Sipaucins A–C, sesquiterpenoids from Siparuna pauciflora

The phytochemical investigation of the leaves of Siparuna pauciflora yielded three novel sesquiterpenoids: the germacrane sipaucin A, the elemane sipaucin B and sipaucin C, comprising a new type of carbon skeleton. In addition, four known aporphine alkaloids— nor-boldine, boldine, laurotetanine, and N-methyl-laurotetanine—were obtained. The evaluation of the antiplasmodial activity of the isolated compounds against two strains of Plasmodium falciparum (PoW, Dd2) showed a moderate activity of nor-boldine. From the leaves of Siparuna pauciflora (Monimiaceae) three sesquiterpenoids—sipaucins A–C—were isolated together with four known aporphine alkaloids.