Development of a solid-supported cysteinyl probe for the isolation of electrophiles from plant pollen extracts

Recent research showed that plant secondary metabolites in pollen may exacerbate the protein-mediated allergic reaction in pollen allergy. It was found that allergenic pollen from various plant families contain significant amounts of electrophiles which may covalently bind to nucleophilic groups of proteins, such as thiol moieties. Electrophiles in pollen of the Asteraceae species are typically sesquiterpene lactones, but the nature of electrophilic metabolites in allergenic pollen of other plant families is unknown. We developed a solid-supported cysteinyl probe in order to selectively extract physiologically relevant electrophiles from pollen extracts, and to enable their subsequent characterization by on-line and off-line spectroscopic analysis. The validity of this approach was evaluated with a selection of structurally different model compounds and with a spiked model extract.