1. IIUM Research, Invention and Innovation Exhibition 2011 Enhancing Quality Research and Innovation for Societal Development Norsidah Ku zaifah a, Ahmad Asmadi Yusof b, Azizi Ayob c, Kamisah Yusof d a Department of Basic Medical Sciences, Kuliyyah of Medicine, International Islamic University of Malaysia, Pahang, Malaysia, b Faculty of Traditional and Complementary Medicine, Cyberjaya University College of Medical Sciences, Selangor, Malaysia, c PT Dexa Medica, Jakarta, Indonesia, d Department of Pharmacology, Faculty of Medicine, Universiti Kebangsaan Malaysia, Kuala Lumpur, Malaysia. ID: 151 Palm-tocotrienol rich fraction has hypohomocysteinemic effect in rats fed high methionine diet. Introduction: Hyperhomocysteinemia is associated with increased risk of cardiovascular disease (1). It is associated with elevation of oxidative stress (2). The aim of this study was to determine the effects of palm-tocotrienol rich fraction (TRF), a known anti- oxidant, at various doses on plasma total homocysteine level (tHcy) and activity of hepatic cystathionine-β-synthase (CBS) in rats fed high methionine diet, as compared to folate. Methodology: Forty-two male Wistar rats were divided into six groups. Group 1 was the control. Groups 2 to 6 were fed 1% methionine diet for 10 weeks. From week 6 onward, folate (8 mg/kg diet) or palm TRF (30, 60 or 150 mg/kg diet) were added into the diet of groups 3, 4, 5 and 6. Body weights were recorded weekly. The rats were then sacrificed and plasma tHcy at week 0, 5 and 10, and the activity of liver cystathionine-β-synthase were determined. Statistical analysis: Statistical Package for Social Sciences (SPSS) 11.5 was used. Data is presented as Mean ± SEM. P < 0.05 is considered significant. Methionine 1% (M) Blood samples Week 0. Body weight (weekly) 5 weeks 5 weeks Rats were sacrificed Blood samples (Week 5). Supplemen added to third to sixth groups diet Methionine 1% (M) (Group 2) Male Wistar Rats (180-200g). n = 7 per group M+Folate 8 mg/kg diet (M+Folate) M+TRF 60 mg/kg diet (M+TRF60) M+TRF 30 mg/kg diet (M+TRF30) M+TRF 150 mg/kg diet (M+TRF150) Liver Blood Basal diet (Group 1) Methionine 1% (Group 3) Methionine 1% (Group 4) Methionine 1% (Group 5) Methionine 1% (Group 6) Basal diet (Control) Figure 3 CBS activity in liver of rat fed either basal diet (control), 1% methionine diet (M) (week 0- 10), 1% methionine diet + folate (8 mg/kg diet) or palm tocotrienol rich fraction (TRF) (30, 60 or 150 mg/kg diet) for 5 weeks (week 6-10). The result is expressed as means ± SEM (n = 7). * P < 0.05 vs. Control # P < 0.05 vs. Methionine Results: High methionine diet did not affect body weight. It raised plasma total homocysteine (tHcy) but was prevented by palm TRF at various doses, as well as folate. However, unlike folate, palm TRF significantly caused reduction of liver CBS activity. Figure 1 The body weight of rat fed either basal diet (control), 1% methionine diet (M) (week 0- 10), 1% methionine diet + folate (8 mg/kg diet) or palm tocotrienol rich fraction (TRF) (30, 60 or 150 mg/kg diet) for 5 weeks (week 6-10). The result is expressed as means ± SEM (n = 7). No significant difference (P > 0.05). Figure 2 Percent changes of total plasma homocysteine (tHcy) of rat fed either basal diet (control), 1% methionine diet (M) (week 0-10), 1% methionine diet + folate (8 mg/kg diet) or palm tocotrienol rich fraction (TRF) (30, 60 or 150 mg/kg diet) for 5 weeks (week 6-10). The result is expressed as means ± SEM (n = 7). * P < 0.05 vs. Control (of the same week compared). # P < 0.05 vs. Methione (of the same week compared). Conclusions: Palm TRF was comparable to folate in reducing plasma tHcy in rat fed high methionine diet. Furthermore, it probably has a negative feedback effect on liver CBS resulting in its significant reduction. Keywords: homocysteine, palm tocotrienol rich fraction, folate, cystathionine-β-synthase References: 1.McCully, K. S. 2007. Homocysteine, vitamins, and vascular disease prevention. American Journal of Clinical Nutrition 86: 1563S-1568S. 2.Topal, G., Brunet, A., Millanvoye, E., Boucher, J-L., Rendu, F., Devynck, M. & David-Dufilho, M. 2004. Homocysteine induces oxidative stress by uncoupling of NO synthase activity through reduction of tetrahydrobiopterin. Free Radical Biology & Medicine 12: 1532-1541. Acknowledgement: This work was supported by grant (FF-013-2006) from Faculty of Medicine, Universiti Kebangsaan Malaysia. The authors would also like to thank Puan Azizah Osman, Puan Rosnah Ramli and Associate Profesor Dr Nur Aini Umar for their technical assistance.