A search for natural bioactive compounds in Bolivia through a multidisciplinary approach. Part V. Evaluation of the antimalarial activity of plants used by the Tacana Indians

One hundred and twenty-five extracts of 122 different plant species traditi onally used by the Tacana, a native community living in lowland forest at t he base of the last foothills of the Cordillera Oriental of the Bolivian An des, were screened for antimalarial activity in vitro on Plasmodium falcipa rum chloroquine resistant (D2) and sensitive strains (F32), and were evalua ted in vivo on rodent malaria Plasmodium berghei. Five ethanolic stembark e xtracts showed marked activity either in vitro or in vivo, and only one of them, Bowdichia virgilioides being traditionally used against malaria, was active in vitro (IC50 = 1 mug/ml on both strains) and in vivo (51% at 100 m g/kg). Other active extracts were from Caesalpinia pluviosa bark displaying activity in vitro against chloroquine resistant strain (IC50 8.3 mug/ml), traditionally used against dysentery; two Lauraceae bark extracts, Nectandr a aff. hihua and Licaria canella respectively used for construction purpose s and against stomach ache, both displaying activity in vitro against P. fa lciparum sensible and resistant strains (IC50 around 4 mug/ml); finally, th e bark of a strongly aromatic Burseraceae, Protium glabrescens exuding an a nti-inflammatory and analgesic resin, was active in vivo only (61% at 100 m g/kg). Results are discussed in relation with Tacana traditional medicine. (C) 2001 Elsevier Science Ireland Ltd. All rights reserved.