Development of a new extraction method for the quantification of lignans in espresso and roasted and ground coffee by HPLC-MS/MS triple quadrupole

From biological point of view, lignans are interesting antioxidant compounds. They are part of phytoestrogens, natural molecules of plant origins, characterized by oestrogenic and anti-oestrogenic activities [1]. The analytical methods for lignan analysis change depending on different matrix and monitored compounds. Most used long purification, clean-up or derivatization steps [2]. Our goal was to develop an analytical method to quantify three lignans, i.e., secoisolariciresinol (SECO), lariciresinol (LARI) and matairesinol (MAT) in espresso (EC) and roasted and ground (R&G) coffee, avoiding long preparation and extraction processes. High performance liquid chromatography-mass spectrometry/mass spectrometry (HPLC-MS/MS) equipped with electrospray ionization (ESI) source was chosen as analytical instrument. Different hydrolytic and extraction processes, including acidic hydrolysis, enzymatic digestions and organic solvent extractions have been evaluated in liquid matrix (EC) and in solid matrix (R&G coffee). The most performing extraction process in EC and in R&G coffee were chosen, and once validated, applied to several 100% Coffea arabica ECs and different roasted and ground coffee samples. SECO (from 27.9 to 52.0 µg l-1 in EC; from 84.4 to 257.8 µg Kg-1 in ground coffee) and LARI (from 5.3 to 27.8 µg l-1 in EC; from 26.1 to 86.2 µg Kg-1 in ground coffee) were found in all coffee samples. Regular consumption of coffee can contribute to dietary lignan intakes. References [1] Landete JM. Plant and mammalian lignans: a review of source, intake, metabolism, intestinal bacteria and health. Food Res Int. 2012;46:410-424. [2] Willför SM, Smeds A I, Holmbom BR. Chromatographic analysis of lignans. J Chromatogr. A. 2006;1112:64-77.