Overcoming Extraction Hurdles and Assessing Biological Activity in a Major Invasive Seaweed Species in Europe, Rugulopteryx okamurae

The brown seaweed <i>Rugulopteryx okamurae</i> is a major invasive species in Europe, menacing local ecosystems. The challenge lies in assessing application routes for this biomass, testing different extraction technologies (overnight agitation, mechanical homogenization, pH-shift, ionic liquid-, and ultrasound-assisted extractions) and parameters. There was a higher yield in the extracts homogenized with 70% ethanol, especially with 1:20, <i>w</i>/<i>v</i>, biomass-solvent ratio, than in aqueous extracts. As to overnight agitation, 70% ethanol produced results (24.5-28.3%) similar to those found in the homogenized extracts. However, in the former, the best biomass-solvent proportion was 1:10, <i>w</i>/<i>v</i>. Mineral matter yield presented specific patterns, reaching 59.6 ± 1.1% (70% ethanol) and 82.3 ± 0.1% (water). The highest total polyphenol level was attained in the 70% ethanol, 1:20, <i>w</i>/<i>v</i>, extract, 310.7 ± 22.1 mg GAE/100 g dw seaweed. This extract had a higher FRAP/ABTS. The extract attained with overnight agitation, 70% ethanol, 1:10, <i>w</i>/<i>v</i>, had 48% COX-2 inhibition as anti-inflammatory activity. Besides showing the potential of <i>R. okamurae</i> for pharmacological purposes, especially in the antioxidant and anti-inflammatory area, this study enabled us to rank technologies and conditions for the utilization of this abundant biomass resource by the industry.