Antiplasmodial Bis-Indole Alkaloids from the Bark of Flindersia pimenteliana

Three new (1–3) and 2 known (4–5) bis-indole alkaloids were identified from the bark of Flindersia pimenteliana (Rutaceae). The structures of 1–3 were elucidated on the basis of their (+)-HRESESIMS and 2D NMR spectroscopic data. Antiplasmodial activity for 1–3 against chloroquine sensitive (3D7) and chloroquine-resistant (Dd2) Plasmodium falciparum is also reported, with IC50 values ranging from 0.96 to 2.41 µg/mL. These results expand our knowledge of the structure-activity relationships of potently antiplasmodial isoborreverine-type alkaloids, the bioactivity of which have recently attracted significant attention in the literature.