Ent-kauranoids from Isodon rubescens var. taihangensis

Two new compounds, rubescensins Q and R ( 1 and 2 ), and a new acetonide derivative ( 3 ) of lasiodonin, together with thirteen known analogues, oridonin ( 4 ), ponicidin ( 5 ), wikstroemioidin B ( 6 ), lasiodonin ( 7 ), lasiokaurin ( 8 ), enmenol ( 9 ), 1- O -- d -glucopyranosyl-enmenol ( 10 ), trichokaurin ( 11 ), the acetonide of maoyecrystal F ( 12 ), rabdoternins A-D ( 13 - 16 ), 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.