Chemical Speciation Influences Comparative Activity of Selenium-Enriched Garlic and Yeast in Mammary Cancer Prevention

Ip, Clement; Birringer, Marc; Block, Eric; Kotrebai, Mihály; Tyson, Julian F.; Uden, Peter C.; Lisk, Donald J.

doi:10.1021/jf000051f

Cited by 264 publications

(127 citation statements)

References 25 publications

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“…With Protease XIV (Sigma, St. Louis), a selenomethionine content of Se yeast of 85 % of total Se was observed [18]. Other authors, as quoted in [10], observed selenomethionine contents of different batches or brands of yeast ranging from 81 to 84 % of total Se, with 80 to 90 % of the total Se accounted for.…”

Section: Selenium Yeast Analysismentioning

confidence: 96%

Selenium yeast: Composition, quality, analysis, and safety

Schrauzer

2006

Pure and Applied Chemistry

117

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Selenium yeast, produced by growing select strains of Saccharomyces cerevisiae in Se-rich media, is a recognized source of organic food-form Se, but the determination of its exact composition with respect to the Se species present produced conflicting results. Improved methods of analysis have since revealed it to contain 90+ % of its Se in the form of selenomethionine, the principal organic nutritional form of Se for higher animals and humans. The safety record of Se yeast is excellent: During the three decades of its world-wide use as a source of supplemental Se, no cases of Se poisoning have occurred due to dosage or formulation errors.

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Section: Selenium Yeast Analysismentioning

confidence: 96%

Selenium yeast: Composition, quality, analysis, and safety

Schrauzer

2006

Pure and Applied Chemistry

117

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“…2,3 Cancer chemoprevention is associated with inorganic selenium salts, selenoamino acids and organoselenium compounds such as methaneselenol CH 3 SeH. [4][5][6] Selenoproteins contain selenium in the form of selenocysteinyl residues; proteins that contain this element in the form of selenomethionyl residues are not formally classified as selenoproteins. Analytical techniques for the determination of selenium species have been reviewed, [7][8][9][10] but many methods have only been applied to a few commercially available standards.…”

Section: Introductionmentioning

confidence: 99%

Element selective characterization of stability and reactivity of selenium species in selenized yeast

Uden

Boakye

Kahakachchi

et al. 2004

J. Anal. At. Spectrom.

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The concerted application of element specific atomic spectral detection for chromatographic eluent monitoring allows previously unexploited qualitative and quantitative analytical concepts to be developed for the determination of selenium species. Selenium speciation is vital in order to better understand its metabolism and biological significance in clinical chemistry, biology, toxicology, and nutrition. Fluoroacid ion pair HPLC with ICP-MS detection and GC derivatization with atomic emission detection (AED) together aid analysis and elucidation of reaction pathways of selenium compounds in high selenium enriched yeast, as used widely in nutritional and clinical cancer preventative studies. Comparisons between currently produced and archived selenized yeasts show major differences in speciation. The formation of selenomethionine selenoxide and the identification of Se-S bonded S-(selenomethyl)-cysteine in archived nutritional yeast may be important for short and long term stability and nutritional activity studies.

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“…3 Selenium-enriched plants accumulate selenium in different forms: cereals and yeast predominantly as SeMet, and Allium plants as Se-methylselenocysteine (SeMeSeCys). [4][5][6] Bodo et al determined the selenium species in Brazil nuts and, because of the high fat content of the samples, they defatted them first by extraction with cyclohexane; only 0.2% of selenium was lost in this procedure. 7 The main selenium species in these nuts was SeMet, representing 96% of the total Se content; traces of selenocystine (SeCys2) were also found.…”

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confidence: 99%

Selenium Species Determination in Selenium-Enriched Pumpkin (Cucurbita pepo L.) Seeds by HPLC-UV-HG-AFS

et al. 2005

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In the last decade, many studies have been conducted to enhance the selenium content of edible plants by different types of cultivation. Although it is not known if Se exerts any beneficial effects on the plants themselves, Se enrichment of plants improves the nutritional status of selenium in man. Recently, some studies have shown that appropriate selenium addition to plants promotes their growth and is also supposed to increase their antioxidative capacity, helping to decrease oxidative stress in plants. 1,2 The reactivity and nutritional bioavailability of selenium in selenium-enriched plants depend not only on the total concentration, but predominantly on the selenium species present. Consequently, it is very important to determine the chemical species of selenium present in plants. 3 Selenium-enriched plants accumulate selenium in different forms: cereals and yeast predominantly as SeMet, and Allium plants as Se-methylselenocysteine (SeMeSeCys). [4][5][6] Bodo et al. determined the selenium species in Brazil nuts and, because of the high fat content of the samples, they defatted them first by extraction with cyclohexane; only 0.2% of selenium was lost in this procedure. 7 The main selenium species in these nuts was SeMet, representing 96% of the total Se content; traces of selenocystine (SeCys2) were also found. Another study on selenium speciation in some nuts (Brazil nuts, walnuts…) was made by Kannamkumarath et al. and much lower contents for Se in the form of SeMet were obtained (19 -25%). They used chloroform and methanol (2:1) to remove fat.8 All nuts were purchased on the market, so no data on the origin of samples were given.A renewed nutritional interest in pumpkins has arisen because of its high nutritional value; the pumpkin contains many nutritional sterols, vitamins B and E, and minerals such as Ca, K, P, Mg, Mn, Fe and Zn. Pumpkin seeds have been used for centuries in traditional medicine, mainly in the case of problems of the kidney or the urinary tract, and against tapeworms. They are normally only a moderate source of selenium. But lately several studies were made to enhance the selenium content in edible plants by different types of cultivation. In our previous work, we already studied the ability of pumpkin seeds to accumulate selenium by foliar application of an aqueous solution containing 1 mg Se/L and we found that the Se content of Se treated plants was about 3.5-fold higher than in nontreated ones. So it was concluded that pumpkin seeds are an appropriate food item for selenium enrichment. 9 For determination of water soluble species of selenium in biological samples, the most often used techniques are ion exchange (cation and anion) and reverse phase liquid chromatography with different detection systems (ICP-MS, AAS, AFS, ETAAS). 10 In the literature, HPLC is most often used in connection with ICP-MS, 4,11-15 HG-AAS 16 and HG-AFS. 7,[17][18][19] For separation of volatile selenium species, GC may be used. 20 The aim of this work was to identify and quantify the selenium species in ...

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Chemical Speciation Influences Comparative Activity of Selenium-Enriched Garlic and Yeast in Mammary Cancer Prevention

Cited by 264 publications

References 25 publications

Selenium yeast: Composition, quality, analysis, and safety

Selenium yeast: Composition, quality, analysis, and safety

Element selective characterization of stability and reactivity of selenium species in selenized yeast

Selenium Species Determination in Selenium-Enriched Pumpkin (Cucurbita pepo L.) Seeds by HPLC-UV-HG-AFS

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