Selenium bioactive compounds produced by beneficial microbes.

Selenium (Se) is an essential trace element present as selenocysteine (SeCys) in selenoproteins, which have an important role in thyroid metabolism and the redox system in humans. Se deficiency affects between 500 and 1000 million people worldwide. Increasing Se intake can prevent from bacterial and viral infections. Se deficiency has been associated with cancer, Alzheimer, Parkinson, decreased thyroid function, and male infertility. Se intake depends on the food consumed which is directly related to the amount of Se in the soil as well as on its availability. Se is unevenly distributed on the earth's crust, being scarce in some regions and in excess in others. The easiest way to counteract the symptoms of Se deficiency is to enhance the Se status of the human diet. Se salts are the most toxic form of Se, while Se amino acids and Se-nanoparticles (SeNPs) are the least toxic and most bio-available forms. Some bacteria transform Se salts into these Se species. Generally accepted as safe selenized microorganisms can be directly used in the manufacture of selenized fermented and/or probiotic foods. On the other hand, plant growth-promoting bacteria and/or the SeNPs produced by them can be used to promote plant growth and produce crops enriched with Se. In this chapter we discuss bacterial Se metabolism, the effect of Se on human health, the applications of SeNPs and Se-enriched bacteria, as well as their effect on food fortification. Different strategies to counteract Se deficiency by enriching foods using sustainable strategies and their possible implications for improving human health are discussed.

Protective effects of sodium humate and its zinc and selenium chelate on the oxidative stress, inflammatory, and intestinal barrier damage of Salmonella Typhimurium-challenged broiler chickens.

The objective of this study was to investigate the protective effects and mechanisms of dietary administration of sodium humate (HNa) and its zinc and selenium chelate (Zn/Se-HNa) in mitigating Salmonella Typhimurium (S. Typhi) induced intestinal injury in broiler chickens. Following the gavage of 109 CFU S. Typhi to 240 broilers from 21-d to 23-d aged, various growth performance parameters such as body weight (BW), average daily gain (ADG), average daily feed intake (ADFI), and feed ratio (FCR) were measured before and after infection. Intestinal morphology was assessed to determine the villus height, crypt depth, and chorionic cryptologic ratio. To evaluate intestinal barrier integrity, levels of serum diamine oxidase (DAO), D-lactic acid, tight junction proteins, and the related genes were measured in each group of broilers. An analysis was conducted on inflammatory-related cytokines, oxidase activity, and Nuclear Factor Kappa B (NF-κB) and Nuclear factor erythroid2-related factor 2 (Nrf2) pathway-related proteins and mRNA expression. The results revealed a significant decrease in BW, ADG, and FCR in S. typhi-infected broilers. HNa tended to increase FCR (P = 0.056) while the supplementation of Zn/Se-HNa significantly restored BW and ADG (P < 0.05). HNa and Zn/Se-HNa exhibit favorable and comparable effects in enhancing the levels of serum DAO, D-lactate, and mRNA and protein expression of jejunum and ileal tight junction. In comparison to HNa, Zn/Se-HNa demonstrates a greater reduction in S. Typhi shedding in feces, as well as superior efficacy in enhancing the intestinal morphology, increasing serum catalase (CAT) activity, inhibiting pro-inflammatory cytokines, and suppressing the activation of the NF-κB pathway. Collectively, Zn/Se-HNa was a more effective treatment than HNa to alleviate adverse impact of S. Typhi infection in broiler chickens.

Selenosugar, selenopolysaccharide, and putative selenoflavonoid in plants.

Selenium (Se) is a naturally occurring essential micronutrient that is required for human health. Selenium supports cellular antioxidant defense and possesses bioeffects such as anti-inflammation, anti-cancer, anti-diabetic, and cardiovascular and liver protective effects arising from Se-enhanced cellular antioxidant activity. Past studies on Se have focused on elucidating Se speciation in foods, biofortification strategies to produce Se-enriched foods to address Se deficiency in the population, and the biochemical activities of Se in health. The bioavailability and toxicity of Se are closely correlated to its chemical forms and may exhibit varying effects on body physiology. Selenium exists in inorganic and organic forms, in which inorganic Se such as sodium selenite and sodium selenate is more widely available. However, it is a challenge for safe and effective supplementation considering inorganic Se low bioavailability and high cytotoxicity. Organic Se, by contrast, exhibits higher bioavailability and lower toxicity and has a more diverse composition and structure. Organic Se exists as selenoamino acids and selenoproteins, but recent research has provided evidence that it also exists as selenosugars, selenopolysaccharides, and possibly as selenoflavonoids. Different food categories contain various Se compounds, and their Se profiles vary significantly. Therefore, it is necessary to delineate Se speciation in foods to understand their impact on health. This comprehensive review documents our knowledge of the recent uncovering of the existence of selenosugars and selenopolysaccharides and the putative evidence for selenoflavonoids. The bioavailability and bioactivities of these food-derived organic Se compounds are highlighted, in addition to their composition, structural features, and structure-activity relationships.

Characterization of Selenium Speciation in Se-Enriched Crops: Crop Selection Approach.

Accurately quantifying selenium (Se) speciation and transformation in Se-enriched crops is highly significant for human health. The investigation of Se species in Se-enriched crops involves assessing the enrichment of both organic and inorganic Se species, considering their plant families and edible parts. The staple crops of rice, corn, and wheat showed no or less inorganic Se with the increase of total Se; however, potatoes expressed a proportion of selenate [Se(VI)]. In addition, the organic Se proportions in Se-enriched crops of Cruciferous, Brassicaceae, and Umbelliferae plant families were relatively lower than the proportion of inorganic Se. Concurrently, the edible parts of the Se-enriched gramineous or cereal crops enriched with organic Se and crops with fruit, stem, leaf, and root as edible parts contain the maximum percentage of organic Se with a certain proportion of inorganic Se. This study contributes to a sparse body of literature by meticulously discerning appropriate Se-enriched crop selection through a comprehensive evaluation of Se speciation and its organic and inorganic accumulation potential.

Investigation of selenium and selenium species in Cardamine violifolia using in vitro digestion coupled with a Caco-2 cell monolayer model.

Inadequate Se intake can enhance vulnerability to certain health risks, with supplementation lessening these risks. This study investigated the bioavailability of Se and Se species in five Se compounds and in Se-rich Cardamine violifolia using in vitro digestion coupled with a Caco-2 cell monolayer model, which enabled the study of Se transport and uptake. Translocation results showed that SeCys2 and MeSeCys had high translocation rates in C. violifolia leaves (CVLs). The uptake rate of organic Se increased with time, and MeSeCys exhibited a higher uptake rate than that for SeCys2 and SeMet. The translocation mechanisms of SeMet, Se(IV), and Se(VI) were passive transport, whereas those of SeCys2 and MeSeCys were active transport. The bioavailability of organic Se was higher than that of inorganic Se, with a total Se bioavailability in CVLs of 49.11 %. This study would provide a theoretical basis for the application of C. violifolia in the functional food.

Selenium speciation studies in cancer patients to evaluate the responses of biomarkers of selenium status to different selenium compounds.

This work presents the first systematic comparison of selenium (Se) speciation in plasma from cancer patients treated orally with three Se compounds (sodium selenite, SS; L-selenomethionine, SeMet; or Se-methylselenocysteine, MSC) at 400 µg/day for 28 days. The primary goal was to investigate how these chemical forms of Se affect the plasma Se distribution, aiming to identify the most effective Se compound for optimal selenoprotein expression. This was achieved using methodology based on HPLC-ICP-MS after sample preparation/fractionation approaches. Measurements of total Se in plasma samples collected before and after 4 weeks of treatment showed that median total Se levels increased significantly from 89.6 to 126.4 µg kg-1 Se (p < 0.001), particularly when SeMet was administered (190.4 µg kg-1 Se). Speciation studies showed that the most critical differences between treated and baseline samples were seen for selenoprotein P (SELENOP) and selenoalbumin after administration with MSC (p = 5.8 × 10-4) and SeMet (p = 6.8 × 10-5), respectively. Notably, selenosugar-1 was detected in all low-molecular-weight plasma fractions following treatment, particularly with MSC. Two different chromatographic approaches and spiking experiments demonstrated that about 45% of that increase in SELENOP levels (to ~ 8.8 mg L-1) with SeMet is likely due to the non-specific incorporation of SeMet into the SELENOP affinity fraction. To the authors' knowledge, this has not been reported to date. Therefore, SELENOP is probably part of both the regulated (55%) and non-regulated (45%) Se pools after SeMet administration, whereas SS and MSC mainly contribute to the regulated one.

Advances in drug structure-activity-relationships for the development of selenium-based compounds against HIV.

INTRODUCTION: Selenium possesses numerous advantageous properties in the field of medicine, and a variety of selenium-containing compounds have been documented to exhibit anti-HIV activity. This paper aims to categorize these compounds and conduct SAR analysis to offer guidance for drug design and optimization. AREAS COVERED: The authors present a comprehensive review of the reported SAR analysis conducted on selenium-based compounds against HIV, accompanied by a concise discussion regarding the pivotal role of selenium in drug development. EXPERT OPINION: In addition to the conventional bioisosterism strategy, advanced strategies such as covalent inhibition, fragment-based growth and drug repositioning can also be incorporated into research on selenium-containing anti-HIV drugs. Ebselen, which acts as an HIV capsid inhibitor, serves as a valuable probe compound for the discovery of novel HIV integrase inhibitors. Furthermore, it is crucial not to underestimate the potential toxicity associated with organic selenium compounds despite no reported instances of severe toxicity.

Speciation of Selenium Nanoparticles and Other Selenium Species in Soil: Simple Extraction Followed by Membrane Separation and ICP-MS Determination.

The application of selenium nanoparticle (SeNP)-based fertilizers can cause SeNPs to enter the soil environment. Considering the possible transformation of SeNPs and the species-dependent toxicity of selenium (Se), accurate analysis of SeNPs and other Se species present in the soil would help rationally assess the potential hazards of SeNPs to soil organisms. Herein, a novel method for speciation of SeNPs and other Se species in soil was established. Under the optimized conditions, SeNPs, selenite, selenate, and seleno amino acid could be simultaneously extracted from the soil with mixtures of tetrasodium pyrophosphate (5 mM) and potassium dihydrogen phosphate (1.2 µM), while inert Se species (mainly metal selenide) remained in the soil. Then, extracted SeNPs can be effectively captured by a nylon membrane (0.45 µm) and quantified by inductively coupled plasma mass spectrometry (ICP-MS). Other extracted Se species can be separated and quantified by high-performance liquid chromatography coupled with ICP-MS. Based on the difference between the total Se contents and extracted Se contents, the amount of metal selenide can be calculated. The limits of detection of the method were 0.02 µg/g for SeNPs, 0.05 µg/g for selenite, selenate, and selenocystine, and 0.25 µg/g for selenomethionine, respectively. Spiking experiments also showed that our method was applicable to real soil sample analysis. The present method contributes to understanding the speciation of Se in the soil environment and further estimating the occurrence and application risks of SeNPs.

Study on CdSe/ZnS Quantum Dot Fluorescence Immunoprobe for Detection of Aflatoxin B1 in 5 Traditional Chinese Medicines.

Aflatoxin is a highly toxic substance, of which aflatoxin B1 is the most toxic and carcinogenic among aflatoxins. In this paper, the team used homemade CdSe/Zns quantum dots to construct a fluorescent immunoprobe and all-antigen coupling with aflatoxin B1. It used a self-developed fluorescence intensity detector to detect aflatoxin B1 in five traditional Chinese medicines, namely, ginseng, Panax ginseng, Chuanxiong rhizome, rhubarb, and yam. The recoveries were 80.0-102.0%; the relative standard deviations (RSD)were from 2.4 to 9.2.

Mechanistic Insight into the Abiotic Interactions of Selenate and Selenite with Natural Organic Matter.

Natural organic matter (NOM) decreases the selenium (Se) mobility in soil and sediment. Biotic dissimilatory reduction of selenate and selenite and assimilation of the reduced Se species into biomolecules are thought to be primarily responsible for this decreased Se mobility. However, the possibility of Se immobilization due to the abiotic interaction of Se species with NOM is still poorly understood. Equilibrating selenate and selenite with a model NOM (Pahokee peat soil), followed by X-ray absorption spectroscopic analysis, this study shows that the NOM can abiotically reduce highly mobile selenate into relatively less mobile selenite. NOM can sorb Se species, especially selenite, considerably. Preloading of the NOM with Fe(III) increases the sorption of selenite and selenate by several orders of magnitude. Modeling of the Se and Fe K-edge EXAFS data revealed that Se species are sorbed to NOM due to indirect complexation with the organically complexed Fe(O,OH)6 octahedra through the corner- (2C) and edge-sharing (1E) and direct complexation with the oxygen-containing functional groups of the NOM. This study concludes that the abiotic reduction and complexation of the Se species with NOM can be the additional or alternative route of Se immobilization in the NOM-rich soil and sediment.

Antimicrobial Coatings for Medical Textiles via Reactive Organo-Selenium Compounds.

Bleached and cationized cotton fabrics were chemically modified with reactive organoselenium compounds through the nucleophilic aromatic substitution (SNAr) reaction, which allowed for organo-selenium attachment onto the surface of cotton fabrics via covalent bonds and, in the case of the cationized cotton fabric, additional ionic interactions. The resulting textiles exhibited potent bactericidal activity against S. aureus (99.99% reduction), although only moderate activity was observed against E. coli. Fabrics treated with reactive organo-selenium compounds also exhibited fungicidal activities against C. albicans, and much higher antifungal activity was observed when organo-selenium compounds were applied to the cationized cotton in comparison to the bleached cotton. The treatment was found to be durable against rigorous washing conditions (non-ionic detergent/100 °C). This paper is the first report on a novel approach integrating the reaction of cotton fabrics with an organo-selenium antimicrobial agent. This approach is attractive because it provides a method for imparting antimicrobial properties to cotton fabrics which does not disrupt the traditional production processes of a textile mill.

Human serum albumin-bound selenium (Se-HSA) in serum and its correlation with other selenium species.

INTRODUCTION: Selenium (Se) is a trace element with different toxicological and nutritional properties according to its chemical forms. Among the wide range of selenium species, human serum albumin-bound selenium (Se-HSA) has still uncertain composition in terms of organic or inorganic selenium species. This study aimed at investigating the relation between Se-HSA levels with total selenium and the specific organic and inorganic selenium species. METHODS: We determined levels of total selenium and selenium species in serum of participants enrolled in two populations of the Emilia-Romagna region, in Northern Italy. Anion exchange chromatography coupled with inductively coupled plasma dynamic reaction cell mass spectrometry was used as quantification method. Correlations between Se-HSA and the other selenium compounds were analyzed using linear regression and restricted cubic spline regression models, adjusted for potential confounders. RESULTS: The first cohort comprised 50 participants (men/women: 26/24) with median (interquartile range, IQR) age 50 (55-62) years, while the second was composed of 104 participants (M/W: 50/54), median (IQR) age 48 (44-53) years. Median (IQR) levels of total selenium were 118.5 (109-136) µg/L and 116.5 (106-128) µg/L, respectively, while Se-HSA was 25.5 µg/L (16.2-51.5) and 1.1 (0.03-3.1) µg/L, respectively. In both populations, Se-HSA was positively associated with inorganic selenium species. Conversely, Se-HSA was inversely associated with organic selenium, especially with selenoprotein P-bound-Se (Se-SELENOP) and less strongly with selenomethionine-bound-Se (Se-Met), while the relation was null or even positive with other organic species. Evaluation of non-linear trends showed a substantially positive association with inorganic selenium, particularly selenite, until a concentration of 30 µg/L, above which a plateau was reached. The association with Se-SELENOP was inverse and strong until 100 µg/L, while it was almost null at higher levels. CONCLUSIONS: Our findings seem to indicate that Se-HSA incorporates more selenium when circulating levels of inorganic compounds are higher, thus supporting its mainly inorganic nature, particularly at high circulating levels of selenite.

Nutritional Supplementation and Enhanced Antioxidant Function by Dietary Intake of Selenoneine and Other Selenium Compounds in Red Seabream Pagrus major.

Selenoneine, 2-selenyl-Nα, Nα, Nα-trimethyl-L-histidine, is the major organic selenium compound in marine fish. To characterize biological antioxidant function of selenoneine in fish, the accumulation of selenoneine and other selenium compounds, i. e., sodium selenite and selenomethionine, in the muscle and other tissues of red seabream. We reared red seabream by feeding of 1% dry pellet containing of sodium selenite, selenomethionine, or selenoneine of body weight twice a day for 4 weeks. After that, we replaced to 1% of normal commercial dry pellet of body weight twice a day for 1 week from the selenium supplementation, and tissue distribution of total selenium was determined. Selenium supplementation with selenoneine, selenomethionine, and sodium selenite enhanced selenium accumulation in the white muscle, kidney, and hepatopancreas in comparison with the control group. By the dietary intake of selenoneine, total selenium concentrations were increased in the white muscle, heart, kidney, spleen, hepatopancreas, brain, and blood cells in a dose-dependent manner during the trials after 2 weeks. Dietary intake of selenoneine as well as sodium selenite and selenomethionine reduced oxidation-reduction potential (ORP). Selenoneine concentrations in the white muscle and blood cells were accumulated for 4 weeks by the selenoneine intake, whereas selenoneine concentration was not elevated by the intake of selenomethionine and sodium selenite, suggesting that tissue selenoneine levels might be derived from only selenoneine-containing diet. The uptake factor of selenoneine from the artificial feed containing selenoneine was calculated to be 0.0062 in the white muscle and 4.0 in the blood. The half-life of total selenium in the blood cells and white muscle were estimated to be 60 days in the white muscle and 30 days in the blood.

The redox riddle of selenium sulfide.

Selenium sulfide, in analogy with selenium dioxide, is often considered as SeS2. At closer inspection, however, selenium sulfide represents a large family of rather complicated molecules which differ depending on the mode of preparation. Together, these compounds share extraordinarily low solubility in virtually any solvent with a biological activity rather impressive for such simple molecules. The surface reactivity of such microscopic and nanoscopic materials, prepared chemically or by fermentation, may provide an answer to this riddle and explain activities by a combination of physical, redox, metal binding, covalent, and non-covalent interactions with biomolecules and cells.

Bioaccumulation of CdSe Quantum Dots Show Biochemical and Oxidative Damage in Wistar Rats.

Cadmium selenium quantum dots (CdSe QDs) with modified surfaces exhibit superior dispersion stability and high fluorescence yield, making them desirable biological probes. The knowledge of cellular and biochemical toxicity has been lacking, and there is little information on the correlation between in vitro and in vivo data. The current study was carried out to assess the toxicity of CdSe QDs after intravenous injection in Wistar male rats (230 g). The rats were given a single dose of QDs of 10, 20, 40, and 80 mg/kg and were kept for 30 days. Following that, various biochemical assays, hematological parameters, and bioaccumulation studies were carried out. Functional as well as clinically significant changes were observed. There was a significant increase in WBC while the RBC decreased. This suggested that CdSe quantum dots had inflammatory effects on the treated rats. The various biochemical assays clearly showed that high dose induced hepatic injury. At a dose of 80 mg/kg, bioaccumulation studies revealed that the spleen (120 g/g), liver (78 g/g), and lungs (38 g/g) accumulated the most. In treated Wistar rats, the bioretention profile of QDs was in the following order: the spleen, liver, kidney, lungs, heart, brain, and testis. The accumulation of these QDs induced the generation of intracellular reactive oxygen species, resulting in an alteration in antioxidant activity. It is concluded that these QDs caused oxidative stress, which harmed cellular functions and, under certain conditions, caused partial brain, kidney, spleen, and liver dysfunction. This is one of the most comprehensive in vivo studies on the nanotoxicity of CdSe quantum dots.

Relationships between Molecular Characteristics of Novel Organic Selenium Compounds and the Formation of Sulfur Compounds in Selenium Biofortified Kale Sprouts.

Due to problems with selenium deficiency in humans, the search for new organic molecules containing this element in plant biofortification process is highly required. Selenium organic esters evaluated in this study (E-NS-4, E-NS-17, E-NS-71, EDA-11, and EDA-117) are based mostly on benzoselenoate scaffolds, with some additional halogen atoms and various functional groups in the aliphatic side chain of different length, while one compound contains a phenylpiperazine moiety (WA-4b). In our previous study, the biofortification of kale sprouts with organoselenium compounds (at the concentrations of 15 mg/L in the culture fluid) strongly enhanced the synthesis of glucosinolates and isothiocyanates. Thus, the study aimed to discover the relationships between molecular characteristics of the organoselenium compounds used and the amount of sulfur phytochemicals in kale sprouts. The statistical partial least square model with eigenvalues equaled 3.98 and 1.03 for the first and second latent components, respectively, which explained 83.5% of variance in the predictive parameters, and 78.6% of response parameter variance was applied to reveal the existence of the correlation structure between molecular descriptors of selenium compounds as predictive parameters and biochemical features of studied sprouts as response parameters (correlation coefficients for parameters in PLS model in the range-0.521 ÷ 1.000). This study supported the conclusion that future biofortifiers composed of organic compounds should simultaneously contain nitryl groups, which may facilitate the production of plant-based sulfur compounds, as well as organoselenium moieties, which may influence the production of low molecular weight selenium metabolites. In the case of the new chemical compounds, environmental aspects should also be evaluated.

Selenium Uptake, Translocation, and Metabolization Pattern during Barley Malting: A Comparison of Selenate, Selenite, and Selenomethionine.

Selenium (Se) is an essential trace element for human and animal health. Understanding the uptake and translocation of Se in crops is critical from the perspective of Se biofortification. In this study, barley was malted to investigate the uptake, translocation, and metabolism of exogenous Se including Na2SeO4, Na2SeO3, and selenomethionine (Se-Met). The results showed that the uptake rates of different forms of Se in barley decreased in the following order: Se-Met > Na2SeO3 > Na2SeO4, with the peak uptake occurring at the end of the steeping stages. In the early stages of germination, Se was mainly distributed in the husk and endosperm. Exogenous Se upregulated the transcription levels of Se transport and metabolic enzyme genes in the barley to varying degrees, which promoted Se transformation in various tissues, and improved Se bioeffectiveness. Compared to the Na2SeO3 and Se-Met groups, more Se was transferred from husk and endosperm to acrospire and rootlets in the Na2SeO4 group during the germination stage. Na2SeO4 and Se-Met stimulated the development of rootlets, and accelerated Se metabolism, resulting in a higher Se loss rate. Thus, these comparative findings provide new insights into Se uptake, transformation, and metabolization in barley.

Photocatalytic treatment of organoselenium in synthetic mine-impacted effluents.

Biological selenium reduction processes are commonly employed as the best available technology (BAT) for selenium removal; however, as a by-product they produce trace amounts of organoselenium compounds with orders of magnitude greater bioaccumulation potential and toxicity. Here, we assessed buoyant photocatalysts (BPCs) as a potential passive advanced oxidation process (P-AOP) for organoselenium treatment. Using a synthetic mine-impacted water solution, spiked with selenomethionine (96 µg/L) as a representative organoselenium compound, photocatalysis with BPCs fully eliminated selenomethionine to <0.01 µg/L with conversion to selenite and selenate. A theoretical reaction pathway was inferred, and a kinetics model developed to describe the treatment trends and intermediates. Given the known toxic responses of Lepomis macrochirus and Daphnia magna to organoselenium, it was estimated that photocatalysis could effectively eliminate organoselenium acute toxicity within a UV dose of 8 kJ/L (1-2 days solar equivalent exposure), by transformation of selenomethionine to less hazardous oxidized Se species. Solar photocatalysis may therefore be a promising passive treatment technology for selenium-impacted mine water management.

Inorganic and Organic Selenium Speciation of Seleno-Yeasts Used as Feed Additives: New Insights from Elemental Selenium Determination.

Seleno-Yeasts (SY) used as feed additives are known to contain different Selenium (Se) species. Seleno-Yeasts has been shown, on previous analytical methods, to contain selenomethionine (SeMet), selenocysteine (SeCys), selenate (SeIV) and selenite (SeVI), and various other organic and inorganic Se forms identified but rarely quantified. A new advanced method has allowed elemental Se (Se0), an inorganic Se species, to be quantified, thereby obtaining better insight into the proportion of inorganic Se in SY products. The study aimed to quantify the Se0 in SY products and assess the proportion of inorganic Se in SY. The Se speciation of 13 fresh commercials SY from different suppliers and batches, was assayed for the total Se, inorganic Se species (SeIV, SeVI and Se0), and organic Se species (SeMet and SeCys). Results on total Se were in line with the expected Se concentrations for all evaluated samples. The proportion of Se present as Se0 ranged from 3.6% to 51.8%. The quantity of Se0 in the SY products, added to SeIV and SeVI, indicated an average proportion of inorganic Se of 14.2% for the 13 analyzed SY products. The proportion of Se as SeMet ranged from 19.0% to 71.8%, (average of 55.8%), and a large variability in the SeMet content was observed. The SeCys content was also variable, with an average of 3.8%, relative to the total Se. In conclusion, advances in the analytical characterization have revealed that SY products can have a significantly high proportion of inorganic Se, which could affect the bioavailability of Se from SY supplements and explain their variable and lower bio-efficacy than pure SeMet supplements, such as hydroxy-selenomethionine.

Design, synthesis, spectroscopic characterizations, single crystal X-ray analysis, in vitro xanthine oxidase and acetylcholinesterase inhibitory evaluation as well as in silico evaluation of selenium-based N-heterocyclic carbene compounds.

Herein, eight new NHC-based selenourea derivatives were synthesized and characterized by using spectroscopic method (1H, 19F, and 13C NMR, FT-IR), and elemental analysis techniques. These compounds were synthesized by mixing benzimidazolium salts, potassium carbonate, and selenium powder in ethyl alcohol. Additionally, the molecular and crystal structures of the three compounds (1c, 2b, and 2c) were determined using the single-crystal x-ray diffraction (XRD) method. Diffraction analysis demonstrated the partial carbon-selenium double-bond character of these compounds. All compounds were determined to be highly potent inhibitors for AChE and XO enzymes. The IC50 values for the compounds were found in the range of 0.361-0.754 µM for XO and from 0.995 to 1.746 µM for AChE. The DNA binding properties of the compounds were investigated. These compounds did not have a remarkable DNA binding property. Also, DPPH radical scavenging activities of the compounds were also investigated. Compounds (1c), (2a), (3a), and (3b) exhibited more pronounced DPPH radical scavenging activity when compared to other compounds. Docking studies were applied by using AutoDock 4 to determine interaction mechanism of the selected compounds (1a), (1b), and (3b). The compound (1b) has good binding affinity (-9.78 kcal/mol) against AChE, and (-6.86 kcal/mol) for XO target. Drug similarity properties of these compounds compared to positive controls were estimated and evaluated by ADMET analysis. Furthermore, molecular dynamics simulations have been applied to understand the accuracy of docking studies. These findings and the defined compounds could be potential candidates for the discovery and progress of effective medicine(s) for AChE and XO in the future.Communicated by Ramaswamy H. Sarma.