Selenosugars are the major urinary metabolites responsible for the physiological excretion of selenium. Understanding selenium metabolism relies on accurately detecting and identifying selenosugars. However, the research has been hindered by inconsistent terminologies used for selenosugar, varying analytical practices, and an incomplete understanding of the biological pathway for selenosugar biosynthesis.
A recently published review study addresses these longstanding challenges by providing the first harmonized operational nomenclature, standardized analytical recommendations, and an updated framework for mammalian selenium metabolism. The team of scientists, led by Professor Yasumitsu Ogra from the Graduate School of Pharmaceutical Sciences at Chiba University, Japan , establishes standardized terminology, defines rigorous analytical guidelines, and presents an updated metabolic model that integrates evidence accumulated over two decades. The team comprises Dr. Ryszard Lobinski (affiliated with the Department of Chemistry, Warsaw University of Technology, Poland, and the Institute of Analytical and Physical Chemistry for the Environment and Materials at the CNRS-UPPA, France); Dr. Noriyuki Suzuki from Faculty of Pharmaceutical Sciences, Toho University, Japan; Dr. Roger A. Sunde from Department of Nutritional Sciences, University of Wisconsin-Madison, USA; and Dr. Joanna Szpunar from the Institute of Analytical and Physical Chemistry for the Environment and Materials, CNRS-UPPA, France. Their research findings were published online in the Biological Trace Element Research journal on July 31, 2026, and it will be available in the print issue Volume 204, Issue 9 on 1st September 2026.
"Individual researchers had been naming selenosugars arbitrarily since their discovery in the early 2000s, which motivated us to establish a standardized nomenclature. We also focused on establishing a standardized analytical framework, as selenosugar detection and identification largely depend on it," mentioned Prof. Ogra. The publication represents the outcome of an international collaborative effort supported by the Academic Research & Innovation Management Organization, Chiba University, bringing together complementary expertise from multiple disciplines to develop consensus recommendations for the field.
The team introduced an operational and harmonized nomenclature to replace the diverse collection of names previously used for selenosugars. The proposed system retains essential structural information while providing concise and intuitive names that can be consistently adopted by researchers worldwide. The proposed naming system consists of a root symbol for the sugar and a set of specific symbols to describe the chemical modifications within the molecule. By eliminating ambiguity between precursor molecules, derivatives, and excretory products, the framework creates a unified scientific language for the benefit of future investigations.
The authors also established what they describe as the minimum analytical criteria for reliable selenosugar identification. The recommended workflow combines complementary analytical technologies to overcome the limitations associated with individual methods. High-performance liquid chromatography coupled with inductively coupled plasma mass spectrometry (HPLC–ICP–MS) provides sensitive selenium-specific detection and quantification, HPLC–electrospray ionization tandem MS confirms molecular information, and nuclear magnetic resonance spectroscopy serves as the definitive tool for structural validation. Together, these complementary techniques form the recommended analytical workflow, or 'gold standard,' for reliable selenosugar identification and future selenium speciation studies.
"To avoid misidentifications, we propose molecular confirmation as well as element-specific confirmation. Analysis of authentic standards, following additional measures for accurate mass measurement, and providing information regarding the stability of the selenosugars are also important aspects of the analysis," explained Prof. Ogra.
While selenosugars represent the major urinary metabolite in humans, they have also been identified in various animal taxa, including both mammalian and non-mammalian species, underscoring the diversity of selenium speciation and metabolic pathways across diverse biological systems. The position paper also proposes a substantial revision to the existing framework of selenium metabolism. The proposed framework places selenosugars at the center of mammalian selenium homeostasis, identifying them as the dominant terminal products responsible for selenium detoxification and urinary excretion.
The updated metabolic pathway integrates evidence on recognized intermediates, protein-bound selenosugars, and conjugated selenium species, providing a more comprehensive picture of how selenium is transported, stored, and ultimately eliminated from the body. At the same time, the study also highlights research gaps in understanding the enzymatic mechanisms responsible for selenosugar biosynthesis and why selenium is excreted in sugar-bound forms.
As investigations increasingly shift from simply identifying selenium metabolites toward understanding their biological functions and clinical significance, the new framework is expected to enable deeper exploration of selenium metabolism in health and disease.
"Widespread adoption of these recommendations and continued integration of analytical chemistry with biochemical and systems-level approaches will improve the consistency and reproducibility of selenium research while advancing our understanding of selenium homeostasis," concluded Prof. Ogra.
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About Professor Yasumitsu Ogra from Chiba University, Japan
Dr. Yasumitsu Ogra is Professor and Dean of the Graduate School of Pharmaceutical Sciences at Chiba University, Japan, where he leads the Laboratory of Toxicology and Environmental Health. He obtained his Ph.D. from Chiba University in 1996. His research focuses on the biological roles of trace elements, particularly selenium and other metals, combining advanced analytical chemistry with toxicology and metabolomics. He has published over 250 highly-cited research papers to date and is a member of prestigious academic societies, including The Royal Society of Chemistry and The Asian Congress of Toxicology.
Funding:
Ryszard Lobinski and Joanna Szpunar are grateful for the support of the JSPS Program for Forming Japan's Peak Research Universities (J-PEAKS) Grant Number JPJS00420230002. This work was supported by JSPS KAKENHI Grant Number 24H00749.
Reference:
Title of original paper: Selenosugars in Animals and Humans: Operational Nomenclature, Analysis, Occurrence, and Metabolic Pathways
Authors: Yasumitsu Ogra1, Noriyuki Suzuki2, Yasunori Fukumoto1, Yu-ki Tanaka1, Roger A. Sunde3, Joanna Szpunar4, and Ryszard Lobinski4,5
Affiliations:
1Laboratory of Toxicology and Environmental Health, Graduate School of Pharmaceutical Sciences, Chiba University, Japan
2Faculty of Pharmaceutical Sciences, Toho University, Japan
3Department of Nutritional Sciences, University of Wisconsin, Madison, USA
4Institute of Analytical and Physical Chemistry for the Environment and Materials, CNRS-UPPA, France
5Chair of Analytical Chemistry, Department of Chemistry, Warsaw University of Technology, Poland
Journal: Biological Trace Element Research
DOI: https://doi.org/10.1007/s12011-026-05268-2
