Studies on antitumor activity diterpenoids from Isodon excisoides

Five ent-kaurane diterpenoids were obtained from the dried leaves of Isodon excisoides((Sun ex C.H.Hu)C.Y.Wu et H.W.Li)distributed in Gansu Province.Their structures were identified as Kamebacetal-A(Ⅰ),Glaucocalyxin-A(Ⅱ),Kamebanin(Ⅲ),Wangzaozin-A(Ⅳ)and Leukamenin-E(Ⅴ)by spectroscopic means,respectively.The cytotoxicity was tested in vitro by SRB assay.The results indicate that the five compounds showed significant cytotoxic activity against BEL-7402 and HO-8910 cell lines.