Quantitative analysis of fucose in fucoidans from Sargassum spp. in Jeju Island, South Korea using 3-methyl-1-phenyl-5-pyrazolone derivatization and RP-HPLC-UV method

Sargassum species are representative brown algae found worldwide, with 27 species native to the coast of Jeju Island in South Korea. Fucoidans are derived from brown algae and exhibit a variety of biological activities. Analysis of the monosaccharide composition is necessary for an in-depth study of fucoidans. However, quantitative analysis of fucoidans with complex structures according to species and habitat is insufficient. Furthermore, complex pre-processing is often required to analyze sugars, making it less economical. This study aimed to validate high-performance liquid chromatography (HPLC)-UV analysis based on 3-methyl-1-phenyl-5-pyrazolone (PMP) derivatization of monosaccharides. The proposed method had a short running time and could be repeated economically using UV detection. The detected PMP-fucose was confirmed to be uninterfered by comparing the analytical chromatograms of the internal standard solution. This analytical method was characterized for system suitability, precision, accuracy, linearity, limit of detection (LOD), and limit of quantification (LOQ), demonstrating satisfactory results. The quantification was verified by comparison with the quantitative results of commercial fucoidan obtained using high-performance anion-exchange chromatography (HPAEC) coupled with pulsed amperometric detection (PAD). Furthermore, the antioxidant effects of algal polysaccharides from Sargassum spp. isolated on Jeju Island was evaluated using a zebrafish model. Polysaccharides from Sargassum coreanum (SCpol) and Sargassum autumnale (SApol) showed remarkable free radical scavenging activities. In addition to the results obtained in the zebrafish experiments, all species-derived polysaccharides showed antioxidant potential. In conclusion, this study demonstrates a useful analytical method using HPLC-UV and PMP derivatives for the effective determination of monosaccharide contents, including fucose, in Sargassum spp.