3,4-Seco-spirostane sapogenins with cytotoxic activity from Allium umbilicatum boiss

Abstract Two new sapogenins, named seco-umbilicagenins A and B ( 1 and 2) , possessing a new chemical structure based on a 3,4-seco-spirostane skeleton, were isolated from Allium umbilicatum Boiss . The chemical structures of seco-umbilicagenins A and B were established through a combination of extensive spectroscopic analysis, mainly nuclear magnetic resonance spectroscopy and mass spectrometry, and chemical methods as (2 S ,25 R )-2,5α,6β-trihydroxy-3,4-seco-spirosta-3,4-dioic acid ( 1 ) and (2 S ,25 R )-2,4,5α-trihydroxy-6- oxo -3,4-seco-spirostan-3-oic acid ( 2 ). Interestingly, the isolated compounds exhibited cytotoxic activity on J-774, murine monocyte/macrophage, and WEHI-164, murine fibrosarcoma, cell lines. To the best of our knowledge this is the first time that 3,4-seco-spirostane sapogenins are isolated from natural sources, being this skeleton obtained by synthetic modification of intact sapogenins.