Impact of Ecklonia radiata extracts on the neuroprotective activities against amyloid beta (Aβ_1-42) toxicity and aggregation

The impact of extract composition on the neuroprotective activities of Ecklonia radiata was investigated in multiple neuroprotective assays in vitro. A total of six fractions (crude extract (CE), phlorotannin (PT), polysaccharide (PS), free sugar (FS), low molecular weight (LM), and high molecular weight (HM)) prepared from E. radiata were used to determine their effects against Aβ1-42 and oxidative stress in neuronal cell line PC-12. Only three fractions (CE, PS, and HM) demonstrated cytotoxicity in at least the highest concentration (100 μg/mL) tested in PC-12 cells. All fractions inhibited apoptosis induced by Aβ1-42 and enhanced neurite outgrowth activity. With the exception of HM, other fractions inhibited the aggregation of Aβ1-42 and demonstrated antioxidant activity against the toxicity induced by hydrogen peroxide. This study highlights the potential of using brown seaweed E. radiata components for improving neuroprotective activities. Such extracts could be potentially used as functional food or dietary supplements to support neurological function.