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

Abstract 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 (25 R )-19-norspirosta-1,3,5 (10)-triene-4-methyl-2-ol ( 1 ), (25 R )-spirost-1,4-diene-3-one-2,6-diol ( 2 ), (25 R )-spirost-1,4-diene-3-one-2-ol ( 3 ), (25 R )-spirost-4-ene-3-one-2-ol ( 4 ), yuccagenin ( 5 ), gitogenin ( 6 ) and tigogenin ( 7 ).