Planta Med. 2002 Oct; 68(10): 946-8.

ent-Kaurane diterpenoids from the leaves of Isodon xerophilus.

Li SH, Niu XM, Peng LY, Zhang HJ, Yao P, Sun HD.

State Key Laboratory of Phytochemistry and Plant Resources in West China, Kunming Institute of Botany, The Chinese Academy of Sciences, Heilongtan, Kunming, Yunnan, P. R. China.

From the ethanolic extract of the leaves of Isodon xerophilus, three new ent-kaurane diterpenoids named xerophilusins L-N (1 - 3), together with three known ones designated as rabdoternin A (4), longikaurin F (5) and ponicidin (6), were isolated and structurally elucidated. Compound 6 demonstrated most potent cytotoxic activity against K562 and T24 human tumor cell lines with IC(50) = 0.09 and 0.32 microg/ml, respectively.