Further Studies on Steroidal Glycosides from Bulbs, Roots and Leaves of Allium sativum L.

A new furostanol glycoside (2), named sativoside-B1, was isolated from garlic, bulbs of Allium sativum L., along with proto-desgalactotigonin (3). The structure of 2 was established to be (25R)-26-O-β-D-glucopyranosyl-22-hydroxy-5α-furostane-3β, 6β, 26-triol 3-O-β-D-glucopyranosyl-(1→3)-O-β-D-glucopyranosyl-(1→2)-O-[β-D-glucopyranosyl-(1→3)]-O-β-D-glucopyranosyl-(1→4)-O-β-D-galactopyranoside.From roots of this plant, two new steroidal glycosides, named sativoside-R1 (16) and sativoside-R2 (15) were isolated and their structures were determined to be (25R)-26-O-β-D-glucopyranosyl-22-hydroxy-5α-furostane-3β, 26-diol 3-O-β-D-glucopyranosyl-(1→3)-O-β-D-glucopyranosyl-(1→2)-O-[β-D-xylopyranosyl-(1→3)]-O-β-D-glucopyranosyl-(1→4)-O-β-D-galactopyranoside (16) and its corresponding spirostanol glycoside (15). Besides these glycosides, three known glycosides, 3, desgalactotigonin (13) and F-gitonin (14) were isolated and identified.In a glycoside fraction of the leaves of A. sativum, steroidal glycosides were not detected by thin layer chromatography analysis.