Trigonelline-induced neurite outgrowth in human neuroblastoma SK-N-SH cells.

Extension of dendrites and axons in neurons may compensate and rescue damaged neuronal networks in the dementia brain. Our aim is to isolate and identify constituents of coffee beans exhibiting neurite outgrowth activity. Among the extracts of raw and roasted coffee beans, a methanol fraction of the ethanol extract (1 microg/ml) of raw beans increased significantly the percentage of cells with neurites in human neuroblastoma SK-N-SH cells. Among subfractions of this methanol fraction was a basic fraction (5 microg/ml) which exhibited significant neurite outgrowth activity. Finally, trigonelline in the basic fraction was identified to be active as far neurite extension was concerned. Treatment with trigonelline (30 microM) increased the percentage of cells with neurites at 3 and 6 d after treatment. In addition, the number of neurites reacting positively to phosphorylated neurofilament-H was increased by treatment with 30 microM trigonelline for 6 d, suggesting enhancement of axonal extension. These results show that trigonelline promotes functional neurite outgrowth.