Pyridoxine

To examine the development and tracking of long-term vitamin B-6 status from infancy to early adolescence, measurements of erythrocyte pyridoxal 5'-phosphate concentration (EPLP), the erythrocyte aspartate transaminase (EAST) stimulation test including measurements of basal activity (EASTo) and activation coefficient (alpha EAST), were made in a follow-up study of healthy children aged 2 (n = 139), 4 (n = 147), 6 (n = 157), 9 (n = 159) and 12 mo (n = 188) and 5 y (n = 148). The EAST stimulation test was repeated at 11 y (n = 153). Vitamin B-6 status, high during infancy, reached the adult level by 5 y of age. The 10th to 90th percentile ranges for EPLP values were 61-201 nmol/L at 4 mo, 49-101 nmol/L at 12 mo and 27-59 nmol/L at 5 y. The respective ranges for Easto were 16-24 microkat/L at 4 mo, 13-19 microkat/L at 12 mo, 9-14 microkat/L at 5 y and 25-39 microkat/L at 11 y of age. For alpha EAST values were 1.29-1.54 at 4 mo, 1.48-1.77 at 12 mo, 1.70-2.07 at 5 y and 2.00-2.57 at...

The aim of the clinical study was to evaluate the effect of Testofen, a standardized Trigonella foenum-graecum (Fenugreek) extract and mineral formulation, on male libido (sexual drive, urge or desire) in a double blind randomized placebo controlled study. The study recruited 60 healthy males aged between 25 and 52, without erectile dysfunction and randomized to an oral dose (two tablets per day) of the active treatment (600 mg Testofen per day) or placebo for 6 weeks. The primary outcome measure was the DISF-SR (male) self-administered QOL total score and the four domain scores. The secondary outcome was specific quality of life parameters. Testofen had an overall positive effect on physiological aspects of libido. In particular, there was a significant increase in the subdomains of sexual arousal and orgasm. Testofen had a positive effect on QOL in self-reported satisfaction with muscle strength, energy and well-being but did not have an effect on mood or sleep. Serum prolactin and testosterone levels remained within the reference range. It was concluded that Testofen demonstrated a significant positive effect on physiological aspects of libido and may assist to maintain normal healthy testosterone levels. Copyright © 2011 John Wiley & Sons, Ltd.

The objective of this study was to investigate whether zinc, along with pyridoxine, is effective in improving performance and egg quality of laying hens. One hundred and twenty, 28-week-old Hy-Line laying hens were assigned to four treatment groups, 30 hens each. The birds were fed a basal diet or the basal diet supplemented with either 30 mg of zinc/kg of diet, 8 mg of pyridoxine/kg of diet, or 30 mg of zinc plus 8 mg of pyridoxine/kg of diet. Feed conversion (P < 0.01) and egg production (P < 0.01) improved most when both zinc and pyridoxine were supplemented to the diet. Eggshell weights were also greatest (P < 0.01) when the diet was supplemented with both pyridoxine and zinc. Egg-shape index was, however, greatest with zinc-supplemented diet (P < 0.004). Haugh unit was greatest in eggs of hens fed a diet supplemented with both zinc and pyridoxine (P < 0.01). Dietary zinc and pyridoxine supplementations together increased plasma calcium and phosphorous concentrations (P < 0.002). The results of the present study suggested that zinc (30 ppm) and pyridoxine (8 ppm) supplements, when used together, are recommended in terms of a better performance and egg quality in laying hens.

Although several prospective studies have shown that low folate intake and low circulating folate are associated with increased risk of coronary heart disease (CHD), the findings are inconsistent. We studied the associations of dietary intake of folate, vitamin B(6), and vitamin B(12) with the risk of acute coronary events in a prospective cohort study of 1980 Finnish men 42 to 60 years old examined in 1984 to 1989 in the Kuopio Ischemic Heart Disease Risk Factor Study. Nutrient intakes were assessed by 4-day food record. During an average follow-up time of 10 years, 199 acute coronary events occurred. In a Cox proportional hazards model adjusted for 21 conventional and nutritional CHD risk factors, men in the highest fifth of folate intake had a relative risk of acute coronary events of 0.45 (95% CI 0.25 to 0.81, P=0.008) compared with men in the lowest fifth. This association was stronger in nonsmokers and light alcohol users than in smokers and alcohol users. A high dietary intake of vitamin B(6) had no significant association and that of vitamin B(12) a weak association with a reduced risk of acute coronary events. The present work in CHD-free middle-aged men is the first prospective cohort study to observe a significant inverse association between quantitatively assessed moderate-to-high folate intakes and incidence of acute coronary events in men. Our findings provide further support in favor of a role of folate in the promotion of good cardiovascular health.

The early onset of atherosclerotic lesions in homocystinuric individuals has implicated homocyst(e)ine in the development of atherosclerosis. Two trials were conducted in which diets totally or partially deficient in vitamin B-6 were fed to pigs to investigate the accumulation of homocyst(e)ine in the plasma and the development of vascular lesions. In one trial plasma free homocyst(e)ine levels were 179 and 43 mumol/liter in deficient and adequate pigs, respectively, on day 24, while cysteine levels were 39 and 155 mumol/liter. The concentration of plasma protein-bound homocysteine and cysteine reflected the plasma-free values. Because pigs deficient in pyridoxine could be used only over short time intervals, pigs in trial 2 received 0, 0.03, 0.3 or 3 mg (i.e., 0, 2, 20 or 200% of allowance) of supplemental pyridoxine . HCl per kilogram diet. After 12 weeks pigs deficient and adequate in vitamin B-6 were injected intravenously with Evan&#39;s blue dye and the vascular trunk perfused...

In search for better mimics of the glutathione peroxidase enzymes, pyridoxine-like diselenides 6 and 11, carrying a 6-bromo substituent, were prepared. Reaction of 2,6-dibromo-3-pyridinol 5 with sodium diselenide provided 6 via aromatic nucleophilic substitution of the 2-bromo substituent. LiAlH4 caused reduction of all four ester groups and returned 11 after acidic work-up. The X-ray structure of 6 showed that the dipyridyl diselenide moiety was kept in an almost planar, transoid conformation. According to NBO-analysis, this was due to weak intramolecular Se...O (1.1 kcal/mol) and Se...N-interactions (2.5 kcal/mol). That the 6-bromo substituent increased the positive charge on selenium was confirmed by NPA-analysis and seen in calculated and observed 77Se NMR-shifts. Diselenide 6 showed a more than 3-fold higher reactivity than the corresponding des-bromo compound 3a and ebselen when evaluated in the coupled reductase assay. Experiments followed for longer time (2 h) confirmed that...

The long-term vitamin requirements of men (n=22) with moderate hyperhomocysteinemia (plasma total homocysteine concentration > 16.3 μmol/1) were investigated over a period of 48 weeks. An initial 6-week period of vitamin supplementation (1.0 mg folic acid, 10 mg pyridoxine, 0.05 mg cyanocobalamin) reduced plasma homocysteine levels 54.7% (P<0.001). However, 18 weeks after vitamin therapy was discontinued, only seven participants (subgroup A) still had plasma homocysteine levels of 16.3 μmol/l or lower. The remainder of the participants (subgroup B) required a second 6-week period of vitamin therapy to normalize the elevated plasma homocysteine levels. Substitution of vitamin supplementation by dietary guidelines to increase folate intake from food products failed to maintain normal plasma homocysteine levels in participants from subgroup B. Long-term vitamin supplementation may be required in some individuals to prevent hyperhomo-cysteinemia.