DNA triplex stabilization property of natural anthocyanins

The DNA tripler stabilization property of seven natural anthocyanins (five monoglucosides and two diglucosides) has been measured by the mean of tripler thermal denaturation experiments. We have noticed a difference between the diglucosides that do not modify this melting temperature and the monoglucosides (namely 3-O-beta-D-glucopyranoside of malvidin, peonidin, delphinidin, petunidin and cyanidin) which present a weak but significant stabilizing effect. It appears clearly that the difference between the two series could be due to the supplementary sugar moiety at the 5 position for the diglucosylated compounds, that would make them too crowded to allow interaction with the tripler. Among the monuglucoside series, the most active compounds are the only ones to embody a catechol B-ring in their structure that could be important for such an interaction. The need to have pure and fully characterized compounds to run these measurements, made it possible for us to unambiguously assign the H-1 and C-13 NMR spectra with the help of 2D NMR experiments. Thus, missing data of compounds not totally described earlier, are provided herein. (C) 2000 Elsevier Science Ltd. All rights reserved.