Spirombandakamine A and Cyclombandakamines A and A, Polycyclic Naphthylisoquinoline Dimers, with Antiprotozoal Activity, from a Congolese Plant.

Spirombandakamine A () is only the third known naphthylisoquinoline dimer with a spiro-fused novel molecular framework and the first such representative to possess a relative -configuration at the two chiral centers in both tetrahydroisoquinoline subunits. It was found in the leaves of a botanically as yet unidentified Congolese plant, which is morphologically closely related to the Central African taxon . Likewise isolated were the new cyclombandakamines A () and A (), which belong to another most recently discovered type of unusual oxygen-bridged naphthylisoquinoline dimers and two previously described "open-chain" analogues, mbandakamines C () and D (). The full absolute stereostructures of these compounds were assigned by combining spectroscopic, chemical, and chiroptical methods. Preliminary biomimetic investigations indicated that both spirombandakamine- and cyclombandakamine-type dimers result from the oxidation of their open-chain mbandakamine-type congeners. The new dimeric alkaloids - displayed potent growth-inhibitory activity against , the protozoal pathogen causing malaria, and moderate effects on , the parasite responsible for African sleeping sickness.