Technical note: Quantification of lignans in the urine, milk, and plasma of flaxseed cake–fed dairy sheep

Mammalian lignans are phytoestrogens with important bioactivities, and their concentrations in livestock milk may influence the health of consumers. This research aimed to establish a method quantify multiple mammalian biofluids dairy sheep using ultra-HPLC-triple quadropole mass spectrometry multiple-reaction monitoring. Secoisolariciresinol, 2-[(4-hydroxy-3-methoxyphenyl)methyl]-3-[(3-hydroxyphenyl)methyl]-1,4-butanediol, enterodiol (ED), enterolactone (EL), ED-sulfate (ED-S), EL-sulfate (EL-S) were purified from urine flaxseed cake–fed sheep. The structures these identified by combination nuclear magnetic resonance spectra. These used as standards optimize quantification conditions urine, milk, plasma On this basis, lignan metabolites quantified. To improve analysis sensitivity, pretreated acetonitrile containing 1% formic acid passed through HybridSPE-PL 55261-U column (Supelco, Bellefonte, PA). limit ranged 1.43 18.3 ng/mL plasma, 1.01 18.7 milk. linearity calibration curves at least 217 Regression coefficient above 0.99 for secoisolariciresinol, ED, EL, ED-S, EL-S, indicating satisfactory relationships between peak areas range. relative ED-glucuronide EL-glucuronide (EL-G) different compared based on chromatogram areas. contained all forms (i.e., ED-glucuronide, EL-G.); EL-S; EL-G. Milk-to-plasma concentration ratios indicated that free more permeable than sulfated conjugates. found provide benefits sheep-product analytical established work could be products.