Synergistic effect of tocotrienol-rich fraction (TRF25) of rice bran and lovastatin on lipid parameters in hypercholesterolemic humans

Tocotrienols exert hypocholesterolemic action in humans and animals. Lovastatin is widely used for that purpose. Both agents work by suppressing the activity of β-hydroxy-β-methylglutaryl coenzyme A reductase through different mechanisms, post-transcriptional vs competitive inhibition. A human study with 28 hypercholesterolemic subjects was carried out in 5 phases of 35 days each, to check the efficacy of tocotrienol-rich fraction (TRF25) of rice bran alone and in combination with lovastatin. After placing subjects on the American Heart Association (AHA) Step-1 diet (phase II), the subjects were divided into two groups, A and B. The AHA Step-1 diet was continued in combination with other treatments during phases III to V. Group A subjects were given 10 mg lovastatin, 10 mg lovastatin plus 50 mg TRF25, 10 mg lovastatin plus 50 mg α-tocopherol per day, in the third, fourth, and fifth phases, respectively. Group B subjects were treated exactly to the same protocol except that in the third phase, they were given 50 mg TRF25 instead of lovastatin.