Two new dihydrobenzofuran lignans from Rabdosia lophanthoides (Buch.-Ham.ex D.Don) Hara

Two new dihydrobenzofuran lignanosides, (7R,8S)-4,3′,9′-trihydroxyl-3-methoxyl-7,8-dihydrobenzofuran-1′-propylneolignan-9-O-(6-O-syringoyl)-β-d-glucopyranoside, named lophanthoside B (1) and (7R,8S)-4,9,9′-trihydroxyl-3-methoxyl-7,8-dihydrobenzofuran-1′-propylneolignan-3′-O-β-d-glucopyranoside (2), an enantiomer of umbroside, along with four known dihydrobenzofuran lignans (3–6), were isolated from 50% acetone extract of Rabdosia lophanthoides (Buch.-Ham.ex D.Don) Hara. Their structures were elucidated by NMR and MS experiments.