10 research outputs found
Enantioseparation and quantitative determination of two homologous beta amino acids found in Fabaceae plants
Non-protein amino acids are important metabolites of the Fabaceae family, possessing valuable biological effects in addition to their toxic properties. We have previously identified two non-protein amino
acids homoproline and homopipecolic acid in Ononis species for the first time, and herein the study
was extended to investigate further Fabaceae species (O. spinosa, O. arvensis, M. sativa, A. vulneraria) with
medicinal, food or cosmetic uses. As the enantiomers of these beta amino acids can carry different activity or toxicity, our aim was to develop a chiral separation method for homoproline and homopipecolic
acid enantiomers and apply it to plant samples. For this purpose, dansylated derivatives were prepared
and a cyclodextrin-modified capillary electrophoresis in addition to a chiral HPLC method were developed. Although baseline separation was achieved by CE applying mono-(6-N-pyrrolidine-6-deoxy)-β-CD,
mono-(6-N-piperidine-6-deoxy)-β-CD or sulfated-gamma-cyclodextrin at pH 6.0, the HPLC method was
found to be more suitable for the analysis of the plant samples. Both homoproline and homopipecolic
acid were confirmed in plant samples as racemates. The quantitative determination of homoproline and
homopipecolic acid in several Fabaceae species were also aimed. Since these molecules can be found
in the plants as esters, sample preparation was optimized to liberate the target molecules. Several SPE
methods were tested for sample purification and a HPLC-MS/MS method using C8 stationary phase was
developed and validated. The presence of homoproline and homopipecolic acid could be confirmed in all
species ranging from 1 ÎĽg/g through 500 ÎĽg/g homopipecolic acid and 6 ÎĽg/g to 60 ÎĽg/g homoproline and
significant changes could be observed between species, geographical origins, and botanical parts. Generally O. spinosa root samples were found to be the richest sources of the two amino acids, but a high
variance could be observed between species