A Peculiar Yellow Flower Coloration of Camellia Using Aluminum-flavonoid Interaction

Abstract

The yellow coloration mechanism of Camellia chrysantha flowers has been a mystery because the pigments which produce their deep yellow color could not be found in the flower. We sought to solve the mystery regarding the characteristic accumulation of aluminum ions by camellia plants. Deep yellow C. chrysantha flowers contained aluminum ions at three times the concentration found in pale yellow flowers. Three quercetin derivatives, 3-rutinoside, 3-glucoside, and 7-glucoside, were identified as major flavonoids in both flowers. There were no significant differences in their flavonoid content or pH, which was 5.8. The deep yellow flowers of C. chrysantha contained flavonoids and aluminum ions in a ratio of 1 to 0.5. When quercetin 3-rutinoside solution, which was originally almost colorless and had an absorption maximum around 350 nm at pH 5.8, was prepared with an aluminum ion concentration similar to the endogenous ratio, the solution developed a deep yellow color. This mixture also had an absorption spectrum like that of C. chrysantha petals, which had an absorption maximum around 420 nm. After removing the cations using an ion exchange column, the yellow coloration of the C. chrysantha petal extract changed to a paler color; the coloration was restored by the addition of aluminum ions. We concluded that the deep yellow color of the C. chrysantha flower is generated by the chelation of aluminum ions by quercetin derivatives, which is a unique yellow 'dyeing' system of these flowers.

Effect of Various Herbal Medicine Extracts on the Physico-chemical Properties of Emulsion-type Pork Sausage

“…Green tea extract has been found to contain many polyphenolic flavonoids [43], and this was further confirmed by Bozkurt [44]. Herbal medicine extracts also contain many flavonoids, including catechin hydrate, gallocatechin, epicatechin, and epigallocatechin, which contribute to the yellow coloration of the plants [35,36,45,46]. Therefore, this was considered to contribute to the increase in yellowness as well as chroma and hue values in the emulsion-type pork sausage, while the redness was decreased.…”

Biosynthesis and regulation of flavonoids in buckwheat

“…Unlike other crops, buckwheat is resistant to aluminum: it takes up aluminum in the roots and transfers it to leaves and stems where it accumulates in vacuoles (Ma et al 1997). Aluminum can bind with flavonoids, including flavonols, altering flower color (Tanikawa et al 2008). Because there is no report of the relationship between the movement of flavonols and aluminum, further study is desirable.…”

Aluminum Ions Are Involved in Purple Flower Coloration in <i>Camellia japonica</i> ‘Sennen-fujimurasaki’

“…Camellia japonica also accumulates Al (Yamada, 1980). Previously, we showed that the deep yellow flower color of C. chrysantha (Hu) Tuyama is generated by chelation of Al ions by quercetin derivatives, which are naturally pale yellow flavonols (Tanikawa et al, 2008). Thus, we hypothesized that Al ions may be involved in developing the purple color of C. japonica flowers.…”

“…We have reported that chelation of Al ions with flavonols causes a deep yellow coloration of flowers in another camellia species, C. chrysantha (Tanikawa et al, 2008). Both anthocyanins and flavonols are types of flavonoids.…”