In vitro evaluation of functional properties of extracts of Fucus vesiculosus obtained with different conventional solvents

Fucus vesiculosus is a rich source of bioactive substances with many biochemical functions that provide it a variety of biological effects. Over the years, significant research efforts have been made to extract bioactive compounds by applying different methodologies for various applications. There are several solvents used for the extraction of natural products since the choice of solvent must be based primarily on the characteristics of the matrices and the properties of the molecular classes to be obtained. Therefore, the aim of this study was to investigate the efficiency of different conventional solvents to maximize the yield of polyphenol and flavonoid content as well as the antioxidant, antimicrobial and anti-inflammatory capacity. The different extracts of F. vesiculosus were analyzed for the Total Polyphenol Content (TPC) and the Total Flavonoid Content (TFC). As well the antioxidant, antimicrobial, and anti-inflammatory capacities were evaluated. The results concerning the content of bioactive molecules disclosed that the extraction carried out with the methanol (50 %) was the one that gave the highest yield in both polyphenol (2.27 ± 0.17 mg GAE/ 50 mg of sample) and flavonoid content (187.12 ± 12.86 mg CE/50 mg of sample) compared to acetone and ethanol extracts. Regarding the functional properties, the results obtained disclose that the extract of F. vesiculosus had a high antioxidant capacity (90 % inhibition of radical scavenging activity). Additionally, the growth inhibition assay disclosed that F. vesiculosus can reduce significantly (p < 0.05) the growth of E. coli F18⁺, in particular when the alga is extracted with methanol and acetone. As well, a concentration of 1 mg/mL of F. vesiculosus inhibits the protein denaturation by 60 %, highlighting a potential anti-inflammatory activity. In conclusion, this study discloses the richness of bioactive molecules in F. vesiculosus and the resulting functional properties, highlighting also the power of methanol as extraction solvent.