Furostanol Saponins from the Bulbs of Welsh Onion, Allium fistulosum L

An extensive phytochem. anal. of the polar exts. from bulbs of Welsh onion Allium fistulosum L. led to the isolation of nine saponins, four of them, named fistulosaponins G (1a/1b), H (2), I (3a/3b), and J (4), have never been reported previously. Fistulosaponins G and I were isolated as a couple of isomers in equil. On the basis of 2D NMR and mass spectrometry data, the structure of the novel compds. were elucidated as (25R)-26-[(β-D-glucopyranosyl)oxy]-3β,22β-dihydroxyfurost-5-en-1β-yl O-α-L-rhamnopyranosyl-(1 → 4)-O-α-L-rhamnopyranosyl-(1 → 4)-β-D-glucopyranoside (1a) with its 22α epimer (1b), (25R)-26-[(β-D-glucopyranosyl)oxy]-3β-hydroxyfurost-5,20-dien-1β-yl O-α-L-rhamnopyranosyl-(1 → 4)-O-α-L-rhamnopyranosyl-(1 → 4)-β-D-glucopyranoside (2), (25R)-26-[(β-D-glucopyranosyl)oxy]-3β,22β-dihydroxyfurost-5-en-1β-yl O-α-L-rhamnopyranosyl-(1 → 4)-β-D-glucopyranoside (3a) with its 22α epimer (3b), and (25R)-26-[(β-D-glucopyranosyl)oxy]-3β-hydroxyfurost-5,20-dien-1β-yl O-α-L-rhamnopyranosyl-(1 → 4)-β-D-glucopyranoside (4). This is the first report of furostanol saponins in A. fistulosum bulbs. In addn., data on the antibacterial tests of the isolated saponins against Escherichia coli and Enterococcus faecalis are reported. [on SciFinder(R)]