Secondary metabolites from two Hispaniola Ageratina species and their cytotoxic activity

Study of the aerial parts of the two species of Ageratina : A. dictyoneura and A. illita afforded four new ent -labdane diterpenoids ( 1 – 4 ). Two known labdanes: 2β,3α,15-trihydroxy-ent-labd-7-ene ( 5 ), and 2β,3α-trihydroxy- ent -labd-7-en-15-oic acid ( 6 ); two sesquiterpene lactones: 8β-hydroxy-β-cyclocostunolide ( 7 ) and eupatoriopicrin ( 8 ), one benzofuran, and six flavonoids were also isolated. Their chemical structures were determined based on extensive spectroscopic study, comparison with reported data and chemical transformations. The cytotoxicity of the new ent- labdane diterpenoids 1 – 3 , sesquiterpene lactone 7 , and the flavonoid: quercetin 3,7-dimethylether were assessed against the human myeloid leukemia U-937 cell line and found that compound 7 and quercetin 3,7-dimethylether were cytotoxic against this cell line.