Determination of the Amino Acid Pattern in Different Parts ofAllium sativumandAllium ursinumby RP-HPLC

Abstract

A number of GC and HPLC methods have been developed for the analysis of the more lipophilic compounds in garlic, whereas the determination of the genuine sulfur-containing and ubiquitous amino acids using HPLC has been neglected. By further developing the HPLC method of Ziegler (1), the amino acid patterns of Allium sativum L. and Allium ursinum L. leaves and bulbs will be presented. Freeze-dried plant material was extracted with 50% methanol followed by sample clean-up and pre-column derivatization. The obtained isoindole derivatives were separated using RP-HPLC employing two different isocratic mobile phases, optimized by means of the "PRISMA" model (2). For detection a fluorescence (Xex 230 nm, Xem 420 nm) and an amperometric detector (glassy-carbon electrode at a potential of 750 mV versus Ag/AgC1) were coupled. After testing of nineteen ubiquitous L-amino acids and eight L-cysteine derivatives, the identification of the extract constituents was performed on the basis of the ratio of their fluorescence and amperometric detector signals and their retention times.The identified amino acids and their semiquantitative determination will be presented.