Steroidal Glycosides from Allium tuberosum Seeds and Their Roles in Promoting Testosterone Production of Rat Leydig Cells

A systematic phytochemical study on the components in the seeds of Allium tuberosum was performed, leading to the isolation of 27 steroidal glycosides (SGs 1–27). The structures of SGs were identified mainly by nuclear magnetic resonance and mass spectrometries as well as the necessary chemical evidence. In the SGs, 1–10 and 22–26 are new steroidal saponin analogues. An in vitro bioassay indicates that 1, 2, 7, 8, 10, 13–15, 20, 23, and 26 display promotional roles in testosterone production of rat Leydig cells with the EC(50) values of 1.0 to 4.5 μM, respectively.