Journal List > J Nutr Health > v.48(1) > 1081375

J Nutr Health. 2015 Feb;48(1):1-8. Korean.
Published online February 28, 2015.  https://doi.org/10.4163/jnh.2015.48.1.1
© 2015 The Korean Nutrition Society
Effects of an aqueous extract of purple sweet potato on nonalcoholic fatty liver in high fat/cholesterol-fed mice
You Jin Lee,1 Yoon Kyoung Yang,2 You Jin Kim,1 and Oran Kwon1
1Department of Nutritional Science and Food Management, Ewha Womans University, Seoul 120-750, Korea.
2Department of Nutritional Science and Food Management, Soongeui Women's College, Seoul 100-751, Korea.

To whom correspondence should be addressed. tel: +82-2-3277-6860, Email: orank@ewha.ac.kr
Received November 12, 2014; Revised December 14, 2014; Accepted January 28, 2015.

This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.


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.

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

Figures


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.
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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.
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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) LDLC. 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.
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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.
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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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Tables


Table 1
Composition of experimental diets1) (Unit: g/kg diet)
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Notes

This study was performed with the support of the Food Functionality Evaluation Program funded by the Ministry of Agriculture, Food and Rural Affairs through Korea Food Research Institute and "Cooperative Research Program for Agriculture Science & Technology Development (Project title: Research on New Functional Food Materials with Domestic Agricultural Products, Project No. PJ00845002)" Rural Development Administration, Republic of Korea.

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