Selenium is an essential micronutrient that plays a crucial role in maintaining human health. Selenium deficiency is seriously associated with various diseases such as Keshan disease, Kashin–Beck disease, cataracts, and others. Conversely, selenium supplementation has been found to have multiple effects, including antioxidant, anti-inflammatory, and anticancer functions. Compared with inorganic selenium, organic selenium exhibits higher bioactivities and a wider range of safe concentrations. Consequently, there has been a significant development of selenium-enriched foods which contain large amounts of organic selenium in order to improve human health. This review summarizes the physiological role and metabolism of selenium, the development of selenium-enriched foods, the physiological functions of selenium-enriched foods, and provides an analysis of total selenium and its species in selenium-enriched foods, with a view to laying the foundation for selenium-enriched food development.

Rapeseed is the third largest oil crop in the world and the largest oil crop in China. The multi-functional development and utilization of rapeseed is an effective measure for the high-quality development of rapeseed industry in China. In this study, several basic nutrients of eight rapeseed sprouts and five bean sprouts (3–5 varieties each) were determined, including sugar, crude protein, crude fiber, vitamin E, minerals, fatty acids, amino acids, and glucosinolates. Data analysis revealed that compared with bean sprouts, rapeseed sprouts were nutritionally balanced and were richer in active nutrients such as glucose, magnesium, selenium, vitamin E, and glucosinolate. Moreover, rapeseed sprouts exhibited reasonable amino acid composition and abundant unsaturated fatty acids (accounting for 90.32% of the total fatty acids). All these results indicated the potential of rapeseed sprout as a functional vegetable. Subsequently, three dominant nutrients including vitamin E, glucosinolate, and selenium were investigated in seeds and sprouts of 44 B. napus L. varieties. The results showed that germination raised the ratio of α-tocopherol/γ-tocopherol from 0.53 in seeds to 9.65 in sprouts, greatly increasing the content of α-tocopherol with the strongest antioxidant activity among the eight isomers of vitamin E. Furthermore, germination promoted the conversion and accumulation of glucosinolate components, especially, glucoraphanin with strong anti-cancer activity with its proportion increased from 1.06% in seeds to 1.62% in sprouts. In addition, the contents of selenium, vitamin E, and glucosinolate in rapeseed sprouts were highly correlated with those in seeds. Furthermore, these three dominant nutrients varied greatly within B. napus varieties, indicating the great potential of rapeseed sprouts to be further bio-enhanced. Our findings provide reference for the multi-purpose development and utilization of rapeseed, lay a theoretical foundation for the development of rapeseed sprout into a functional vegetable, and provide a novel breeding direction.

Cadmium (Cd) is a recognized environmental contaminant, present in soil, water, and food, which has been reported to cause male reproductive damage in vivo and vitro. Selenium-enriched rapeseed flowering stalks exhibit protective effects against Cd-induced reproductive damage, yet the bioactive components and underlying mechanisms remain unclear. We optimized the process of obtaining the crude extract (CE) via single-factor experiments. Subsequent bioassay-guided fractionation identified the water extract (WE) as significantly more effective in alleviating Cd-induced cytotoxicity compared to the petroleum ether extract, ethyl acetate extract, and n-butanol extract. High-performance liquid chromatography–inductively coupled plasma mass spectrometry (HPLC-ICP-MS) analysis revealed that WE contained the highest contents of methylselenocysteine (MeSeCys) and selenocystine (SeCys₂) among four fractions. Both MeSeCys and SeCys₂ exhibited protective effects against Cd-induced cytotoxicity. To further elucidate the underlying mechanisms, network pharmacology, RNA-Seq, qPCR, and Western blotting analysis were employed. The results revealed that WE exhibited good free radical scavenging capabilities, and the protective mechanisms of WE, MeSeCys, and SeCys₂ against Cd-induced cytotoxicity were related to a reduction in oxidative damage, the inhibition of the ERK/p38 MAPK signaling pathway, and the suppression of cell cycle arrest, inflammation, and apoptosis triggered by Cd exposure. Collectively, these findings suggest that selenium-enriched rapeseed flowering stalks may serve as a promising dietary supplement in the prevention of Cd-induced reproductive toxicity.

Male infertility, a global health issue marked by spermatogenic failure, hinges on selenium (Se) as a key element for normal spermatogenesis. Among different Se species, Se-methylselenocysteine (MeSeCys) has been developed as a natural organic Se supplement with potent antioxidant and anti-inflammatory properties, but its direct effects on male reproduction need to be further explored. This study investigated the effect of MeSeCys on GC-1 spg (GC-1) and GC-2 spd (ts) (GC-2) cell lines, which mimic early stages. Treatment with 75 μmol/L MeSeCys for 24 h markedly enhanced the viability of both cell lines, with a more pronounced effect observed in GC-1 than in GC-2 cells. Moreover, this study demonstrated that MeSeCys enters cells through SLC7A11 or LRP8 channels and elevates intracellular Se levels in both GC-1 and GC-2 cells, with higher levels observed in GC-1 cells. RNA sequencing (RNA-seq) and bioinformatics analysis revealed that MeSeCys may regulate selenocompound metabolism and the glutathione metabolism pathway in both cell lines, increasing their intracellular glutathione (GSH) levels. Importantly, in GC-1 cells, MeSeCys specifically modulates the mTOR pathway, which further modulates glutathione metabolism and intracellular redox balance. This finding provides novel insights into the beneficial effects of MeSeCys on male reproductive cells, highlighting its potential as a nutritional supplement for male reproductive health.

Chemotherapy treatment of colorectal cancer (CRC) with cisplatin (CDDP) faces drug resistance and cytotoxicity issues, highlighting the urgent need for combination strategies. Selenium-enriched rapeseed extracts exhibit anticancer effects; however, their bioactive components and mechanisms remain unclear. Here, we applied different solvents to fractionate extracts of selenium-enriched rapeseed and found that the water extract (WE) fraction significantly enhanced the cytotoxic effect of CDDP on cancer cells without damaging normal cells, namely, HK-2 and NCM460. High-performance liquid chromatography–inductively coupled plasma–mass spectrometry (HPLC-ICP-MS) analysis revealed methylselenocysteine (MSC) and selenocysteine (SeCys₂) as the main selenium species in the WE. Through cell biology and integrative multi-omics analysis, we found a synergistic anti-CRC cell effect upon combining CDDP with MSC, sulforaphane (SFN), celastrol (Cel), indole-3-carbinol (I3C), α-linolenic acid (ALA) or linoleic acid (LA). We propose that CDDP-WE (cisplatin and water extract) combination treatment holds promise for improving antitumor efficacy against chemo-refractory cells.