J Nutr Health.  2015 Feb;48(1):1-8. 10.4163/jnh.2015.48.1.1.

Effects of an aqueous extract of purple sweet potato on nonalcoholic fatty liver in high fat/cholesterol-fed mice

• Lee YJ
• Yang YK
• Kim YJ
• Kwon O

• KMID: 2327171
• DOI: http://doi.org/10.4163/jnh.2015.48.1.1

Abstract

PURPOSE
Anthocyanins from purple sweet potato (PSP) have been investigated in vitro and in animals and found to have a protective effect against oxidative hepatic damage. In this study, we investigated that aqueous extract of PSP can ameliorate the dysfunction of lipid metabolism in mice fed a high fat/cholesterol diet.
METHODS
Forty C57BL/6J mice were randomly divided into 5 groups (n = 8) and fed one of the following diets for 8 weeks; normal fat (NF) diet; high fat/cholesterol (HFC) diet; HFC with 1.25% PSP (HFPL) diet; HFC with 2.5% PSP (HFPM) diet; HFC with 5% PSP (HFPH) diet.
RESULTS
Non-alcoholic fatty liver was manifested in the HFC group by showing increased levels in plasma alanine aminotransferase (ALT) activity, total cholesterol (TC) and low density lipoprotein cholesterol (LDL-C), increased level of TC and presence of many large lipid droplets in the liver, and increased fat cell size in the HFC group compared with the NF group. However, administration of HFC induced a significant decrease in food intake, resulting in decrease in fat mass. Coadministration of PSP did not lead to reversal of body weight changes, ALT activity, and lipid levels in plasma and the liver, but suppressed excess enlargement of the fat cell size through increasing carnitine palmitoyltransferase-1 (CPT-1) gene expression in the liver. Accordingly, the number of fat droplets in the liver was reduced in PSP administered groups.
CONCLUSION
Taken together, these results suggest that PSP may have a protective effect on the dysfunction of lipid metabolism. Conduct of further studies on the coordinated regulation of PSP for lipid metabolic homeostasis at the liver-adipose tissue axis is needed.

Keyword

purple sweet potato; aqueous extract; high fat/cholesterol diet; non-alcoholic fatty liver

MeSH Terms

Adipocytes
Alanine Transaminase
Animals
Anthocyanins
Axis, Cervical Vertebra
Body Weight Changes
Carnitine
Cholesterol
Cholesterol, LDL
Diet
Eating
Fatty Liver*
Gene Expression
Homeostasis
Ipomoea batatas*
Lipid Metabolism
Liver
Mice*
Plasma
Alanine Transaminase
Anthocyanins
Carnitine
Cholesterol
Cholesterol, LDL

Figure

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  Fig. 1. Effects of purple sweet potato extract on food intake and body weight in high fat/cholesterol diet-fed C57BL/6 mice: (A) food intake, (B) energy intake, (C) total body weight gain and (D) body weight changes by week. NF, normal fat control; HFC, high fat control; HFPL, HFC + PSP 1.25%; HFPM; HFC + PSP 2.5%; HFPH, HFC + PSP 5%. Values are expressed as Mean ± SE (n = 8 for each group). Means with different letters on the bar are significantly different from each other at p < 0.05 by Duncan's multiple range test.

• 

  Fig. 2. Effects of purple sweet potato extract on liver enzymes in plasma and liver histology in high fat/cholesterol-fed C57BL/6 mice: (A) AST, (B) ALT and (C) liver histology. NF, normal fat control; HFC, high fat control; HFPL, HFC + PSP 1.25%; HFPM; HFC + PSP 2.5%; HFPH, HFC + PSP 5%. Values are expressed as Mean ± SE (n = 8 for each group). Means with different letters on the bar are significantly different from each other at p < 0.05 by Duncan's multiple range test. Histology bar represents 50 μm.

• 

  Fig. 3. Effects of purple sweet potato extract on plasma lipid levels in high fat/cholesterol-fed C57BL/6 mice: (A) TG, (B) TC, and (C) LDL-C. NF, normal fat control; HFC, high fat control; HFPL, HFC + PSP 1.25%; HFPM; HFC + PSP 2.5%; HFPH, HFC + PSP 5%. Values are expressed as Mean ± SE (n = 8 for each group). Means with different letters on the bar are significantly different from each other at p < 0.05 by Duncan's multiple range test.

• 

  Fig. 4. Effects of purple sweet potato extract on lipid and mRNA levels in the liver of high fat/cholesterol-fed C57BL/6 mice: (A) TC, (B) TG, and (C) mRNA levels. NF, normal fat control; HFC, high fat control; HFPL, HFC + PSP 1.25%; HFPM; HFC + PSP 2.5%; HFPH, HFC + PSP 5%; SREBP-1c, sterol regulatory element-binding protein-1c; FAS, fatty acid synthase; CPT-1, carnitine palmitoyltransferase-1. Values are expressed as Mean ± SE (n = 8 for each group). Means with different letters on the bar are significantly different from each other at p < 0.05 by Duncan's multiple range test.

• 

  Fig. 5. Effects of purple sweet potato extract on fat mass and epididymal fat tissue histology in high fat/cholesterol-fed mice: (A) adipose tissue weight and (B) adipose tissue histology. NF, normal fat control; HFC, high fat control; HFPL, HFC + PSP 1.25%; HFPM; HFC + PSP 2.5%; HFPH, HFC + PSP 5%. Values are expressed as Mean ± SE (n = 8 for each group). Means with different letters on the bar are significantly different from each other at p < 0.05 by Duncan's multiple range test. Histology bar represents 50 μm.

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