Chromatograms catechin

Alkaloids produce variously colored chromatogram zones (yellow, pink, brown, purple) on a light background [2]. Indole and the catechins appear red [4, 5, 8, 9, 12, 16]. If the catechins are acetylated it is necessary to heat to 105 °C for 5 min after treatment with the reagent [8]. Lysergic acid derivatives should also be heated to 75 °C for 5 min. 

Note The reagent can also be applied by first treating the chromatogram with an unacidified solution of vanillin and then exposing it to hydrochloric acid vapor [3, 9], Catechin derivatives should be evaluated rapidly (within 10 min), since the red coloration is not stable in daylight and fades relatively quickly [5, 9]. 

Fig. 2.56. HPLC chromatogram of (a) Golden peel and (b) Golden pulp extracts at 280 nm. Peaks 1 = procyanidin B3 2 = procyanidin Bl 3 = ( + )-catechin 4 = procyanin B2 5 = chlorogenic acid 6 = ( — )-epicatechin 7 = caffeic acid 8 = phloretin derivative 9 = phloridzin 10 = rutin 11, 12 and 13 = flavonol glucosides. Reprinted with permission from A. Escarpa et al. [160].

Fig. 2.62. HPLC chromatogram of (a) jasmin (green) tea, (b) Fujian Oolong tea, (c) pu-erh tea and (d) black tea at 280 nm. Peak identification 1 = gallic acid (GA) 2 = (-)-epigallocatechin (EGC) 3 = (-)-epigallocatechin gallate (EGCG) 4 = epicatechin (EC) 5 = (-)-epicatechin gallate (ECG) 6 = caffeine (CA) 7 = ( — )-catechin gallate (CG). Reprinted with permission from Y. Zuo et al. [178].

Fig. 2.71. HPLC chromatogram of the neutral (a) and acidic fractions (b) and the acid-catalysed hydrolysed product of freshly squeezed cranberry juice (c) at 280 nnm. Peaks in a 1 = ( + )-cate-chin 2 = myicetin 3 = quercetin (added as internal standard). Peaks in b 1 = anthocyanin derivative I 2 = benzoic acid 3 = p-anisic acid 4 = quercetin (added as internal standard). Peaks in c 1 = ( + )-catechin 2 = anthocyanin derivative I 3 = anthocyanin derivative II 4 = benzoic acid 5 = anthocyanin derivative III 6 = p-anisic acid 7 = myricetin 8 = quercetin. Reprinted with permission from H. Chen et al. [188].

Another study employed a similar RP-HPLC method for the determination of trails- and d.v-rcsvcratrol, catechin, epicatechin, quercetin and rutin in wines and musts. Wine samples were filtered and diluted when necessary and used for analysis without any other pretreatment. Separation was performed in an ODS column (150 X 4 mm i.d. paricle size 5 71m) at ambient temperature. The gradient began with ACN-5 per cent aqueous acetic acid (9 91, v/v) for 0-10 min to 25 75 in 1 min hold for 11 min to 70 30 in 1 min, hold for 5 min. The flow rate was 1 ml/min. Analytes were detected by DAD. Fluorescence detection used 280/315 nm (excitation/emission) for catechin and epicatechin 314/370 nm for fims-resveratrol and 260/370 nm for d.v-rcsvcratrol. Chromatograms of a red wine sample obtained at different... 

Fig. 2.79. Chromatograms of a white (I) and red wine sample (II). (LC-DAD signals at three different wavelenghts 256, 324, 365 nm). Peak identification 1 = gallic acid 2 = protocatechuic acid 3 = p-hydroxybenzoic acid 4 = vanillic acid 5 = caffeic acid 6 = (+)-catechin 7 = syringic acid 8 = p-coumaric acid 9 = ( — )-epicatechin 10 = ferulic acid 11 = fraras-resveratrol 12 = rutin 13 = myricetin 14 = cw-resveratrol 15 = quercetin A = caftaric acid B = coutaric acid. Reprinted with permission from M. Castellari et al. [196],...

Fig. 2.82. Chromatograms for a red wine sample using gradient elution and photodiode array detection. Flow rate, lml/min. Peak identification 1 = catechin 2 = epicatechin 4 = irans-resveratrol 6 = quercetin. Reprinted with permission from P. Vinas et al. [198].

Fig. 2.114. RP-HPLC profiles of ACTs and SEC fractions (fr.) of ACTs. Each lyophilized sample was dissolved in water (1 mg/ml), and analysed by RP-HPLC. Upper chromatogram RP-HPLC profile of ACTs. Lower chromatograms with fraction numbers RP-HPLC profiles of SEC fractions of ACTs. The numbers of identified peaks in each chromatogram are (1) procyanidin B1 (PB1), (2) (+)-catechin, (3) procyanidin B2 (PB2), (4) procyanidin Cl (PCI), 5 (—)-epicatechin (EC). AU means relative absorbance units (at 280 nm). For details on the RP-HPLC conditions see text. Reprinted with permission from A. Yanagida et al. [253].

Fig. 2.115. Mass chromatograms of catechin monomers (m/z 289) and procyanidin oligomers (dimer through hexamers m/z 577 to 1729). C, ( + )-catechin, EC, ( — )-epicatechin, and PB2, procyanidin B2 as identified by the retention times of authentic standard. Reprinted with permission from J. Wollgast et al. [256].

Figure 11.3.2 HPLC chromatogram of neutral polyphenolics found in Niagara grapes detected at 280 nm. Retention time 8.599 min, procyanidin B3 9.781 min, procyanidin B1 13.409 min, catechin 16.138 min, procyanidin B2 20.781 min, epicatechin 22.281 min, catechin-catechin-gallate 23.925 min, catechin-catechin-gallate isomer 28.955 min, catechin-gallate. AU, absorbance units. Reproduced from Lee and Jaworski (1987) with permission from the American Society for Enology and Viticulture.

Example chromatograms are shown in Figures 11.4.3 and II. 4.4. Generally speaking, epi-catechin extension subunits are the most prevalent subunits found in plant tissues of interest as foodstuff. Some additional references are given at the end of this unit that provide information on the subunit composition of various plant species. 

Two predominant phenolic compounds (neochlorogenic and chlorogenic acids) in prunes and prune juice can be analyzed by reversed-phase HPLC with diode array detection along with other phenolic compounds (65). Phenolic compounds were extracted from prunes with methanol and aqueous 80% methanol and analyzed by HPLC. Ternary-gradient elution (a) 50 mM NaH4H2P04, pH 2.6, (b) 80% acetonitrile/20% (a), and (c) 200 mM phosphoric acid, pH 1.5, was employed for an 80-min run time. Four wavelengths were monitored for quantitation 280 nm for catechins and benzoic acids, 316 nm for hydroxycinnamates, 365 nm for flavonols, and 520 nm for anthocyanins. Phenolic analysis of pitted prune extract is presented in an HPLC chromatogram in Fig. 9, which is based on work done by Donovan and Waterhouse (65). 

Figure 3. Chromatograms top, catechin untreated bottom, catechin after acidification. Both samples were eluted in System I.

Figure 20-10. UV chromatogram of the on-flow experiment injecting a mixture of eight flavonoids (A catechin -i- epicatechin B flsetin C quercetin D apigeniu E narin-genin F baicalein G galangin). (Reprinted from reference 40, copyright 2003, with permission from Elsevier.)...

The on-flow experiment was carried out on a mixture of eight flavonoids (Fig. 2) (20 pg each). MS and NMR data were obtained during this on-flow experiment. The UV chromatogram is depicted in Fig. 3. Table 1 and Fig. 4 show the pseudo-molecular ion information, where M is the molecular weight with all the hydroxyl protons deuterated, in negative mode, for the eight flavonoids obtained in this on-flow experiment. Fig. 5 is the 2-D data set (time vs. chemical shift) where each NMR spectrum was acquired for 16 scans and decreasing the delays (total time per spectrum of 20 s). Fig. 6 depicts the NMR traces of each flavonoid extracted from the 2-D data set. It is notable that catechin... 

Figure 2.19 Chromatogram relative to analysis of monomer catechins in the skins extract (fraction diethyl ether from Ci8 cartridge) (sample volume injected lOp-L). 1. (+)-catechin, 2. (—)-epicatechin...

Figures 2.21,2.22 and 2.23 show the chromatograms relative to analysis of catechins and procyanidins prior to fractionation in the cartridge, of catechins monomer (fraction diethyl ether) and of procyanidins dimer (fraction ethyl acetate), respectively. As evidenced by Figures 2.20 and 2.23, the main procyanidin in seeds is procyanidin B2, however in skins procyanidin Bl prevails.

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