Flavonol 3-O-Glycosides Series of Vitis vinifera Cv. Petit Verdot Red Wine Grapes

Abstract

Petit Verdot grape skins by solid-phase extraction using a combination of reverse-phase and ion-exchanging materials. This procedure allowed us to separate a fraction of anthocyanin-free flavonol 3-O-glycosides that was further split into neutral and acidic subfractions, thus facilitating flavonol identification. By means of semipreparative reverse-phase high-performance liquid chromatography, we isolated several of these flavonol 3-O-glycosides for structural elucidation. The identification of different flavonol 3-O-glycosides was based on liquid chromatography-diode array detection-electrospray ionization-tandem mass spectrometry and NMR data when available. The results suggest that red grape flavonol 3-O-glycosides comprise three different complete series, according to the nature of the sugar moiety linked to the C-3 position. The 3-O-glucosides were the main derivative of the six possible flavonol aglycones (kaempferol, quercetin, isorhamnetin, myricetin, laricitrin, and syringetin), whereas the 3-O-galactoside derivatives were found as minor compounds for all of the flavonol aglycones. The 3-O-glucuronides are the third kind of red grape flavonol derivatives and normally account as minor compounds for all of the flavonol aglycones, with the exception of quercetin 3-O-glucuronide, which was as abundant as quercetin 3-O-glucoside. In addition, the presence of quercetin 3-O-(6"-rhamnosyl)-glucoside (rutin) was also detected as a trace compound in the skins of Petit Verdot grapes.

Functional Differentiation of the Glycosyltransferases That Contribute to the Chemical Diversity of Bioactive Flavonol Glycosides in Grapevines (Vitis vinifera)

“…It must be noted that, for the 3-O-glucoside and the 3-O-galactoside of quercetin, only the sum of both stereoisomers was determined because our analytical systems could not separate these isomers in crude samples. Both isomers are present in the leaves and berry skins (exocarp) of grapevine and in red wines (Hmamouchi et al, 1996;Downey et al, 2007;Castillo-Munoz et al, 2009).…”

“…Dietary intake of grapevine-based products results in diverse biological effects that are beneficial to human health, in part due to polyphenols, such as flavonoids (e.g., flavonols, proanthocyanidins, and anthocyanins) (Renaud and de Lorgeril, 1992;Corder et al, 2001Corder et al, , 2006Baur et al, 2006). Flavonols, such as kaempferol, quercetin, and isorhamnetin, are an important class of bioactive flavonoids, which are most abundant as their 3-O-glycosides (i.e., glucoside, glucuronoside, galactoside, and rutinoside) in the berries, seeds, and leaves of grapevine (Hmamouchi et al, 1996;Castillo-Munoz et al, 2009).…”

“…Dietary intake of grapevine-based products results in diverse biological effects that are beneficial to human health, in part due to polyphenols, such as flavonoids (e.g., flavonols, proanthocyanidins, and anthocyanins) (Renaud and de Lorgeril, 1992;Corder et al, 2001Corder et al, , 2006Baur et al, 2006). Flavonols, such as kaempferol, quercetin, and isorhamnetin, are an important class of bioactive flavonoids, which are most abundant as their 3-O-glycosides (i.e., glucoside, glucuronoside, galactoside, and rutinoside) in the berries, seeds, and leaves of grapevine (Hmamouchi et al, 1996;Castillo-Munoz et al, 2009).In this plant, biosynthesis of flavonol glycosides primarily serves to protect the plant from excess UV light (Price et al, 1995;Matus et al, 2009). Flavonol aglycons are biosynthesized from dihydroflavonols by the action of flavonol synthase (Vv FLS), a 2-oxoglutarate-dependent dioxygenase, which is temporally regulated by an R2R3-Myb transcription factor, Vv MYBF1 (Fujita et al, 2006;Czemmel et al, 2009).…”

Effect of Oak Chip Addition at Different Winemaking Stages on Phenolic Composition of Moravia Agria Red Wines

“…The non-anthocyanin phenolic compounds (flavonols, hydroxycinnamic acids, flavan-3-ol monomers, and resveratrol-type stilbenes) were analysed by injection of the anthocyanin-free wine phenolic extracts, using the same chromatographic equipment and conditions previously described (Castillo-Muñoz et al, 2009). Quantification was done by extracting DAD chromatograms at 360 nm (flavonols), 320 nm (hydroxycinnamic acid derivatives and resveratrol-type stilbenes), and 280 nm (flavan-3-ol monomers).…”

“…All the aforementioned phenolic compounds were identified on the basis of their UV spectra and using standards that matched those previously identified by LC-MS using the same HPLC equipment and under the same chromatographic conditions (Castillo-Muñoz et al, 2009;Nixdorf & Hermosín-Gutiérrez, 2010). …”