HPLC method for analysis of secoisolariciresinol diglucoside in flaxseeds

A method was developed for the analysis of secoisolariciresinol diglucoside (SDG) in flaxseeds. The analytical method involves extraction of defatted flaxseed flour with dioxane/ethanol, aqueous base-hydrolysis, solid-phase purification of an SDG-containing fraction, and quantitative analysis by high-performance liquid chromatography (HPLC). Pure SDG was isolated from flaxseed using different column chromatographic methods and used, as external standard, for the calibration of the method and for quantification. The method was then applied to study the variation in SDG content in flaxseeds from 14 cultivars grown in Sweden and 15 cultivars grown in Denmark. The SDG content varied between 11.7 and 24.1 mg/g in defatted flaxseed flour and between 6.1 and 13.3 mg/g in whole flaxseeds.