Biomedical Research 2009; 20 (1): 25-27 Erythrocyte antioxidant enzymes and their correlation with malon- dialdehyde in malaria. Benedicta D’Souza, Vivian D’Souza, Swagata H, Vijayalaxmi K, Namratha A.S. Department of Biochemistry, Centre for Basic Sciences, Kasturba Medical College, Bejai, Mangalore, India. Abstract Invasion of human erythrocytes by malaria parasites causes alterations in antioxidant po- tential of the red cells. The present study was undertaken to investigate the erythrocyte an- tioxidant enzymes like superoxide dismutase(SOD), catalase(CAT) in malaria patients. Oxi- dative stress was estimated by measuring malondialdehyde(MDA) which is a marker for lipid peroxidation. 30 malaria patients were enrolled in this study. They were divided into 2 groups of 15 each with Plasmodium vivax malaria and Plasmodium falciparum malaria. Re- sults were compared with 20 healthy control subjects. Significant decrease(p<0.001) in SOD and CAT and increase in MDA (p<0.001) indicates that there is reduction in antioxidant en- zymes and increased vulnerability to free radical damage in erythrocytes. This study there- fore emphasizes the need for early treatment of malaria patients to reduce the red cell dam- age. Key words: Malaria, MDA, Superoxide dismutase, catalase Accepted October 15 2008 Introduction Plasmodium infected human erythrocytes are under in- creased oxidative stress exerted by the malarial parasite [1,2 ]. Malarial parasite is capable of generating reactive oxygen species ( ROS ) within the erythrocytes and the ROS resulting from immune activation can further dam- age the uninfected erythrocytes [ 3 ]. It is also known that erythrocytes are equipped with antioxidant enzymes that could protect them against damage [4]. In the present study attempt has been made to assess the changes in an- tioxidants enzymes like superoxide dismutase (SOD) and catalase (CAT) in human erythrocytes infected with Plasmodium falciparum and Plasmodium vivax. The cor- relation between antioxidant enzymes and malodialde- hyde (MDA) is also included under this study. Materials and Methods The study group consisted of 30 untreated malaria pa- tients between the age group of 18 to 60 years of both sexes. These patients attended “Malaria Clinic” OPD at Wenlock District Hospital, Mangalore, with the symp- toms of fever and rigor, headache, vomiting. Signs in- clude splenomegaly, hepatomegaly and anemia. The con- trol group included 20 healthy individuals of both sexes of the same age group. A finger prick blood sample was taken to prepare thick and thin blood films to determine the presence or absence of malaria parasites. Patients with malaria were enrolled in the study after informed consent was obtained from the patients. This study was approved by Institutional Ethical Committee of Kasturba Medical College, Manga- lore. Of the total 30 malaria patients, 15 patients had Plasmodium vivax and 15 patients had Plasmodium falci- parum malaria. Sample Collection 5ml of venous blood samples were collected randomly in EDTA bottles from malaria patients and normal healthy subjects. Blood samples were centrifuged at 3000g for 10 minutes. Plasma was discarded. The cells were washed three times in cold saline. The RBC’s were then suspended in an equal volume of 0.9℅ saline and used for the estimation of malondialdehyde(MDA), superox- ide dismutase(SOD) and catalase(CAT). Lipid peroxidation( MDA) : The method of Stocks et al was followed [5]. Malondialdehyde a secondary product