Hindawi Publishing Corporation Journal of Parasitology Research Volume 2013, Article ID 703781, 5 pages http://dx.doi.org/10.1155/2013/703781 Research Article Cajachalcone: An Antimalarial Compound from Cajanus cajan Leaf Extract E. O. Ajaiyeoba, 1 O. O. Ogbole, 1 O. O. Abiodun, 2 J. S. Ashidi, 3 P. J. Houghton, 4 and C. W. Wright 5 1 Department of Pharmacognosy, University of Ibadan, Ibadan 200284, Nigeria 2 Department of Pharmacology & Terapeutics, University of Ibadan, Ibadan 200284, Nigeria 3 Department of Biological Sciences, Olabisi Onabanjo University, Ago-Iwoye 110001, Nigeria 4 Department of Pharmacy, King’s College London, 150 Stamford Street, London SE1 8WA, UK 5 Te School of Pharmacy, University of Bradford, West Yorkshire BD7 1DP, UK Correspondence should be addressed to E. O. Ajaiyeoba; edajaiye@gmail.com Received 4 February 2013; Accepted 16 April 2013 Academic Editor: Wej Choochote Copyright © 2013 E. O. Ajaiyeoba et al. Tis is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Cajanus cajan L, a member of the family Fabaceae, was identifed from the Nigerian antimalarial ethnobotany as possessing antimalarial properties. Te bioassay-guided fractionation of the crude methanol extract of C. cajan leaves was done in vitro using the multiresistant strain of Plasmodium falciparum (K1) in the parasite lactate dehydrogenase assay. Isolation of compound was achieved by a combination of chromatographic techniques, while the structure of the compound was elucidated by spectroscopy. Tis led to the identifcation of a cajachalcone, 2  ,6  -dihydroxy-4-methoxy chalcone, as the biologically active constituent from the ethyl acetate fraction. Cajachalcone had an IC 50 value of 2.0 g/mL (7.4 M) and could be a lead for anti-malarial drug discovery. 1. Introduction Malaria is a vector borne disease, caused by the Plasmodium parasite. According to WHO report, there were estimated 216 million episodes of malaria in 2010, of which approximately 81%, or 174 million cases, were in the African region. Tere were estimated 655,000 malaria deaths in 2010, of which 91% were in Africa. Approximately 86% of malaria deaths globally were of children under 5 years of age [1]. In addition to acute disease episodes and deaths in Africa, malaria also contributes signifcantly to anaemia in children and pregnant women, adverse birth outcomes such as spontaneous abor- tion, stillbirth, premature delivery, and low birth weight, and overall child mortality. Included in the WHO report was the fact that resis- tance to artemisinin, a vital component of drugs used in the treatment of P. falciparum malaria, has been reported in a growing number of countries in Southeast Asia. Resistance to pyrethroids, the insecticides used in ITNs and most commonly used in IRS, has been reported in 27 countries in Africa and 41 countries worldwide [1]. Unless properly man- aged, such resistance potentially threatens future progress in malaria control. Te search for new antimalarial drugs requires identifcation of new biochemical targets for drug development and development of new chemical entities [2, 3]. Epidemiological studies have provided convincing evi- dence that natural dietary compounds, which humans con- sume as food, possess many biological activities [4]. One plant food that has been shown to be therapeutic against a number of diseases is pigeon pea, Cajanus cajan L. (Fabaceae), an important grain legume crop in the tropics and subtropics. Te extracts of pigeon pea are commonly used to treat diabetes, fever, dysentery, hepatitis, and measles worldwide [5, 6]. Cajanus cajan has been used traditionally as a laxative and was identifed as an antimalarial remedy [7]. In continuation of our study of the Nigerian ethnomedicine