Cytotoxic and anti-inflammatory ent-kaurane diterpenoids from Isodon wikstroemioides.

Seven new ent-kaurane diterpenoids, isowikstroemins A-G (1-7), were isolated from EtOAc extracts of the aerial parts of Isodon wikstroemioides. Their structures were elucidated by extensive spectroscopic analysis. The isolates were evaluated for their cytotoxicity against five human tumor cell lines, and compounds 1-4 exhibited significant activity with IC50 values ranging from 0.9 to 7.0 μM. In addition, compounds 1, 2, 3, 4, and 7 exhibited inhibitory activity against nitric oxide (NO) production in LPS-activated RAW264.7 macrophages.