Multivariate optimization of selective pressurized liquid extraction for bioactive all-trans fucoxanthin and its isomers from Undaria pinnatifida

This study aimed to develop an efficient and sustainable method to recover both all-trans fucoxanthin (FX) and its cis isomers from Undaria pinnatifida (UP). Pressurized liquid extraction (PLE) conditions (time, temperature, and ethanol in ethyl acetate) were optimized using multivariate analysis to maximize FX yield. Temperature notably influenced extraction, with cis and trans isomers showing similar thermal stability. Ethyl acetate showed higher selectivity than ethanol for isolating FX isomers. The optimal PLE conditions were: 115 °C, 100 % ethyl acetate, and 1 min. The recovery of FX isomers was further enhanced by performing three extraction cycles, resulting in a twofold increase in all-trans and cis isomers. The FX-rich extract showed antioxidant capacity, anti-inflammatory properties, and potent anticancer effects against lung carcinoma NCI-H460 and breast adenocarcinoma MCF-7 cell lines. To our knowledge, this is the first systematic evaluation of cis-FX extraction from UP using PLE. Overall, this study provides an innovative, standardized approach for selectively extracting bioactive FX isomers, unlocking their health potential and advancing sustainable valorization of brown algae.