Selenium Biotransformation and Fractionation of Selenopeptide from Germinated Perilla (Perilla frutescens) Seeds

Plant-based bioactive compounds have been recognized as promising alternatives to conventional chemical treatments. Selenium (Se), a trace element, can be incorporated into proteins to enhance the bioactivity of plant-derived peptides. Perilla frutescens seeds are high-protein plants that have shown the ability to absorb Se and biosynthesize selenopeptides. This study examined Se biotransformation during the germination of perilla seeds to synthesize selenoprotein, investigating enzymatic hydrolysis using Alcalase and Flavourzyme as single enzymes, as well as their combinations. The results showed that Alcalase hydrolysates produced Se-peptides with the highest degree of hydrolysis and antioxidant activity. Hydrolysates were purified via ultrafiltration and size-exclusion chromatography, and Se-peptides were characterized by LC-MS/MS. Nine peptides containing Se-binding residues such as cysteine, methionine, and glutamic acid confirmed successful Se incorporation. The Se-peptides demonstrated strong antioxidant activity (ABTS: 66.30%, FRAP: 54.93%), ACE inhibition (83.87%), and cytotoxicity against A549 lung cancer cells (85.88% viability). Compared to non-Se-peptides, Se-enriched peptides showed superior bioactivity, highlighting their potential as functional ingredients in food and pharmaceutical applications.