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 ± 0.8 lg/g dry weight (DW), 10.5 ± 0.6 lg/g DW) and also in roasted
beans of C. canephora (8.0 ± 0.9 lg/g DW, 7.3 ± 0.5 lg/g DW). Melatonin
(3.0 ± 0.6 lg/50 mL) and 5-HT (4.0 ± 0.7 lg/50 mL) were detected in
coffee brew. In C. arabica, 5-HT was high in green beans (12.5 ± 0.8 lg/g
DW) compared with roasted beans (8.7 ± 0.4). The levels of melatonin were
higher (9.6 ± 0.8 lg/g DW) in roasted beans compared with green beans
(6.8 ± 0.4 lg/g DW). Both melatonin (3.9 ± 0.2 lg/50 mL) and 5-HT
(7.3 ± 0.6 lg/50 mL) 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.