Prenylated dihydrochalcones from Boronia bipinnata that inhibit the malarial parasite enzyme target hemoglobinase II

High-throughput screening of a plant and marine invertebrate extract library to find natural products that inhibit the malarial parasite enzyme target hemoglobinase, II led to the isolation of two new active prenylated chalcones, bipinnatones A (1) and B (2), from aerial parts of the Queensland shrub Boronia bipinnata. Their structures were assigned from interpretation of 2D NMR and high-resolution ESIMS data. Compounds 1 and 2 inhibited hemoglobinase II with IC50 values of 64 and 52 mu M, respectively.