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 Aβ (1-40), and its possible mechanisms. The results indicated that fucoidan could ameliorate Aβ-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 Aβ-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 Aβ-induced AD rats, and the mechanisms appeared to be due to regulating the cholinergic system, reducing oxidative stress and inhibiting the cell apoptosis.