Anthocyanins spectroscopy

Giusti, M.M. and Wrolstad, R.E., Characterization and measurement of anthocyanins by UV-visible spectroscopy, in Handbook of Food Analytical Chemistry Pigments, Colorants, Flavors, Texture, and Bioactive Food Components, Wrolstad, R.E. et al., Eds., John Wiley Sons, New York, 2005, 19. 

McGhie, T.K., Rowan, D.R., and Edwards, P.J., Structural identification of two major anthocyanin components of boysenberry by NMR spectroscopy, J. Agric. Food Chem., 54, 8756, 2006. 

Giusti, M.M. et al.. Electrospray and tandem mass spectroscopy as tools for anthocyanin characterization, J. Agric. Food Chem., Al, 4657, 1999. 

Many techniques for the analysis of anthocyanins have been used for almost a century and are still of importance, along with considerable advances in technologies such as mass spectroscopy (MS) and nuclear magnetic resonance (NMR). This section summarizes the analytical procedures for quantitative and qualitative analyses of anthocyanins, including classical and modem techniques. 

Many methods are currently available for the qualitative analysis of anthocyanins including hydrolysis procedures," evaluation of spectral characteristics, mass spectroscopy (MS), " nuclear magnetic resonance (NMR), and Fourier transform infrared (FTIR) spectroscopy. - Frequently a multi-step procedure will be used for... 

NMR spectroscopy is the most powerful method for structural elucidation in solution and advances in NMR techniques have made significant impacts on anthocyanin studies. Complete structural characterization of anthocyanins is possible with one- and two-dimensional NMR techniques. However, relatively large quantities of... 

Many recent stndies of NMR spectroscopy have been reported for structure elucidation of anthocyanins from many plant materials such as carrot, tart berries, boysenberries, " flowers, black soybeans, and anthocyanin and flavonol derivatives in red wine. Ginsti et al. (1998) structurally elucidated two novel diacylated anthocyanins and two monoacylated anthocyanins from radish Raphanus sativus) by one- and two-dimensional NMR. Anderson et al. (2006) applied two-dimensional NMR to characterize carboxypyranoanthocyanins. Two 3-deoxyantho-cyanins, lnteolinidin-5-glncoside, and apigeninidin-5-glucoside were identified by Swinny et al. nsing H and C NMR. 

To detect adulteration of wine. Bums et al. (2002) found that the ratios of acetylated to p-coumaroylated conjugates of nine characteristic anthocyanins served as useful parameters to determine grape cultivars for a type of wine. Our laboratory utilized mid-infrared spectroscopy combined with multivariate analysis to provide spectral signature profiles that allowed the chemically based classification of antho-cyanin-containing fruits juices and produced distinctive and reproducible chemical fingerprints, making it possible to discriminate different juices. " This new application of ATR-FTIR to detect adulteration in anthocyanin-containing juices and foods may be an effective and efficient method for manufacturers to assure product quality and authenticity. 

Goto, T., Takase, S., and Kondo, T., PMR spectra of natural acylated anthocyanins determination of stereostructure of awobanin, shisonin and violanin (Commelina communis, Viola tricolor, Perilla orimoides). Tetrahedron Lett, 27, 2413, 1978. Agrawal, P.K., NMR spectroscopy in the structural elucidation of ohgosaccharides and glycosides, Phytochemistry, 31, 3307, 1992. 

Keepers, J.W. and James, T.L., A theoretical smdy of distance determinations from NMR two-dimensional nuclear Overhauser effect spectra, J. Mag. Resort, 57, 404, 1984. Kemp, W., Organic Spectroscopy, 3rd ed., W.H. Ereeman, New York, 1991. Figueiredo, P. et al., New aspects of anthocyanin complexation intramolecular copigmentation as a means for colour loss Phytochemistry, 41, 301, 1996. 

The anthocyanin profile of the flowers of Vanda (Orchidaceae) was investigated with a similar technique. Flowers (2 kg) were extracted with 101 of methanol-acetic acid-water (9 l 10,v/v) at ambient temperature for 24 h. The extract was purified by column chromatography, paper chromatography, TLC and preparative RP-HPLC. Analytical HPLC was carried out in an ODS column (250 X 4.6 mm, i.d.) at 40°C. Gradient conditions were from 40 per cent to 85 per cent B in 30 min (solvent A 1.5 per cent H3P04 in water solvent B 1.5 per cent H3P04, 20 per cent acetic acid and 25 per cent ACN in water). The flow rate was 1 ml/min and analytes were detected at 530 nm. The chemical structures of acylated anthocyanins present in the flowers are compiled in Table 2.90. The relative concentrations of anthocyanins in the flower extracts are listed in Table 2.91. It can be concluded from the results that the complex separation and identification methods (TLC, HPLC, UV-vis and II NMR spectroscopy, FAB-MS) allow the separation, quantitative determination and identification of anthocyanins in orchid flowers [262],... 

NMR spectroscopy has been used to study flavonoids only in a few cases. Natural abundance NMR spectra have been recorded for 11 methoxyflavones, and NMR data for some 3-arylidenechromanones and flavanones have recently been discussed in terms ofmesomeric and steric substituent interactions. NMR spectroscopy has also been used to study the effect of sugar on anthocyanin degradation and water mobility in a roselle anthocyanin model system. ... 

MS. This section will rather briefly concentrate on some of the more recent applications of UV absorption spectroscopy in the flavonoid field. It will mainly cover online UV absorption spectroscopy in chromatography (Section 2.5.1). Because of the current importance of UV Vis in the study of anthocyanins, some more UV Vis spectral details have been included related to this pigment group (Section 2.5.2). Section 2.5.3 indicates the recent use of this technique in studies of flavonoids interacting with other compounds. 

Whittemore, N.A. et al., A quenched molecular dynamics-rotating frame Overhauser spectroscopy study of a series of semibiosynthetically monoacylated anthocyanins, J. Org. Chem., 69, 1663, 2004. 

Quagliano, L.G. et al., Raman study of anthocyanins as a function of the temperature. In Spectroscopy of Biological Molecules New Directions, 8th European Conference on the Spectroscopy of Biological Molecules, Enschede, Netherlands, 187, 1999. 

Four cyanidin 4 -glucosides have recently been isolated from pigmented scales of red onion. These structures were established by extensive use of 2D NMR spectroscopy and electrospray LC MS. The previous report on 4 -glucosyl linkages in two anthocyanins from... 

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