Journal of Ethnopharmacology 101 (2005) 95–99 Evaluation of plants used for antimalarial treatment by the Maasai of Kenya A. Koch a , P. Tamez b , J. Pezzuto c , D. Soejarto a,∗ a Department of Medicinal Chemistry and Pharmacognosy, MC/877, University of Illinois at Chicago (UIC), Chicago, IL 60612, USA b Department of Pathology, Northwestern University, 303 East Chicago Avenue, Chicago, IL 60611, USA c College of Pharmacy, Nursing and Health Sciences, Purdue University, 1330 Heine Pharmacy Bldg., West Lafayette, IN 47907, USA Received 20 January 2005; received in revised form 28 March 2005; accepted 28 March 2005 Available online 4 May 2005 Abstract Semi-structured interviews with three Maasai herbalists led to the identification and collection of 21 species of plants used to treat malaria. Extracts were evaluated using in vitro antimalarial and cytotoxicity assays. Of the species tested, over half were antiplasmodial (IC 50 < 10 g/ml), and all but one (Gutenbergia cordifolia Benth.) displayed selectivity for the malaria parasite Plasmodium falciparum as indicated by a lack of cytotoxicity (ED 50 > 20 g/ml) against cultured KB cells. The results of this preliminary investigation support the traditional knowledge of Maasai herbalists and justify ethnomedical inquiry as a promising method, specifically, in antimalarial therapy, to yield leads for drug discovery. © 2005 Elsevier Ireland Ltd. All rights reserved. Keywords: Antimalarial; Kenya; Traditional medicine; Plasmodium; Maasai 1. Introduction Malaria continues to kill over a million people each year, with more than 90% of these cases found in sub-Saharan Africa (World Health Organization, 2000). In many popu- lations affected by malaria, available drugs are often unaf- fordable or inaccessible, and increasing drug resistance by the malaria parasite, Plasmodium falciparum, is of signifi- cant concern (Sofowora, 1996; World Health Organization, 2001; Greenwood and Mutabingwa, 2002). As an alterna- tive, medicinal plants are often used to treat diseases as se- rious as malaria. Historically, plants have been a prominent source of antimalarial drugs (quinine, artemisinin). More- over, those plants currently used by indigenous people to treat malaria should be documented and investigated as po- tential sources of new antimalarial drugs. This project inves- tigated antimalarial plants used by the Maasai community of ∗ Corresponding author. Tel.: +1 312 996 8889; fax: +1 312 413 5894. E-mail address: dds@uic.edu (D. Soejarto). southwestern Kenya. Through interviews focused on plants indicated as treatments for malaria and/or malaria-like symp- toms (periodic fever, sweating, headache/backache, chills), 21 species were documented, collected and tested for in vitro antimalarial activity. 2. Materials and methods 2.1. Interviews and plant collection Three herbalists, as recognized by the Maasai community in the Kajiado district of southwestern Kenya, were inter- viewed after obtaining prior informed consent in accordance with a UIC Institutional Review Board (IRB) approved pro- tocol. Interviews took place during August and September of 1998 in three different villages within the Kajiado district (Table 1). Plants mentioned during interviews were collected in their natural habitats with plant collection permits obtained from the Kenyan Ministry of Education, Science 0378-8741/$ – see front matter © 2005 Elsevier Ireland Ltd. All rights reserved. doi:10.1016/j.jep.2005.03.011