We previously reported that Smilacis chinae rhizome inhibits amyloid b protein (25—35) (Ab (25—35))-induced
neurotoxicity in cultured rat cortical neurons. The present study evaluated the neuroprotective effect of
oxyresveratrol isolated from Smilacis chinae rhizome against Ab (25—35)-induced neurotoxicity on cultured rat
cortical neurons. Oxyresveratrol over the concentration range of 1—10mM significantly inhibited 10mM Ab (25—
35)-induced neuronal cell death, which was measured by a 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl-tetrazolium
bromide (MTT) assay and Hoechst 33342 staining. Oxyresveratrol (10mM) inhibited 10mM Ab (25—35)-induced
elevation of cytosolic calcium concentration ([Ca2]c), which was measured by a fluorescent dye, Fluo-4 AM.
Oxyresveratrol (1, 10mM) also inhibited glutamate release into medium and reactive oxygen species (ROS) generation
induced by 10mM Ab (25—35). These results suggest that oxyresveratrol prevents Ab (25—35)-induced
neuronal cell damage by interfering with the increase of [Ca2]c, and then by inhibiting glutamate release and
ROS generation. Furthermore, these effects of oxyresveratrol may be associated with the neuroprotective effect
of Smilacis chinae rhizome.