Fucoidan, a sulfated polysaccharide from brown algae, improves cognitive impairment induced by infusion of Aβ peptide in rats

Fucoidan is a complex sulfated polysaccharide, derived from marine brown seaweed. In the present study, we investigated the effects of fucoidan on improving learning and memory impairment in rats induced by infusion of A beta (1-40), and its possible mechanisms. The results indicated that fucoidan could ameliorate A beta-induced learning and memory impairment in animal behavioral tests. Furthermore, fucoidan reversed the decreased activity of choline acetyl transferase (ChAT), superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) and content of acetylcholine (Ach), as well as the increased activity of acetylcholine esterase (AchE) and content of malondialdehyde (MDA) in hippocampal tissue of A beta-injected rats. Moreover, these were accompanied by an increase of Bcl-2/Bax ratio and a decrease of caspase-3 activity. These results suggested that fucoidan could ameliorate the learning and memory abilities in All-induced AD rats, and the mechanisms appeared to be due to regulating the cholinergic system, reducing oxidative stress and inhibiting the cell apoptosis. (C) 2011 Elsevier B.V. All rights reserved.