Novel tocotrienols of rice bran modulate cardiovascular disease risk parameters of hypercholesterolemic humans

Tocotrienols inhibit cholesterol synthesis by post-transcriptionally suppressing β-hydroxy-β-methylglutaryl-coenzyme A reductase activity. A double blind, 12-week study was performed to investigate the effect of a novel tocotrienol-rich fraction (TRF 25; obtained by molecular distillation from speci...

Full description

Saved in:
Bibliographic Details
Published inThe Journal of nutritional biochemistry Vol. 8; no. 5; pp. 290 - 298
Main Authors Qureshi, Asaf A., Bradlow, Basil A., Salser, Winston A., Brace, Larry D.
Format Journal Article
LanguageEnglish
Published New York, NY Elsevier Inc 01.05.1997
Elsevier Science
Subjects
Online AccessGet full text

Cover

Loading…
More Information
Summary:Tocotrienols inhibit cholesterol synthesis by post-transcriptionally suppressing β-hydroxy-β-methylglutaryl-coenzyme A reductase activity. A double blind, 12-week study was performed to investigate the effect of a novel tocotrienol-rich fraction (TRF 25; obtained by molecular distillation from specially processed rice bran oil) on cardiovascular disease risk factors of hypercholesterolemic human subjects (serum total cholesterol >5.69 mmol/L). After acclimation to an alcohol-free regimen (baseline) participants were assigned to the National Cholesterol Education Program (NCEP) Step-1 diet (saturated fat <19%, total fat <30% of total calories and cholesterol <7.76 mmol/L). The participants were evaluated after 4 weeks of exposure to the NCEP Step-1 diet; one group of 21 participants was continued on the NCEP Step-1 diet for 4 weeks receiving an additional 1.2 gm corn oil (placebo group) and a second group of 20 received 200 mg TRF 25 dissolved in 1.0 gm corn oil (TRF 25 group). Serum total cholesterol and LDL-cholesterol levels of all the participants, stable during the baseline phase of the study, decreased 5% and 8%, respectively, during the 4-week NCEP Step-1 diet. Placebo continuing on the NCEP Step-1 diet for an additional 4 weeks experienced additional but modest decreases in serum total cholesterol (2%) and LDL-cholesterol (3%), yielding significant ( P < 0.05) decreases when compared with the baseline values. These responses confirm the cholesterol-lowering action of a low fat, low cholesterol diet. Participants receiving TRF 25 had 12% and 16% reductions ( P < 0.05) in total cholesterol and LDL-cholesterol levels during the 4-week experimental phase; during the two phases (NCEP Step-1 diet plus treatment) the serum total cholesterol and LDL-cholesterol levels of these participants were decreased ( P < 0.05) by 17% and 24%, respectively. TRF 25-mediated decreases in Apo B, Lp(a), platelet factor 4 and thromboxane B 2 (15%, 17%, 14%, and 31%, respectively) were significant ( P < 0.05). There was no change in the levels of HDL-cholesterol and apolipoprotein A-I by this treatment. The treatments also resulted in remarkable increases in the levels of LDL-bound antioxidants, especially tocotrienols, which have substantially greater antioxidant activity than vitamin E.
ISSN:0955-2863
1873-4847
DOI:10.1016/S0955-2863(97)89667-2