Neuroprotective compounds from Reynoutria sachalinensis.

Glutamate is a neurotransmitter in central nervous system. Overexpression of glutamate leads to oxidative stress, resulting in several neurodegenerative disorders that include Alzheimer's disease. The n-hexane fraction of stems and ethyl acetate (EtOAc) fraction of flowers of Reynoutria sachalinensis provide neuroprotection against glutamate-induced oxidative toxicity in HT22 cells. In this study, 1-decanol (1), β-amyrin (2), dammaran-3β-ol (3), campesterol (4), daucosterol (5), ergosterol peroxide (6), emodin 8-O-β-D-glucopyranoside (7), quercetin (8) and isoquercitrin (9) were isolated from n-hexane fractions of stems and EtOAc fractions of flowers of R. sachalinensis. Their neuroprotective activity was evaluated by MTT assay. 1-Decanol, campesterol, ergosterol peroxide, quercetin and isoquercitrin exhibited neuroprotective activity. These compounds decreased reactive oxygen species level, showed anti-oxidant activity with DPPH radical and in a H2O2 scavenging assay. Therefore, the neuroprotective activity of 1-decanol, campesterol, ergosterol peroxide, quercetin and isoquercitrin are associated with antioxidant activity.