title: Palm tocotrienol-rich fraction reduced plasma homocysteine and heart oxidative stress in rats fed with a high-methionine diet.
abstract: Oxidative stress contributes to cardiovascular diseases. We aimed to study the effects of palm tocotrienol-rich fraction (TRF) on plasma homocysteine and cardiac oxidative stress in rats fed with a high-methionine diet. Forty-two male Wistar rats were divided into six groups. The first group was the control. Groups 2-6 were fed 1% methionine diet for 10 weeks. From week 6 onward, folate (8 mg/kg diet) or palm TRF (30, 60 and 150 mg/kg diet) was added into the diet of groups 3, 4, 5 and 6. The rats were then killed. Palm TRF at 150 mg/kg and folate supplementation prevented the increase in plasma total homocysteine (4.14 ± 0.33 and 4.30 ± 0.26 vs 5.49 ± 0.25 mmol/L, p < 0.05) induced by a high-methionine diet. The increased heart thiobarbituric acid reactive substance in rats fed with high-methionine diet was also prevented by the supplementations of palm TRF (60 and 150 mg/kg) and folate. The high-methionine group had a lower glutathione peroxidase activity (49 ± 3 vs 69 ± 4 pmol/mg protein/min) than the control group. This reduction was reversed by palm TRF at 60 and 150 mg/kg diet (p < 0.05), but not by folate. Catalase and superoxide dismutase activities were unaffected by both methionine and vitamin supplementations. In conclusion, palm TRF was comparable to folate in reducing high-methionine diet-induced hyperhomocysteinemia and oxidative stress in the rats' hearts. However, palm TRF was more effective than folate in preserving the heart glutathione peroxidase enzyme activity.
authors.affiliation: Department of Basic Medical Sciences, Kuliyyah of Medicine, International Islamic University of Malaysia, Pahang, Malaysia.
authors.forename: Ku-Zaifah
authors.initials: KZ
authors.lastname: Norsidah
authors.forename: Ahmad Yusof
authors.initials: AY
authors.lastname: Asmadi
authors.forename: Ayob
authors.initials: A
authors.lastname: Azizi
authors.forename: Othman
authors.initials: O
authors.lastname: Faizah
authors.forename: Yusof
authors.initials: Y
authors.lastname: Kamisah
mesh_terms: D000284:Administration, Oral; D000818:Animals; D002374:Catalase / Q000378:metabolism; D029784:Cycas / Q000737:chemistry*; D004032:Diet; D019587:Dietary Supplements; D005492:Folic Acid / Q000008:administration & dosage; D005979:Glutathione Peroxidase / Q000378:metabolism; D006321:Heart / Q000187:drug effects; D006710:Homocysteine / Q000097:blood; D020138:Hyperhomocysteinemia / Q000139:chemically induced / Q000378:metabolism / Q000517:prevention & control*; D008297:Male; D008715:Methionine / Q000008:administration & dosage / Q000009:adverse effects*; D010936:Plant Extracts / Q000737:chemistry*; D051381:Rats; D017208:Rats, Wistar; D013482:Superoxide Dismutase / Q000378:metabolism; D017392:Thiobarbituric Acid Reactive Substances / Q000378:metabolism; D024508:Tocotrienols / Q000008:administration & dosage* / Q000302:isolation & purification
chemical_list: D010936:Plant Extracts; D017392:Thiobarbituric Acid Reactive Substances; D024508:Tocotrienols; D006710:Homocysteine; D005492:Folic Acid; D008715:Methionine; D002374:Catalase; D005979:Glutathione Peroxidase; D013482:Superoxide Dismutase