David J. Fuller

Molecular structure of fagopyritol A1 (O-α-d-galactopyranosyl-(1→3)-d-chiro-inositol) by NMR

The molecular structure of fagopyritol A1, a novel galactopyranosyl cyclitol from buckwheat seeds, was determined to be O-alpha-D-galactopyranosyl-(1 --> 3)-D-chiro-inositol by 1H and 13C NMR. Fagopyritol A1 is a positional isomer of fagopyritol B1 (O-alpha-D-galactopyranosyl-(1 --> 2)-D-chiro-inositol), representing a different series of fagopyritol oligomers. Trimethylsilyl derivatives of both compounds have similar mass spectra, but each may be identified by different abundance ratios of fragments with m/z 305/318 and 318/319.

Purification and molecular structure of two digalactosyl d-chiro-inositols and two trigalactosyl d-chiro-inositols from buckwheat seeds

Two digalactosyl D-chiro-inositols and two trigalactosyl D-chiro-inositols, members of the fagopyritol A series and fagopyritol B series, were isolated from buckwheat (Fagopyrum esculentum Moench) seeds. Structures of the first three were determined by 1H and 13C NMR. Fagopyritol B2 is alpha-D-galactopyranosyl-(1-->6)-alpha-D-galactopyranosyl-(1-->2) -1D-chiro-inositol, and fagopyritol A2 is alpha-D-galactopyranosyl-(1-->6)-alpha-D-galactopyranosyl-(1-->3)- 1D-chiro-inositol. Fagopyritol A3, a trigalactosyl D-chiro-inositol, is alpha-D-galactopyranosyl-(1-->6)-alpha-D-galactopyranosyl-(1 -->6) -alpha-D-galactopyranosyl-(1-->3)- 1 D-chiro-inositol. From analysis of hydrolysis products, the second trigalactosyl D-chiro-inositol, fagopyritol B3, isalpha-D-galactopyranosyl-(1-->6)-alpha-D-galactopyranosyl-(1-->6) -alpha-D-galactopyranosyl-(1-->2)-1D-chiro-inositol.