Porrigenins A and B, novel cytotoxic and antiproliferative sapogenins isolated from Allium porrum.

Four new sapogenins, porrigenins A (2a) and B (3a), identified as (25R)-5 alpha-spirostan-2 beta,3 beta,6 beta-triol and (25R)-2-oxo-5 alpha-spirostan-3 beta,6 beta-diol, respectively, and neoporrigenins A (2b) and B (3b) were also isolated from Allium porrum. In addition, the known agigenin (1a) and its 25S epimer, neoagigenin (1b), were also identified. Their structure elucidation was provided by comprehensive spectroscopic analyses. Compounds 1a, 2a, and 3a exhibited cytotoxicity and high antiproliferative activity on four different tumor cell lines in vitro.