Studies on cytotoxicity of the diterpenoids from Isodon japonica

Objective To research the diterpenoids of Isodon japonica and their cytotoxicity. Methods Diterpenoids of Isodon japonica were separated and purified by silica gel column chromatography. Their structures and cytotoxicity were determined by spectroscopic methods and MTT colorimetric assay, respectively.Results Fourteen known ent-kaurane diterpenoids were isolated and identified from the leaves of Isodon japonica: effusain A (1), lasiodonin (2), skikokianin (3), rabdosichuanin D (4), oridion (5), lasiokaurin (6), 1α-O-β-D-glucopyranosyl-enmenol (7), rabdoternin A (8), epinodosin (9), epinodosinol (10), isodonal (11), isodonoiol (12), rabdosin B (13), rabdosinate (14). Compounds 1, 2, 3, 5, 6, 9, 11, 12 and 13 exhibited significant inhibition on HL-60, HO-8910 and A-549 tumor cell lines. Conclusion Isodon japonica is abundant in Ent -kaurane diterpenoids with cytotoxicity.