Profiling and quantification of regioisomeric caffeoyl glucoses in Solanaceae vegetables.

Based on the recently developed tandem MS based hierarchical scheme for the identification of regioisomeric caffeoyl glucoses, selected vegetables were profiled with respect to their caffeoyl glucose content. The dietary plants profiled were tomato, pepper, chilli and aubergine, all members of the Solanaceae family. 6-O-caffeoyl glucose was found to be the predominant isomer. In processed food such as tomato puree and ketchup a larger number of caffeoyl-glucose isomers formed through acyl migration reactions were observed. A LC-MS based quantitative method was developed, validated and caffeoyl glucose regioisomers quantified for the first time in dietary plants with quantitative data obtained from representative 30 food samples.