α-globulin-rich rice cultivar, low glutelin content-1 (LGC-1), decreases serum cholesterol concentration in exogenously hypercholesterolemic rats

Xingyu Yuan, Yutaro Minobe, Yasutake Tanaka, Yumi Fukuda, Yumiko Furukawa, Motonori Miyago, Takuya Mizokami, Wei Ting Tsai, Zhe Jiang, Li Tao Tong, Taiki Akasaka, Bungo Shirouchi, Yoshiko Toyosawa, Toshihiro Kumamaru, Masao Sato

Research output: Contribution to journalArticlepeer-review

Abstract

BACKGROUND: Rice α-globulin has been reported to have serum cholesterol-lowering activity in rats. However, it is still unclear whether α-globulin exerts this effect when taken as one of the dietary components. In the present study, we investigated the effect of two cultivars of rice, low glutelin content (LGC)-1 and LGC-Jun, on reducing serum cholesterol in exogenously hypercholesterolemic (ExHC) rats. LGC-1 is enriched in α-globulin (10.6 mg g−1 rice flour, which is an approximately 1.5 times higher α-globulin content than in Koshihikari a predominant rice cultivar in Japan), whereas LGC-Jun is a globulin-negative cultivar. METHODS: ExHC rats, the model strain of diet-induced hypercholesterolemia, were fed 50% LGC-1 or LGC-Jun and 0.5% cholesterol-containing diets for 2 weeks, followed by measurement of cholesterol metabolism parameters in serum and tissues. RESULTS: Serum cholesterol and non-high-density lipoprotein cholesterol levels were significantly lower in the LGC-1 group compared to the LGC-Jun group. Cholesterol intestinal absorption markers, hepatic and serum levels of campesterol and β-sitosterol, and lymphatic cholesterol transport were not different between the two groups. Levels of 7α-hydroxycholesterol, an intermediate of bile acid synthesis, showed a downward trend in the livers of rats that were fed LGC-1 (P = 0.098). There was a significant decrease in the hepatic mRNA expression of Cyp7a1 (a synthetic enzyme for 7α-hydroxycholesterol) in the LGC-1 group compared to the LGC-Jun group. CONCLUSION: Dietary LGC-1 significantly decreased serum cholesterol levels in ExHC rats. The possible mechanism for the cholesterol-lowering activity of LGC-1 is partial inhibition of bile acid and cholesterol synthesis in the liver.

Original languageEnglish
JournalJournal of the Science of Food and Agriculture
DOIs
Publication statusAccepted/In press - 2021

All Science Journal Classification (ASJC) codes

  • Biotechnology
  • Food Science
  • Agronomy and Crop Science
  • Nutrition and Dietetics

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