Procyanidin B2 3″--gallate Isolated from Prevents Glutamate-Induced HT22 Cell Death by Blocking the Accumulation of Intracellular Reactive Oxygen Species.

In this study, we examined the neuroprotective effects of MeOH extract and bioactive compounds obtained from seeds using HT22 cells from the murine hippocampal cell line as its underlying molecular basis, which has not yet been elucidated. Our study showed that the MeOH extract of seeds strongly protected HT22 cells from glutamate toxicity. To clarify the responsible compound for the neuroprotective effects, we took an interest in procyanidins of since procyanidins are known to exhibit high structural diversity and neuroprotective activity. To isolate the procyanidins efficiently, a phytochemical investigation of the MeOH extract from seeds using the LC/MS-guided isolation approach was applied, and procyanidin B2 3″--gallate () was successfully isolated. The structure of was elucidated by analyzing the nuclear magnetic resonance spectroscopic data and LC/MS analysis. The neuroprotective activities of were thoroughly examined using HT22 cells. Compound exhibited a strong antioxidant efficacy and blocked glutamate-mediated increase in the reactive oxygen species (ROS) accumulation. Furthermore, compound significantly inhibited the phosphorylation of extracellular signal-regulated kinase, p38, and c-Jun N-terminal kinase, which were increased by glutamate. These findings prove that the extract of seeds containing procyanidin B2 3″-O-gallate, which is a strong neuroprotective component, can be used as a functional food forattenuating and regulating neurological disorders.