Six new cytotoxic and anti-inflammatory 11, 20-epoxy-ent-kaurane diterpenoids from Iso Isodon wikstroemioides

The present study was designed to determine the chemical constituents of EtOAc extracts of the aerial parts of Isodon wikstroemioides. Compounds 1–8 were isolated and purified by normal-phase silica gel and reversed-phase C18silica gel column chromatography and HPLC. Their structures were elucidated by extensive spectroscopic methods. Most of them were evaluated for their in vitro cytotoxicity against human cancer HL-60, SMMC-7721, A-549, MCF-7, and SW-480 cells and their inhibitory activity against nitric oxide (NO) production in LPS-activated RAW264.7 macrophages. Among the eight 11, 20-epoxy-ent-kauranoids isolated, compounds 1–6 (isowikstroemins H-M) were new diterpenoids. Compounds 1, 3, and 7 exhibited significant cytotoxicity with IC50 values ranging from (0.84 ± 0.02) to (4.09 ± 0.34) μmol·L−1, while compounds 4 and 5 showed selective cytotoxicity. In addition, compounds 1, 3, 4, and 7 exhibited inhibitory activity against nitric oxide (NO) production in LPS-activated RAW264.7 macrophages. These results provide a basis for future development of these compounds as anti-cancer and anti-inflammatory agents.

Six new 11, 20-epoxy-ent-kauranoids along with two known ones isolated from Isodon wikstroemioides. Seven compounds were evaluated for their in vitro cytotoxicity against five human tumor cell lines, and three of them exhibited significant activity, two of them showed selective cytotoxicity. Furthermore, we tested the inhibitory activity against NO production in LPS-activated RAW 264.7 macrophages and found four of these compounds exhibited interesting activity.Figure optionsDownload as PowerPoint slide