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Isoflavonoids and peptides from meju, long-term fermented soybeans, increase insulin sensitivity and exert insulinotropic effects in vitro.

Authors :
Kwon DY
Hong SM
Ahn IS
Kim MJ
Yang HJ
Park S
Source :
Nutrition (Burbank, Los Angeles County, Calif.) [Nutrition] 2011 Feb; Vol. 27 (2), pp. 244-52. Date of Electronic Publication: 2010 Jun 11.
Publication Year :
2011

Abstract

Objective: Although soybeans have been shown to alleviate metabolic syndromes, fermented soybeans may have even greater effects. We investigated the antidiabetic effects of meju, a soy food that is fermented up to 2 mo, and the mechanism by which it exerts its effects.<br />Methods: Meju was prepared by a traditional fermentation process: soybeans were fermented outdoors for 20 or 60 d. Methanol (M-60) and water (W-60) extracts from meju that had fermented for 60 d contained mostly isoflavonoid aglycones and small peptides, respectively, as opposed to mostly glycosylated isoflavonoids and proteins in the original soybeans.<br />Results: Daidzein, M-60, and W-60 had better insulin-sensitizing actions by activating peroxisome proliferator-activated receptor-γ in 3T3-L1 adipocytes than did unfermented soybeans. In addition, Min6 insulinoma cells treated with genistein, M-60, and W-60 had greater glucose-stimulated insulin secretion capacity and greater β-cell viability than those treated with unfermented soybeans. This improvement was associated with insulin/insulin-like growth factor-1 signaling that was activated by the tyrosine phosphorylation of insulin receptor substrate-2 and serine phosphorylation of Akt, and this in turn increased pancreatic and duodenal homeobox-1 expression. Furthermore, genistein, daidzein, and M-60 stimulated glucagon-like peptide-1 secretion in enteroendocrine NCI-H716 cells, which generated insulinotropic actions.<br />Conclusion: The compositional changes in isoflavonoids and peptides that occurred during a longer fermentation period, without the use of salt, enhanced the antidiabetic effect of soybeans.<br /> (Copyright © 2011 Elsevier Inc. All rights reserved.)

Details

Language :
English
ISSN :
1873-1244
Volume :
27
Issue :
2
Database :
MEDLINE
Journal :
Nutrition (Burbank, Los Angeles County, Calif.)
Publication Type :
Academic Journal
Accession number :
20541368
Full Text :
https://doi.org/10.1016/j.nut.2010.02.004