Short communication The screening of extracts from Goniothalamus scortechinii , Aralidium pinnatifidum and Andrographis paniculata for anti-malarial activity using the lactate dehydrogenase assay M.J. Siti Najila a, *, A. Noor Rain a , A.G. Mohamad Kamel b , S.I. Syed Zahir b , S. Khozirah d , S. Lokman Hakim c , I. Zakiah a , A.K. Azizol d a Herbal Medicine Research Centre, Institute for Medical Research, Jalan Pahang, 50588 Kuala Lumpur, Malaysia b Faculty of Allied Health Sciences, Universiti Kebangsaan Malaysia, Jalan Raja Muda Abdul Aziz, Kuala Lumpur, Malaysia c Infectious Disease Research Centre, Institute for Medical Research, Jalan Pahang, 50588 Kuala Lumpur, Malaysia d Forest Institute Research Malaysia, Kepong, Kuala Lumpur, Malaysia Received 4 February 2002; received in revised form 1 June 2002; accepted 17 June 2002 Abstract Goniothalamus scortechinii , Andrographis paniculata and Aralidium pinnatifidum were selected for the study based on their ethnomedicinal values. They were screened for anti-malarial activity towards Plasmodium falciparum in vitro using the lactate dehydrogenase (LDH) assay. The crude extract of G. scortechinii exhibited the most potent schizonticidal activity compared to the other extracts. It is effective against both the chloroquine resistant isolate, Gombak A and the sensitive strain, D10 of Plasmodium falciparum . Furthermore a better IC 50 value was obtained against the resistant strain, (9 mg/ml) compared to the sensitive strain, 40 mg/ml. When the crude extract was fractionated into 3 fractions, the chloroform fraction yielded the best activity, exhibiting equipotency against both strains of parasite used; IC 50 of 23.53 mg/ml against Gombak A and 21.06 mg/ml against D10. # 2002 Elsevier Science Ireland Ltd. All rights reserved. Keywords: Plasmodium falciparum ; In vitro anti-malarial activity; Medicinal plants; Lactate dehydrogenase assay 1. Introduction Approximately 300 million people worldwide are affected by malaria and between 1 and 1.5 million people die from it every year. Here in Malaysia, figures since 1995 showed that the incident rate relating to Malaria has been declining from 296.7 to 48.3 in 1999. However the mortality rate has been steadily increasing (Health Facts 2000, Department of Public Health, Ministry of Health, Malaysia http://dph.gov.my/Divi- sion/dcd/fakta/MSIA%20Facts.htm). This could be at- tributed in part to the widespread problem of parasite drug resistance. While in some parts of the world chloroquine (CQ) has been officially considered useless, the situation in Malaysia is not that severe. Montgom- ery and Eyles first reported CQ resistance in Malaysia in 1963 (Montgomery and Eyles, 1963). Subsequent re- ports in 1966 and 1968 confirmed the existence of CQ resistance in the Peninsular and East Malaysia. The latest figures reported an overall resistance of 63.3% to CQ, with more than 45% of the cases of grade RII and RIII (Hakim et al., 1996). Thus, in an effort to overcome and curb this growing problem, attention has been focused on medicinal plants, in the hope that they can provide new and novel anti-malarial agents. The tropical forest in this region remains a genetic treasure house for bioprospecting, especially for natural products with useful bioactivities. In Malaysia, medic- inal plants grow in abundance, much of which have still to be subjected to rigorous investigations to prove the associated claims of medicinal use. Plants, especially those used in ‘ubat kampung’ (traditional medicine) need to be continually studied for scientific proof of their efficacy. The few examples of existing test drug e.g. * Corresponding author. Tel.:  /603-4040-2461; fax:  /603-2693- 4114 E-mail address: siti_najila@hotmail.com (M.J. Siti Najila). Journal of Ethnopharmacology 82 (2002) 239  /242 www.elsevier.com/locate/jethpharm 0378-8741/02/$ - see front matter # 2002 Elsevier Science Ireland Ltd. All rights reserved. PII:S0378-8741(02)00183-6