Three new steroidal saponins (1-3) and a known saponin (4) were isolated from Ophiopogon japonicus (Thunb.) Ker-Gawl. Their structures were determined by spectroscopic analyses and chemical derivatization. The isolated compounds (1-4) were potent inducers of neuritogenesis on PC12 cells. Compound 1 showed the highest neuritogenic activity of 46% at 1 μM. The study of structure-activity relationships suggests that aglycone is important for the neuritogenic activity of the compounds. Specific inhibitor experiments and Western blot analysis suggest that 1-induced neuritogenic activity depends on the activation of mitogen-activated protein kinase kinase (MEK)/extracellular signal regulated kinase (ERK) signaling pathway on PC12 cells.
Keywords: ERK phosphorylation; Neuritogenic activity; Ophiopogon japonicus; Steroidal saponins.
Copyright © 2013 Elsevier Inc. All rights reserved.