Abstract
Bioassay-guided fractionation of the crude extract of Mitrephora thorelii (Annonaceae) led to the isolation of two clerodane-type diterpenes. Their structures were characterised on the basis of spectroscopic methods as 6α,16,18-trihydroxycleroda-3(4),13(14)-dien-15,16-olide (1) and 16-hydroxycleroda-3(4),13(14)-dien-15,16-olide (2). Compound 1 is a new compound. Compounds 1 and 2 exhibited inhibitory activity against the proliferation of human hepatoma BEL-7402 cells in vitro. Compound 2 also showed an in vivo anti-tumour effect against the growth of hepatoma H22 in mice.
Acknowledgements
The authors are grateful to the Shanghai Committee of Science and Technology for partial financial support (No. 03DZ19228, to W.Z.) and the National Natural Science Foundation of China (No. 30370729, to L.L.).