New secoiridoids from the fruits of Ligustrum lucidum

Three new secoiridoids, nuezhenelenoliciside (1), isojaslanceoside B (2), 6′-O-trans-cinnamoyl-secologanoside (3), were isolated from the dried fruits of Ligustrum lucidum. Their structures were elucidated by comprehensive spectroscopic analysis. Among them, 1 featured a rare rearrangement product of secoiridoid, which underwent the cleavage of chemical bond between C-1 and O-2, and the reformation of a new iridoid ring between C-8 and O-2. In addition, all compounds were tested for their osteogenic activity on pre-osteoblastic MC3T3-E1 cells. As a result, 1 and 3 exhibited potent effects on promoting cell proliferation of pre-osteoblast cells.