Voyage of selenium from environment to life: Beneficial or toxic?

Abstract

Selenium (Se), a naturally occurring metalloid, is an essential micronutrient for life as it is incorporated as selenocysteine in proteins. Although beneficial at low doses, Se is hazardous at high concentrations and poses a serious threat to various ecosystems. Due to this contrasting ‘dual' nature, Se has garnered the attention of researchers wishing to unravel its puzzling properties. In this review, we describe the impact of selenium's journey from environment to diverse biological systems, with an emphasis on its chemical advantage. We describe the uneven distribution of Se and how this affects the bioavailability of this element, which, in turn, profoundly affects the habitat of a region. Once taken up, the subsequent incorporation of Se into proteins as selenocysteine and its antioxidant functions are detailed here. The causes of improved protein function due to the incorporation of redox‐active Se atom (instead of S) are examined. Subsequently, the reasons for the deleterious effects of Se, which depend on its chemical form (organo‐selenium or the inorganic forms) in different organisms are elaborated. Although Se is vital for the function of many antioxidant enzymes, how the pro‐oxidant nature of Se can be potentially exploited in different therapies is highlighted. Furthermore, we succinctly explain how the presence of Se in biological systems offsets the toxic effects of heavy metal mercury. Finally, the different avenues of research that are fundamental to expand our understanding of selenium biology are suggested.

Selenium Modification of Natural Products and Its Research Progress

“…Other researchers believe that selenium yeast [110] can be added to foods such as bread and milk. This form of selenium is more easily absorbed by the human body, effectively increasing the selenium content of foods and improving their nutritional value [111].…”

The Clothes Matter—Exploiting Agronomical Functions of Trichogenic Selenium Nanoparticles Sharing Activities with Biological Systems Wherein (Were) Formed

“…In areas with selenium deficiencies in the soil, selenium was applied to cultivated plants to increase Se levels in the food chain via biofortification [8,[24][25][26]. Biofortification is considered to produce a better effect on human and animal health than direct supplementation, especially in the case of selenium, which is well known to have a narrow physiological window [16,27,28]. Biofortification treatments on cultivated plants produced effects similar to biostimulants [29,30].…”

The Clothes Matter—Trichogenic Selenium Nanoparticles Share activities with the Biological Systems wherein Formed

“…Due to its physical, chemical, and biological characteristics, selenium (Se) is regarded as an element of great potential in a variety of scientific fields, such as biomedical, food, agricultural, and environmental fields [1][2][3]. Selenium is known to have a narrow physiological window [4,5]. Therefore, in areas with selenium deficit in soil, biofortification is considered to produce better results than direct supplementation [3,6].…”