  Fucoidan is a generic term for a class of fucose rich, structurally diverse
sulfated polysaccharides that are found in brown algae and other marine
organisms. Depending on the species from which the fucoidan is extracted, a
wide variety of biological activities including antitumor, antiinflammatory,
immune-modulating, antiviral, antibacterial and pro- and anticoagulant
activities has been described. Fucoidans have the advantage of low toxicity and
oral bioavailibiity and are viable drug candidates, preclinical and pilot
clinical trials show promising results. The availability of robust assays, in
particular for analysing the blood levels of fucoidan, is a fundamental
requirement for pharmacokinetic analysis in drug development projects. This
contribution describes the application of a commercially availbale,
protein-free fluorescent probe assay (Heparin Red) for the direct
quantification of several fucoidans (from Fucus vesiculosus, Macrocystis
pyrifera, and Undaria pinnatifida) in human plasma. By only minor adapation of
the established protocol for heparin detection, a concentration range 0,5 to 20
microgram per mL fucoidan can be addressed. A preliminary analysis of matrix
effects suggests acceptable interindividual variability and no interference by
endogeneous chondroitin sulfate. This study identifies the Heparin Red assay as
a simple, time-saving mix-and-read method for the quantification of fucoidans
in human plasma.
