Chemistry of Flavonoids in Color Development

Evaluation of cowpea mini core accessions for resistance to flower bud thrips Megalurothrips sjostedti Trybom (Thysanoptera: Thripidae)

“…According to Asante, Tamo, and Jackai (), early and late flowering are plant phenological traits that can allow cultivars to escape pest damage. The purple coloration of stem or pod shown in some cultivars might result in anthocyanin pigments or flavonoid content (Yoshida, Oyama, & Kondo, ) reported to confer antibiosis resistance to insect pests (Dabire‐Binso, Ba, Sanon, Drabo, & Bi, ; Lattanzio, Arpaia, Cardinali, Venere, & Linsalata, ). Further studies are necessary to confirm the exact mechanism present in each of the identified resistant cowpea lines.…”

Quantum Chemical Investigation of the Intramolecular Copigmentation Complex of an Acylated Anthocyanin

“…10,[16][17][18][19][20][21][22][23] In the plant vacuoles where anthocyanins concentrate, [24][25][26] the anthocyanin cation AH + can chelate with metal cations 23,27 such as Al 3+ and/or form complexes with colorless organic copigment molecules, such as electron-rich derivatives of hydroxybenzoic or hydroxycinnamic acids, flavones or one of the colorless neutral forms of the anthocyanin itself. 10,[16][17][18][19][20][21][22][23] Metal cation chelation can lead to large changes in the color, primarily from red to blue as, for example, in Hydrangea, 28 but is limited to anthocyanins with two or more free OH groups in the B-ring 23,27,29 (i.e., anthocyanins derived from cyanidin, delphinidin and petunidin). In contrast, copigmentation via complexation with organic molecules results in much smaller red shifts of the absorption, but can increase the pH at which hydration occurs, consistent with steric hindrance to attack of water and charge transfer from the copigment to the anthocyanin as an important contributor to the stability of the anthocyanin-copigment complex.…”

“…In contrast, copigmentation via complexation with organic molecules results in much smaller red shifts of the absorption, but can increase the pH at which hydration occurs, consistent with steric hindrance to attack of water and charge transfer from the copigment to the anthocyanin as an important contributor to the stability of the anthocyanin-copigment complex. 10,[16][17][18][19][20][21][22][23] One limitation of this bimolecular copigmentation is the range of stability constants for the complexation, 21,23 which rarely exceed 10 4 M -1 , requiring mM or greater local copigment concentrations in order to achieve a substantial percentage of complexation of the anthocyanin. Some plants have overcome the entropic limitations of bimolecular copigmentation by covalently attaching one or more copigment molecules to the sugar residues of the anthocyanin (e.g., acyl ester derivatives), [18][19][20]22,23 transforming the copigmentation into an entropically much more favorable intramolecular complexation phenomenon.…”

Simulating Absorption Spectra of Flavonoids in Aqueous Solution: A Polarizable QM/MM Study

“…In addition to their therapeutic usages, flavonoids play a crucial biological activities in plants and animals [ 12 , 13 , 14 , 15 , 16 ]. In plants, flavonoids are responsible for the colour and aroma of flowers and fruits [ 17 , 18 , 19 , 20 ]. One of the most relevant examples is given by wine, and in particular red wine, in which flavonoids provide organoleptic and disease prevention properties [ 21 , 22 , 23 , 24 , 25 , 26 ].…”