Isolation, chiral separation and absolute configuration determination of lignanoids from an aqueous extract of the Angelica sinensis root head

From an aqueous extract of the Angelica sinensis root head (guitou), nine pairs of lignanoid enantiomers (+)-/(-)-1-(+)-/(-)-9, including three pairs of new structures (+)-/(-)-1-(+)-/(-)-3 and two pairs of chiral separated enantiomers for the first time (+)-/(-)-4 and (+)-/(-)-5, were isolated and chirally separated by column chromatography over different types of resin, normal and reversed phase silica gels, together with HPLC techniques using reversed phase and chiral columns. Their structures were determined by spectroscopic data analysis, theoretic calculation of electronic circular dichroism (ECD) spectra, and single-crystal X-ray diffraction. The chiral separated new enantiomers named (+)-/(-)-angelignanins Q-T (+)-/(-)-1-(+)-/(-)-4 and (+)-/(-)-daphneresinol (+)-/(-)-5, respectively.