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

Two digalactosyl D-chiro-inositols and two trigalactosyl D-chiuo-inositols, members of the fagopyritol A series and fagopyritol B series, were isolate d from buckwheat (Fagopyrum esculentum Moench) seeds. Structures of the fir st three were determined by H-1 and C-13 NMR. Fagopyritol B2 is alpha -D-ga lactopyranosyl-(1->6)-alpha -D-galactopyranosyl-(1->2)-1D-chiro-inositol , and fagopyritol A2 is alpha -D-galactopyranosyl-(1->6)-alpha -D-galactopyra nosyl-(1->3)-1D-chiro-inositol. Fagopyritol A3, a trigalactosyl D-chiro-ino sitol, is alpha -D-galactopyranosyl-(1->6)-alpha -D-galacto-pyranosyl-(1->6 )-alpha -D-galactopyranosyl-(1->3)-1D-chiro-inositol. From analysis of hydr olysis products, the second trigalactosyl D-chiro-inositol, fagopyritol B3, is alpha -D-galactopyranosyl-(1->6)-alpha -D-galactopyranosyl-(1->6)-alpha -D-galactopyranosyl-(1->2)-1D-chiro-inositol. (C) 2001 Elsevier Science Lt d. All rights reserved.