Cassane furanoditerpenoids from the seed kernels of Caesalpinia bonduc from Thailand.

Three new cassane furanoditerpenoids ( 1- 3), together with 13 known cassane diterpenes ( 4- 16), were isolated from the EtOAc extract of the seed kernels of Caesalpinia bonduc. Their structures were elucidated on the basis of spectroscopic analysis, mainly NMR and MS. Compounds 1- 3 exhibited good antimalarial activity against the multidrug-resistant K1 strain of Plasmodium falciparum, while compound 4 was inactive. None of the compounds were cytotoxic against any of the tumor cell lines tested.