抄録
Neural stem cells (NSCs) can differentiate to neural cells such as neurons and astrocytes, therefore regenerative medicine based on natural products are urgent to neural diseases. We recently focused on the basic helix-loop-helix (bHLH) transcriptional factors, which control proliferation and differentiation of NSCs. To quickly find the ligands of bHLH factors from natural products extract, we developed the Hes I immobilized sepharose beads-HPLC method. Flavonoid glycosides (1-3) have been isolated rapidly by this method. Compounds 1 and 3 had the inhibitory activity against the Hes 1 dimer formations, and accelerated the neuron differentiation of mouse neural stem cells (MEB5). As a "natural products + diversity-oriented synthesis (DOS)" derived library, the heterocyclic-substituted chromones or flavonoids library was constructed by our efficient synthesis method and solid phase synthesis. By constructed cell-based assay, several compounds were found as moderate Hes 1 promoter inhibitors. Compound 4 actually inhibited Hes 1 mRNA expression in NSCs. Interestingly, 4 led the NSCs to astrocyte selective differentiation. We also searched upregulators of Ngn2 expression, which is bHLH differentiation activator. The cell-based assay for Ngn2 promoter activity was constructed. By Ngn2 promoter activity guided separation, several activators were isolated from Butea superba. Of them, three compounds (5-7) showed neuron selective differentiation of NSCs.
