Effects of blueberry leaf and stem extracts on hepatic lipid levels in rats consuming a high-sucrose diet

Authors

  • Yasushi Matsuura University of Miyazaki
  • Hiroyuki Sakakibara University of Miyazaki
  • Maho Kawaguchi University of Miyazaki
  • Emi Murayama University of Miyazaki
  • Daigo Yokoyama University of Miyazaki
  • Chizuko Yukizaki Miyazaki Prefectural Food Research and Development Center
  • Hisato Kunitake University of Miyazaki
  • Masanobu Sakono University of Miyazaki

DOI:

https://doi.org/10.31989/ffhd.v8i9.538

Abstract

Background: Blueberry stems, a by-product of blueberry leaf tea production, are typically discarded. We evaluated the effects of hot-water extracts of rabbiteye blueberry (Vaccinium virgatum Aiton; RB species) leaves and stems on hepatic lipid levels in rats consuming a high-sucrose diet.

Methods: Male Sprague-Dawley rats were divided into groups that received a control high-sucrose diet alone or supplementation with 2.0% blueberry leaf extract or 0.5% or 2.0% blueberry stem extract. Blood and hepatic lipid levels, hepatic lipogenic enzyme activity, and hepatic quercetin metabolites were evaluated after 28 days of ad libitum consumption.

Results: Supplementation with the extracts did not affect body weight gain, food intake, liver and white adipose tissue weights, or serum lipid levels. Hepatic triglyceride and total cholesterol levels were reduced in the groups that received 2.0% supplementation of either extract. Hepatic malic enzyme activity was also reduced in those groups. Quercetin and its glycosides, the major polyphenols identified in the extracts, accumulated in the liver as quercetin aglycone and quercetin metabolites. 

Conclusion: We demonstrated how daily consumption of blueberry leaf and stem extracts can decrease hepatic lipid levels, potentially downregulating malic enzyme activity. These effects were intensive in leaf extracts. The active compounds existed in both extracts may be quercetin and its glycosides. Therefore, blueberry stems and leaves may be an attractive candidate novel functional food.

Keywords: Blueberry leaf; blueberry stem; quercetin; hepatic lipid; rat; functional food

Author Biographies

  • Yasushi Matsuura, University of Miyazaki
    Interdisciplinary Graduate School of Agriculture and Engineering
  • Hiroyuki Sakakibara, University of Miyazaki
    Faculty of Agriculture
  • Maho Kawaguchi, University of Miyazaki
    Faculty of Agriculture
  • Emi Murayama, University of Miyazaki
    Faculty of Agriculture
  • Daigo Yokoyama, University of Miyazaki
    Interdisciplinary Graduate School of Agriculture and Engineering
  • Hisato Kunitake, University of Miyazaki
    Faculty of Agriculture
  • Masanobu Sakono, University of Miyazaki
    Faculty of Agriculture

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Published

2018-09-30

Issue

Vol. 8 No. 9 (2018): September 2018

Section

Research Articles

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