Two new lignans, an aryltetralol and its methyl ether analogous, were isolated from Holostylis reniformis (Aristolochiaceae) together with futokadsurin C and (À)-8 0-epi-aristoligone. The latter was also obtained as an enantiomeric mixture by synthesis and was transformed into aryltetralols and aryltetralenes that were subjected to chiral-HPLC separations. The compound structures were determined by spectroscopic methods. Several of these lignans had their antiplasmodial activity (against Plasmodium falciparum, W2 clone, anti-HRPII) and toxicity to mammalian kidney cells (MDL 50) evaluated. (À)-Cyclogalgravin and (À)-aristoligol exhibited activity (IC 50 $ 10.8 and 8.4 mM, respectively), the latter exhibited lower toxicity.