Production of Undaria pinnatifida sporophyll extract using pilot-scale ultrasound-assisted extraction: Extract characteristics and antioxidant and anti-inflammatory activities

Owing to increasing demand for eco-friendly technology, the number of studies on extraction technology using lower organic solvents for energy conservation is increasing. Previously, we developed an ultrasound-assisted extraction (UAE) method of Undaria pinnatifida sporophyll that reduces extraction time and improves extraction yield. In the present study, we extracted U. pinnatifida sporophyll, which contained polysaccharide and fucoxanthin, using solvent-free circulatory UAE. With small pilot-scale circulatory UAE, the yield of U. pinnatifida sporophyll extract was improved to 52%, compared to that with a conventional method (24.7%) and lab-scale horn-type UAE (43%). After 3 h of UAE, fucoxanthin was obtained at a 3% yield and low-molecular-weight polysaccharides were detected. The antioxidant activity of the extract was increased after 3 h of UAE, as assessed by DPPH-scavenging, reducing power, and ferric reducing antioxidant power assays. Pilot-scale circulatory UAE conditions were optimized to 960 W, 20 kHz, 30 °C, and 3 h; the extract obtained using this method showed inhibitory effects on nitric oxide production and activator protein-1 (AP-1) transactivity.