Isolation of natural product antimalarial compounds from tropical Queensland and Papua New Guinean plants

Abstract

By utilizing the enormous chemical diversity of natural products new compounds can be found targeting the malaria parasite Plasmodium falciparum, following precedent set by the isolation of quinine and artemisinin from plant biota. A subset of a natural product extract library was screened for antimalarial activity using the 3H-hypoxanthine radioisotopic assay. The library contained 794 plant extracts from biota collected in Papua New Guinea and tropical Queensland encompassing 123 plant families. Ninety-three of these extracts displayed >40% inhibition against 3D7 parasites at 312μge/mL extract concentration. By retesting these extracts in dose response, antimalarial activity was confirmed in 48 of these extracts against both 3D7 and Dd2 parasites at concentrations between 78 and 390μge/mL. Some of the extracts displayed IC50 values of <20μge/mL against 3D7 and Dd2 and were 12 – 30 times more selective for the parasite than the HeLa-WT mammalian cell line. Progress on the isolation of active compounds from PNG extracts will be reported.