Fucoxanthin Content and Antioxidant Activity in Supercritical CO2 , Enzymatic and Natural Hydrophobic deep Eutectic Solvent Extracts of Sargassum wightii Seaweed

Abstract

Brown seaweeds are potential sources of bioactive compounds which can be beneficial in the development of novel nutraceuticals and cosmeceuticals. Green chemistry techniques, namely supercritical fluid (SFE), enzymatic and natural deep eutectic solvent (NaDES) extraction, were employed on Sargassum wightii seaweed. LC-MS/MS estimation revealed that the SFE technique could extract the maximum amount of fucoxanthin (3.00±0.04 mg g-1 seaweed), followed by NaDES (1.7±0.006 mg g-1 seaweed) and enzymatic extraction (0.17±0.003 mg g-1 seaweed). However, total phenolic content, expressed as mg gallic acid equivalent g-1 extract, was highest in enzymatic (90±2.6), followed by SFE (61.02 ±1.4) and NaHDES (55.35± 2.06) extracts. The DPPH free radical scavenging activity was highest in the SFE extract (IC50 2.07±0.04 µg gallic acid equivalent). There was no significant difference in the DPPH free radical scavenging activity between the enzymatic (IC50 13±3.24 µg gallic acid equivalent) and NaDES extracts (IC50 16.64±2.04 µg gallic acid equivalent). Interestingly, ABTS free radical scavenging activity was highest in the enzymatic extract (IC50 11±2.06 µg Trolox equivalent), followed by SFE and NaDES extracts. The study reveals that all the three methods are excellent alternatives to harmful organic solvents. The result indicates that SFE is the best method among all the employed techniques.