Total phenolic content and biological activities of enzymatic extracts from Sargassum muticum (Yendo) Fensholt
Abstract
Seaweeds are potentially excellent sources of bio-
active metabolites that could represent useful leads in the de-
velopment of new functional ingredients in pharmaceutical
and cosmetic industries. In the last decade, new marine
bioprocess technologies have allowed the isolation of sub-
stances with biological properties. The brown alga
Sargassum muticum (Yendo) Fensholt (Ochrophyta) was en-
zymatically 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 antiox-
idant power (FRAP) antioxidant, tyrosinase, elastase, and bio-
film 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 IC50 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 enzymat-
ic extracts showed no cytotoxic effect towards the kidney Vero
cells. Meanwhile, only S. muticum Neutrase and Alcalase ex-
tracts exhibited potential antiviral activity. In addition,
S. muticum Viscozyme and Shearzyme extracts showed prom-
ising 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 extrac-
tion in recovering phenolic content and in improving its
bioactivity.