Isolation and antioxidant capacity of fucoidan from selected Malaysian seaweeds

Abstract

The objective of this research was to screen and isolate fucoidan from Malaysian seaweeds and subsequently determine its antioxidant capacity. A screening test employing a colorimetric method was conducted on five types of Malaysian brown and red seaweeds. It was found that Sargassum binderi contained the highest fucoidan content (6.16 ± 0.08%). Thus, fucoidan was isolated from S. binderi (yield 7.5%, purity 89.63%) for the determination of its antioxidant capacity. The isolated fucoidan was identified using high performance anion exchange chromatography (HPAEC) and attenuated total reflectance Fourier transform infra-red (ATR-FTIR) spectroscopy. The antioxidant assays performed were total phenolic content (TPC), free-radical scavenging activity (DPPH), reducing power, superoxide anion scavenging activity (SOA) and hydroxyl radical scavenging activity (OH). The antioxidant capacity of the extracted fucoidan (Fsar) was compared with those of a commercial food-grade fucoidan (Fysk) and of BHA, BHT and ascorbic acid. All the antioxidant assays performed showed either Fsar has significantly higher (p < 0.05) or do not differ significantly (p > 0.05) in activities compared to that of Fysk. At the same time, both Fsar and Fysk showed significant (p < 0.05) antioxidant capacity in terms of superoxide anion and hydroxyl radical scavenging activities compared to those of the synthetic antioxidants. This shows that Fsar has the potential to be commercialised as a functional food product or as bioingredients with high antioxidative properties.