Sargassum muticum is an invasive brown macroalga and several attempts have been made to control and eradicate this species with little success because its time consuming and costly. Thus, exploitation of this biomass for the extraction of bioactive compounds could be an interesting strategy to add value to food supplements and functional foods [1]. Among these compounds, fucoxanthin (Fx) has been gaining attention for its promising biological activities such as antioxidant, antimicrobial, anticancer, antihypertensive, anti-inflammatory, anti-diabetic, anti-obesity, neuroprotective, anti-angiogenic and photoprotective properties [1]. Fucoxanthin is the most abundant and characteristic pigment in brown algae accounting for approximately 10% of the total carotenoids in nature [2,3]. The aim of this study was to optimize the extraction yield (grams extract per 100 grams of macroalgae dried weight, g E/100 g Ma dw) and Fx content (mg Fx/g E) from Sargassum muticum using ultrasound-assisted extraction (UAE). For this purpose, a response surface methodology (RSM) study with an experimental design of a five-level circumscribed central composite design (28 independent experiments) was applied to optimize three main UAE variables: ethanol concentration (S, 35-100%), time (t, 5-55 min) and power (P, 100-500 W). A second order polynomial model was used to fit the experimental data (obtained by triplicate). Based on the model prediction (R²=0.965), the optimal conditions that individually maximize extraction yield were 29.98 ± 1.03 g E/100 g Ma dw at a t value of 45.00 ± 3.35 min, S value of 37.50 ± 3.06% and P value of 409.46 ± 10.12 W. While for maximizing the Fx content (R²=0.8199) the response was 0.93 ± 0.10 mg Fx/g Ma dw at a t value of 45.00 ± 3.35 min, S value of 84.22 ± 4.59% and P value of 339.73 ± 9.22 W. The results here found for Fx content and the extraction yield with UAE conditions shows a promising approach for the recovery of bioactive compounds from S. muticum with potential application in nutraceutical and food industry sectors. This will also contribute to sustainably manage the expansion of S. muticum and the restoration of the ecosystem in coastal areas.

References:

1. Lourenço-lopes, C.; Garcia-oliveira, P.; Carpena, M.; Fraga-corral, M.; Jimenez-lopez, C.; Pereira, A.G. Scientific Approaches on Extraction , Purification and Stability for the Commercialization of Fucoxanthin Recovered from Brown Algae. 2020.
2. Lockowandt, L.; Pinela, J.; Roriz, C.L.; Pereira, C.; Abreu, R.M.V.; Calhelha, R.C.; Alves, M.J.; Barros, L.; Bredol, M.; Ferreira, I.C.F.R. Chemical features and bioactivities of cornflower (Centaurea cyanus L.) capitula: The blue flowers and the unexplored non-edible part. Ind. Crops Prod. 2019, 128, 496–503.
3. Pereira, A.G.; Otero, P.; Echave, J.; Carreira-Casais, A.; Chamorro, F.; Collazo, N.; Jaboui, A.; Lourenço-Lopes, C.; Simal-Gandara, J.; Prieto, M.A. Xanthophylls from the Sea: Algae as Source of Bioactive Carotenoids. Mar. Drugs 2021, 19, 188.

Acknowledgments: The research leading to these results was supported by MICINN supporting the Ramón y Cajal grant for M.A. Prieto (RYC-2017-22891), the María Zambrano grant for R. Perez-Gregorio (CO34991493-20220101ALE481), and the FPU grants for A. Carreira-Casais (FPU 16/06135) and A. Soria-Lopez (FPU2020/06140); by Xunta de Galicia for supporting the program EXCELENCIA-ED431F 2020/12 the post-doctoral grant of M. Fraga-Corral (ED481B-2019/096) and L. Cassani (ED481B-2021/152), Authors are grateful to Ibero-American Program on Science and Technology (CYTED—AQUA-CIBUS, P317RT0003), to the Bio Based Industries Joint Undertaking (JU) under grant agreement No 888003 UP4HEALTH Project (H2020-BBI-JTI-2019). The JU receives support from the European Union’s Horizon 2020 research and innovation program and the Bio Based Industries Consortium. The project SYSTEMIC Knowledge hub on Nutrition and Food Security, has received funding from national research funding parties in Belgium (FWO), France (INRA), Germany (BLE), Italy (MIPAAF), Latvia (IZM), Norway (RCN), Portugal (FCT), and Spain (AEI) in a joint action of JPI HDHL, JPI-OCEANS and FACCE-JPI launched in 2019 under the ERA-NET ERA-HDHL (n° 696295).