Effects of euxanthone on neuronal differentiation

The growth inhibitory and differentiation inducing effects of euxanthone (1 ,7-dihydroxyxanthone) from the medicinal plant Polygala caudata on the neur oblastoma (Neural 2A, subclone BU-I) were investigated. At the concentratio n range of 0 - 100 mu M, euxanthone inhibits the growth of BU-1 cells in a dose dependent manner. The 50% growth inhibitory concentration (IC50) was 4 1 mu M. Significant induction of morphological differentiation and neurite growth was observed at the concentration of 100 mu M. Frequency of prolifer ative neuroblastoma cells was determined after induction of differentiation . The frequency of proliferating BU-I cells was markedly reduced from 1/1.1 to <1/99. Confocal microscopy also confirmed that the morphological differ entiation of BU-1 was associated with the expression of neurite specific ma rker MAP-2 protein in neurites. These data suggest that euxanthone may be o ne of the neuropharmacological active compounds in the medicinal plant Poly gala caudata.