end was dipped in the dissolution vessel. The dissolution process could be monitored through computer. The results show that the high, middle and low concentration group's recovery of metronidazole is 100.8%, 99.8% and 100.6%; and RSD is 2.5, 0.8 and 1.1 respectively, The high, middle and low Concentration group's recovery of vitamin B6 is 98.8%, 100.8% and 98.8%; and RSD is 4.1, 4.1 and 2.5 respectively. This process of analysis can test the whole process of drug and get dissolution graph. The study shows that this process analysis can reflect the real dissolution of drug and obtain the total information.

[Simultaneous synchronous spectrofluorimetric determination of vitamin B1, B2 and B6 by PARAFAC]

In the present study, a synchronous spectronfluorimetric method has been applied to the simultaneous determination of vitamin B1, B2 and B6. However, their spectra are overlapped so it is difficult to determine them individually. The parallel factor analysis (PARAFAC) was applied to the resolution of the overlapped spectra of mixtures of vitamin B1, B2 and B6. The delta wavelength range used was from 20 to 120 nm, and the excitation wavelength range was selected from 200 to 500 nm. From the measured fluorescence data a four-factor PARAFAC model was established, and was applied to the determination of a set of synthetic validation samples and some commercial samples with satisfactory results. This work shows that PARAFAC method is a powerful chemometric tool to the determination of mixtures of vitamin Bl, B2 and B6.

[Simultaneous determination of water-soluble vitamins C, B1, B2 and B6 in almonds by high performance liquid chromatography]

A method has been developed for the simultaneous determination of four water-soluble vitamins C, B1, B2 and B6 in almond by high performance liquid chromatography. The contents of vitamins C, B1, B2 and B6 in almonds in Pucheng County, Shaanxi Province were determined under optimized conditions as follows. In the first step, the sample was prepared by acid hydrolysis. In the second step, the separation was performed on an Inertsil ODS-3 column (25 cm x 4.6 mm i. d. , 5.0 microm) with a mobile phase of 0.05 mol/L KH2PO4 (pH 6.0)-methanol (70: 30, v/v) and a detection wavelength at 265 nm. The linear ranges of four vitamins were within 5.0 - 50.0 mg/L (r = 0. 999 0 - 0. 999 7). At the spike level ranged between 5.0 - 20.0 mg/kg, the average recoveries of the four vitamins in the Pucheng almond ranged from 91.77% to 99.30% with relative standard deviations between 0.31% and 1.98%. For vitamins B2 and B1, the contents were found to be 4.27 - 4.53 mg/kg and 0.799 - 0.838 mg/kg, respectively, while vitamins C and B6 were not discovered in Pucheng almonds. The method is simple, rapid, reproducible and accurate.

Validation of a screening method for the simultaneous identification of fat-soluble and water-soluble vitamins (A, E, B1, B2 and B6) in an aqueous micellar medium of hexadecyltrimethylammonium chloride

Simultaneous determination of the fat-soluble vitamins A and E and the water-soluble vitamins B1, B2 and B6 has been carried using a screening method from fluorescence contour graphs. These graphs show different colour zones in relation to the fluorescence intensity measured for the pair of excitation/emission wavelengths. The identification of the corresponding excitation/emission wavelength zones allows the detection of different vitamins in an aqueous medium regardless of the fat or water solubility of each vitamin, owing to the presence of a surfactant which forms micelles in water at the used concentration (over the critical micelle concentration). The micelles dissolve very water insoluble compounds, such as fat-soluble vitamins, inside the aggregates. This approach avoids the use of organic solvents in determining these vitamins and offers the possibility of analysing fat- and water-soluble vitamins simultaneously. The method has been validated in terms of detection limit, cut-off limit, sensitivity, number of false positives, number of false negatives and uncertainty range. The detection limit is about microg L(-1). The screening method was applied to different samples such as pharmaceuticals, juices and isotonic drinks.

Simultaneous determination of vitamins C, B6 and PP in pharmaceutics using differential pulse voltammetry with a glassy carbon electrode and multivariate calibration tools

In this work, the artificial neural networks (ANN) and partial least squares (PLS) were applied to data obtained by differential pulse voltammetry for the determination of vitamins in synthetic and pharmaceutical samples. For calibration purposes, both synthetic and commercial samples were employed as standards. From the results it was possible to verify that ANN is the best method for modeling the data due to the fact that interactions among electro-active components result in non-linear response on the glassy carbon electrode. The results achieved for the determination of vitamins in pharmaceutical samples using ANN method provided a maximum value for relative error of 0.40% for VC, 8.3% for VPP and 9.1% for VB6. The proposed methodology is simple, rapid and can be easily used to control quality laboratories as an alternative analysis method.

Direct determination of diclofenac in pharmaceutical formulations containing B vitamins by using UV spectrophotometry and partial least squares regression

This work proposes a simple and rapid analytical procedure for determination of diclofenac (DCF) in the presence of B vitamins, based on UV measurements and partial least squares (PLS). The interference of thiamine (THI) and pyridoxine (PYR) were modelled using an experimental design constructed in the ranges of 10-50 micromoll(-1) for DCF and THI and 15-75 micromoll(-1) for PYR. The procedure was repeated at five different pH values (between 3 and 6) and the best results were observed at pH 5, presenting a root mean square error of prediction (RMSEP) of 0.80 micromoll(-1) for DCF. The procedure was successfully applied to simultaneous determination of DCF, THI and PYR in synthetic mixtures and in a pharmaceutical formulation that contains a simple excipient (lactose). For determination of a more complex formulation that contains 15 different substances in the excipient, including some UV absorbing ones, the procedure was only able to determine DCF, since the excipient interferences disturbed THI and PYR predictions. Figures of merit, such as selectivity, analytical sensitivity, limit of detection and precision were determined for the DCF prediction model and the determinations were verified by an independent method, HPLC.

Voltammetric determination of pyridoxine (Vitamin B6) by use of a chemically-modified glassy carbon electrode

A novel carbon nanotube-modified glassy carbon electrode was described for the direct determination of pyridoxine. The electrochemical behavior of pyridoxine was investigated, and a well-defined oxidation peak with high sensitivity was observed at the modified electrode. Owing to the unique structure and extraordinary properties of multi-wall carbon nanotube (MWNT), the MWNT-modified glassy carbon electrode shows obvious electrocatalytic activity to the oxidation of pyridoxine, since it greatly enhances the oxidation peak current of pyridoxine as well as lowers its oxidation overpotential. Based on this, a very sensitive and simple voltammetric method was developed for the measurement of pyridoxine. A sensitive linear voltammetric response for pyridoxine was obtained in the concentration range of 5 x 10(-7)-1 x 10(-4)mol/L, and the detection limit is 2 x 10(-7)mol/L using differential pulse voltammetry. Compared with other voltammetric methods, this proposed method possesses many advantages such as very low detection limit, fast response, low cost and simplicity. The practical application of this new analytical method was demonstrated with pyridoxine drugs.

Evaluation of vitamin B6 status and RDA in young Koreans

AIMS AND METHODS

The vitamin B6 status of 294 healthy young Koreans (149 men, 145 women), aged 17-25 years, was estimated to establish the Korean Recommended Dietary Allowance (RDA) for vitamin B6. The dietary vitamin B6 intake was estimated based on a three-day recall method.

RESULTS

The average daily vitamin B6 intake of the subjects was 1.504 +/- 0.825 mg/day (1.567 +/- 0.968 mg/day for men and 1.439 +/- 0.644 mg/day for women). The average ratio of vitamin B6 intake to daily protein intake was 0.019 +/- 0.001 mg/g (0.015 +/- 0.001 mg/g for men and 0.023 +/- 0.001 mg/g for women). Foods from animal and plant sources provided 35.68 +/- 16.16 and 64.18 +/- 16.29% of total vitamin B6. Plasma pyridoxal 5'-phosphate (PLP) concentration of the subjects was 29.26 +/- 16.84 nmol/l (30.52 +/- 20.18 nmol/l for men and 28.21 +/- 13.28 nmol/l for women). The vitamin B6 intake of the subjects whose PLP concentration was >30 nmol/l was 0.019 +/- 0.001 mg vitamin B6/g protein intake (0.017 +/- 0.001 and 0.023 +/- 0.001 mg vitamin B6/g protein intake for men and women, respectively). The intake of vitamin B6 was significantly (p < 0.01-p < 0.001) positively correlated with the intake of all other nutrients. However, no significant correlation was found between PLP concentration and all nutrients examined.

CONCLUSION

Our suggested adequate Korean RDA for vitamin B6 in young Koreans is 1.6 mg/day or 0.02 mg/g of protein intake in men and 1.5 mg/day or 0.02 mg/g of protein intake in women.

Biosynthesis of vitamin B6: direct identification of the product of the PdxA-catalyzed oxidation of 4-hydroxy-l-threonine-4-phosphate using electrospray ionization mass spectrometry

PdxA (E.C. 1.1.1.262) catalyzes a key step in the biosynthesis of vitamin B(6): the nicotinamide-dependent oxidation of 4-hydroxy-l-threonine-4-phosphate (HTP) to a product tentatively identified as 3-amino-1-hydroxyacetone 1-phosphate (AHAP). To date, the evidence for the formation of AHAP, while self-consistent, has been largely circumstantial, and does not exclude the possibility that the actual product of the enzyme-catalyzed oxidation of HTP might be 2-amino-3-oxo-4-hydroxybutyric acid 4-phosphate which could undergo rapid, non-enzyme-catalyzed decarboxylation once released from the protein. Use of negative ion electrospray ionization mass spectrometry (ESI-MS) and tandem mass spectrometric analysis (MS-MS) confirms that AHAP is the product of the PdxA-catalyzed reaction.

Determination of Vitamin B6 in pharmaceutical formulations by flow injection-solid phase spectrophotometry

In this work, a new solid phase spectrophotometric method in association with flow injection analysis for Vitamin B6 (pyridoxine) determination has been developed with direct measurement of light-absorption in C18 material. In the developed method, successive passage of the complex, previously formed in the flowing stream, and eluent through the flow cell and continuous monitoring of the process provided the analytical information needed to determine pyridoxine. Pharmaceutical samples containing Vitamin B6 were previously dissolved in 0.1 mol l(-1) phosphate buffer solution (pH 7.5) and a sample volume of 235 microl was injected directly into carrier stream consisting of a mixture of methanol and 0.1 mol l(-1) phosphate buffer solution adjusted to pH 7.0 (1+1, v/v). The blue indophenol dye produced from the reaction between pyridoxine and N,N-diethyl-p-phenylenediamine after oxidation by potassium hexacyanoferrate(III) was quantitatively retained on C18 support and the spectrophotometric detection was performed simultaneously at 633 nm. The retained complex was quickly eluted from C18 material with the eluent stream consisting of a mixture of methanol and 0.01 mol l(-1) HCl (6+4, v/v). The results showed that the proposed method is simple, rapid and the analytical response is linear in the concentration range of 0.5-10 and 0.2-4 mg l(-1) using 235 and 860 microl of sample, respectively. The limits of detection are 0.15 and 0.060 mg l(-1) and the R.S.D. are 3.6% (at 2 mg l(-1) level) and 4.0% (at 1 mg l(-1) level) using sample volume of 235 and 860 microl, respectively. The system presented an analytical throughput of 15 determinations per hour when a sample volume of 235 microl was utilized. The procedure was successfully applied to the determination of Vitamin B6 in pharmaceutical formulations containing vitamins of B group and others active principles such as Vitamin C and minerals.

Effect of vitamin supplements on some aspects of performance, vitamin status, and semen quality in boars12

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.

Potentiometric membrane sensors for the selective determination of pyridoxine hydrochloride (vitamin B6) in some pharmaceutical formulations

The construction and general performance characteristics of two novel potentiometric PVC membrane sensors responsive to the pyridoxine hydrochloride known as vitamin B6 (VB6) are described. These sensors are based on the use of the ion-association complexes of the pyridoxine cation with phosphomolybdate, and phosphotungstate counter anions as ion pair in a plasticized PVC matrix. The electrodes show a stable, near-Nernstian response for 6x10(-5)-1x10(-2) M VB6 at 25 degrees C over the pH range 2-4 with a cationic slope of 54.0+/-0.5 and 54.5+/-0.4 per concentration decade for pyridoxine-phosphomolybdate and pyridoxine-phosphotungstate respectively. The two electrodes have the same lower detection limit (4x10(-5) M) and the response times are 45-60 and 30-45 s in the same order for both. Selectivity coefficients for VB6 relative to a number of interfering substances were investigated. There is negligible interference from many cations, some vitamins and pharmaceutical excipients. Direct potentiometric determination of 15-2000 microg/ml pyridoxine shows an average recovery of 98.0% and 99.0% with relative standard deviation 1.5% and 1.2% at 100.0 microg/ml for pyridoxine-phosphomolybdate and pyridoxine-phosphotungstate electrodes, respectively. The determination of VB6 in some pharmaceutical preparations using the proposed electrodes gave an average recovery of 98.0 and 99.0% of the nominal value and a mean standard deviation of 1.1% and 0.9% (n=10) for pyridoxine-phosphomolybdate and pyridoxine-phosphotungstate electrodes, respectively. The results compare favorably with data obtained by the British Pharmacopoeia method.

[Application of artificial neural network to simultaneous spectrofluorimetric determination of vitamin B1, B2 and B6]

By means of artificial neural network and Levenberg-Marquardt back-propagation training algorithm, the three components of vitamin B1, B2, B6 were determined simultaneously, in which the spectra overlapped. In the range of 390-520 nm, the fluorescence intensities at 15 wavelengths were taken as a character of the artificial neural network, and samples were arranged by the method of equality design. The mean recoveries of vitamin B1, vitamin B2, and vitamin B6 were 99.86%, 99.60% and 99.49% respectively. The RSDs of the results were 1.7%, 1.6%, and 1.7%.

Chemometrics assisted spectroscopic determination of vitamin B6, vitamin B12 and dexamethasone in injectables

A spectrophotometric method is described and applied to resolve ternary mixtures of the corticosteroid dexamethasone sodium phosphate and the vitamins B6 and B12. It involves multivariate calibration based on partial least-squares regression. The model was built with UV-vis absorption spectra, and was evaluated by cross-validation on a number of synthetic mixtures. Satisfactory results for both artificial and commercial samples were obtained. A spectrofluorometric method was also developed for the determination of B6 in the presence of vitamin B12 and dexamethasone. The results provided by both methods for pharmaceutical formulations were compared successfully. None of the described procedures require sample pre-treatment steps.

Gene-gene interaction between the cystathionine beta-synthase 31 base pair variable number of tandem repeats and the methylenetetrahydrofolate reductase 677C > T polymorphism on homocysteine levels and risk for neural tube defects

INTRODUCTION

Most studies showed that mothers of children with NTD have elevated homocysteine levels pointing to a disturbed homocysteine metabolism as a risk factor for NTD. Folate lowers homocysteine levels by remethylation of homocysteine to methionine. Homocysteine can be irreversibly converted to cystathionine by the vitamin B6-dependent enzyme CBS. Recently, our group showed that a 31 bp VNTR in the CBS gene was associated with decreased CBS activity and increased tHcy levels after methionine loading in a CVD population.

AIM

The aim of our study was to investigate whether this VNTR influences tHcy levels and risk for NTD. In addition, we assessed the role of vitamin B6 as an effect modifier in this possible interaction. We examined possible gene-gene interaction with the MTHFR 677C > T polymorphism. We screened genomic DNA of 88 NBD patients, 100 mothers, 88 fathers, and 505 controls for this CBS 31 bp VNTR.

RESULTS

In this study population five different alleles with 16,17, 18, 19, and 21 times the 31 bp repeat were observed that constituted 10 different genotypes. The most common 18/18 VNTR genotype was associated with higher tHcy levels compared with the 17/18 and 18/19 VNTR genotypes. Vitamin B6 levels did not influence this association. In addition, no association with risk for NTD was found. Combination of the CBS VNTR with the MTHFR 677C > T polymorphism revealed an additional increase in homocysteine levels in 18-18 individuals compared with 17-18 peers within subjects homozygous mutant for the MTHFR 677C > T polymorphism.

CONCLUSIONS

The present study indicates that the number of 31 bp repeat elements in the CBS gene influences tHcy levels. This VNTR seems not to be associated with an increased risk for NTD.

An optimized method for the simultaneous determination of vitamins B1, B6, B12 in multivitamin tablets by high performance liquid chromatography

A simple, precise, rapid and selective HPLC-RP method has been developed for the simultaneous determination of thiamine hydrochloride (B(1)) 150 mg, pyridoxine hydrochloride (B(6)) 150 mg, and hydroxocobalamine chloride (B(12)) 0.150 mg in multivitamin tablets. The method uses a Hypersil-BDS C(18) reversed phase column and gradient elution. The aqueous mobile phase contained 0.015% triethylamine adjusted to pH 2.7 with 1 N sulfuric acid and acetonitrile. Separation and quantitation was achieved by changing the proportion of the system linearly with a time-schedule programme. Detection was carried out using a dual-beam UV detector set at 280, 350 nm. Good linearity was observed between the concentration of the analytes and peak area (r=0.9999, 0.9998). Sample preparation was relatively simple whereas excipients present in the dosage forms did not interfere with the peaks of interest. Recovery of the compound from the B(1), B(6), B(12) was quantitative.

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.

Availability of vitamin B6 from different food sources

The present study was conducted to investigate the precaecal digestibility of vitamin B6 from selected food sources including eggs, bananas, white cabbage, corn, milk powder, fish, barley, soybeans, brown rice, wheat bran, brewer's yeast, rye and soybean meal. These foods were chosen for their relevance in human and animal nutrition and prepared as they are usually eaten by humans. As confirmed by further investigations the precaecal digestibility is a valuable measure for determining the availability of native B-vitamins. Therefore, pigs were fitted with an end-to-end ileo-rectal anastomosis for digesta passing straight from ileum to rectum, thus avoiding endogenous vitamin synthesis by the colon. Three weeks after surgery the digestibility experiments were carried out during which the animals were fed various experimental diets for a period of 12 days and digesta were collected quantitatively twice a day during the final 5 days of this period. The concentration of vitamin B6 in foods and chyme was determined by high pressure liquid chromatography. Precaecal digestibility of vitamin B6 from all tested food sources ranged from 51 to 91% in the following order: cabbage diet > banana diet > fish diet > milk powder diet > brewer's yeast diet > soybeans diet > soybean meal diet > egg diet/corn diet > barley diet > wheat bran diet > rye diet. Only boiled brown rice had a very low vitamin B6 availability of 16%. The digestibility of vitamin B6 from plant products (excluding the rice) was on average 10% lower when compared with animal products (71 versus 79%).

Liquid chromatographic analysis of vitamin B6 in soy-based infant formula

A liquid chromatographic (LC) method is described for determination of total vitamin B6 in soy-based infant formula. Total vitamin B6 is quantitated by using ion-pair LC after precolumn transformation of phosphorylated and free vitamers into pyridoxol. The limit of detection is 0.3 ng and the limit of quantitation is 1.0 ng on-column (injection volume = 100 microL). Linear response ranged from 39 to 616 ng/mL (r2 = 0.99986). Analysis of a soy-based infant formula control fortified at 6 different concentration levels gave recoveries that averaged 104%. Assay of SRM 1846 gave results within the certified range (8.6 +/- 0.086 mg/kg versus the certified value of 8.4 +/- 1.0 mg/kg). The method provides a rapid and specific assay for the analysis of total vitamin B6 in fortified soy-based infant formula.

[Simultaneous determination of metronidazolum and vitamin B6 by the derivative spectrophotometry]

A new method for simultaneous determination of metronidazolum and vitamin B6 was established by the third derivative spectrophotometry in 0.1 mol/L HCl solution. The detection limits were 0.81 microg/mL for metronidazolum and 0.16 microg/mL for vitamin B6. The linear range of determination was 1.6-22.4 microg/mL for both metronidazolum and vitamin B6. This method has been applied to the determination of metronidazolum and vitamin B6 in tabellae metronidazoli compositae with satisfactory results. The coefficients of variation are below 2.26 and 2.65% and the recoveries are 93-102% and 99-101% for metronidazolum and vitamin 6, respectively.

[Preliminary study on separation of three vitamins by capillary zone electrophoresis and micellar electrokinetic chromatography with amperometric electrochemical detection]

In this paper, separation of water soluble vitamins C (VC), B1 (VB1) and B6 (VB6) has been studied preliminarily by capillary zone electrophoresis (CZE) and micellar electrokinetic capillary chromatography (MECC) with a home-made amperometric electrochemical detector at the working electrode [carbon fiber (5 microm o.d.)] potential of 510-540 mV (vs. SCE). It has been shown that each of the three vitamins has more than one peak in NH3-NH4Cl (pH 9.0) which were mainly caused by the decomposition products in weak base medium and by heat except those from impurities. The electrochemical detector has better performance for the three vitamins from CZE and MECC. They can be separated either by CZE or by MECC. The separation by CZE is better than that by MECC with sodium dodecyl sulfate (SDS). SDS and buffer acidity can influence the retention time, peak sequence and height. The separation efficiency of CZE in 0.01 mol/L NH3-NH4Cl was 468 800 theoretical plates for VC.