Selenium Analysis and Speciation in Dietary Supplements Based on Next-Generation Selenium Ingredients

Abstract

Selenium is essential for humans and the deficit of Se requires supplementation. In addition to traditional forms such as Se salts, amino acids, or selenium-enriched yeast supplements, next-generation selenium supplements, with lower risk for excess supplementation, are emerging. These are based on selenium forms with lower toxicity, higher bioavailability, and controlled release, such as zerovalent selenium nanoparticles (SeNPs) and selenized polysaccharides (SPs). This article aims to focus on the existing analytical systems for the next-generation Se dietary supplement, providing, at the same time, an overview of the analytical methods available for the traditional forms. The next-generation dietary supplements are evaluated in comparison with the conventional/traditional ones, as well as the analysis and speciation methods that are suitable to reveal which Se forms and species are present in a dietary supplement. Knowledge gaps and further research potential in this field are highlighted. The review indicates that the methods of analysis of next-generation selenium supplements should include a step related to chemical species separation. Such a step would allow a proper characterization of the selenium forms/species, including molecular mass/dimension, and substantiates the marketing claims related to the main advantages of these new selenium ingredients.

Plant Biostimulant Effects of Baker’s Yeast Vinasse and Selenium on Tomatoes through Foliar Fertilization

“…Tomato plants are Se non-accumulator plants, being sensitive to a rather low concentration of selenium. The physiological effects of selenium are very diverse and still not completely understood-besides involvement in the catalytic center of the redox enzymes, selenium seems to be involved into cellular signaling, epigenetic effects, and protein folding [74]. We propose vinasse as an affordable source of glycine betaine, to be used together with Se salts, not only because of similarity between the effects on plants-e.g., increased tolerance to water stress, well known for both Se [11] and glycine betaine [30], but mainly to reduce the potential hazard of selenium.…”

“…We propose vinasse as an affordable source of glycine betaine, to be used together with Se salts, not only because of similarity between the effects on plants-e.g., increased tolerance to water stress, well known for both Se [11] and glycine betaine [30], but mainly to reduce the potential hazard of selenium. Moreover, glycine betaine could be used also as methyl donor, to support Se metabolism and its physiological effects [74]. Recent studies highlight the role of glycine-betaine on the metabolic processes, including epigenetic effects, protein folding, and association and regulation of enzymes activity [75].…”

Plant Biostimulants Based on Selenium Nanoparticles Biosynthesized by Trichoderma Strains

“…were shown to be able to bio-synthesize selenium nanoparticles (SeNPs) [3]. Selenium (Se) is known to have beneficial effects on plant and animal metabolism at low concentrations, being involved in protection against reactive oxygen species (ROS) in the form of selenoproteins [4]. Se can also act as a protective agent against the harmful effects of heavy metals [5].…”

“…Se can also act as a protective agent against the harmful effects of heavy metals [5]. Nevertheless, Se has a narrow physiological window, and the toxicity depends on Se species, SeNPs being much less toxic than Se salts [4].The aim of this study was to develop and test a plant biostimulant based on SeNPs bio-synthesized by Trichoderma spp. by monitoring its effects on different stages of plant growth, as well as some biochemical markers of these effects.…”

“…Se can also act as a protective agent against the harmful effects of heavy metals [5]. Nevertheless, Se has a narrow physiological window, and the toxicity depends on Se species, SeNPs being much less toxic than Se salts [4].…”