The effect of different drying methods on antioxidant compounds and fucoxanthin content of brown seaweed from the intertidal zone of West Aceh, Indonesia

Sargassum ilicifolium and Padina australis are two of the brown seaweed found on the coast of West Aceh. This research aimed to determine the antioxidant action and fucoxanthin content of S. ilicifolium and P. australis. The samples used in this study include fresh, freeze-dried, and sun-dried S. ilicifolium and P. australis. Each sample was extracted using ethanol 96% for 12 hours. The partition was undertaken using n-hexane and methanol. The antioxidant activity of the extract was analysed using the DPPH radical scavenging activity method. Fucoxanthin content in brown seaweed extract was analysed using high-performance liquid chromatography (HPLC) and mass spectrophotometry. The result revealed that the antioxidant action (IC50) of S. ilicifolium extract ranged from 799.00±1.66 ~ 1884.48±425.64 µg mL-1, and P. australis extract ranged from 171.50±43.13 ~ 460.88±78.09 µg mL-1. Fucoxanthin of brown seaweeds S. ilicifolium and P. australis possesses high antioxidant activity in a fresh sample of S. ilicifolium (IC50 799.00±1.66 µg mL-1) and the freeze-dried sample of P. australis (IC50 171.50±43.13 µg mL-1). The presence of fucoxanthin from brown seaweed S. ilicifolium and P. australis indicated the presence of a monoisotopic ion molecule at the m/z value of 640.977 [M+H].