Cis–Trans Configuration of Coumaric Acid Acylation Affects the Spectral and Colorimetric Properties of Anthocyanins

Abstract

The color expression of anthocyanins can be affected by a variety of environmental factors and structural characteristics. Anthocyanin acylation (type and number of acids) is known to be key, but the influence of acyl isomers (with unique stereochemistries) remains to be explored. The objective of this study was to investigate the effects of cis–trans configuration of the acylating group on the spectral and colorimetric properties of anthocyanins. Petunidin-3-rutinoside-5-glucoside (Pt-3-rut-5-glu) and Delphinidin-3-rutinoside-5-glucoside (Dp-3-rut-5-glu) and their cis and trans coumaroylated derivatives were isolated from black goji and eggplant, diluted in pH 1–9 buffers, and analyzed spectrophotometrically (380–700 nm) and colorimetrically (CIELAB) during 72 h of storage (25 °C, dark). The stereochemistry of the acylating group strongly impacted the spectra, color, and stability of the Dp and Pt anthocyanins. Cis acylated pigments exhibited the greatest λmax in all pH, as much as 66 nm greater than their trans counterparts, showing bluer hues. Cis acylation seemed to reduce hydration across pH, increasing color intensity, while trans acylation generally improved color retention over time. Dp-3-cis-p-cou-rut-5-glu exhibited blue hues even in pH 5 (C*ab = 10, hab = 256°) where anthocyanins are typically colorless. Cis or trans double bond configurations of the acylating group affected anthocyanin spectral and stability properties.

Geroprotective effects ofAronia melanocarpafruit extract onDrosophila melanogaster

“…The chromatogram (Fig 1) shows the main jumps: at 10.54 min - delphinidin (Glu), 13.38 min - delphinidin (Rut), 16.64 min - cyanidin (Glu), which indicates that these substances are the main ones in the analyzed extract. Delphinidin and cyanidin are anthocyanidins, they are found in many bright blue-red fruits and berries, such as Manitoba berries, Saskatoon berry (Hosseinian and Beta 2007), eggplant (Sigurdson et al 2018), more delphinidin will be collected. Cyanidin is the most common in raspberries, strawberries (Hosseinian and Beta 2007), and black chokeberry (Jurikova et al 2017), sour cherry (Ertan et al 2018) in apple skin (Ban et al 2009), acai (Yamaguchi et al 2015).…”

Coloration of Flowers by Flavonoids and Consequences of pH Dependent Absorption

“…This conforms to the general characteristic of flavylium compounds, where the distinctly absorbing cation converts into colorless hemiketal and cis - and trans -chalcone forms ( Mazza and Brouillard, 1990 ; Pina et al, 2012 ). At higher pH various anionic quinonoidal bases are created ( Mazza and Brouillard, 1990 ; Pina et al, 2012 ; Rakić et al, 2015 ; Dangles and Fenger, 2018 ; Sigurdson et al, 2018 ), which process can be approximated with a two-component logistic function. The differences in the absorbance spectra of Figures 2 , 3 in the long-wavelength range suggest that the absorption spectra of the quinonoidal bases depend on being cyanidin- or pelargonidin-based derivatives.…”

Metal Chelates of Petunidin Derivatives Exhibit Enhanced Color and Stability

“…Our previous study showed that the petunidin-3-trans-p-coumaroyl-rutinoside-5-glucoside isolate contributed most of the color expression of the black goji extract. It also showed superior stability compared to crude extracts over time [24,25].…”