An improved HPLC method for the investigation of <scp>L</scp>‐selenomethionine metabolism in rat gut contents

Krittaphol, Woravimol; McDowell, Arlene; Thomson, Christine D.; Tucker, Ian G.; Fawcett, J. Paul; Mikov, Momir

doi:10.1002/bmc.1239

Cited by 8 publications

(11 citation statements)

References 21 publications

(25 reference statements)

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“…The present study of the metabolism of SeMet and selenite by gut content suspensions from four segments of the rat intestinal tract shows that both compounds are metabolized to the greatest extent in suspensions of caecum contents as previously observed [27]. Bacterial counts and protein analysis showed that the number of cells and the protein concentrations in suspensions of caecum and colon contents were similar indicating the microbiota in rat caecum are inherently more metabolically active towards SeMet and selenite than the microbiota in colon.…”

Section: Discussionsupporting

confidence: 59%

“…SeMet was analyzed by high performance liquid chromatography with fluorescence detection as previously described [27]. Selenite was measured by hydride generation atomic absorption spectrometry (HGAAS) involving reduction of Se (IV) to hydrogen selenide (H 2 Se) using hydrochloric acid (HCl) combined with sodium borohydride (NaBH 4 ) [28,29].…”

Section: Assay Of Semet and Selenitementioning

confidence: 99%

“…Another study of selenocysteine compounds (Se-p-methoxybenzylselenocysteine and Se-methylselenocysteine) presented to gastrointestinal bacterial species showed that the derivatives were transformed by β-lyase to hydrogen selenide and methylated to methylselenol [26]. We have previously shown that metabolism of SeMet by the gut microbiota in rat is highest in the caecum [27] but it is not known whether methylated selenium compounds are formed.…”

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confidence: 97%

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Biotransformation of l-Selenomethionine and Selenite in Rat Gut Contents

Krittaphol

McDowell

Thomson

et al. 2010

Biol Trace Elem Res

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L-selenomethionine (SeMet) and sodium selenite are widely used selenium nutritional supplements with potential benefit in preventing cancer. However, supplementation is not without risks of toxicity if intake is too high. The aim of the present study was to investigate SeMet and selenite metabolism in the gastrointestinal tract with particular focus on the formation of the volatile selenium excretion products, dimethylselenide (DMSe) and dimethyldiselenide (DMDSe). Adult male Wistar rats (n = 5) were euthanized, their intestinal tracts removed and the contents of jejunum, ileum, caecum and colon used to prepare 10% suspensions in saline. SeMet and selenite (0.5-0.6 mM) were then incubated with these suspensions at 37°C for 3 h. Caecum and colon contents were the most metabolically active towards SeMet with 30% and 15% metabolized over 3 h. DMDSe was the only volatile selenium metabolite detected accounting for 8.7 ± 1.3% of the selenium lost in caecum contents. Selenite was completely metabolized by caecum contents and 73% by colon contents under the same conditions forming DMSe (5.7 ± 0.9% of the selenium lost in caecum) and a precipitate of red amorphous elemental selenium. Based on previous literature and these results, we conclude that the gut microbiota contributes to the excretion of excess selenium through the production of methylated selenium compounds and elemental selenium.

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Section: Discussionsupporting

confidence: 59%

Section: Assay Of Semet and Selenitementioning

confidence: 99%

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confidence: 97%

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Biotransformation of l-Selenomethionine and Selenite in Rat Gut Contents

Krittaphol

McDowell

Thomson

et al. 2010

Biol Trace Elem Res

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“…Such conditions suggest that there are mechanisms for genetic adaptation that might be involved in oscillations in the Se intake, which are mediated by polymorphisms, complexation of SELENOP with toxic elements such as cadmium, arsenic, and mercury forming products of Se excretion (75,76). The metabolism of Se by intestinal bacteria also favors the excretion of excess of Se (41,77).…”

Section: Selenium Toxicitymentioning

confidence: 99%

Selenium in Human Health and Gut Microflora: Bioavailability of Selenocompounds and Relationship With Diseases

et al. 2021

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This review covers current knowledge of selenium in the dietary intake, its bioavailability, metabolism, functions, biomarkers, supplementation and toxicity, as well as its relationship with diseases and gut microbiota specifically on the symbiotic relationship between gut microflora and selenium status. Selenium is essential for the maintenance of the immune system, conversion of thyroid hormones, protection against the harmful action of heavy metals and xenobiotics as well as for the reduction of the risk of chronic diseases. Selenium is able to balance the microbial flora avoiding health damage associated with dysbiosis. Experimental studies have shown that inorganic and organic selenocompounds are metabolized to selenomethionine and incorporated by bacteria from the gut microflora, therefore highlighting their role in improving the bioavailability of selenocompounds. Dietary selenium can affect the gut microbial colonization, which in turn influences the host's selenium status and expression of selenoproteoma. Selenium deficiency may result in a phenotype of gut microbiota that is more susceptible to cancer, thyroid dysfunctions, inflammatory bowel disease, and cardiovascular disorders. Although the host and gut microbiota benefit each other from their symbiotic relationship, they may become competitors if the supply of micronutrients is limited. Intestinal bacteria can remove selenium from the host resulting in two to three times lower levels of host's selenoproteins under selenium-limiting conditions. There are still gaps in whether these consequences are unfavorable to humans and animals or whether the daily intake of selenium is also adapted to meet the needs of the bacteria.

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“…SeMet was analyzed by high performance liquid chromatography with fluorescence detection as described elsewhere [16]. Selenite was analyzed by hydride generation atomic absorption spectrometry (HGAAS) [17,18] and DMSe and DMDSe by gas chromatography-mass spectrometry [8,19] as described elsewhere [4].…”

Section: Methodsmentioning

confidence: 99%

Metabolism of l-Selenomethionine and Selenite by Probiotic Bacteria: In Vitro and In Vivo Studies

Krittaphol

Wescombe²,

Thomson

et al. 2011

Biol Trace Elem Res

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Since selenium supplements have been shown to undergo biotransformation in the gut, probiotic treatment in combination with selenium supplements may change selenium disposition. We investigated the metabolism of L-selenomethionine (SeMet) and selenite by probiotic bacteria in vitro and the disposition of selenium after probiotic treatment followed by oral dosing with SeMet and selenite in rats. When SeMet was incubated anaerobically with individual antibiotic-resistant probiotic strains (Streptococcus salivarius K12, Lactobacillus rhamnosus 67B, Lactobacillus acidophilus L10, and Bifidobacterium lactis LAFTI® B94) at 37°C for 24 h, 11-18% was metabolized with 44-80% of SeMet lost being converted to dimethyldiselenide (DMDSe) and dimethylselenide (DMSe). In similar incubations with selenite, metabolism was more extensive (26-100%) particularly by the lactobacilli with 0-4.8% of selenite lost being converted to DMSe and DMDSe accompanied by the formation of elemental selenium. Four groups of rats (n = 5/group) received a single oral dose of either SeMet or selenite (2 mg selenium/kg) at the time of the last dose of a probiotic mixture or its vehicle (lyoprotectant mixture used to maintain cell viability) administered every 12 h for 3 days. Another three groups of rats (n = 3/group) received a single oral dose of saline or SeMet or selenite at the same dose (untreated rats). Serum selenium concentrations over the subsequent 24 h were not significantly different between probiotic and vehicle treated rats but appeared to be more sustained (SeMet) or higher (selenite) than in the corresponding groups of untreated rats. Probiotic treated rats given SeMet also had selenium concentrations at 24 h that were significantly higher in liver and lower in kidney than untreated rats given SeMet. Thus, treatment with probiotics followed by SeMet significantly affects tissue levels of selenium.

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An improved HPLC method for the investigation of L‐selenomethionine metabolism in rat gut contents

Cited by 8 publications

References 21 publications

Biotransformation of l-Selenomethionine and Selenite in Rat Gut Contents

Biotransformation of l-Selenomethionine and Selenite in Rat Gut Contents

Selenium in Human Health and Gut Microflora: Bioavailability of Selenocompounds and Relationship With Diseases

Metabolism of l-Selenomethionine and Selenite by Probiotic Bacteria: In Vitro and In Vivo Studies

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