Lignans from the roots of Echinops giganteus

Two new lignans, 1 and 2, were isolated from the Cameroonian medicinal plant, Echinops giganteus (Compositae). Their structures were elucidated by extensive NMR spectroscopy and mass spectrometry. Two new lignans, (+)-4-(3-methylbutanoyl)-2,6-di(3,4-dimethoxy)phenyl-3,7-dioxabicyclo[3.3.0]octane and (+)-4-hydroxy-2,6-di(3,4-dimethoxy)phenyl-3,7-dioxabicyclo[3.3.0]octane, together with the known lupeol and sitosteryl β- d-glucopyranoside, have been isolated from the roots of Echinops giganteus var. lelyi C. D. Adams (Compositae). The structures were elucidated on the basis of spectral studies and comparison with published data.