Promotion of neuronal differentiation of PC12h cells by natural lignans and iridoids.

We studied the effect of (+)- and (-)-syringaresinol, (+)-syringaresinol glucosides, syringin, aucubin and catalpol on neurite outgrowth of a cultured cell line of paraneuron, PC12h cells. Of these compounds, (+)-syringaresinol diglucoside and partly glucosidase-hydrolyzed aucubin were found to be the most potent in promotion of the neurite outgrowth and stimulated responses to a high concentration of KCl and to carbachol in the cells, as observed by increase of the concentration of cytosolic free calcium. It is suggested that some of these herb-derived compounds can induce neuronal differentiation in PC12h cells.