Flower Colors and their Anthocyanins in Matthiola incana Cultivars (Brassicaceae)

The flower colors and anthocyanin constitution of eight cultivars of Vintage series bedding Stock (Matthiola incana) were surveyed to determine the relation between their flower colors and anthocyanin components. Thirteen anthocyanins were isolated from the flowers of these cultivars as major anthocyanins, and their structures were identified by chemical and spectroscopic techniques. Among them, a novel anthocyanin, cyanidin 3-caffeoyl-sambubioside-5-malonyl-glucoside (pigment 1) was found in single and double flowers in cultivars of 'Vintage Lavender' and 'Vintage Burgundy'. Furthermore, two anthocyanins, cyanidin 3-p-coumaroyl-sambubioside-5-malonyl-glucoside (pigment 2) and cyanidin 3-feruloyl-sambubioside-5-malonyl-glucoside (pigment 3), were also found in these cultivars for the first time in Matthiola incana flowers. Regarding the flower color variation in these cultivars, the hue values (b(star)/a(star)) of these flower colors were roughly responsible for the numbers of hydroxycinnamic acid residues in anthocyanin molecules and also hydroxyl patterns of the B-ring in anthocyanidins. These flower colors were classified into eight groups, based on the hue values of their flowers, and were arranged as follows. In violet flowers (hue values b(star)/a(star)=-0.66 and -0.69, V 84A) of group A, cyanidin 3-dihydroxycinnamoyl-sambubioside-5-malonyl-glucosides were major anthocyanin pigments. In purple flowers (-0.43 and -0.45, P 75A) and red-purple flowers (-0.14 and -0.16, RP 74A) of groups B and D, pelargonidin 3-dihydroxycinnamoyl-sambubioside-5-malonyl-glucosides were major anthocyanin pigments. In red-purple flowers (-0.21 and -0.24, RP 72A) of group C, cyanidin 3-monohydroxycinnamoyl-sambubioside-5-malonyl-glucosides were major anthocyanin pigments. In red flowers (0.05 and 0.06, RP 66A) of group E, pelargonidin 3-monohydroxycinnamoyl-sambubioside-5-malonyl-glucosides were major anthocyanin pigments. In copper (0.23 and 0.16, R 54A) and peach (2.37 and 2.09, R38C) of groups F and G, pelargonidin 3-glucoside was a major anthocyanin pigment, and a small amount of pelargonidin 3-glucoside was present in yellow flowers of group H. From these results, the relation between flower colors and the bluing effects of acylated anthocyanins with hydroxycinnamic acids was discussed in flowers of Matthiola incana cultivars of Vintage series.