Effects of a Newly Developed Enzyme-Assisted Extraction Method on the Biological Activities of Fucoidans in Ocular Cells

Abstract

Fucoidans from brown seaweeds are promising substances as potential drugs against age-related macular degeneration (AMD). The heterogeneity of fucoidans requires intensive research in order to find suitable species and extraction methods. Ten different fucoidan samples extracted enzymatically from Laminaria digitata (LD), Saccharina latissima (SL) and Fucus distichus subsp. evanescens (FE) were tested for toxicity, oxidative stress protection and VEGF (vascular endothelial growth factor) inhibition. For this study crude fucoidans were extracted from seaweeds using different enzymes and SL fucoidans were further separated into three fractions (SL_F1-F3) by ion-exchange chromatography (IEX). Fucoidan composition was analyzed by high performance anion exchange chromatography (HPAEC) after acid hydrolysis. The crude extracts contained alginate, while two of the fractionated SL fucoidans SL_F2 and SL_F3 were highly pure. Cell viability was assessed with an 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium (MTS) assay in OMM-1 and ARPE-19. Protective effects were investigated after 24 h of stress insult in OMM-1 and ARPE-19. Secreted VEGF was analyzed via ELISA (enzyme-linked immunosorbent assay) in ARPE-19 cells. Fucoidans showed no toxic effects. In OMM-1 SL_F2 and several FE fucoidans were protective. LD_SiAT2 (Cellic®CTec2 + Sigma-Aldrich alginate lyase), FE_SiAT3 (Cellic® CTec3 + Sigma-Aldrich alginate lyase), SL_F2 and SL_F3 inhibited VEGF with the latter two as the most effective. We could show that enzyme treated fucoidans in general and the fractionated SL fucoidans SL_F2 and SL_F3 are very promising for beneficial AMD relevant biological activities.

Evaluation of a Brown Seaweed Extract from Dictyosiphon foeniculaceus as a Potential Therapeutic Agent for the Treatment of Glioblastoma and Uveal Melanoma

“…Middle-and low-molecular weight fucoidans from Laminaria hyperborea lowered the cell viability of OMM-1 cells [19], whereas enzymatically treated extracts from Laminaria digitata, Fucus distichus subsp. evanescens as well as various extracts from Saccharina latissima with different fucose content and degree of sulfation did not exhibit any anti-tumor effects on OMM-1 [20]. Dithmer et al, 2017 tested the effects of Fucus vesiculosus fucoidan from Sigma Aldrich on five different uveal melanoma cell types and on the one hand, this fucoidan had an anti-proliferative effect on the primary uveal melanoma cells Mel270, but not on the OMM-1 cells [38].…”

“…Among these positive effects are anti-oxidative, anti-inflammatory, anti-tumor and anti-angiogenic properties [12][13][14][15], making it highly interesting for cancer and skin therapies [16,17]. Fucoidans have also been described by our group for their anti-oxidative, VEGF (vascular endothelial growth factor) lowering and binding effects [18][19][20][21]. In general they do not lower cell viability as tested in different cell types like ARPE-19 (human retinal pigment epithelium), HL-60 (acute myeloid leukemia), Raji (Burkitt lymphoma), HeLa (cervix carcinoma), A-375 (skin melanoma), HCT-116 (colon carcinoma), Hep G2 (hepatocellular carcinoma) and HaCaT (keratinocytes) after 24 h of treatment [22].…”

Functional Characterization of a New GH107 Endo-α-(1,4)-Fucoidanase from the Marine Bacterium Formosa haliotis

“…These effects have mainly been shown in vitro in different cell systems, but in some cases also in vivo in animal systems, including anticancer [ 7 , 8 , 9 , 10 , 11 , 12 ], anti-inflammatory [ 1 , 13 ], anticoagulant [ 14 , 15 ], immune-modulatory [ 16 ], and most recently, potentially protective effects against age-related macular degeneration induced vision loss [ 17 ]. Although details of the structure-function of fucoidans remain unclear, it is evident that structural integrity is critical for achieving particular effects [ 1 , 2 , 17 ]. Fucoidan extracts have already been partly commercialized as functional food ingredients or dietary supplements [ 5 , 18 ], but the heterogeneous nature of fucoidan is an obstacle to achieving regulatory approval for clinical pharmaceutical uses.…”

Fucoidans as Scientifically and Commercially Important Algal Polysaccharides

“…In the article by Dörschmann, P. et al [ 8 ], the authors enzymatically extracted Saccharina latissima fucoidan and isolated its low-molecular weight fraction. The results showed that the enzyme-treated fucoidans and the fractionated low-molecular-weight fucoidans are very promising for beneficial age-related macular degeneration-relevant biological activities.…”