Nutr Res Pract.  2016 Oct;10(5):501-506. 10.4162/nrp.2016.10.5.501.

Corn silk extract improves cholesterol metabolism in C57BL/6J mouse fed high-fat diets

• Cha JH
• Kim SR
• Kang HJ
• Kim MH
• Ha AW
• Kim WK

• KMID: 2434084
• DOI: http://doi.org/10.4162/nrp.2016.10.5.501

Abstract

BACKGROUND/OBJECTIVES
Corn silk (CS) extract contains large amounts of maysin, which is a major flavonoid in CS. However, studies regarding the effect of CS extract on cholesterol metabolism is limited. Therefore, the purpose of this study was to determine the effect of CS extract on cholesterol metabolism in C57BL/6J mouse fed high-fat diets.
MATERIALS/METHODS
Normal-fat group fed 7% fat diet, high-fat (HF) group fed 25% fat diet, and high-fat with corn silk (HFCS) group were orally administered CS extract (100 mg/kg body weight) daily. Serum and hepatic levels of total lipids, triglycerides, and total cholesterol as well as serum free fatty acid, glucose, and insulin levels were determined. The mRNA expression levels of acyl-CoA: cholesterol acyltransferase (ACAT), cholesterol 7-alpha hydroxylase (CYP7A1), farnesoid X receptor (FXR), lecithin cholesterol acyltransferase (LCAT), low-density lipoprotein receptor, 3-hyroxy-3-methylglutaryl-coenzyme A reductase (HMG-CoA reductase), adiponectin, leptin, and tumor necrosis factor α were determined.
RESULTS
Oral administration of CS extract with HF improved serum glucose and insulin levels as well as attenuated HF-induced fatty liver. CS extracts significantly elevated mRNA expression levels of adipocytokines and reduced mRNA expression levels of HMG-CoA reductase, ACAT, and FXR. The mRNA expression levels of CYP7A1 and LCAT between the HF group and HFCS group were not statistically different.
CONCLUSIONS
CS extract supplementation with a high-fat diet improves levels of adipocytokine secretion and glucose homeostasis. CS extract is also effective in decreasing the regulatory pool of hepatic cholesterol, in line with decreased blood and hepatic levels of cholesterol though modulation of mRNA expression levels of HMG-CoA reductase, ACAT, and FXR.

Keyword

Corn silk; maysin; cholesterol; high-fat; adiponectin

MeSH Terms

Adipokines
Adiponectin
Administration, Oral
Animals
Blood Glucose
Cholesterol*
Diet
Diet, High-Fat*
Fatty Liver
Glucose
Homeostasis
Insulin
Leptin
Metabolism*
Mice*
Oxidoreductases
Phosphatidylcholine-Sterol O-Acyltransferase
Receptors, Lipoprotein
RNA, Messenger
Silk*
Sterol O-Acyltransferase
Triglycerides
Tumor Necrosis Factor-alpha
Zea mays*
Adipokines
Adiponectin
Cholesterol
Glucose
Insulin
Leptin
Oxidoreductases
Phosphatidylcholine-Sterol O-Acyltransferase
RNA, Messenger
Receptors, Lipoprotein
Silk
Sterol O-Acyltransferase
Triglycerides
Tumor Necrosis Factor-alpha

Figure

• 

  Fig. 1 Effect of Corn silk extract on lipid deposition in the liver

• 

  Fig. 2 Effect of Corn silk extract on mRNA expression of adipocytokines in adipose tissue of mouse fed high-fat diet Total RNA was isolated using TRI-reagent and cDNA was synthesized using 3 µg of total RNA with SuperScriptⅡ reverse transcriptase. Real-time PCR was performed using SYBR green and standard procedures to assess mRNA expression of primer in adipose tissue (epididymal fat pad) samples obtained from each group. An Applied Biosystem StepOne softwere v2.1 was used. Each bar represents the mean ± S.D, and different letters above each bar indicate significant differences among groups at α = o.o5 as determined by Duncan's multiple range test. TNF-α; tumor necrosis factor-α.

• 

  Fig. 3 Effect of Corn silk extract on mRNA expression of enzymes related to cholesterol metabolism in livers of mice fed high-fat diet Total RNA was isolated using TRI-reagent, and cDNA was synthesized using 3 µg of total RNA with SuperScriptⅡ reverse transcriptase. Real-time PCR was performed using SYBR green and standard procedures to assess mRNA expression of primer in liver samples obtained from each group. An Applied Biosystem StepOne softwere v2.1 was used. Each bar represents the mean ± S.D, and different letters above each bar indicate significant differences among groups at α = o.o5 as determined by Duncan's multiple range test. ACAT; acyl-CoA: cholesterol acyltransferase, CYP7A1; cholesterol 7-alpha hydroxylase, FXR; farnesoid X receptor, LCAT; lecithin cholesterol acyltransferase, LDL-R; low density lipoprotein receptor, HMG-CoA reductase; 3-hyroxy-3-methylglutaryl-coenzyme A reductase.

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