Abstract 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 ...