Sinomenine inhibits Aβ-induced increase in the level of nitric oxide (NO) in BV2 cells. BV2 cells were treated with oligomeric Aβ (ADDL) in the presence or absence of sinomenine. NO release was estimated using the Griess reagent. ADDL treatment of BV2 cells increased the level of NO, but sinomenine inhibited the effect of ADDL on NO level (n = 7 in all groups). Asterisks denote significant differences (p < 0.05).