Validated LC-MS/MS Method for the Quantification of Free and Bound Lignans in Cereal-Based Diets and Feces

Despite the extensive literature describing the biological effects of phenolic compounds from cereals, little is known about their bioaccessibility in the food matrix. This paper describes a validated LC-MS/MS method for the quantification of free and total content (free + bound) of eight plant lignans (matairesinol, hydroxymatairesinol, secoisolariciresinol, lariciresinol, isolariciresinol, syringaresinol, medioresinol, and pinoresinol) and two enterolignans (enterodiol and enterolactone) in cereal-based diets/bread and feces. The method consisted of alkaline methanolic extraction combined with enzymatic hydrolyses, for the measurement of the total concentration of lignans, and methanolic extraction combined with enzymatic hydrolysis, for the measurement of free lignans, followed by solid phase extraction (SPE). The strength of this LC-MS/MS method is that it can be combined with different types of samples, because the SPE and LC-MS/MS platforms are similar to our previously published method for plasma and urine.