Inhibitory and Antioxidant Activities of Saccharina japonica Extracts Processed by Subcritical Water Extraction and Enterococcus faecalis Fermentation.

Marine algae, notably Saccharina japonica, are valuable sources of essential nutrients, including carbohydrates, vitamins, and minerals, as well as bioactive compounds, such as phenols and pigments. In this study, subcritical water extraction of S. japonica, a brown seaweed, was conducted using a 10% (w/v) seaweed slurry at a temperature of 140°C for 10 min. The concentrations of mannitol, laminarin, and total phenolic content were determined to be 18.93 g/l, 10.79 g/l, and 1.94 mg GAE/g, respectively. The S. japonica fermented using Enterococcus faecalis (SFL) resulted in a maximum biomass production of 4.43 g dcw/l and exhibited an inhibitory activity of 78.69% against pancreatic lipase. The S. japonica fermented using E. faecalis (SFE) extracts exhibited α-glucosidase inhibitory and antioxidant activities of 59.23% and 65.60%-66.57%, respectively, at a concentration of 3.0 mg/ml. These results facilitate the development of functional seaweed food formulations derived from microbial fermentation.