UHPLC-MS/MS quantification of atractyligenin glycosides in Arabica coffee and coffee brew

Analytically tangible dietary biomarkers for monitoring subjects and compliance control are essential to reduce the bias arising from the subjects' self-reported dietary patterns in interventional nutritional studies and cross-sectional studies aimed at unraveling coffee's impact on health. Atractyligenin (1) and its glycosides 2-O-β-D-glucosylatractyligenin (2), 2′-O-isovaleryl-2-O-β-D-glucosylatractyligenin (3) and 3′-O-β-D-glucosyl-2′-O-isovaleryl-2-O-β-D-glucosylatractyligenin (4) represent an coffee-specific compound class with substantial abundance in Coffea arabica and have been discussed as biomarker candidates for coffee consumption. Compounds 2 – 4 were isolated from roasted coffee or synthesized from commercially available precursors as references to establish a UHPLC-MS/MS method and a sample preparation protocol based on hot water extraction for quantification in roasted coffee powder and brew. Coffee powders contained a total of 2.2 – 4.1 µmol/g atractyligenin derivatives with 2 (46.8 – 63.6 %) and 4 (18.9 – 35.7 %) as the major constituents and 1 (5.5 – 14.8 %) and 3 (6.0 – 12.1 %) as minor constituents. Assessment of extraction rates into the brew was confirmed to be nearly quantitative (79.1 – 98.3 %) in Espresso brew, Turkish coffee brew, French Press, and cold brew. The developed method enables the straightforward and robust quantification of atractyligenin derivatives in roasted coffee to quantitatively assess dietary exposure and support nutritional studies on coffee's impact on health.