Naphthohydroquinones and lignans from the roots of Plocama pendula, a Canary Island paleoendemism

Two naphthohydroquinones, mollugin 6-methyl ether and plocanaphthin, have been obtained from the roots of Plocama pendula (Rubiaceae), a paleoendemism of the Canary Islands. The former is a new compound, while the latter has now been isolated for the first time from nature. Other compounds obtained from this species were the lignans syringaresinol, pinoresinol and lariciresinol, and the coumarin scopoletin.

Research highlights
► Mollugin 6-methyl ether is a new naphthohydroquinone.
► The naphtohydroquinone plocanaphthin has been isolated by the first time from nature.
► Phytochemical data support the morphological classification of Putoria and Plocama as two different genus of Rubiaceae family.