Antimalarial 4-phenylcoumarins from the stem bark of Hintonia latiflora.

The EtOAc extract of the stem bark of Hintonia latiflora showed the suppression of total parasitemia and the chemosuppression of schizont numbers, when tested in vivo against Plasmodium berghei infection in mice. Bioassay-directed fractionation of the EtOAc extract, using the in vitro 16 h and the in vivo 4-day suppression tests on P. berghei schizont numbers, led to the isolation of the new compound 5-O-beta-D-glucopyranosyl-7,4'-dimethoxy-3'-hydroxy-4-phenylcoumarin (1), along with the known 5-O-beta-D-glucopyranosyl-7-methoxy-3',4'-dihydroxy-4-phenylcoumarin (2). The structure of compound 1 was established on the basis of spectroscopic data interpretation. Compounds 1 and 2 suppressed the development of P. berghei schizonts in vitro with IC50 values of 24.7 and 25.9 microM, respectively. Compound 2 suppressed the development of schizonts at the dose of 40 mg/kg by 70.8% in the in vivo assay.