Four new labdane-type diterpenoid glycosides from Diplopterygium laevissimum

Four new labdane-type diterpenoid glycosides, laevissiosides A-D (1–4) were isolated from the 95% ethanol extract of Diplopterygium laevissimum (Christ) Nakai, along with two known analogues, 18- β-D-glucopyranosyl ester-sclareol (5) and 18-hydroxy-sclareol (6). The structures of compounds 1–4 were elucidated by extensive 1D and 2D NMR spectroscopy as well as high-resolution MS analyses. All isolated compounds were evaluated for their cytotoxic effects.