Synthesis of vitamin-selenium complex and its effects on proteins and tumor cells

A selenium-vitamin P complex (SEVP) was synthesized and its structure was determined by IR, LC-MS and (1)H NMR. Its biological effects on bovine serum albumin (BSA) and human colon carcinoma tumor cells were studied by molecular spectra, MTT and flow cytometry. The interaction of SEVP and BSA was discussed by fluorescence quenching method and Förster non-radiation energy transfer theory. The thermodynamic parameters ΔH(θ), ΔG(θ), ΔS(θ) at different temperatures were calculated and the results indicate the interaction is an exothermic as well as entropy-driven process. Hydrogen bond and electrostatic force played major role in the reaction. The binding geometry and conformation changes of BSA were investigated by fluorescence probe technique and circular dichroism (CD) spectra. The effects of SEVP on human colon carcinoma tumor cells HT29 were tested by MTT method and flow cytometry (FCM). The MTT results show the proliferation of HT29 tumor cells were inhibited by SEVP and the inhibition was associated with dose and time. The FCM analysis disclosed SEVP interrupted the DNA synthesis of tumor cells at S phase.

Intestinal absorption of water-soluble vitamins in health and disease

Our knowledge of the mechanisms and regulation of intestinal absorption of water-soluble vitamins under normal physiological conditions, and of the factors/conditions that affect and interfere with theses processes has been significantly expanded in recent years as a result of the availability of a host of valuable molecular/cellular tools. Although structurally and functionally unrelated, the water-soluble vitamins share the feature of being essential for normal cellular functions, growth and development, and that their deficiency leads to a variety of clinical abnormalities that range from anaemia to growth retardation and neurological disorders. Humans cannot synthesize water-soluble vitamins (with the exception of some endogenous synthesis of niacin) and must obtain these micronutrients from exogenous sources. Thus body homoeostasis of these micronutrients depends on their normal absorption in the intestine. Interference with absorption, which occurs in a variety of conditions (e.g. congenital defects in the digestive or absorptive system, intestinal disease/resection, drug interaction and chronic alcohol use), leads to the development of deficiency (and sub-optimal status) and results in clinical abnormalities. It is well established now that intestinal absorption of the water-soluble vitamins ascorbate, biotin, folate, niacin, pantothenic acid, pyridoxine, riboflavin and thiamin is via specific carrier-mediated processes. These processes are regulated by a variety of factors and conditions, and the regulation involves transcriptional and/or post-transcriptional mechanisms. Also well recognized now is the fact that the large intestine possesses specific and efficient uptake systems to absorb a number of water-soluble vitamins that are synthesized by the normal microflora. This source may contribute to total body vitamin nutrition, and especially towards the cellular nutrition and health of the local colonocytes. The present review aims to outline our current understanding of the mechanisms involved in intestinal absorption of water-soluble vitamins, their regulation, the cell biology of the carriers involved and the factors that negatively affect these absorptive events.

Determination of fat-soluble vitamins and carotenoids in standard reference material 3280 multivitamin/multielement tablets by liquid chromatography with absorbance detection

The concentrations of selected fat-soluble vitamins and carotenoids in Standard Reference Material (SRM) 3280 Multivitamin/Multielement Tablets have been determined by two independent LC methods, with measurements performed by the National Institute of Standards and Technology (NIST). This SRM has been prepared as part of a collaborative effort between NIST and the National Institutes of Health Office of Dietary Supplements. The SRM is also intended to support the Dietary Supplement Ingredient Database that is being established by the U.S. Department of Agriculture. The methods used at NIST to determine the concentration levels of vitamins A and E, and beta-carotene in the SRM used RPLC with absorbance detection. The relative precision of these methods ranged from 2 to 8% for the analytes measured. SRM 3280 is primarily intended for use in validating analytical methods for the determination of selected vitamins, carotenoids, and elements in multivitamin/multielement tablets and similar matrixes.

Dietary supplement laboratory quality assurance program: the first five exercises

The National Institute of Standards and Technology (NIST) has established a Dietary Supplement Laboratory Quality Assurance Program (DSQAP) in collaboration with the National Institutes of Health Office of Dietary Supplements. Program participants measure concentrations of active and/or marker compounds as well as nutritional and toxic elements in food and dietary supplements distributed by NIST. Data are compiled at NIST, where they are analyzed for accuracy relative to reference values and concordance among the participants. Performance reports and certificates of completion are provided to participants, which can be used to demonstrate compliance with current Good Manufacturing Practices as promulgated by the U.S. Food and Drug Administration. The DSQAP has conducted five exercises to date, with total participation including more than 75 different laboratories and many more individual analysts.

Chemometric methods for the simultaneous determination of some water-soluble vitamins

Two spectrophotometric methods, derivative and multivariate methods, were applied for the determination of binary, ternary, and quaternary mixtures of the water-soluble vitamins thiamine HCI (I), pyridoxine HCI (II), riboflavin (III), and cyanocobalamin (IV). The first method is divided into first derivative and first derivative of ratio spectra methods, and the second into classical least squares and principal components regression methods. Both methods are based on spectrophotometric measurements of the studied vitamins in 0.1 M HCl solution in the range of 200-500 nm for all components. The linear calibration curves were obtained from 2.5-90 microg/mL, and the correlation coefficients ranged from 0.9991 to 0.9999. These methods were applied for the analysis of the following mixtures: (I) and (II); (I), (II), and (III); (I), (II), and (IV); and (I), (II), (III), and (IV). The described methods were successfully applied for the determination of vitamin combinations in synthetic mixtures and dosage forms from different manufacturers. The recovery ranged from 96.1 +/- 1.2 to 101.2 +/- 1.0% for derivative methods and 97.0 +/- 0.5 to 101.9 +/- 1.3% for multivariate methods. The results of the developed methods were compared with those of reported methods, and gave good accuracy and precision.

Natural antioxidants: fascinating or mythical biomolecules?

Research on the use, properties, characteristics and sources of antioxidants especially phenolic compounds, flavonoids, vitamins, synthetic chemicals and some micronutrients began in the late 18^th century. Since then antioxidant research has received considerable attention and over a hundred thousand papers have been published on the subject. This has led to a rampant use of antioxidants in order to try to obtain and preserve optimal health. A number of nutraceuticals and food supplements are frequently fortified with synthetic or natural antioxidants. However, some research outcomes have led to the belief that antioxidants exist as mythical biomolecules. This review provides a critical evaluation of some common in vitro antioxidant capacity methods, and a discussion on the role and controversies surrounding non-enzymatic biomolecules, in particular phenolic compounds and non-phenolic compounds, in oxidative processes in an attempt of stemming the tidal wave that is threatening to swamp the concept of natural antioxidants.

Behavior of acetyl-L-carnitine injections (Nicetile fiale) with different drugs used for combined therapy

INTRODUCTION

Acetyl-L-carnitine (Nicetile fiale; Biofutura Pharma S.p.A., Sigma Tau group, Milano, Italy) is a compound widely used for the treatment of many diseases, such as neuropathies, diabetic polyneuropathy, and Parkinson's disease. It is frequently administered via the intramuscular route with other drugs, such as steroidal anti.inflammatories, muscle relaxants, and vitamins.

METHODS

In the present study the behavior of acetyl-L-carnitine injections (Nicetile fiale) with different drugs used for combined therapy was studied. Physicochemical properties including color, clarity, pH, and drug content were observed before and after mixing at room temperature.

RESULTS

The content of all the active drugs after mixing remained optimal within 10% of their nominal values.

CONCLUSIONS

The measurements demonstrate the physicochemical compatibility between Nicetile fiale and the other tested products, meaning that there is no evidence of interactions and degradation.

[Selective separation of vitamin C and 2-ketogluconic acid by facilitated pertraction]

The removal of vitamin C from a mixture with 2-ketogluconic acid by using a bulk liquid membrane (BLM) has been investigated. The studies on facilitated pertraction of vitamin C with Amberlite LA-2 indicated the major parameters that affect the separation efficiency: pH gradient between the two aqueous phases, carrier concentration in the liquid membrane and phase mixing intensity. The overall results obtained in this work showed that liquid membrane system can effectively be used to selectively separate vitamin C from its mixture with the fermentation by-product, 2-ketogluconic acid.

Global conformational change associated with the two-step reaction catalyzed by Escherichia coli lipoate-protein ligase A

Lipoate-protein ligase A (LplA) catalyzes the attachment of lipoic acid to lipoate-dependent enzymes by a two-step reaction: first the lipoate adenylation reaction and, second, the lipoate transfer reaction. We previously determined the crystal structure of Escherichia coli LplA in its unliganded form and a binary complex with lipoic acid (Fujiwara, K., Toma, S., Okamura-Ikeda, K., Motokawa, Y., Nakagawa, A., and Taniguchi, H. (2005) J Biol. Chem. 280, 33645-33651). Here, we report two new LplA structures, LplA.lipoyl-5'-AMP and LplA.octyl-5'-AMP.apoH-protein complexes, which represent the post-lipoate adenylation intermediate state and the pre-lipoate transfer intermediate state, respectively. These structures demonstrate three large scale conformational changes upon completion of the lipoate adenylation reaction: movements of the adenylate-binding and lipoate-binding loops to maintain the lipoyl-5'-AMP reaction intermediate and rotation of the C-terminal domain by about 180 degrees . These changes are prerequisites for LplA to accommodate apoprotein for the second reaction. The Lys(133) residue plays essential roles in both lipoate adenylation and lipoate transfer reactions. Based on structural and kinetic data, we propose a reaction mechanism driven by conformational changes.

An update on vitamin E, tocopherol and tocotrienol-perspectives

Vitamin E, like tocotrienols and tocopherols, is constituted of compounds essential for animal cells. Vitamin E is exclusively synthesized by photosynthetic eukaryotes and other oxygenic photosynthetic organisms such as cyanobacteria. In order to prevent lipid oxidation, the plants mainly accumulate tocochromanols in oily seeds and fruits or in young tissues undergoing active cell divisions. From a health point of view, at the moment there is a great interest in the natural forms of tocochromanols, because they are considered promising compounds able to maintain a healthy cardiovascular system and satisfactory blood cholesterol levels. Some evidence suggests that the potency of the antioxidant effects may differ between natural or synthetic source of tocochromanols (vitamin E).

Miller's Best/Enhanced Practices for Flour Fortification at the Flour Mill

Background

Cereal flour fortification has been identified as an effective mass fortification intervention as part of a national public health strategy to overcome micronutrient deficiencies and improve the health status of populations, especially women and children.

Objective

The effectiveness of cereal flour fortification programs requires the use of micronutrient premixes that provide the desired health benefits.

Method

The Miller's Best/Enhanced Practices for Flour Fortification at the flour mill has been developed to provide specific guidance to millers and government officials to ensure that flour fortification practices are carried out in a way that results in the anticipated public health impact.

Results

The paper provides information specific to the use of micronutrient premixes, feeders, the fortification process, and quality control systems to ensure that both minimum and enhanced practices can be followed by the millers.

Conclusions

Guidelines for basic and best/enhanced practices to be followed for each stage of the flour fortification process at the flour mill are presented. The paper is designed to be a companion to the Recommended Practices for the Production and Procurement of Premix used in Cereal Fortification Programs and supplementary to existing food quality manuals and systems, such as Good Manufacturing Practices, Food Quality Systems, and Hazard Analysis and Critical Control Points. Other stakeholders involved in flour fortification programs have the responsibility to follow best practices of their own to ensure optimum effectiveness.

Persistent organic pollutants (PCDD/Fs, dioxin-like PCBs, marker PCBs, and PBDEs) in health supplements on the Spanish market

During the last years, consumption of health supplements has increased in our society. They are recommended as an additional source of minerals, vitamins, omega-3 and omega-6 fatty acids, in the diet. A lot of these supplements contain oils among their components (fish oils or vegetable oils), especially those recommended for their omega-3 content. Due to their persistence and lipophilic characteristics, polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), dioxin-like polychlorinated biphenyls (PCBs), marker PCBs, and polybrominated diphenyl ethers (PBDEs) bioaccumulate in fat tissues, especially in those animals, as fish, which show low metabolic capability. Therefore, the consumption of nutritional supplements with oil components can increase the intake of persistent organic pollutants (POPs) through the diet. The aim of this study was to analyse 15 of these supplements commercialized in Spain to determinate their POPs concentrations and their intake for their consumers. Concentrations of POPs in the dietary supplements studied (PCDD/Fs: 0.04-2.4 pg TEQ g(-1); dl-PCBs: 0.01-12.1 pg TEQ g(-1); marker PCBs: 0.17-116 ng g(-1); and PBDEs: 0.07-18.2 ng g(-1)) were in the low-medium range of those reported in literature for other countries. Vegetable oil and mineral-based supplements showed concentrations of POPs clearly lower than those based on fish oil. Among these, those based on cod liver oil presented the highest concentrations detected in the study, exceeding the maximum levels established in European regulations for marine oils for human consumption. In general, the intake of POPs via the consumption of these supplements would be lower than the intake derived from fish consumption.

Evaluation of selected food supplements containing antioxidants

Seven commercial food supplements present on the Polish market were evaluated for their in vitro antioxidant capacity. The selected products were in the form of hard gelatin capsules. They contained the extracts from chokeberry, cranberry, blueberry and green tea. The mixture of vitamins and minerals as well as the product containing vitamin C in substantial dose were included into comparison. The products were examined using three methods in order to evaluate their antioxidant capacity: electron paramagnetic resonance (EPR), Trolox equivalent antioxidant capacity (TEAC), oxygen radical absorbing antioxidant capacity (ORAC) assays. Total polyphenolic content was determined according to Folin-Ciocalteu method The results were calculated per capsule. All studied preparations showed antioxidant properties and may provide substantial antioxidant protection. The in vitro antioxidant capacity varied considerably and was associated with the content of polyphenols in the capsule. The supplement with 250 mg of green tea extract was the most potent antioxidant in all assays. Nevertheless it must be remembered that the amounts of extracts were different in encapsulated products. As the quality of extracts and their properties are miscellaneous, there is a need to standardize dietary antioxidant supplements with respect to their antioxidant capacity if effective doses are to be recommended.

Measurement of water-soluble B vitamins in infant formula by liquid chromatography/tandem mass spectrometry

A method has been developed for the simultaneous measurement of multiple B vitamins (i.e., B1, B2, B3, B5, and B6) in infant formulas by LC-MSIMS. The vitamins were extracted with acidic solvent, followed by protein precipitation at a pH range of 4.5 to 5.5, and filtered. This simplified procedure eliminates many of the potential sources of laboratory error and facilitates rapid and efficient analysis. As is common in most cases, isotope internal standards were added to account for variations in sample preparation, as well as changes in MS measurement. In this method, isotope-labeled internal standards of B1, B3, B5, and B6 were used. The factors affecting analytical performance were investigated and optimized. In addition, the stability of these vitamins in the extraction solution was investigated. An acidic condition (5 mM HCl) was applied to successfully stabilize B1, which had shown a decrease in signal when other solvents were used. The quantitative extraction and good stability allowed isotope standards to be added to the filtered sample solution, instead of to the extraction solvent. The addition of the isotope to the small portion of the filtered sample solution significantly reduces cost. A comprehensive evaluation of the analysis of the standard reference material and good spike recovery of the vitamins (100 +/- 6%) demonstrates the accuracy of the method. The results for commercially available infant formula samples were also compared with those obtained using the current microbiological method.

The vitamin nicotinamide: translating nutrition into clinical care

Nicotinamide, the amide form of vitamin B(3) (niacin), is changed to its mononucleotide compound with the enzyme nicotinic acide/nicotinamide adenylyltransferase, and participates in the cellular energy metabolism that directly impacts normal physiology. However, nicotinamide also influences oxidative stress and modulates multiple pathways tied to both cellular survival and death. During disorders that include immune system dysfunction, diabetes, and aging-related diseases, nicotinamide is a robust cytoprotectant that blocks cellular inflammatory cell activation, early apoptotic phosphatidylserine exposure, and late nuclear DNA degradation. Nicotinamide relies upon unique cellular pathways that involve forkhead transcription factors, sirtuins, protein kinase B (Akt), Bad, caspases, and poly (ADP-ribose) polymerase that may offer a fine line with determining cellular longevity, cell survival, and unwanted cancer progression. If one is cognizant of the these considerations, it becomes evident that nicotinamide holds great potential for multiple disease entities, but the development of new therapeutic strategies rests heavily upon the elucidation of the novel cellular pathways that nicotinamide closely governs.

Measurement of vitamin D in foods and nutritional supplements by liquid chromatography/tandem mass spectrometry

Vitamin D is a fat-soluble vitamin with great nutritional interest. An HPLC/MS/MS method was developed to measure vitamin D with atmospheric pressure chemical ionization. Under the experimental parameters used, the LOQ was 0.018 IU/g or 0.45 ng/g, which greatly enhances the capability of measurement of vitamin D at low levels in foods and supplements. This method was validated with spike recovery of 100 +/- 15% and the RSD of less than 10% for most sample matrixes, including infant formula, cheese, cereal and cereal-based foods, multivitamin supplements, and pet foods. The results for vitamin D were compared with those obtained by other methods.

Effects of various vitamins and coenzymes Q on reactions involving α-hydroxyl-containing radicals

Effects of vitamins B, C, E, K and P, as well as coenzymes Q, on formation of final products of radiation-induced free-radical transformations of ethanol, ethylene glycol, alpha-methylglycoside and glucose in aqueous solutions were studied. Based on the obtained results, it can be concluded that there are substances among vitamins and coenzymes that effectively interact with alpha-hydroxyl-containing radicals. In the presence of these substances, recombination reactions of alpha-hydroxyalkyl radicals and fragmentation of alpha-hydroxy-beta-substituted organic radicals are suppressed. It has been established that the observed effects are due to the ability of the vitamins and coenzymes under study to either oxidize alpha-hydroxyl-containing radicals yielding the respective carbonyl compounds or reduce them into the initial molecules.

Profiling of polar metabolites in biological extracts using diamond hydride-based aqueous normal phase chromatography

Highly polar metabolites, such as sugars and most amino acids are not retained by conventional RP LC columns. Without sufficient retention low concentration compounds are not detected due ion suppression and structural isomers are not resolved. In contrast, hydrophilic interaction chromatography (HILIC) and aqueous normal phase chromatography (ANP) retain compounds based on their hydrophilicity and therefore provides a means of separating highly polar compounds. Here, an ANP method based on the diamond hydride stationary phase is presented for profiling biological small molecules by LC. A rapid separation system based upon a fast gradient that delivers reproducible chromatography is presented. Approximately 1000 compounds were reproducibly detected in human urine samples and clear differences between these samples were identified. This chromatography was also applied to xylem fluid from soyabean (Glycine max) plants to which 400 compounds were detected. This method greatly increases the metabolite coverage over RP-only metabolite profiling in biological samples. We show that both forms of chromatography are necessary for untargeted comprehensive metabolite profiling and that the diamond hydride stationary phase provides a good option for polar metabolite analysis.

Vitamin free radicals and their anticancer action. Review

The antimumor effect of antioxidant vitamins (C, E and beta-carotene) as well as of the vitamins B1 up to B6 and B11 under the action of oxidizing (OH, O(2)(*-)) and reducing free radicals (e(aq)(-), H) is discussed. In addition, the synergistic action of vitamins on cytostatic agents under the influence of free radicals and the involved reaction mechanisms are briefly discussed. The very fast kinetics of electron transfer taking place within a biological molecule (vitamin B11) is shown for demonstration of the complicated free radical processes in the organism.

Biological and pharmacological activities of squalene and related compounds: potential uses in cosmetic dermatology

Squalene is a triterpene that is an intermediate in the cholesterol biosynthesis pathway. It was so named because of its occurrence in shark liver oil, which contains large quantities and is considered its richest source. However, it is widely distributed in nature, with reasonable amounts found in olive oil, palm oil, wheat-germ oil, amaranth oil, and rice bran oil. Squalene, the main component of skin surface polyunsaturated lipids, shows some advantages for the skin as an emollient and antioxidant, and for hydration and its antitumor activities. It is also used as a material in topically applied vehicles such as lipid emulsions and nanostructured lipid carriers (NLCs). Substances related to squalene, including β-carotene, coenzyme Q10 (ubiquinone) and vitamins A, E, and K, are also included in this review article to introduce their benefits to skin physiology. We summarize investigations performed in previous reports from both in vitro and in vivo models.