Palm-tocotrienol rich fraction has hypohomocysteinemic effect
ID: 151
in rats fed high methionine diet.
Norsidah Ku zaifah a , Ahmad Asmadi Yusof b, Azizi Ayob c, Kamisah Yusof d
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,
cPT Dexa 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 antioxidant, 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.
Male Wistar Rats (180-200g). n = 7 per group
Blood samples Week 0. Body weight (weekly)
5
weeks
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)
Blood samples (Week 5). Supplemen added to third to sixth groups diet
Basal diet
(Control)
Methionine
1%
(M)
M+Folate
8 mg/kg diet
(M+Folate)
M+TRF
30 mg/kg diet
(M+TRF30)
M+TRF
60 mg/kg diet
(M+TRF60)
M+TRF
150 mg/kg diet
(M+TRF150)
5
weeks
Statistical analysis:
Statistical Package for Social Sciences (SPSS) 11.5 was used. Data is
presented as Mean ± SEM. P < 0.05 is considered significant.
Rats were sacrificed
Liver
Blood
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 010), 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
Figure 3 CBS activity in liver of rat fed either basal diet (control), 1% methionine diet (M) (week 010), 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
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.
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