Characterization, quantification, and in vivo effects of vitamin B6 antagonists from flaxseed on amino acid metabolism in a rodent model of moderate vitamin B6 deficiency

Vitamin B6, or more specifically the active form pyridoxal 5ʹ-phosphate (PLP), plays a crucial role as a cofactor for numerous enzymes linked to carbohydrate, fatty acid, and amino acid metabolism. There is a high prevalence of moderate vitamin B6 deficiency in the population that may be further exacerbated through the ingestion of vitamin B6 antagonists present in the food supply. For example, flaxseed contains the anti-pyridoxine factor 1-amino D-proline (1ADP) in the form of a dipeptide called linatine. In order to address these issues, the current study was designed to: 1) characterize and quantify the total amount of anti-pyridoxine factors present in flaxseed through the use of UPLC/ESI-MS analysis, 2) investigate the in vivo effects of synthetic and flaxseed-derived 1ADP on amino acid metabolism using a rat model of moderate B6 deficiency, and 3) identify novel biomarkers of vitamin B6 inadequacy using a LC-Qtof-MS based non-targeted metabolomics approach. The total anti-pyridoxine content, measured as 1ADP equivalents, in the flaxseed extract was found to be 177-437 μg/g of whole flaxseed, depending on the variety tested. Plasma biochemical analyses revealed that B6 vitamers, particularly PLP concentrations were reduced (P≤0.001), due to 1ADP ingestion (10 mg/kg diet) irrespective of the sources. Oral ingestion of flaxseed-derived 1ADP in moderately vitamin B6-deficient rats increased plasma cystathionine (P≤0.001), and decreased plasma α-aminobutyric acid (P≤0.001) and glutamic acid (P=0.017) concentrations compared to the controls. However, the ingestion of synthetic 1ADP elicited greater perturbations in amino acid profile compared to the flaxseed-derived 1ADP, which was predominantly in the form of the dipeptide linatine. Additionally, oral ingestion of the synthetic as well as the flaxseed-derived 1ADP significantly (P≤0.05) inhibited the activities of hepatic PLP-dependent enzymes involved in transsulphuration reactions of methionine metabolism. The use of a non-targeted metabolomics approach identified ten potential lipophilic markers of vitamin B6-insufficiency: glycocholic acid, glycoursodeoxycholic acid, murocholic acid, N-docosahexaenoyl GABA, N-arachidonoyl GABA, lumula, nandrolone, orthothymotinic acid, cystamine and 3-methyleneoxindole. These data serve to highlight potential deleterious effects of anti-pyridoxine factors linked to flaxseed in a population at risk for moderate vitamin B6 deficiency.October 201

B Vitamins and Their Roles in Gut Health

B vitamins act as coenzymes in a myriad of cellular reactions. These include energy production, methyl donor generation, neurotransmitter synthesis, and immune functions. Due to the ubiquitous roles of these vitamins, their deficiencies significantly affect the host’s metabolism. Recently, novel roles of B vitamins in the homeostasis of gut microbial ecology and intestinal health continue to be unravelled. This review focuses on the functional roles and biosynthesis of B vitamins and how these vitamins influence the growth and proliferation of the gut microbiota. We have identified the gut bacteria that can produce vitamins, and their biosynthetic mechanisms are presented. The effects of B vitamin deficiencies on intestinal morphology, inflammation, and its effects on intestinal disorders are also discussed.</jats:p

Endogenous Phenolics in Hulls and Cotyledons of Mustard and Canola: A Comparative Study on Its Sinapates and Antioxidant Capacity

Endogenous sinapic acid (SA), sinapine (SP), sinapoyl glucose (SG) and canolol (CAN) of canola and mustard seeds are the potent antioxidants in various lipid-containing systems. The study investigated these phenolic antioxidants using different fractions of canola and mustard seeds. Phenolic compounds were extracted from whole seeds and their fractions: hulls and cotyledons, using 70% methanol by the ultrasonication method and quantified using HPLC-DAD. The major phenolics from both hulls and cotyledons extracts were SP, with small amounts of SG, and SA with a significant difference of phenolic contents between the two seed fractions. Cotyledons showed relatively high content of SP, SA, SG and total phenolics in comparison to hulls (p &lt; 0.001). The concentration of SP in different fractions ranged from 1.15 ± 0.07 to 12.20 ± 1.16 mg/g and followed a decreasing trend- canola cotyledons &gt; mustard cotyledons &gt; mustard seeds &gt; canola seeds &gt; mustard hulls &gt; canola hulls. UPLC-tandem Mass Spectrometry confirmed the presence of sinapates and its fragmentation in these extracts. Further, a high degree of correlation (r = 0.93) was noted between DPPH scavenging activity and total phenolic content

Dietary Vitamin B6 Deficiency Impairs Gut Microbiota and Host and Microbial Metabolites in Rats

Vitamin B6 plays a crucial role as a cofactor in various enzymatic reactions but bacteria-produced vitamin B6 is not sufficient to meet host requirements. Our objective was to assess the impact of diet-derived vitamin B6 on gut microbiota and host serum metabolomics. Sprague&ndash;Dawley rats (n = 47) were fed a control, low B6 (LB6) or high B6 (HB6) diet for six weeks. Serum and cecal samples were collected for biochemical, metabolomics and gut microbiota profiling. There was a significant sex effect for gut microbiota and several metabolic markers. Bodyweight and percent body fat were significantly reduced in LB6 compared to control and HB6 rats. Microbial beta-diversity differed significantly between LB6 and the control and HB6 rats in both sexes. Lachnospiraceae_NK4A136_group and Bacteroides were the primary taxa driving the difference between LB6 and control. There was a significant separation of cecal and serum metabolites of LB6 compared to control and HB6 rats. In the cecum, arginine biosynthesis was impaired, while vitamin B6 metabolism, lysine degradation and nicotinate and nicotinamide metabolism were impaired in serum metabolite profiles. Cecal propionate and butyrate were significantly reduced in LB6 rats irrespective of sex. Host vitamin B6 deficiency but not excess significantly alters gut microbial composition and its metabolites

Dietary Vitamin B6 Deficiency Impairs Gut Microbiota and Host and Microbial Metabolites in Rats

Vitamin B6 plays a crucial role as a cofactor in various enzymatic reactions but bacteria-produced vitamin B6 is not sufficient to meet host requirements. Our objective was to assess the impact of diet-derived vitamin B6 on gut microbiota and host serum metabolomics. Sprague–Dawley rats (n = 47) were fed a control, low B6 (LB6) or high B6 (HB6) diet for six weeks. Serum and cecal samples were collected for biochemical, metabolomics and gut microbiota profiling. There was a significant sex effect for gut microbiota and several metabolic markers. Bodyweight and percent body fat were significantly reduced in LB6 compared to control and HB6 rats. Microbial beta-diversity differed significantly between LB6 and the control and HB6 rats in both sexes. Lachnospiraceae_NK4A136_group and Bacteroides were the primary taxa driving the difference between LB6 and control. There was a significant separation of cecal and serum metabolites of LB6 compared to control and HB6 rats. In the cecum, arginine biosynthesis was impaired, while vitamin B6 metabolism, lysine degradation and nicotinate and nicotinamide metabolism were impaired in serum metabolite profiles. Cecal propionate and butyrate were significantly reduced in LB6 rats irrespective of sex. Host vitamin B6 deficiency but not excess significantly alters gut microbial composition and its metabolites.</jats:p