Fucoidan isolated from Sargassum wightii Greville ameliorates intracerebro-ventricular streptozotocin induced cognitive deficits, oxidative stress and amyloidosis in Wistar rats

Abstract

Marine algae have always been an important part of diet as well as traditional medicine. They are known to consist of number of bioactive polysaccharides, fucoidan being the principal polysaccharide. The present study aimed to evaluate the protective effect of fucoidan isolated from Sargassum wightii Greville against streptozotocin induced cognitive deficits, oxidative stress and amyloidosis. Streptozotocin 3 mg/kg intracerebroventricular injection was administered by stereotaxic surgery induce sporadic Alzheimer's disease. Animals were subjected to behavioural analysis including Morris water maze, open field and single trial passive avoidance test. At the end of the study, animals were sacrificed and biochemical and histochemical studies were carried out. Streptozotocin treated animals exhibited poor performance in behavioural analysis indicating significant cognitive deficits. Marked elevation in hippocampal MDA, nitrite, AGE, AChE activity and reduction in GSH, SOD was observed in disease group. Upsurge in Aβ protein and Tau protein indicated streptozotocin induced neuronal damage in hippocampus. Treatment with fucoidan 100 and 200 mg/kg significantly ameliorated the behavioural deficits, oxidative stress, hyperphosphorylated tau protein and amyloidosis induced by intracerebroventricular streptozotocin. Histochemical studies further invigorated the neuroprotective role of fucoidan in the brain cortex and hippocampus of experiment animals. It may be suggested that fucoidan ameliorated streptozotocin induced Alzheimer's disease like pathological changes including cognitive deficits, oxidative stress and amyloidosis.