Floral Pigments from the Blue Flowers of Nemophila menziesii ‘Insignis Blue’ and the Purple Flower of Its Variants

Abstract

Two anthocyanins (pigments 1 and 2) were detected from the blue flowers of Nemophila menziesii ‘Insignis blue’ and the purple flowers of its variants as the main floral anthocyanins. These two anthocyanins were isolated from the blue flowers and elucidated to be petunidin 3- O -[6- O -( cis - p -coumaroyl)- b -glucopyranoside]-5- O -[6- O -(malonyl)- b -glucopyranoside] (1) and petunidin 3- O -[6- O -( trans - p -coumaroyl)- b -glucopyranoside]-5-O -[6- O -(malonyl)- b -glucopyranoside] (2), respectively, by chemical and spectroscopic means, and pigment 1 was confirmed as a new anthocyanin in plants. Two flavonol glycosides (pigments 3 and 5) and two flavone glycosides (pigments 4 and 6) were also isolated from the blue flowers, and were identified to be kaempferol 3-(6-rhamnosyl)-glucoside-7-glucoside (3), apigenin 7,4′-di-glucoside (4), kaempferol 3-(2,6-di-rhamnosyl)-glucoside (5), and apigenin 7-glucoside-4′-(6-malonyl)-glucoside (6) as major flavonoids. Among these four flavonoids, however, pigments 4 and 6 (flavones) were not detected in the purple flowers. These results might be attributed to color production in blue and purple flowers.