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Antidiabetic Effects of a Standardized Egyptian Rice Bran Extract
Author(s) -
Kaup Rebecca M.,
Khayyal Mohamed T.,
Verspohl Eugen J.
Publication year - 2013
Publication title -
phytotherapy research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.019
H-Index - 129
eISSN - 1099-1573
pISSN - 0951-418X
DOI - 10.1002/ptr.4705
Subject(s) - bran , tocotrienol , nutraceutical , ferulic acid , insulin , traditional medicine , food science , in vitro , in vivo , chemistry , pharmacology , antioxidant , biology , biochemistry , microbiology and biotechnology , medicine , vitamin e , tocopherol , raw material , organic chemistry
An extract was prepared from Egyptian stabilized rice bran and standardized to contain 2% γ‐oryzanol in addition to its content of other bioactives, notably tocotrienol and policosanol. The standardized extract was found to have a concentration‐dependent effect on insulin release in vitro , which, however, is not mediated by γ‐tocotrienol in rice bran (detected by HPLC) as could have been expected. Policosanol and γ‐oryzanol have insulinotropic effects. The in vitro data of rice bran directly translate into in vivo data of rats by using a glucose tolerance test (increase in plasma insulin). Tocotrienols are well known for their apoptotic effect on tumor cells; nevertheless, an attempt was made to study glucose uptake in HEP‐G2 cells, which needs to induce an insulin‐resistant state by TNF‐α. The Egyptian rice bran extract has an antidiabetic effect. γ‐Oryzanol, which is a possible precursor of the insulinotropic compound ferulic acid, is a candidate for this effect. Therefore, it is reasonable to assume that the prevalence of diabetes or at least a prediabetic (type 2) situation can be ameliorated by the investigated rice bran extract. The potential usefulness of the extract as a nutraceutical is currently undergoing more thorough investigations. Copyright © 2012 John Wiley & Sons, Ltd.