The effect of different substitute groups and molecular weights of fucoidan on neuroprotective and anticomplement activity

Ten fucoidan (FPS) derivatives were successfully synthesized, and their potential neuroprotective and anticomplement activities were investigated employing various established in vitro systems. The aim of the present study was to investigate the effects of different substitute groups and molecular weights of fucoidan on neuroprotective and anticomplement activities. All FPS derivatives possessed considerable neuroprotective and anticomplement activities and had stronger activities than FPS in certain tests. The in vitro results found that sulfated and benzoylated derivatives could reverse the decreased mitochondrial activity and decreased lactate dehydrogenase (LDH) and reactive oxygen species (ROS) release induced by 6-hydroxydopamine (6-OHDA, P < 0.01 or P < 0.001), which provides further evidence that sulfate and benzoylate groups could enhance the neuroprotective activity of fucoidan. In anticomplement experiments, all samples showed anticomplement activity in both systems; however, the sulfated and benzoylated derivatives showed better activity than fucoidan, with higher molecular weights showing the strongest activity. Available data suggested that substituted groups of fucoidan played an important role on neuroprotective and anticomplement activities. The mechanism of the influence of the neuroprotective and anticomplement activities of samples of the substituted groups was indicated.