Extraction and functional characterization of fucoidans and alginates from Ecklonia maxima: A focus on skin, immune, and intestinal health

Abstract

Polysaccharides from the brown seaweed Ecklonia maxima (EM), were structurally characterized using high performance size exclusion chromatography (HPSEC), Fourier-transform infrared spectroscopy (FTIR) and proton nuclear magnetic resonance (1H NMR) spectroscopy, and assessed for immunomodulation. MTT and AlamarBlue assays evaluated their effects on cell viability and proliferation (skin cells; HDF, HaCaT). Nitric oxide (NO) production and phagocytosis activities were evaluated using RAW264.7 cells. In addition, Caco-2 cells were exposed to EM polysaccharides, including fucoidans and alginates, with the aim of evaluating their potential toxicity towards intestinal cells. The expression levels of tumor necrosis factor alpha (TNF-α) and transforming growth factor beta (TGF-β1) were measured by qPCR at 24 h after treatment with fucoidans (EM-1A, EM-1B, EM-2B, EM-3B) and alginates (EM-2A, EM-3A) polysaccharide fractions, demonstrating that EM-2A and 3A effectively inhibited inflammation, while EM-2B increased wound healing in HaCaT. Skin cell proliferation and migration were significantly increased (0.13 μg/μL), while exposure of RAW264.7 cells to cold or hot-extracted (2A, 2B) polysaccharides did not affect cell proliferation within 24 h. Cell proliferation in Caco-2 cells were significantly reduced by EM-1A fraction at 72 h, inhibiting cell proliferation (p < 0.001). Phagocytosis activity was significantly higher in EM-2B (122.3 ± 1.2%, p < 0.0001), suggesting pro-inflammatory potential. HDF cell proliferation was higher in EM-3A, whereas SOD activity was lower than controls (LPS: 27.3 ± 1.3%). Fucoidan from fraction 2B fraction accelerated skin cell proliferation and migration, showing their potential as bioactive compounds. The findings suggest that EM fucoidan and alginate polysaccharides would be useful for the development of products for food, pharmaceutical and biotechnology applications.