A new analytical method for the simultaneous quantification of isoflavones and lignans in 25 green coffee samples by HPLC-MS/MS

Green coffee, the raw material of roasted coffee and coffee beverages, is one of the most widely traded cornmodifies worldwide. There is a dearth of studies on its content in phytoestrogens such as isoflavones and lignans. Previously, we developed an efficient method for the simultaneous quantification of 6 isoflavones (daidzin, genistin, daidzein, genistein, formononetin and biochanin A) and 3 lignans (secoisolariciresinol, matairesinol and lariciresinol) in green coffee by using HPLC-MS/MS. Several extraction processes were evaluated and the best performing, base hydrolysis followed by enzymatic digestion, was validated and used to analyse 25 different coffee samples, 1 Coffea canephora and 24 Coffea arabica, from different countries. Lignans (total content 286.5-8131.8 mu g kg(-1)) were found in higher concentration than isoflavones (total content 3.4-300.0 mu g kg(-1)) and the most abundant were secoisolariciresinol (172.6-5714.1 mu g kg(-1)) and lariciresinol (113.9-2417.7 mu g kg(-1)). Notably, the Ethiopian coffee samples contained the highest levels of these compounds.