New features of intramolecular copigmentation by acylated anthocyanins

Three series of structurally related anthocyanins, extracted from the red-p urple flowers of Dendrobium 'Pramot', xLaeliocattleya cv. Mini Purple, Blet illa striata and Phalaenopsis all belonging to the Orchidaceae family and a nother series extracted from the pink flowers of Senecio cruentus (Composit ae) allowed the confirmation of the existence of strong intramolecular copi gmentation effects. These interactions confer stability to the coloured for ms of the molecules, in a wide range of slightly acidic to neutral aqueous media. Moreover, the existence of structural relationships among the four s eries stressed the different influences exerted by the diverse substituent groups. The existence of a malonylglucoside attached to position 3 of all b ut three of the molecules put forward a new role for the malonyl residue, i n this particular position. (C) 1999 Published by Elsevier Science Ltd. All rights reserved.