Optimized isolation and pharmacological activities of sulfated polysaccharides from the red seaweed Delesseria sanguinea

The red seaweed Delesseria sanguinea dominantly populates a large artificial reef at Nienhagen in the Baltic Sea. It contains substantial amounts of sulfated polysaccharides (D.s.-SP), which consist of a homogenous fraction of branched sulfated xylogalactans (gal:xyl ˜5.4) and exhibit a pharmacological profile indicating anti-inflammatory and anti-skin aging potencies [1–3].

Compared with heparin, D.s.-SP revealed stronger inhibitory effects on the enzymes elastase, hyaluronidase, heparanase, collagenase as well as on complement activation, cell adhesion to P-selectin and cytokine release from LPS-activated monocytes, but have only moderate anticoagulant activity. Their hyaluronidase and complement inhibitory activities proved even superior than those of the anti-inflammatory β-1,3-glucan sulfate PS3.

Crucial for an economic use is the availability of adequate amounts of D.s.-SP with reproducible high quality. For evaluation and optimization, 30 D.s. batches were harvested and extracted since 2005 resulting in almost 200 D.s.-SP batches.

By a standardized procedure (extraction (EX) with water for 8h at 85°C), the D.s.-SP can be isolated in reproducible high quality. However, as found by a second 8h-EX, the first 8h-EX is incomplete. Subsequently modified EX-procedures led to following yields: 8.8%(1×8h-EX), 13.3%(2×4h-EX), 15.0%(2×2h-EX) and 17.9%(4×2h-EX). Consequently, a 2×2h-EX (15.0%) seems to be a rational compromise. Moreover, the D.s.-SP obtained by shorter EX contained less glucose, which partly represents co-extracted starch: 14.4%(1×8h-EX), 10.92%(2×4h-EX), 9.0%(2×2h-EX) and 11.74%(4×2h-EX). The glucose content was further reduced by precipitating the extracted D.s.-SP with 70% instead of 90% ethanol.

In conclusion, after stepwise optimization of the isolation procedure, the D.s.-SP from Nienhagen are ready for an economic use.

Acknowledgement: This project is financed by the EU (FIAF/EFF) and the LFALF Mecklenburg-Vorpommern.

References: 1. Groth I, Grünewald N, Alban S (2009) Glycobiology 19: 408–417.

2. Grünewald N, Alban S (2009) Biomacromolecules 10(11): 2998–3008.

3. Grünewald N, Groth I, Alban S (2009) Biomacromolecules 10(5): 1155–1162.