Anti-apoptotic effects of hyperoside via inhibition of NR2B-containing NMDA receptors

Abstract Hyperoside (Hyp) is a flavonoid compound isolated from a folk remedy, Rhododendron ponticum L. leaves. It has been shown to have neuroprotective effects both in vivo and in vitro . However, little is known about the effects of Hyp on the neuronal apoptosis induced by glutamate. The present study showed that Hyp significantly attenuated, in a concentration-dependent manner, the apoptosis induced by the exposure of cultured neurons to NMDA. Western blot analysis revealed that Hyp antagonized the expression of excess NR2B-containing NMDA receptors; however, it had no effect on the expression of NR2A-containing NMDA receptors. Our results demonstrate that the neuroprotective effect of Hyp owes, at least partially, to its differential modulation of NR2A- and NR2B-containing NMDA receptors.