K.Yu. Kalinichenko, Ya.F. Kopytko, T.A. Sokolskaya, E.A. Timochina

Studied quantitative and qualitative composition of free and bound amino acids juice obtained from fresh leaves of burdock (Arctium lappa L.), Asteraceae. The analysis was performed by HPLC with ninhydrin post column derivatisation and VIS detection on the amino acid analyzer «Biotronik LC-2000» (Germany) equipped with analytical column (size 0,622 cm) filled with cation exchange resin «Durrum DC  4A». In the juice of burdock identified 15 amino acids. In significant quantities found asparaginic acid (10.26 and 20.9 mg before and after hydrolysis respectively), proline (9.12 and 13.3 mg), leucine (8.36 and 15.2), and alanine and lysine , the contents of the latter after acid hydrolysis is increased by more than five times and reached 30.4 mg. Glycine, histidine and arginine were found in relatively small quantities. Half-cystine and methionine in the juice of burdock are not found. The amount of free amino acids in the samples of juice are 71.25 mg, bound amino acids  177.08 mg. Values of amino acid content before and after hydrolysis differ by almost 2.5 times, indicating that the amino acid in the juice of burdock contained mainly in bound form, in the form of peptides. Thus, it was found that the juice of burdock contains a large number of amino acids that can cause its pharmacological effect.