Cytotoxic diterpenoids from the aerial parts of Scoparia dulcis

Abstract

Two formerly undescribed labdane-type diterpenoids, scoparicols C ( 1 ) and D ( 2 ), one previously unreported scopadulane-type diterpenoid 1β-hydroxydulcinodal-13-one ( 3 ), along with six known biogenetically related analogs ( 4 − 9 ) were separated from the aerial parts of a traditional ethnological herb, Scoparia dulcis . Spectroscopic techniques including MS NMR and ECD were employed to characterize the structures of these molecules. While the oxidation at C-1 in 3 was reported for scopadulane-type diterpenoids for the first time, compound 7 was first obtained as a natural product in the present work. The cytotoxicity of all the isolates against four tumor cell lines (MCF-7, MDA-MB231, Hela and A549) were tested, with selective compounds showing activity in the IC 50 range of 4.31–28.6 μM. • Two new labdane and one new scopadulane diterpenoids were obtained from Scoparia dulcis . • The absolute configurations were characterized by different ECD techniques. • Oxidation at C-1 in compound 3 was reported for the first time for scopadulane diterpenoids. • Three compounds showed cytotoxicity against all tested breast, cervical & lung tumor cells.