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Rice koji reduced body weight gain, fat accumulation, and blood glucose level in high-fat diet-induced obese mice.

Yoshizaki Y, Kawasaki C, Cheng KC, Ushikai M, Amitani H, Asakawa A, Okutsu K, Sameshima Y, Takamine K, Inui A - PeerJ (2014)

Bottom Line: Feed efficiency was significantly reduced in the yellow koji group.Blood glucose levels were significantly lower in the white and red koji groups with HOMA-R and leptin levels being reduced in the white koji group.These results showed that all rice koji have the anti-obesity or anti-diabetes effects although the mechanisms may differ depending on the type of rice koji consumed.

View Article: PubMed Central - HTML - PubMed

Affiliation: Division of Shochu Fermentation Technology, Education and Research Center for Fermentation Studies, Faculty of Agriculture, Kagoshima University , Kagoshima City , Japan.

ABSTRACT
Rice koji is considered a readily accessible functional food that may have health-promoting effects. We investigated whether white, yellow, and red koji have the anti-obesity effect in C57BL/6J mice fed a high-fat diet (HFD), which is a model for obesity. Mice were fed HFD containing 10% (w/w) of rice koji powder or steamed rice for 4 weeks. Weight gain, epididymal white adipose tissue, and total adipose tissue weight were significantly lower in all rice koji groups than in the HFD-rice group after 4 weeks. Feed efficiency was significantly reduced in the yellow koji group. Blood glucose levels were significantly lower in the white and red koji groups with HOMA-R and leptin levels being reduced in the white koji group. White and red koji increased glucose uptake and GLUT4 protein expression in L6 myotube cells. These results showed that all rice koji have the anti-obesity or anti-diabetes effects although the mechanisms may differ depending on the type of rice koji consumed.

No MeSH data available.


Related in: MedlinePlus

Glucose transporter type 4 (GLUT4) protein levels in L6 myotube cells treated with each sample extracts.(A) Western blot analyses of GLUT4 and β–actin in L6 myotube cells. L6 myotube cells were treated for 14 h with steamed rice, white koji, and red koji extracts diluted at a factor of 1,000. (B) The relative signal intensities of GLUT4 to β-actin protein were measured by NIH image J software. Data are expressed as means ± SE (n = 5). Letters above the bars indicate significant differences of P < 0.05 by Dunnett’s multiple comparison (a, b).
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fig-3: Glucose transporter type 4 (GLUT4) protein levels in L6 myotube cells treated with each sample extracts.(A) Western blot analyses of GLUT4 and β–actin in L6 myotube cells. L6 myotube cells were treated for 14 h with steamed rice, white koji, and red koji extracts diluted at a factor of 1,000. (B) The relative signal intensities of GLUT4 to β-actin protein were measured by NIH image J software. Data are expressed as means ± SE (n = 5). Letters above the bars indicate significant differences of P < 0.05 by Dunnett’s multiple comparison (a, b).

Mentions: It was reported that red mold-fermented products could delay the increase in the blood glucose levels in rats and that red koji protects against diabetes (Hsieh & Tai, 2003; Shi & Pan, 2010). This effect of red koji was also confirmed in this study and that of white koji was first recognized (Table 4). Skeletal muscle is the predominant tissue for insulin-stimulated glucose disposal (Koranyi et al., 1991). Glucose enters the muscle cell primarily by facilitated diffusion by utilizing glucose transporter carrier proteins. GLUT4 is the predominantly expressed glucose transporter isoform in muscle (Shepherd & Kahn, 1999), and whole body glucose disposal and GLUT4 expression are correlated in healthy subjects (Koranyi et al., 1991). Therefore, the glucose uptake activity and GLUT4 protein expression level were measured in muscle cells to investigate the mechanism by which white and red koji suppresses blood glucose. L6 myotube cells were exposed to various concentrations of white and red koji extracts or steamed rice extract. Treatment of L6 myotube cells with white and red koji resulted in a dose-dependent increase in 2-NBDG uptake, similar to that in insulin-stimulated cells (Fig. 2). We examined the expression of GLUT4 proteins in L6 myotube cells stimulated with white and red koji extracts. GLUT4 expression increased by approximately 1.5 and 1.6-fold in L6 myotube cells treated with the extract of white and red koji, respectively, compared with cells treated with steamed rice (Fig. 3).


Rice koji reduced body weight gain, fat accumulation, and blood glucose level in high-fat diet-induced obese mice.

Yoshizaki Y, Kawasaki C, Cheng KC, Ushikai M, Amitani H, Asakawa A, Okutsu K, Sameshima Y, Takamine K, Inui A - PeerJ (2014)

Glucose transporter type 4 (GLUT4) protein levels in L6 myotube cells treated with each sample extracts.(A) Western blot analyses of GLUT4 and β–actin in L6 myotube cells. L6 myotube cells were treated for 14 h with steamed rice, white koji, and red koji extracts diluted at a factor of 1,000. (B) The relative signal intensities of GLUT4 to β-actin protein were measured by NIH image J software. Data are expressed as means ± SE (n = 5). Letters above the bars indicate significant differences of P < 0.05 by Dunnett’s multiple comparison (a, b).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4157231&req=5

fig-3: Glucose transporter type 4 (GLUT4) protein levels in L6 myotube cells treated with each sample extracts.(A) Western blot analyses of GLUT4 and β–actin in L6 myotube cells. L6 myotube cells were treated for 14 h with steamed rice, white koji, and red koji extracts diluted at a factor of 1,000. (B) The relative signal intensities of GLUT4 to β-actin protein were measured by NIH image J software. Data are expressed as means ± SE (n = 5). Letters above the bars indicate significant differences of P < 0.05 by Dunnett’s multiple comparison (a, b).
Mentions: It was reported that red mold-fermented products could delay the increase in the blood glucose levels in rats and that red koji protects against diabetes (Hsieh & Tai, 2003; Shi & Pan, 2010). This effect of red koji was also confirmed in this study and that of white koji was first recognized (Table 4). Skeletal muscle is the predominant tissue for insulin-stimulated glucose disposal (Koranyi et al., 1991). Glucose enters the muscle cell primarily by facilitated diffusion by utilizing glucose transporter carrier proteins. GLUT4 is the predominantly expressed glucose transporter isoform in muscle (Shepherd & Kahn, 1999), and whole body glucose disposal and GLUT4 expression are correlated in healthy subjects (Koranyi et al., 1991). Therefore, the glucose uptake activity and GLUT4 protein expression level were measured in muscle cells to investigate the mechanism by which white and red koji suppresses blood glucose. L6 myotube cells were exposed to various concentrations of white and red koji extracts or steamed rice extract. Treatment of L6 myotube cells with white and red koji resulted in a dose-dependent increase in 2-NBDG uptake, similar to that in insulin-stimulated cells (Fig. 2). We examined the expression of GLUT4 proteins in L6 myotube cells stimulated with white and red koji extracts. GLUT4 expression increased by approximately 1.5 and 1.6-fold in L6 myotube cells treated with the extract of white and red koji, respectively, compared with cells treated with steamed rice (Fig. 3).

Bottom Line: Feed efficiency was significantly reduced in the yellow koji group.Blood glucose levels were significantly lower in the white and red koji groups with HOMA-R and leptin levels being reduced in the white koji group.These results showed that all rice koji have the anti-obesity or anti-diabetes effects although the mechanisms may differ depending on the type of rice koji consumed.

View Article: PubMed Central - HTML - PubMed

Affiliation: Division of Shochu Fermentation Technology, Education and Research Center for Fermentation Studies, Faculty of Agriculture, Kagoshima University , Kagoshima City , Japan.

ABSTRACT
Rice koji is considered a readily accessible functional food that may have health-promoting effects. We investigated whether white, yellow, and red koji have the anti-obesity effect in C57BL/6J mice fed a high-fat diet (HFD), which is a model for obesity. Mice were fed HFD containing 10% (w/w) of rice koji powder or steamed rice for 4 weeks. Weight gain, epididymal white adipose tissue, and total adipose tissue weight were significantly lower in all rice koji groups than in the HFD-rice group after 4 weeks. Feed efficiency was significantly reduced in the yellow koji group. Blood glucose levels were significantly lower in the white and red koji groups with HOMA-R and leptin levels being reduced in the white koji group. White and red koji increased glucose uptake and GLUT4 protein expression in L6 myotube cells. These results showed that all rice koji have the anti-obesity or anti-diabetes effects although the mechanisms may differ depending on the type of rice koji consumed.

No MeSH data available.


Related in: MedlinePlus