Five labdane diterpenoids from the seeds of Aframomum zambesiacum.

Abstract Five labdane diterpenoids, ( 3 – 5 ), zambesiacolactone A ( 7 ) and zambesiacolactone B ( 8 ), were isolated from the seeds of Aframomum zambesiacum (Baker) K. Schum., along with five known labdanes and a linear sesquiterpene, nerolidol. Their structures were elucidated by spectroscopic analysis. Their antiplasmodial activity was evaluated in vitro against Plasmodium falciparum . Compound 3 was the most active with an IC 50 value of 4.97 μM.