Selenium (Se) is a chemical element essential to human health because of its bioactive properties, including antioxidative, anticancer, and immunomodulating activities. Despite the high therapeutic potential of Se, its intrinsic properties of poor stability, a narrow therapeutic window, and low bioavailability and bioactivity have limited its clinical applications. Selenium nanoparticles (SeNPs) exhibit lower toxicity and higher bioactivity than other Se forms. Herein, we report a green method for the preparation of monodisperse SeNPs with starch microgel (SM) and epigallocatechin gallate (EGCG) through Se-O bonds and polysaccharide–polyphenol interactions (namely, SM-EGCG-SeNPs). SM-EGCG-SeNPs showed higher stability, bioactivities, and cytotoxicity than SeNPs and SM-SeNPs at the equivalent dose. SM-EGCG-SeNPs induced the apoptosis of cancer cells via the activation of several caspases and reactive oxygen species overproduction. This work proposes a facile method for the design and potentiation of structure-bioactive SeNPs via polysaccharide–polyphenol interactions.

Cardamine violifolia, a species belonging to the Brassicaceae family, is a selenium hyperaccumulator and a nutritious leafy vegetable. Our previous study showed that C. violifolia leaves are rich in total phenolic acids, but the composition and corresponding genes remain unknown. In this study, we investigated the phenolic acid compounds and potential gene regulation network in the outer leaves (OL) and central leaves (CL) of C. violifolia using transcriptome and metabolome analyses. Results showed that the OL contained a higher total phenolic acid content than the CL. Metabolome analysis revealed a total of 115 phenolic acids, 62 of which (e.g., arbutin, rosmarinic acid, hydroxytyrosol acetate, and sinapic acid) were differentially accumulated between the CL and OL of C. violifolia. Transcriptome analysis showed that the differentially expressed genes were significantly enriched in the pathways of secondary metabolite biosynthesis and phenylpropanoid biosynthesis. Conjoint analysis of the transcriptome and metabolome indicated that seven genes (CYP84A1, CYP84A4, CADH9, SGT1, UGT72E1, OMT1, and CCR2) and eight phenolic acids (sinapic acid, sinapyl alcohol, 5-O-caffeoylshikimic acid, sinapoyl malate, coniferin, coniferyl alcohol, L-phenylalanine, and ferulic acid) constituted a possible regulatory network. This study revealed the phenolic acid compounds and possible regulatory network of C. violifolia leaves and deepened our understanding of its nutrient value.

As a popular form of fruit consumption, fresh-cut watermelon is of great convenience for its consumers. Owing to the lack of comprehensive knowledge about the quality changes of fresh-cut watermelon during its shelf life, guidelines and standards are unavailable currently. To clarify the deterioration process and its underlying mechanism in fresh-cut watermelon, the sensory parameters, metabolomics, and microbial community of fresh-cut watermelon during a three-day storage at both room temperature (RT) and refrigerator temperature were systematically studied in this work. Results revealed that the whole property of the watermelon stored at refrigerator temperature kept stable, while pulps stored at RT had substantially deteriorated after 36 h. The decay was reflected in the significant decrease in soluble solid contents, firmness, pH, and color parameters in the sensory perspective. At the metabolic level, significantly declined malate, citrate, uridine, uridine 5-monophosphate, and amino acids, and increased ethanol and lactate contents, were observed as deterioration markers, which partially resulted from the activities of pyruvate dehydrogenase and alcohol dehydrogenase and the burst of genera Enterobacteriaceae and Leuconostocaceae. This study unveiled the underlying mechanisms of quality changes in fresh-cut watermelon under its primary storage conditions to provide fundamental information and potential clues for its quality control and preservation.

Methionine restriction and selenium supplementation are recommended because of their health benefits. As a major nutrient form in selenium supplementation, selenomethionine shares a similar biological process to its analog methionine. However, the outcome of selenomethionine supplementation under different methionine statuses and the interplay between these two nutrients remain unclear. Therefore, this study explored the metabolic effects and selenium utilization in HepG2 cells supplemented with selenomethionine under deprived, adequate, and abundant methionine supply conditions by using nuclear magnetic resonance-based metabolomic and molecular biological approaches. Results revealed that selenomethionine promoted the proliferation of HepG2 cells, the transcription of selenoproteins, and the production of most amino acids while decreasing the levels of creatine, aspartate, and nucleoside diphosphate sugar regardless of methionine supply. Selenomethionine substantially disturbed the tricarboxylic acid cycle and choline metabolism in cells under a methionine shortage. With increasing methionine supply, the metabolic disturbance was alleviated, except for changes in lactate, glycine, citrate, and hypoxanthine. The markable selenium accumulation and choline decrease in the cells under methionine shortage imply the potential risk of selenomethionine supplementation. This work revealed the biological effects of selenomethionine under different methionine supply conditions. This study may serve as a guide for controlling methionine and selenomethionine levels in dietary intake.