Melatonin and serotonin profiles in beans of Coffea species

A high-performance liquid chromatography (HPLC) and an electrospray ionization mass spectrometry (LC/ESI-MS) methods were applied to quantify the profiles of melatonin and serotonin (5-HT) in green and roasted beans of Coffea canephora (robusta) and Coffea arabica (arabica). Both melatonin and 5-HT were detected in green coffee beans (5.8±0.8μg/g dry weight (DW), 10.5±0.6μg/g DW) and also in roasted beans of C. canephora (8.0±0.9μg/g DW, 7.3±0.5μg/g DW). Melatonin (3.0±0.6μg/50mL) and 5-HT (4.0±0.7μg/50mL) were detected in coffee brew. In C. arabica, 5-HT was high in green beans (12.5±0.8μg/g DW) compared with roasted beans (8.7±0.4). The levels of melatonin were higher (9.6±0.8μg/g DW) in roasted beans compared with green beans (6.8±0.4μg/g DW). Both melatonin (3.9±0.2μg/50mL) and 5-HT (7.3±0.6μg/50mL) were detected in coffee brew. Because of the relevance of indoleamines as bioactive molecules with implications for food, nutritional sciences and human health, it was of interest to explore their levels in coffee, an important universal beverage.