Ent-kauranoids from Isodon rubescens var. taihangensis

Two new compounds, rubescensins Q and R, and a new acetonide derivative of lasiodonin, together with thirteen known analogues, oridonin, ponicidin, wikstroemioidin B, lasiodonin, lasiokaurin, enmenol, 1-O-β-D- glucopyranosyl-enmenol, trichokaurin, the acetonide of maoyecrystal F, rabdoternins A-D, have been isolated from Isodon rubescens var. taihangensis. The structures of the new compounds were elucidated on the basis of spectroscopic methods, especially the 2D NMR spectral analysis. Compound 3 exhibited cytotoxicity against K562, Bcap37, CA, CNE, BIU87, BGC823, and HeLa cell lines.