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

Neolignans and lignans with diverse new chemical structures, including eleven pairs of separated chiral enantiomers [(+)-/(-)--(+)-/(-)-, (+)-/(-)-, (+)-/(-)-, and (+)-/(-)--(+)-/(-)-], two achiral compounds ( and ), and an unseparated racemate [(±)-], together with a new natural product () and 21 known derivatives, were isolated from an aqueous extract of the root head (guitou). Among the chiral isolates, (+)-/(-)- and (+)-/(-)- 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 are biosynthesized via different pathways with varying degrees of stereo-controlled manners.