title: Dietary secoisolariciresinol diglucoside and its oligomers with 3-hydroxy-3-methyl glutaric acid decrease vitamin E levels in rats.
abstract: Secoisolariciresinol diglucoside (SDG) is an important dietary lignan that is found at very high levels in flaxseed (1-4 %, w/w). Flaxseed lignans have received much research interest in recent years because of reported phyto-oestrogenic, anticarcinogenic, and anti-atherogenic effects. Previously, flaxseed feeding has been shown to decrease vitamin E concentrations in rats despite the antioxidant potential of SDG in vitro. Sesamin, a sesame lignan, on the other hand has been shown to increase vitamin E concentrations in rats. The aim of the present study was to investigate the effect of dietary SDG and its oligomers on vitamin E and cholesterol concentrations in rats. SDG was extracted from defatted flaxseed flour with a dioxane-ethanol mixture and purified by silica column chromatography. The major oligomers with 3-hydroxy-3-methyl glutaric acid, containing a high ratio of SDG to p-coumaric and ferulic acid glucosides, were purified from the extracts by reversed-phase liquid chromatography. When fed to rats at 0.1 % in the diet for 27 d, both SDG and its oligomers had no effect on animal performance but caused an increase in liver cholesterol and a 2-fold reduction in the levels of alpha- and gamma-tocopherols in rat plasma and liver. It is notable that a phenolic antioxidant, such as SDG, causes a vitamin E-lowering effect in rats. This cannot be explained at present, but warrants further investigations with respect to the magnitude, mechanism, and significance of the observed effect for human nutrition.
authors.affiliation: Department of Food Science, Swedish University of Agricultural Sciences (SLU), Box 7051, S-750 07 Uppsala, Sweden. Jan.Frank@lmv.slu.se
authors.forename: Jan
authors.initials: J
authors.lastname: Frank
authors.forename: Christina
authors.initials: C
authors.lastname: Eliasson
authors.forename: Diane
authors.initials: D
authors.lastname: Leroy-Nivard
authors.forename: Alicja
authors.initials: A
authors.lastname: Budek
authors.forename: Torbjörn
authors.initials: T
authors.lastname: Lundh
authors.forename: Bengt
authors.initials: B
authors.lastname: Vessby
authors.forename: Per
authors.initials: P
authors.lastname: Aman
authors.forename: Afaf
authors.initials: A
authors.lastname: Kamal-Eldin
mesh_terms: D000818:Animals; D000924:Anticholesteremic Agents / Q000008:administration & dosage*; D000975:Antioxidants / Q000008:administration & dosage / Q000737:chemistry; D002072:Butylene Glycols / Q000008:administration & dosage / Q000737:chemistry / Q000494:pharmacology*; D002784:Cholesterol / Q000032:analysis* / Q000097:blood; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D003373:Coumaric Acids / Q000008:administration & dosage / Q000737:chemistry; D004032:Diet; D019597:Flax / Q000737:chemistry; D016166:Free Radical Scavengers / Q000008:administration & dosage / Q000737:chemistry; D005960:Glucosides / Q000008:administration & dosage / Q000737:chemistry / Q000494:pharmacology*; D008099:Liver / Q000737:chemistry; D015093:Meglutol / Q000008:administration & dosage*; D011422:Propionates; D051381:Rats; D017207:Rats, Sprague-Dawley; D012639:Seeds / Q000737:chemistry; D024505:Tocopherols / Q000032:analysis / Q000097:blood; D014810:Vitamin E / Q000097:blood*
chemical_list: D000924:Anticholesteremic Agents; D000975:Antioxidants; D002072:Butylene Glycols; D003373:Coumaric Acids; D016166:Free Radical Scavengers; D005960:Glucosides; D011422:Propionates; D014810:Vitamin E; D002784:Cholesterol; C004999:ferulic acid; D015093:Meglutol; C495469:p-coumaric acid; D024505:Tocopherols; C090142:secoisolariciresinol diglucoside