Total phenolic content and biological activities of enzymatic extracts from Sargassum muticum (Yendo) Fensholt

Seaweeds are potentially excellent sources of bioactive metabolites that could represent useful leads in the development of new functional ingredients in pharmaceutical and cosmetic industries. In the last decade, new marine bioprocess technologies have allowed the isolation of substances with biological properties. The brown alga Sargassum muticum (Yendo) Fensholt (Ochrophyta) was enzymatically hydrolyzed to prepare water-soluble extracts by using six different commercially available carbohydrate-degrading enzymes and two proteases. Evaluation of 2,2-diphenyl-1-picrylhydrazyl (DPPH) and ferric reducing antioxidant power (FRAP) antioxidant, tyrosinase, elastase, and biofilm inhibition, antibacterial and antiviral activities as well as evaluation of cytotoxicity were realized for each extract. Total phenolic content was measured for extract characterization, and solid-phase extraction was useful to purify the enzymatic extract. Soluble total phenolic content of S. muticum Viscozyme extract was highest with 6.4% of dry weight. Enzymatic Celluclast and Viscozyme extracts had the lowest value of DPPH IC(50) indicating a strong antiradical activity, 0.6 mg mL(−1), in comparison with other enzymes. The ferric reducing antioxidant power ranged between 48.7 μM Fe(2+) Eq, digested with Viscozyme, and 60.8 μM Fe(2+) Eq, digested with Amyloglucosidase. Tyrosinase inhibition activity of S. muticum Neutrase extract was 41.3% higher compared to other enzymes. Elastase inhibition activity of S. muticum Shearzyme extract had highest activity (32.8%). All enzymatic extracts showed no cytotoxic effect towards the kidney Vero cells. Meanwhile, only S. muticum Neutrase and Alcalase extracts exhibited potential antiviral activity. In addition, S. muticum Viscozyme and Shearzyme extracts showed promising activity in suppressing the biofilm formation against Pseudomonas aeruginosa and Escherichia coli, respectively. Purification of S. muticum Viscozyme extracts by solid-phase extraction managed to concentrate the phenolic content and improve the bioactivity. These results indicate the promising potential of enzyme-assisted followed by solid-phase extraction in recovering phenolic content and in improving its bioactivity.