Methanol Extract of Polygalae Radix Protects Excitotoxicity in Cultured Neuronal Cells

Abstract

Polygalae Radix (PR) from Polygala tenuifolia (Polygalaceae) is traditionally used in China and Korea, since this herb has a sedative, antiinflammatory, and antibacterial agent. To extend pharmacological actions of PR in the CNS on the basis of its CNS inhibitory effect, the present study examined whether PR HAS THE NEURONS. PR, over a concentration range of 0.05 to 5㎍/㎖ , inhibited KA (500μm)-induced neuronal cell death, which was measured by a trypan blue exclusion test and a 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl-terazolium bromide (MTT) assay. PR (0.5 ㎍/㎖)ingibited glutamate release into medium induced by KA (500 μM), whcih was measured by HPLC. Pretreatment of PR(0.5㎍/㎖) inhibited KA (500 m)-induced elevation of cytosolic calcium concentration([Ca2+]c), which was measured by a fluorescent dye, Fura 2-AM, and generation of reactive oxygen species (ROS). These results suggest that PR prevents KA-induced neuronal cell damage in vitro.