Neuroprotective effects of fucoxanthin and its derivative fucoxanthinol from the phaeophyte Undaria pinnatifida attenuate oxidative stress in hippocampal neurons

Neuroprotective and neurotrophic supports are critical for neuronal survival, outgrowth, and functional activity in the degenerating brain where oxidative stress is a leading cause of neurological disorders. An ethanol extract of the phaeophyte Undaria pinnatifida (UPE) concentration dependently increased the viability of rat hippocampal neurons in both hypoxia-induced oxidative stress and normoxic conditions. UPE, at an optimal 15 mu gmL(-1), significantly reduced reactive oxygen species formation, DNA fragmentation, early and late apoptosis rates, and mitochondrial membrane dysfunction against hypoxia. In addition, the most active neuroprotectant from UPE was identified as fucoxanthin (Fx) by reverse-phase high-pressure liquid chromatography (RP-HPLC) and H-1 NMR. Fucoxanthinol (FxOH), a metabolite after enzymatic hydrolysis of Fx, significantly provided protection from neurite breakage and also enhanced the length of neurites in hypoxia cultures. The findings suggest that UPE and its active component Fx as well as FxOH have the ability to protect central nervous system neurons through anti-excitatory and anti-oxidative actions.