title: Antidiabetic effects of a standardized Egyptian rice bran extract.
abstract: 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.
authors.affiliation: Department of Pharmacology, Institute of Medicinal Chemistry, University of Muenster, Hittorfstr. 58-62, 48149, Münster, Germany.
authors.forename: Rebecca M
authors.initials: RM
authors.lastname: Kaup
authors.forename: Mohamed T
authors.initials: MT
authors.lastname: Khayyal
authors.forename: Eugen J
authors.initials: EJ
authors.lastname: Verspohl
mesh_terms: D000818:Animals; D001786:Blood Glucose / Q000187:drug effects; D002839:Chromans / Q000302:isolation & purification / Q000494:pharmacology; D003373:Coumaric Acids / Q000302:isolation & purification / Q000494:pharmacology; D019587:Dietary Supplements; D005233:Fatty Alcohols / Q000302:isolation & purification / Q000494:pharmacology; D005260:Female; D005951:Glucose Tolerance Test; D056945:Hep G2 Cells; D006801:Humans; D007004:Hypoglycemic Agents / Q000302:isolation & purification / Q000494:pharmacology*; D007328:Insulin / Q000097:blood; D008297:Male; D012275:Oryza / Q000737:chemistry*; D010666:Phenylpropionates / Q000302:isolation & purification / Q000494:pharmacology*; D010936:Plant Extracts / Q000494:pharmacology*; D051381:Rats; D024508:Tocotrienols / Q000302:isolation & purification / Q000494:pharmacology; D014409:Tumor Necrosis Factor-alpha; D014810:Vitamin E / Q000031:analogs & derivatives / Q000302:isolation & purification / Q000494:pharmacology
chemical_list: D001786:Blood Glucose; D002839:Chromans; D003373:Coumaric Acids; D005233:Fatty Alcohols; D007004:Hypoglycemic Agents; D007328:Insulin; D010666:Phenylpropionates; D010936:Plant Extracts; D024508:Tocotrienols; D014409:Tumor Necrosis Factor-alpha; D014810:Vitamin E; C080710:policosanol; C013649:plastochromanol 8; C004999:ferulic acid; C013172:gamma-oryzanol