Abstract
One new prenylated xanthone, 1,5-dihydroxy-3-methoxy-4-isoprenylxanthone (1), along with four previously known prenylated xanthones, ananixanthone (2), 1,3,7-trihydroxy-2,4-diisoprenylaxnthone (3), 8-desoxygartanin (4), and toxyloxanthone A (5), have been isolated from Chrysochlamys tenuis. (Hammel) (Clusiaceae). Compound 1 showed moderate activity (31 ± 9 µM) against a chloroquine-resistant strain of Plasmodium falciparum., and compounds 3 and 5 showed the highest antimalarial potency, IC50 = 20 ± 2 and 16 ± 4 µM, respectively. Evaluated against Trypanosoma cruzi., compound 1 presented negligible activity, but compounds 2, 3, and 4 showed mild antitrypanosomal activity with IC50 values of 23 ± 4, 21 ± 5, and 24 ± 3 µM, respectively. All structures were elucidated by NMR spectroscopy in combination with UV, IR, and MS spectral data.