A new neolignan from the fruits of Arctium lappa L.

In our study of the chemical constituents of the dried mature fruits of Arctium lappa L., ten compounds were isolated by various chromatography methods and preparative HPLC. Their structures were elucidated as (7R,8R)-4,7,9,9'-tetrahydroxy-3,3'-dimethoxy-8-4'-oxyneolign-7'-ene-9'-O-β-D-glucopyranoside (1), (7R,8R)-4,7,9,9'-tetrahydroxy-3,3'-dimethoxy-8-O-4'-neolignan-9'-O-β-D-glucopyranoside (2), (7R,8R)- 4,7,9,9'-tertahydroxy-3,3'-dimethoxy-8-4'-oxyneolignan (3), (7S,8R)-dihydrodehydrodiconiferylalcohol-4-O-β- D-glucopyranoside (4), (7S,8R,7'R,8'R)-pinoresinol-4,4'-di-O-β-D-glucopyranoside (5), (8S,7'S,8'R)-4,4',9'- trihydroxy-3,3'-dimethoxy-7',9-epoxylignan-7-oxo-4'-O-β-D-glucopyranoside (6), 2-methoxy-4-hydroxyphenol- 1-O-β-D-xylopyranosyl-(1→6)-O-β-D-glucopyranoside (7), 3-methoxy-4-hydroxyphenol-1-O-β-D-xylopyranosyl- (1→6)-O-β-D-glucopyranoside (8), 4-hydroxy-3-methoxybenzylalcohol-4-O-β-D-xylopyranosyl-(1→6)-O-β-D- glucopyranoside (9) and 2-phenethyl β-primeveroside (10) by their spectroscopic data (IR, UV, CD, MS, HR-ESI-MS, and 1D and 2D NMR) and comparison to literature data. Compound 1 is a new 8-O-4'-neolignan. Compounds 2-10 were isolated from the dried mature fruits of Arctium lappa L. for the first time.