BETACYANINS FROM FLOWERS OF GOMPHRENA-GLOBOSA

The betacyanins gomphrenin I (betanidin 6-O-beta-glucoside) and its acylated forms gomphrenin II (betanidin 6-O-[6'-O-(E-4-coumaroyl)-beta-glucoside]) and gomphrenin III (betanidin 6-O-[6'-O-E-feruloyl-beta-glucoside]) were isolated from flowers of Gomphrena globosa and their structures elucidated by NMR spectroscopy and ion spray mass spectrometry by comparison with betanin (betanidin 5-O-beta-glucoside) and its feruloyl conjugate lampranthin II (betanidin 5-O-[6'-O-E-feruloyl-beta-glucoside]), which were isolated from Beta vulgaris roots and B. vulgaris cell suspension cultures, respectively. The application of this new mass spectrometric technique to this type of compound is discussed. Unusual H-1 chemical shift differences between gomphrenin I and gomphrenins II and III suggest intramolecular stacking occurring in the latter two compounds.