title: Development and Optimization of an UPLC-QTOF-MS/MS Method Based on an In-Source Collision Induced Dissociation Approach for Comprehensive Discrimination of Chlorogenic Acids Isomers from Momordica Plant Species.
abstract: Chlorogenic acids (CGA) have been profiled in the leaves of Momordica balsamina, Momordica charantia, and Momordica foetida. All three species were found to contain the trans and cis isomers of 4-acyl para-coumaroylquinic acid (pCoQA), caffeoylquinic acid (CQA), and feruloylquinic acid (FQA). To the best of our knowledge, this is the first report of pCoQA and FQA and their cis isomers in these Momordica species. These profiles were obtained by a newly developed UPLC-qTOF-MS method based on the in-source collision induced dissociation (ISCID) method optimized to mimic the MS(2) and MS(3) fragmentation of an ion trap-based MS. The presence of the cis isomers is believed to be due to high UV exposure of these plants. Furthermore, the absence of the 3-acyl and 5-acyl CGA molecules points to a metabolic mark that is unusual and represents a very interesting biochemical phenotype of these species. Our optimized ISCID method was also shown to be able to distinguish between the geometrical isomers of all three forms of CGA, a phenomenon previously deemed impossible with other common mass spectrometry systems used for CGA analyses.
authors.affiliation: Department of Biochemistry, University of Johannesburg, P.O. Box 524, Auckland Park 2006, South Africa.
authors.forename: N E
authors.initials: NE
authors.lastname: Madala
authors.affiliation: Department of Biochemistry, University of Johannesburg, P.O. Box 524, Auckland Park 2006, South Africa.
authors.forename: F
authors.initials: F
authors.lastname: Tugizimana
authors.affiliation: Department of Biochemistry, University of Johannesburg, P.O. Box 524, Auckland Park 2006, South Africa ; CSIR Biosciences, Natural Products and Agroprocessing Group, Pretoria 0001, South Africa.
authors.forename: P A
authors.initials: PA
authors.lastname: Steenkamp