Nano-selenium stablilized by Konjac Glucommannan and its biological activity in vitro

Nano-selenium particles (SeNPs) are considered to have high biological activity and low toxicity, but their stability need to be improved. Konjac glucomannan (KGM) was introduced as a stabilizer for the preparation of SeNPs via ascorbic acid (AA)-sodium selenite (Na2SeO3) redox system in this study, the influence of reaction conditions on the formation of KGM-SeNPs was estimated and the preparation parameters were optimized via orthogonal experiment. It is found that KGM concentration and Se4+ concentration are the two most important parameters that affect the particle size and morphology of KGM-SeNPs, beside of the agglomeration promoted by higher temperature. The optimal product possessed spherical particles with a particle size of 50–150 nm, the selenium content in lyophilized supernatant and lyophilized precipitate were 38.17% and 19.19%, respectively, and infrared spectroscopy analysis showed KGM-SeNPs were mainly compounded by intermolecular electrostatic interaction. KGM-SeNPs exhibited inhibitory effects on Staphylococcus aureus but no on Escherichia coli and Penicillium, strong scavenging activity against ABTS•+ and DPPH•, strong reduction activity on Fe3+ and low cytotoxicity in Caco-2 cells. These results indicated that KGM-SeNPs were expected to be developed as a food-grade antioxidant or selenium supplement in food and pharmaceutical product applications.