Betaxanthin pattern of hairy roots from Beta vulgaris var lutea and its alteration by feeding of amino acids

Betaxanthins from hairy root cultures of Bera vulgaris var. lutea showed two predominating substances, portulaxanthin II and vulgaxanthin I, and several minor components in HPLC profiles. The presence of muscaaurin VII, indicaxanthin, dopaxanthin, vulgaxanthin II, III and IV were suggested, the latter two as new natural compounds. Administration of nine L-amino acids to individual hairy root strains led to an increase in concentration or the appearance of one betaxanthin in each case. These betaxanthins structurally corresponded to the substances applied, except of that from glutamic acid. It was vulgaxanthin I instead of vulgaxanthin II and might be formed due to the function of glutamine synthetase. Also, the D-isomers of amino acids were incorporated into corresponding betaxanthins not only by hairy root cultures but also by seedlings of B. vulgaris var. lutea. The feeding experiments substantiate arguments for a spontaneous condensation of betalamic acid with an amino acid or amine in the course of betaxanthin biosynthesis. Copyright (C) 1997 Elsevier Science Ltd.