Formation of β‐carbolines from 1‐[(1′ ‐carboxy‐2′‐indol‐3′‐yl‐ethyl)amino]‐1‐deoxy‐D‐fructose under electron impact conditions

Abstract

AbstractInterest in β‐carbolines has recently increased owing to their detection in human tissue and in some food products; one of the possible sources of their formation in food is the Amadori rearrangement product (ARP) of tryptophan with glucose, l‐[(1′‐carboxy‐2′‐indol‐3′‐ylethyl)amino] ‐1‐deoxy‐D‐fructose. Based on the intermediates identified in the high‐resolution electron impact spectrum of the tryptophan Amadori product and by B/E and B2/E linked‐scan experiments, a mechanism is proposed for their formation under electron impact conditions. The proposed mechanism is an intramolecular nucleophilic substitution reaction of the dehydrated tryptophan ARP, leading to the formation of 3‐substituted β‐carbolines; this mechanism might shed some light on the origin of their abundant formation in food.