New steroidal sapogenins from the acid hydrolysis product of the whole glycoside mixture of Welsh onion seeds

Two new steroidal sapogenins (1, 2) along with five known steroidal sapogenins were isolated from the acid hydrolysis product of the whole glycoside mixture of Welsh onion (Allium fistulosum L.) seeds. Based on comprehensive spectroscopic analyses, including 2D NMR spectroscopy and mass spectrometry, their structures were elucidated as (25R)-19-norspirosta-1,3,5 (10)-triene-4-methyl-2-ol (1), (25R)-spirost-1,4-diene-3-one-2,6-diol (2), (25R)-spirost-1,4-diene-3-one-2-ol (3), (25R)-spirost-4-ene-3-one-2-ol (4), yuccagenin (5), gitogenin (6) and tigogenin (7).