title: Palm tocotrienol-rich fraction inhibits methionine-induced cystathionine β-synthase in rat liver.
abstract: Oxidative stress plays an important role in cardiovascular diseases. The study investigated the effects of dietary palm tocotrienol-rich fraction on homocysteine metabolism in rats fed a high-methionine diet. Forty-two male Wistar rats were randomly assigned to six groups. Five groups were fed with high-methionine diet (1%) for 10 weeks. Groups 2 to 5 were also given dietary folate (8 mg/kg) and three doses of palm tocotrienol-rich fraction (30, 60 and 150 mg/kg) from week 6 to week 10. The last group was only given basal rat chow. High-methionine diet increased plasma homocysteine after 10 weeks, which was prevented by the supplementations of folate and high-dose palm tocotrienol-rich fraction. Hepatic S-adenosyl methionine (SAM) content was unaffected in all groups but S-adenosyl homocysteine (SAH) content was reduced in the folate group. Folate supplementation increased the SAM/SAH ratio, while in the palm tocotrienol-rich fraction groups, the ratio was lower compared with the folate. Augmented activity of hepatic cystathionine β-synthase and lipid peroxidation content by high-methionine diet was inhibited by palm tocotrienol-rich fraction supplementations (moderate and high doses), but not by folate. The supplemented groups had lower hepatic lipid peroxidation than the high-methionine diet. In conclusion, palm tocotrienol-rich fraction reduced high-methionine-induced hyperhomocysteinaemia possibly by reducing hepatic oxidative stress in high-methionine-fed rats. It may also exert a direct inhibitory effect on hepatic cystathionine β-synthase.
authors.affiliation: Department of Pharmacology, Faculty of Medicine, UKMMC, Universiti Kebangsaan Malaysia, Jalan Yaacob Latif, Cheras, 56000, Kuala Lumpur, Malaysia. kamisah_y@yahoo.com.
authors.forename: Yusof
authors.initials: Y
authors.lastname: Kamisah
authors.affiliation: Department of Pharmacology, Faculty of Medicine, UKMMC, Universiti Kebangsaan Malaysia, Jalan Yaacob Latif, Cheras, 56000, Kuala Lumpur, Malaysia.|Department of Basic Medical Sciences, Kuliyyah of Medicine, International Islamic University of Malaysia, Kuantan, Pahang, Malaysia.
authors.forename: Ku-Zaifah
authors.initials: KZ
authors.lastname: Norsidah
authors.affiliation: Division of Pathology, School of Medicine, International Medical University, Bukit Jalil, Kuala Lumpur, Malaysia.
authors.forename: Ayob
authors.initials: A
authors.lastname: Azizi
authors.affiliation: Department of Anatomy, Faculty of Medicine, UKMMC, Universiti Kebangsaan Malaysia, Cheras, Kuala Lumpur, Malaysia.
authors.forename: Othman
authors.initials: O
authors.lastname: Faizah
authors.affiliation: Department of Pathology, Faculty of Medicine, UKMMC, Universiti Kebangsaan Malaysia, Cheras, Kuala Lumpur, Malaysia.
authors.forename: Mohd Rizal
authors.initials: MR
authors.lastname: Nonan
authors.affiliation: Faculty of Traditional and Complementary Medicine, Cyberjaya University College of Medical Sciences, Cyberjaya, Selangor, Malaysia.
authors.forename: Ahmad Yusof
authors.initials: AY
authors.lastname: Asmadi
mesh_terms: D000818:Animals; D003541:Cystathionine beta-Synthase / Q000378:metabolism*; D004353:Drug Evaluation, Preclinical; D004790:Enzyme Induction; D006710:Homocysteine / Q000097:blood; D015227:Lipid Peroxidation; D008099:Liver / Q000187:drug effects / Q000201:enzymology*; D008297:Male; D008715:Methionine / Q000494:pharmacology; D000073878:Palm Oil; D010936:Plant Extracts / Q000494:pharmacology*; D010938:Plant Oils / Q000737:chemistry; D017208:Rats, Wistar; D024508:Tocotrienols / Q000494:pharmacology*
chemical_list: D010936:Plant Extracts; D010938:Plant Oils; D024508:Tocotrienols; D006710:Homocysteine; D000073878:Palm Oil; D008715:Methionine; D003541:Cystathionine beta-Synthase
keywords: Cystathionine β-synthase; Homocysteine; Methionine; S-Adenosyl homocysteine; S-Adenosyl methionine; Tocotrienol