Norsidah Ku zaifah a , Ahmad Asmadi Yusof b , Azizi Ayob c , Kamisah Yusof d

1. Male Wistar Rats (180-200g). n = 7 per group Blood samples Week 0. Body weight (weekly) Basal diet (Group 1) Methionine 1% (M) (Group 2) Methionine 1% (Group 3) Methionine 1% (Group 4) Methionine 1% (Group 5) Methionine 1% (Group 6) 5 weeks Blood samples (Week 5). Supplemen added to third to sixth groups diet M+Folate 8 mg/kg diet (M+Folate) Methionine 1% (M) Basal diet (Control) M+TRF 60 mg/kg diet (M+TRF60) M+TRF 30 mg/kg diet (M+TRF30) M+TRF 150 mg/kg diet (M+TRF150) 5 weeks Rats were sacrificed Liver Blood Norsidah Ku zaifaha , Ahmad AsmadiYusofb, AziziAyobc, KamisahYusofd aDepartment of Basic Medical Sciences, Kuliyyah of Medicine, International Islamic University of Malaysia, Pahang, Malaysia, bFaculty of Traditional and Complementary Medicine, Cyberjaya University College of Medical Sciences, Selangor, Malaysia, cPTDexa Medica, Jakarta, Indonesia, d Department of Pharmacology, Faculty of Medicine, Universiti Kebangsaan Malaysia, Kuala Lumpur, Malaysia. 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. 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 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). 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). 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: McCully, K. S. 2007. Homocysteine, vitamins, and vascular disease prevention. American Journal of ClinicalNutrition 86: 1563S-1568S. 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. 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 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.