The Hypocholesterolemic Effect of Germinated Brown Rice Involves the Upregulation of the Apolipoprotein A1 and Low-Density Lipoprotein Receptor Genes

Abstract

Germinated brown rice (GBR) is rich in bioactive compounds, which confer GBR with many functional properties. Evidence of its hypocholesterolemic effects is emerging, but the exact mechanisms of action and bioactive compounds involved have not been fully documented. Using type 2 diabetic rats, we studied the effects of white rice, GBR, and brown rice (BR) on lipid profile and on the regulation of selected genes involved in cholesterol metabolism. Our results showed that the upregulation of apolipoprotein A1 and low-density lipoprotein receptor genes was involved in the hypocholesterolemic effects of GBR. Additionally, in vitro studies using HEPG2 cells showed that acylated steryl glycoside, gamma amino butyric acid, and oryzanol and phenolic extracts of GBR contribute to the nutrigenomic regulation of these genes. Transcriptional and nontranscriptional mechanisms are likely involved in the overall hypocholesterolemic effects of GBR suggesting that it may have an impact on the prevention and/or management of hypercholesterolemia due to a wide variety of metabolic perturbations. However, there is need to conduct long-term clinical trials to determine the clinical relevance of the hypocholesterolemic effects of GBR determined through animal studies.

Impact of Cereal Seed Sprouting on Its Nutritional and Technological Properties: A Critical Review

“…They showed that total cholesterol in rats fed with high-cholesterol diets is reduced to a greater extent by brown rice when sprouted for 2 days, than by such rice either nonsprouted or sprouted for just 1 day. Imam et al (2013), with an in vivo rat study, showed that, although the effects on total cholesterol were similar for brown rice and sprouted brown rice, the lipid composition was more favorable for decreasing the CVD risk after consumption of the latter. A corrective effect on hypercholesterolemia of (sprouted) brown rice was observed with hepatoma-bearing rats by Miura et al (2006).…”

“…The main grains used were rice (six in rodents, one in humans) and barley (three in rodents, one in humans) with, to the best of our knowledge, wheat, millet, and oats each used in only one (human) study. Brown rice has been used by various researchers to investigate the effect of sprouting on lipid metabolism or symptoms linked to it (Imam et al., ; Imam, Ismail, Omar, & Ithnin, ; Miura et al., ; Roohinejad et al., ; Wu, Yang, Touré, Jin, & Xu, ). However, the sprouting conditions used differed from one study to another and so did the levels of bioactive compounds such as tocopherol, oryzanol, and GABA (Miura et al., ; Roohinejad et al., ).…”

“…Imam et al. (), with an in vivo rat study, showed that, although the effects on total cholesterol were similar for brown rice and sprouted brown rice, the lipid composition was more favorable for decreasing the CVD risk after consumption of the latter. A corrective effect on hypercholesterolemia of (sprouted) brown rice was observed with hepatoma‐bearing rats by Miura et al.…”

Cholesterol Lowering and Antioxidative Effect of Pregerminated Brown Rice in Hypercholesterolemic Rats

“…The hepatic LDL-R (receptor) clears up LDL-C from the blood circulation, thus indicating an increased expression of LDL-R would be favorable for the increased elimination of LDL-C. The bioactive compounds of GBR, such as phytosterols, GABA, oryzanol and phenolics have previously been ascribed to the up-regulation of LDL-R gene in HEPG2 cells (15,16). Other reports also support that GBR causes upregulation of both apoA-1 and LDL-R genes (17).…”

Therapeutic properties of rice constituents and derivatives (Oryza sativa L.): A review update

“…A study conducted on type 2 diabetic rats has shown that germinated brown rice exerts a hypocholesterolemic effect involving the upregulation of apolipoprotein A1 and of LDL receptor genes (Imam, Ismail et al 2013). An ethyl acetate extract from brown rice, evaluated in vitro on rat smooth muscle cells, has hindered the stimulatory effect of angiotensin II, suggesting antihypertensive properties (Utsunomiya, Takaguri et al 2011).…”