Rec . Nat . Prod . X : X ( 2019 ) XXXX Two New Lignans from Lycopodium japonicum Thunb

Two new lignans, named lycojaponicumoside A (1) and B (2), together with four known compounds (3˗6) were isolated from the n-BuOH extract of Lycopodium japonicum. Their structures were elucidated on the basis of extensive spectroscopic methods, especially various NMR techniques, HRESIMS and circular dichroism (CD). The absolute configuration of compound 1 was established by the calculation of electronic circular dichroism (ECD) curves. All of the compounds were evaluated for their cytotoxic activities against A549 and HepG2 human cancer cell lines, but those compounds did not exhibit cytotoxicity.