Four Prenylflavone Derivatives with Antiplasmodial Activities from the Stem of Tephrosia purpurea subsp. leptostachya.

Four new flavones with modified prenyl groups, namely ()-5-hydroxytephrostachin (), purleptone (), ()-5-hydroxyanhydrotephrostachin (), and terpurlepflavone (), along with seven known compounds (-), were isolated from the CH₂Cl₂/MeOH (1:1) extract of the stem of subsp. , a widely used medicinal plant. Their structures were elucidated on the basis of NMR spectroscopic and mass spectrometric evidence. Some of the isolated compounds showed antiplasmodial activity against the chloroquine-sensitive D6 strains of with ()-5-hydroxytephrostachin () being the most active, IC 1.7 ± 0.1 μM, with relatively low cytotoxicity, IC > 21 μM, against four cell-lines.