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

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 α-d-galactopyranosyl-(1→6)-α-d-galactopyranosyl-(1→2)-1d-chiro-inositol, and fagopyritol A2 is α-d-galactopyranosyl-(1→6)-α-d-galactopyranosyl-(1→3)-1d-chiro-inositol. Fagopyritol A3, a trigalactosyl d-chiro-inositol, is α-d-galactopyranosyl-(1→6)-α-d-galactopyranosyl-(1→6)-α-d-galactopyranosyl-(1→3)-1d-chiro-inositol. From analysis of hydrolysis products, the second trigalactosyl d-chiro-inositol, fagopyritol B3, is α-d-galactopyranosyl-(1→6)-α-d-galactopyranosyl-(1→6)-α-d-galactopyranosyl-(1→2)-1d-chiro-inositol.