80(P2-10) 複雑な天然アントシアニンの構造研究(ポスター発表の部)  [in Japanese] 80(P2-10) STUDIES ON THE STRUCTURE OF COMPLEX NATURAL ANTHOCYANINS  [in Japanese]

Simple anthocyanins are unstable in dilute aqueous solutions around pH 4-7, but some highly acylated anthocyanins were found to be stable in such solutions. Structures of several highly acylated anthocyanins such as gentiodelphin from Gentiana makinoi, platyconin from Platycodon grandiflorum, cinerarin from Cenecio cruentus, heavenly blue anthocyanin (HBA) from Ipomoea tricolor, zebrinin from Zebrina pendula, lobelinins from Lobelia erinus, ternatins from Clitoria ternatea, etc. have been elucidated mainly by means of ^1H NMR including the NOE relief method. Stability of the anthocyanins has been assumed to come from intramolecular sandwichtype stacking of anthocyanidin nucleus and two aromatic acyl moieties. Recently, we have succeeded in obtaining ^1H NMR spectra of the anhydrobase form of some of the complex anthocyanins in a neutral solution, which enabled us to support the stacking.