Fucoidan: Its Binding of Lead and Other Metals

Abstract

A sulfated polysaccharide derived from marine algae [Ascophyllum nodosum] was studied for its ability to bind divalent metal cations [Lead in its ionized form is a hazard to the body. Rapid conversion of Pb into a non-ionized form is of prime importance in the treatment of Pb poisoning. Chelating agents are employed for this purpose.] with specific reference to Pb and Ca. Studies were carried out in vitro by ultrafiltration and in vivo by the ligated intestinal loop technique using rats. Using the efficiency of ion-exchange reactions with divalent cations, the order of preferential binding was established for fucoidan. This polyelectrolyte had the greatest affinity for lead with relatively little binding of calcium. Studies in vivo demonstrated a 70% reduction in the lead absorbed by the rat when using fucoidan. This naturally occurring non-toxic polyelectrolyte is a suitable binding agent for Pb. The insignificant binding of Ca is an important criteria for biological and clinical application. The high biological activity of this compound depends on position and availability of functional groups for the ion-exchange process, and viscosity of the solution.