Background: Several studies have shown that plant saponins promoted osteoblast differentiation
and improved osteoporosis. In the current study, Sea Cucumber Saponin (SCS) with a purity of
80% was extracted from Filipino sea cucumber, with a similar structure to plant saponins.
Objective: This study aims to investigate the effects of SCS on bone formation in vitro and ex vivo.
Results: SCS significantly promoted osteogenic differentiation and mineralization of MC3T3-E1 cells,
as well as new osteoid formation in neonatal mouse calvarias ex vivo. qRT-PCR results indicated that
SCS markedly down-regulated the expression of C/EBPα* and PPARγ at the levels of transcription,
which demonstrate that SCS inhibits the trans-differentiation of MC3T3-E1 cells to an adipocytic phenotype.
Moreover, further studies revealed that SCS increased the expression levels of Runx2 and
OSX. The mechanism revealed that SCS induced the expression of BMP2 and p-Smad1/5, which indicated
that SCS facilitated osteogenesis via activating the BMP2/Smads signaling pathway.
Conclusion: SCS promoted osteogenic differentiation of pre-osteoblasts by activating the BMP2/
Smads molecular pathway, providing a theoretical basis for the development of sea cucumber saponins
for the treatment to bone loss diseases such as osteoporosis.