A sensitive LC-MS/MS assay for the simultaneous analysis of the major active components of silymarin in human plasma

► Silymarin extract contains numerous bioactive flavonolignans and flavonoids. ► Analysis of silychristin, silydianin, silybin A and B, isosilybin A and B, and taxifolin. ► Pure standard compounds were utilized for absolute quantification. ► The lower limit of quantification was 2 ng/ml for each analyte. ► Method was applied to human plasma samples from subjects treated with Legalon®.