Nutr Res Pract.  2014 Dec;8(6):632-637. 10.4162/nrp.2014.8.6.632.

Hypocholesterolemic metabolism of dietary red pericarp glutinous rice rich in phenolic compounds in mice fed a high cholesterol diet

• Park Y
• Park EM
• Kim EH
• Chung IM

• KMID: 2313789
• DOI: http://doi.org/10.4162/nrp.2014.8.6.632

Abstract

BACKGROUND/OBJECTIVES
The purpose of the current study was to investigate the effect of red pericarp glutinous rice rich in polyphenols (Jakwangchalbyeo, red rice) on serum and hepatic levels of cholesterol and hepatic protein expression linked to synthesis and degradation of cholesterol in a hypercholesterolemic mice diet as compared with brown rice.
MATERIALS/METHODS
C57BL/6 male mice were randomly divided into four groups (n = 5 each), which were fed different diets for a period of 12 weeks: American Institute of Nutrition (AIN)-93G diet, AIN-93G diet with 2% cholesterol, brown rice with 2% cholesterol, or red rice with 2% cholesterol. RESULT: Consumption of red rice resulted in a significant decrease in serum level of low-density lipoprotein cholesterol and hepatic levels of triglyceride and total-cholesterol. Expression of acyl-coenzyme A cholesterol acyltransferase-2 (ACAT-2), sterol regulatory element binding protein-2 (SREBP-2), and 3-hydroxyl-3-methylglutaryl coenzyme A (HMG-CoA) reductase was decreased, while expression of phosphorylated adenosine monophosphate activated protein kinase (p-AMPK)/AMPK ratio, cholesterol 7-alpha-hydroxylase (CYP7a1), and sterol 12-alpha-hydroxylase (CYP8b1) was increased in mice fed red rice. Brown rice had similar effects on cholesterol metabolism, but the effect of red rice was significantly greater than that of brown rice.
CONCLUSIONS
The current study suggested that red rice had a hypocholesterolemic effect by lowering hepatic cholesterol synthesis through ACAT-2, HMG-CoA reductase, and SREBP-2, and by enhancing hepatic cholesterol degradation through CYP7a1 and CYP8b1 in mice fed a hypercholesterolemic diet.

Keyword

Red rice; cholesterol metabolism; liver; protein expression; mice

MeSH Terms

Adenosine Monophosphate
Animals
Cholesterol 7-alpha-Hydroxylase
Cholesterol*
Coenzyme A
Diet*
Humans
Lipoproteins
Liver
Male
Metabolism*
Mice*
Oxidoreductases
Phenol*
Polyphenols
Protein Kinases
Steroid 12-alpha-Hydroxylase
Triglycerides
Adenosine Monophosphate
Cholesterol
Cholesterol 7-alpha-Hydroxylase
Coenzyme A
Lipoproteins
Oxidoreductases
Phenol
Polyphenols
Protein Kinases
Steroid 12-alpha-Hydroxylase

Figure

• 

  Fig. 1 Expression of acyl-coenzyme A cholesterol acyltransferase-2 (ACAT-2), sterol regulatory element binding protein-2 (SREBP-2), 3-hydroxyl-3-methylglutaryl coenzyme A reductase (HMG-CoA) and phosphorylated adenosine monophosphate activated protein kinase (p-AMPK)/adenosine monophosphate activated protein kinase (AMPK) ratio. NC, normal control; HC, 2% cholesterol diet; BR-HC, brown rice with 2% cholesterol diet; RR-HC, red rice with 2% cholesterol diet. Values are expressed as the mean ± SEM (n = 5) and the different letters in the rows are significantly different at P < 0.05 using ANOVA with Duncan's multiple range test.

• 

  Fig. 2 Immunofluorescence microscopic imaging of sterol regulatory element binding protein-2 (SREBP-2) in liver. NC, normal control; HC, 2% cholesterol diet; BR-HC, 2% cholesterol with brown rice diet; RR-HC, 2% cholesterol with red rice diet. Images of SREBP-2 antibody (light green), nuclei (DAPI) and merged image were captured at identical times of exposure (4s and 500ms). Bar represent, 100 µm.

• 

  Fig. 3 Expression of cholesterol 7-α-hydroxylase (CYP7a1) and sterol 12-α-hydroxylase (CYP8b1). NC, normal control; HC, 2% cholesterol diet; BR-HC, brown rice with 2% cholesterol diet; RR-HC, red rice with 2% cholesterol diet. Values in the rows with different letters are significantly different at P < 0.05 using ANOVA with Duncan's multiple range test.

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