Diverse neolignans and lignans from an aqueous extract of the Angelica sinensis root head.

Neolignans and lignans with diverse new chemical structures, including eleven pairs of separated chiral enantiomers [(+)-/(-)- 1 -(+)-/(-)- 5 , (+)-/(-)- 8 , (+)-/(-)- 10 , and (+)-/(-)- 12 -(+)-/(-)- 15 ], two achiral compounds ( 6 and 9 ), and an unseparated racemate [(±)- 11 ], together with a new natural product ( 7 ) and 21 known derivatives, were isolated from an aqueous extract of the Angelica sinensis root head (guitou). Among the chiral isolates, (+)-/(-)- 13 and (+)-/(-)- 15 were scalemic pairs with enantiomeric ratios of around 3:1 and 1.5:1, respectively, while others were enantiomeric equivalent pairs. This indicates that the diverse neolignans in A. sinensis are biosynthesized via different pathways with varying degrees of stereo-controlled manners.