A new lignan from Isodon lophanthoides var. gerardianus (Labiatae)

A new lignan, together with a known one, was isolated from Isodon lophanthoides var, gerardianus [Bentham] H. Hara. The structure of the new lignan was elucidated as 1-acetoxyl-2e-piperonyl-6e-[6-methoxyl-piperonyl]-3,7-dioxabicyclo-[3,3,0]-octane mainly by 1D and 2D NMR techniques.