Effects of Fucoidans from Five Different Brown Algae on Oxidative Stress and VEGF Interference in Ocular Cells

Abstract

Background: Fucoidans are interesting for potential usage in ophthalmology, and especially age-related macular degeneration. However, fucoidans from different species may vary in their effects. Here, we compare fucoidans from five algal species in terms of oxidative stress protection and vascular endothelial growth factor (VEGF) interference in ocular cells. Methods: Brown algae (Fucus vesiculosus, Fucus distichus subsp. evanescens, Fucus serratus, Laminaria digitata, Saccharina latissima) were harvested and fucoidans isolated by hot-water extraction. Fucoidans were tested in several concentrations (1, 10, 50, and 100 µg/mL). Effects were measured on a uveal melanoma cell line (OMM-1) (oxidative stress), retinal pigment epithelium (RPE) cell line ARPE19 (oxidative stress and VEGF), and primary RPE cells (VEGF). Oxidative stress was induced by H2O2 or tert-Butyl hydroperoxide (TBHP). Cell viability was investigated with methyl thiazolyl tetrazolium (MTT or MTS) assay, and VEGF secretion with ELISA. Affinity to VEGF was determined by a competitive binding assay. Results: All fucoidans protected OMM-1 from oxidative stress. However, in ARPE19, only fucoidan from Saccharina latissima was protective. The affinity to VEGF of all fucoidans was stronger than that of heparin, and all reduced VEGF secretion in ARPE19. In primary RPE, only the fucoidan from Saccharina latissima was effective. Conclusion: Among the fucoidans from five different species, Saccharina latissima displayed the most promising results concerning oxidative stress protection and reduction of VEGF secretion.

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

“…ARPE-19 cells as an RPE cell line are very resistant against hydrogen peroxide [26]. Therefore we used 0.5 mM tert-butyl hydroperoxide (TBHP) to lower the cell viability of ARPE-19 significantly after 24 h, as previously shown [19]. Again, the LD fucoidan showed no significant effect (Figure 4).…”

“…These optimizations of using SALy and alginate precipitation was used to prepare highly pure and fractionated fucoidans from S. latissima by ion-exchange chromatography (IEX), the purification method was described previously [15], while the bioactivity is tested here. SL was chosen, since previous work has shown that SL fucoidan has biological effects [19]. A further optimization was used, were the alginate was precipitated by CaCl 2 instead of acid, this method is believed to be gentler and is therefore likely to preserve the fucoidan structure better than the use of acid.…”

“…We showed already promising effects of different fucoidans on ocular cells. In brief, fucoidans from past studies were extracted with hot water, followed by precipitation with CaCl 2 and ultrafiltration or dialysis [16][17][18][19]. Fucus vesiculosus fucoidan from Sigma-Aldrich can reduce angiogenesis and VEGF of RPE [13].…”

“…Fucoidans from Fucus serratus, Laminaria digitata (LD) and Fucus distichus subsp. evanescens (FE) were protective against oxidative stress in the uveal melanoma cell line OMM-1 and could inhibit ARPE-19 VEGF production [19] exactly like a other Saccharina latissima fucoidan, which was protective in ARPE-19 and lowered VEGF of primary RPE [19]. Different sized fucoidans from Laminaria hyperborea showed that the large, non-degraded fucoidan is most suitable for oxidative stress protection and VEGF inhibition [17].…”

The Potential of Sulfated Polysaccharides Isolated from the Brown Seaweed Ecklonia maxima in Cosmetics: Antioxidant, Anti-melanogenesis, and Photoprotective Activities

“…Ecklonia maxima is a brown seaweed typically found along the southern Atlantic coast of Africa. Polysaccharides from E. maxima have been reported to have anti-diabetes, anticancer, and antioxidant activities [22][23][24]. However, the cosmeceutical potential of polysaccharides isolated from E. maxima has not been evaluated so far.…”