Antidiabetic effects of a standardized Egyptian rice bran extract.

Kaup, R. M., M. T. Khayyal, and E. J. Verspohl, "Antidiabetic effects of a standardized Egyptian rice bran extract.", Phytotherapy research : PTR, vol. 27, issue 2, pp. 264-71, 2013 Feb.


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.