Neuroprotective compounds isolated from Cynanchum paniculatum.

Ten compounds were isolated from the 80% methanol extract of roots of Cynanchum paniculatum Kitagawa (Asclepiadaceae) and identified as paeonol (1), 4-acetylphenol (2), 2,5-dihydroxy-4-methoxyacetophenone (3), 2,3-dihydroxy-4-methoxyacetophenone (4), acetoveratrone (5), 2,5-dimethoxyhydroquinone (6), vanillic acid (7), resacetophenone (8), m-acetylphenol (9) and 3,5-dimethoxyhydroquinone (10). The protective effect of compounds 1-10 against glutamate-induced cytotoxicity in hippocampal HT22 cell line was evaluated. Among them, compound 4 showed a relatively effective protection of 47.55% (at 10 μM). This result suggested that compounds 4 had neuroprotective effect on the glutamate-induced neurotoxicity in HT22 cells.