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PubMed2006

Evolution of vitamin B2 biosynthesis: 6,7-dimethyl-8-ribityllumazine synthases of Brucella.

The penultimate step in the biosynthesis of riboflavin (vitamin B2) involves the condensation of 3,4-dihydroxy-2-butanone 4-phosphate with 5-amino-6-ribitylamino-2,4(1H,3H)-pyrimidinedione, which is catalyzed by 6,7-dimethyl-8-ribityllumazine synthase (lumazine synthase). Pathogenic Brucella species adapted to an intracellular lifestyle have two genes involved in riboflavin synthesis, ribH1 and ribH2, which are located on different chromosomes. The ribH2 gene was shown previously to specify a lumazine synthase (type II lumazine synthase) with an unusual decameric structure and a very high Km for 3,4-dihydroxy-2-butanone 4-phosphate. Moreover, the protein was found to be an immunodominant Brucella antigen and was able to generate strong humoral as well as cellular immunity against Brucella abortus in mice. We have now cloned and expressed the ribH1 gene, which is located inside a small riboflavin operon, together with two other putative riboflavin biosynthesis genes and the nusB gene, specifying an antitermination factor. The RibH1 protein (type I lumazine synthase) is a homopentamer catalyzing the formation of 6,7-dimethyl-8-ribityllumazine at a rate of 18 nmol mg(-1) min(-1). Sequence comparison of lumazine synthases from archaea, bacteria, plants, and fungi suggests a family of proteins comprising archaeal lumazine and riboflavin synthases, type I lumazine synthases, and the eubacterial type II lumazine synthases.

Amino Acid Sequence↗
PubMed2006

[Status of vitamin A, vitamin B2, iron and an-oxidantive activity in anemic pregnant women in China].

OBJECTIVE: To investigate the status of vitamin A(VA), vitamin B2 (VB2), iron and anoxidative function in anemic and non-anemic pregnant women. METHODS: 426 anemic and 36 non-anemic pregnant women were included in the study. The survey of 24-hour's diet recall of pregnant women was made to evaluate intake of iron, VB2, folic acid, etc by the nutrition software provided by Beijing 301 hospital, iron and VA were measured by Radioimmunoassay (RIA) and by high-pressure liquid chromatography. VB2 status was detected using the assay for erythrocyte glutathione reductase (Egr; EC 1.6.4.2) activity. SOD and GSH-Px activities and MDA were determined using commercial kits. Peripheral blood erythrocyte membrane fluidity was detected by using 1,6-diphenyl-1,3,5-hexatriene as a probe, the degree of fluorescence polarization (P) at 25 degrees C of disrupted cells plasma membranes were compared for a variety of systems. RESULTS: Median intakes of protein and vitamin C met the current Chinese RNIs for pregnancy, whereas intakes of(VA) and VB2 were well below the recommendations. Intake of iron were above 90%, but the main sources of iron are vegetables. Plasma VA (1.25 micromol/L) and iron (20.57 microg/L) were lower, BGRAC (1.79) was higher than that in non-anemia group (VA 1.57 micromol/L, SF 33.16 microg/L, BGRAC 1.52). The level of plasma SOD (77.1U/ml) and the activity of GSH-Px (61.9U) were lower than those in non-anemia group (92.2U/ml, 71.6U, P < 0.05), while MDA (4.58 nmol/ml) level and erythrocyte membrane (P = 0.2622, eta = 2.7465) fluidity were higher than those non-anemia group(MDA = 3.78 nmol/ ml, P = 0.2360, eta = 2.3658). CONCLUSION: Plasam VA, VB2 and iron, antioxidantcapacity and erythrocyte membrane fluidity were decreased in the anemic pregnant women.

Adult↗
PubMed2002

The influence of vitamin B2 intake on the activation coefficient of erythrocyte glutation reductase in the elderly.

OBJECTIVE: To evaluate the influence of dietetic vitamin B2 on the activation coefficient of erythrocyte glutation reductase (alpha-EGR) of a group of elderly people. DESIGN: The study subjects were 133, independently-living elderly people, between 65 and 90 years of age. A dietetic study was performed using a 7-day food record. Riboflavin status was measured by determining the alpha-EGR. RESULTS: Some 23.9% of subjects had riboflavin intakes lower than those recommended. At the biochemical level, 9.8% of subjects (7.7% of men and of 10.6% women) showed alpha-EGR>1.2. Those subjects with riboflavin intakes below 90% of those recommended showed significantly higher alpha-EGR levels (1.15+/-0.16), an indication of a poorer riboflavin status at the biochemical level. Those with greater intakes showed lower alpha-EGR values (1.05+/-0.10). Furthermore, the mean consumption of dairy products (an important source of this vitamin) by subjects is insuficiente (341.1+/-159.8 g/day, 2.1+/-1 servings/day). The data show that those with riboflavin intakes below those recommended took 204.7+/-89.4 g/day of milk products (1.3+/-0.5 servings/day) compared to the 384+/-153.1 g/day (2.4+/-1 servings/day) (p<0.001) consumed by those with higher riboflavin intakes. CONCLUSION: Although the mean riboflavin intake is acceptable, there remain some insufficiencies that require attention. It would seem advisable to recommend the elderly increase their intake of milk products. This would be especially important for subjects who take less than two rations per day.

Aged↗
PubMed1976

Vitamin B2 status in athletes and the influence of riboflavin administration on neuromuscular irritability.

In order to obtain information on the vitamin B2 status in athletes in training, the following aspects were investigated: in one group of athletes, riboflavinuria at rest, during the autumn and winter months (mean values 23.8 and 9.45 mug/h, respectively); in the second group (n = 18), the activity of the nicotinamide-adenine-dinucleotide-phosphate-dependent red blood cell glutathione reductase (EC 1.6.4.2) and its activation by added flavin adenine dinucleotide. In 8 athletes, activation coefficients higher than 1.25 were found, indicating a biochemical deficiency of riboflavin. Erythrocyte transketolase (EC 2.2.1.1) was activated by more than 25% with added thiamine pyrophosphate in 12 cases. In muscle samples of 10 healthy patients (fresh fractures or removing of metal plates from old fractures), glutathione reductase (mean activity 0.846 +/- 0.458 U/g wet weight) was activated by more than 25% in 5 cases. Administration of 10 mg of riboflavin per os resulted in moderate lowering of neuromuscular irritability (musculi vastus medialis and lateralis quadricipitis) particularly for 0.1-msec rectangular stimuli.

Adolescent↗
PubMed1979

[Vitamin B2 deficiency and total parenteral nutrition].

A 15 year old adolescent with Crohn's disease who received total parenteral nutrition for three months developed riboflavin deficiency. The aetiology, the clinical picture and the method of diagnosis of this unusual deficiency are reviewed. The importance of an adequate intake of vitamin B2 and the other B group vitamins, particularly in the malnourished, is emphasied.

Adolescent↗
PubMed1997

Effect of magnesium deficiency on vitamin B2 and B6 status in the rat.

OBJECTIVE: The present study was undertaken to investigate the effect of dietary magnesium (Mg) deficiency on vitamin B2 (riboflavin) and B6 (pyridoxine) status in rats. METHODS: We fed Wistar rats an Mg-deficient diet (56 mg magnesium per kg food) for 70 days. On days 21, 35 and 70 we measured Mg and manganese (Mn) in plasma and whole blood, alkaline phosphatase in plasma, erythrocyte glutathione reductase activity coefficient (AC-EGR) for riboflavin status, and erythrocyte aspartase transaminase activity coefficient (AC-EAST) for vitamin B6 status. RESULTS: Intake of the Mg-deficient diet significantly decreased plasma and whole blood levels of Mg and plasma alkaline phosphatase activity on all sampling days. The Mg deficit had no effect on plasma concentrations of Mn, but significantly increased whole blood levels of this element on days 35 and 70. The Mg-deficient diet had no effect on AC-EGR, and thus appeared not to affect riboflavin status. However, AC-EAST was significantly increased on day 70, implying that the animals were at risk for vitamin B6 deficiency. CONCLUSION: Mg deficiency impairs vitamin B6 status by depleting intracellular Mg and thus inhibits the activity of alkaline phosphatase, a metalloenzyme required for the uptake of pyridoxal phosphate by tissues. Although part of the intraerythrocyte loss of Mg is countervailed by Mn, which can act as a substitute activator of alkaline phosphatase, the degree of compensation is insufficient to fully offset the decrease in activity caused by Mg depletion.

Alkaline Phosphatase↗
PubMed1999

Industrial application of fuzzy control to large-scale recombinant vitamin B2 production.

A fuzzy control system featuring the identification of culture phases by fuzzy logic was applied to the large-scale recombinant vitamin B2 (VB2) production at the Fukuroi factory of Nippon Roche, Fukuroi. Prior to actual operation, the knowledge base for fuzzy control was tuned and verified by a simulation system. Only four rules, formulated as IF approximately THEN instructions and membership functions for state variables, are employed to control the feed rate and pH of the fed-batch culture. By applying fuzzy control, total VB2 production and VB2 yield was increased by 6-16% and 4-11% compared with conventional control, respectively. Operating stability was also improved. The large-scale fermentor used for VB2 production has been successfully operated under the control of the fuzzy system for more than 2 years.

Journal Article↗
PubMed1998

Vitamin B2 interference with TDx drugs-of-abuse assays.

Migraine is a headache condition found in significant frequency in the general population. One recent study has shown that riboflavin, Vitamin B2, is an effective prophylactic treatment for this headache condition. One subject in a recent study conducted by the Division of Forensic Toxicology, Armed Forces Institute of Pathology (AFIP) was taking 200 mg of riboflavin twice daily for the prevention of migraine headaches. When that subject's urine was tested using Abbott TDx drugs-of-abuse assays a number of tests resulted in a MX BKG error and all samples had BLK I values greater than those observed with normal urine specimens. The MX BKG error occurs when the BLK I value is greater than the upper limit determined by the manufacturer for a particular assay. High BLK I values may result if the specimen being analyzed contains a fluorophore that will compete with the fluorescein-labeled antibody used in the assay. This error serves as a notification that an interfering substance may be present and the assay is not performing according to manufacturer-specifications. Upon termination of riboflavin therapy the subject's BLK I values began to decrease within 60 h of the last 200 mg dose. A second subject began chronic riboflavin use to confirm this interferent effect. Elevated BLK I values resulted within 3 h of a single 200 mg dose and MX BKG errors occurred 1 h after a second 400 mg dose. No false negative results were noted with either subject (both subjects used butalbital and the first subject also used hydrocodone and diazepam during the study), suggesting that riboflavin is not an adulterant. Riboflavin use, however, does interfere with the TDx DAU assays and may result in quantitative values being determined which are of questionable validity in the face of an elevated BLK I value or may result in only an MX BKG error and no quantitative value reported. It is unclear if the interfering fluorophore is simply riboflavin itself or a combination of riboflavin and its metabolic products. Results obtained on urine samples collected from individuals using prophylactic riboflavin for migraine prevention and analyzed by TDx may be of questionable validity. Such samples may require analysis utilizing another immunoassay technique that does not employ a fluorescein-labeled antibody.

Fluorescence Polarization Immunoassay↗
PubMed2004

A modified vitamin regimen for vitamin B2, A, and E administration in very-low-birth-weight infants.

INTRODUCTION: Very-low-birth-weight (VLBW; birth weight, <1,500 g) infants receive preterm infant formulas and parenteral multivitamin preparations that provide more riboflavin (vitamin B2) than does human milk and more than that recommended by the American Society of Clinical Nutrition. VLBW infants who are not breast-fed may have plasma riboflavin concentrations up to 50 times higher than those in cord blood. The authors examined a vitamin regimen designed to reduce daily riboflavin intake, with the hypothesis that this new regimen would result in lower plasma riboflavin concentrations while maintaining lipid-soluble vitamin levels. METHODS: Preterm infants with birth weight < or =1,000 g received either standard preterm infant nutrition providing 0.42 to 0.75 mg riboflavin/kg/day (standard group), or a modified regimen providing 0.19 to 0.35 mg/kg/day (modified group). The modified group parenteral vitamin infusion was premixed in Intralipid. Enteral feedings were selected to meet daily riboflavin administration guidelines. Plasma riboflavin, vitamin A, and vitamin E concentrations were measured weekly by high-performance liquid chromatography. Data were analyzed with the independent t test, chi, and analysis of variance. RESULTS: The 36 infants (17 standard group, 19 modified group) had birth weight and gestational age of 779 +/- 29 g and 25.5 +/- 0.3 weeks (mean +/- SEM) with no differences between groups. Modified group infants received 38% less riboflavin (0.281 +/- 0.009 mg/kg/day), 35% more vitamin A (318.3 +/- 11.4 microg/kg/day), and 14% more vitamin E (3.17 +/- 0.14 mg/kg/day) than standard group infants. Plasma riboflavin rose from baseline in both groups but was 37% lower in the modified group during the first postnatal month (133.3 +/- 9.9 ng/mL). Riboflavin intake and plasma riboflavin concentrations were directly correlated. Plasma vitamin A (0.222 +/- 0.022 microg/mL) and vitamin E (22.26 +/- 1.61 /mL) concentrations were greater in the modified group. CONCLUSIONS: The modified vitamin regimen resulted in reduced riboflavin intake and plasma riboflavin concentration, suggesting plasma riboflavin concentration is partially dose dependent during the first postnatal month in VLBW infants. Modified group plasma vitamin A and vitamin E concentrations were greater during the first month, possibly because the vitamins were premixed with parenteral lipid emulsion. Because of the complexity of this protocol, the authors suggest that a parenteral multivitamin product designed for VLBW infants which uses weight-based dosing should be developed.

Analysis of Variance↗
PubMed1999

Riboflavin levels in maternal milk: the influence of vitamin B2 status during the third trimester of pregnancy.

OBJECTIVE: The aim of the present investigation was to study the relationship between riboflavin status during the third trimester of pregnancy and levels of this vitamin in transition milk (days 13 to 14 of lactation) and mature milk (day 40 of lactation). METHODS: The pregnancies and lactation periods of 57 healthy women between 18 and 35 years of age (27+/-3.7 years) were monitored, vitamin intake during the third trimester was determined by recording the consumption of foods over five days and by registering the quantities provided by dietary supplements. Riboflavin status during this stage of pregnancy was determined via the measurement of the activation of erythrocyte glutathione reductase (EGR) by flavine adenine dinucleotide (FAD). Milk riboflavin levels were determined by fluorometry. RESULTS: Those subjects with riboflavin intakes below recommended (1.6 mg/day) (Group L) showed lower consumption of milk products (305.2+/-88.5 g/day) than did those with greater intakes (Group H) (507.9+/-137.2 g/day). The consumption of riboflavin containing supplements was very low and was seen only in two H subjects. Transition and mature milk riboflavin levels were significantly higher in H subjects (948.1+/-700.1 nmol/L for transition milk and 993.8+/-436.6 nmol/L for mature milk) than L subjects (574.9+/-258.7 nmol/L for transition milk and 725.4+/-254.3 nmol/L for mature milk). Subjects with alpha-EGR coefficients over 1.2 in the third trimester showed significantly lower mature milk riboflavin levels (704.1+/-241.8 nmol/L) than did subjects with more satisfactory alpha-EGR coefficients (996.4+/-302.9 nmol/L). CONCLUSION: The influence of maternal vitamin B2 status during pregnancy on breast milk riboflavin levels was confirmed.

Adolescent↗
PubMed2004

Photoinduced interactions between oxidized and reduced lipoic acid and riboflavin (vitamin B2).

As a powerful natural antioxidant, lipoic acid (LipSS) and its reduced form dihydrolipoic acid (DHLA) exert significant antioxidant activities in vivo and in vitro by deactivation of reactive oxygen and nitrogen species (ROS and RNS). In this study the riboflavin (RF, vitamin B2) sensitized UVA and visible-light irradiation of LipSS and DHLA was studied employing continuous irradiation, fluorescence spectroscopy, and laser flash photolysis (LFP). Our results indicate that LipSS and DHLA quench both the singlet state (1RF*) and the triplet state (3RF*) of RF by electron transfer to produce the riboflavin semiquinone radical (RFH.) and the radical cation of LipSS and DHLA, respectively. The radical cation of DHLA is rapidly deprotonated twice to yield a reducing species, the radical anion of LipSS (LipSS.-). When D2O was used as solvent, it was confirmed that the reaction of LipSS with 3RF* consists of a simple electron-transfer step, while loss of hydrogen occurs in the case of DHLA oxidation. Due to the strong absorption of RFH. and the riboflavin ground state, the absorption of the radical cation and the radical anion of LipSS can not be observed directly by LFP. N,N,N',N'-tetramethyl-p-phenylenediamine (TMPD) and N,N,N',N'-tetramethyl benzidine (TMB) were added as probes to the system. In the case of LipSS, the addition resulted in the formation of the radical cation of TMPD or TMB by quenching of the LipSS radical cation. If DHLA is the reducing substrate, no formation of probe radical cation is observed. This confirms that LipSS.- is produced by riboflavin photosensitization, and that there is no oxidizing species produced after DHLA oxidization.

Antioxidants↗
PubMed2006

Influence of folic acid, vitamin B2 and B6 supplementation on feed intake, body and organs weight, and liver fatty acids composition in rats subjected to severe protein deprivation.

Growing rats fed for 3 months a low-protein (LP) diet (4.5% of energy from protein), possessed about 29% lower body weight than animals consuming adequate-protein diet (20% energy from protein). The LP diet feeding caused an increase in daily feed intake followed by a decrease in feed conversion efficiency. The enrichment of LP diet with folic acid, vitamin B2 and B6 (3 times above the level applied in the control diet) did not have any impact on rats BW and supplementation with these vitamins minimize the effect of LP diet on feed intake. The use of examined vitamins had a tendency to diminish an increase in feed conversion ratio caused by the LP nutrition. This effect was significant when all vitamins were added together. Rats fed the LP diet had higher relative weights of lungs, heart, liver and testis. Vitamins enriching the LP diet were observed to decrease a relative weight of lungs (folic acid, vitamin B6 and vitamin mixture), and liver (vitamin B6 and vitamin mixture). A tendency of increasing relative testis weight was also revealed in rats given the LP diet enriched with vitamins. The lower content of hepatic polyunsaturated fatty acids (FA) and a tendency for monounsaturated FA content to be higher were found in rats fed the LP diet. The LP diet enrichment with folic acid caused that these changes were more pronounced and statistically significant. Enrichment of LP diet with vitamins tested may cause a partial reverse of changes observed in the hepatic FA composition.

Animals↗
PubMed2000

The possible role of gradual accumulation of copper, cadmium, lead and iron and gradual depletion of zinc, magnesium, selenium, vitamins B2, B6, D, and E and essential fatty acids in multiple sclerosis.

Multiple sclerosis (MS) has a much higher incidence among caucasians that in any other race. Furthermore: females are much more susceptible than males and white females living in colder, wetter areas are much more susceptible than those living in warmer areas. On the other hand, menstruating women have increased copper (Cu) absorption and half-life, so they tend to accumulate more Cu than males. Moreover, rapidly growing girls have an increased demand for zinc (Zn), but their rapidly decreasing production of melatonin results in impaired Zn absorption, which is exacerbated by the high Cu levels. The low Zn levels result in deficient CuZnSuperoxide dismutase (CuZnSOD), which in turn leads to increased levels of superoxide. Menstruating females also often present with low magnesium (Mg) and vitamin B6 levels. Vitamin B6 moderates intracellular nitric oxide (NO) production and extracellular Mg is required for NO release from the cell, so that a deficiency of these nutrients results in increased NO production in the cell and reduced release from the cell. The trapped NO combines with superoxide to form peroxinitrite, an extremely powerful free radical that leads to the myelin damage of MS. Iron (Fe), molybdenum (Mo) and cadmium (Cd) accumulation also increase superoxide production. Which explains MS in males, who tend to accumulate Fe much faster and Cu much less rapidly than females. Since vitamin D is paramount for Mg absorption, the much reduced exposure to sunlight in the higher latitudes may account for the higher incidence in these areas. Moreover, vitamin B2 is a cofactor for xanthine oxidase, and its deficiency exacerbates the low levels of uric acid caused by high Cu levels, resulting in myelin degeneration. Finally Selenium (Se) and vitamin E prevent lipid peroxidation and EPA and DHA upregulate CuZnSOD. Therefore, supplementation with 100 mg MG, 25 mg vit B6, 10 mg vit B2, 15 mg Zn and 400 IU vit D and E, 100 microg Se, 180 mg EPA and 120 mg DHA per day between 14 and 16 years of age may prevent MS.

Adolescent↗
PubMed2005

Folate, vitamin B6, vitamin B12, and vitamin B2 intake, genetic polymorphisms of related enzymes, and risk of colorectal cancer in a hospital-based case-control study in Japan.

We conducted a case-control study to investigate the association of nutrient intake involved in the one-carbon pathway of folate for DNA methylation and DNA synthesis and the related enzyme genetic polymorphisms with colorectal cancer. Cases were 107 patients newly diagnosed with colorectal cancer. Controls were 224 subjects matched with cases by sex, age, and residential area. Nutrient intake was assessed by a self-administered, semiquantitative food-frequency questionnaire. Four genetic polymorphisms-MTHFR C677T and A1298C, MTRR A66G, and ALDH2 Glu487Lys-were determined using blood samples. Odds ratios were calculated using conditional logistic regression analysis adjusted for smoking, alcohol consumption, body mass index, and dietary fiber intake. Although folate intake was inversely associated with colorectal cancer, this association was attenuated after further controlling for dietary fiber intake. Neither vitamin B6, vitamin B12, nor vitamin B2, nor any genetic polymorphism was significantly associated with colorectal cancer. MTRR polymorphism interacted with the association of folate (P for interaction = 0.04) or vitamin (P for interaction = 0.02) with colorectal cancer, although the other polymorphisms did not interact with any nutrient intake. In conclusion, the study did not support the existing hypothesis of gene-nutrient interaction in colorectal carcinogenesis.

Adult↗
PubMed1983

Impaired collagen maturity in vitamins B2 and B6 deficiency--probable molecular basis of skin lesions.

Solubility of collagen was increased and the proportion of insoluble collagen was reduced in the skin of both riboflavin as well as pyridoxine-deficient rats. Collagen content of the skin, and aldehyde concentration of salt-soluble collagen were also lower in the deficient groups. The alpha:beta subunit ratio of salt-soluble collagen was higher in riboflavin deficiency. In food-restricted weight-matched control groups, similar changes in collagen solubility, but of lesser magnitude were observed. Both food restriction and riboflavin deficiency decreased plasma PLP concentration. Increase in the solubility of collagen, decrease in the aldehyde content of soluble collagen and increase in the alpha:beta subunit ratio of soluble collagen, suggest that the maturation of collagen may be affected in pyridoxine or riboflavin deficiency. These molecular events may be etiologically related to the pathogenesis of the skin lesions in vitamin B2 or B6 deficiency.

Animals↗