ABSTRACT
NMR, MS and analytical data are cited in support of the newly defined complete structures of the major flavonoid pigments and copigments in lisianthus flowers. The copigments newly characterized and found in flowers of all colours are kaempferol-3-O-beta-D-[6-O-rhamnopyranosyl-4-O-E-p- coumaroylgalactopyranoside]-7-O-alpha-L-rhamnopyranoside, its Z-isomer and by analogy, the lesser isorhamnetin and myricetin equivalents. Purple flower pigments with newly defined structures are: delphinidin-3-O-beta-D-[6-O-alpha- L-rhamnopyranosylgalactopyranoside] 5-O-beta-D-[6-E-p- coumaroylglucopyranoside], its Z-isomer, and by analogy the lesser cyanidin equivalent, together with delphinidin-3-O-beta-D-galactopyranoside-5-O-beta-D-[6-E-p- coumaroylglucopyranoside], its Z-isomer, and by analogy the lesser cyanidin equivalent. Different pigment/copigment compositions are shown to account for the basic colour differences between white, cream, pink, mauve and purple flowers, but other factors involved in stabilizing and fine-tuning the colours are pigment concentration, copigmentation and pH control.
