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. 2008 Sep 10;56(17):8130-40.
doi: 10.1021/jf800986s. Epub 2008 Aug 8.

New phenolic components and chromatographic profiles of green and fermented teas

Long-Ze Lin  1 , Pei Chen, James M Harnly
Affiliations

New phenolic components and chromatographic profiles of green and fermented teas

Long-Ze Lin et al. J Agric Food Chem. .

Abstract

A standardized profiling method based on liquid chromatography with diode array and electrospray ionization mass spectrometric detection (LC-DAD-ESI/MS) was applied to establish the phenolic profiles of 41 green teas and 25 fermented teas. More than 96 phenolic compounds were identified that allowed the teas to be organized into five groups. Epigallocatechin gallate (EGCG) was the major phenolic component of green tea made from mature leaves (group 2), while green tea made from the younger buds and leaves (group 1) contained lower flavonoid concentrations. Partially fermented teas (group 3) contained one-half the EGCG content of the green tea. Fully fermented black teas (group 4) had a trace of EGCG, but contained theaflavins. Highly overfermented black tea (group 5) contained only trace amounts of flavonol glycosides and theaflavins. Over 30 phenolics are new for tea, and this is the first phenolic profile to simultaneously detect C- and O-glycosylated flavonoids, catechins, proanthocyanidins, phenolic acid derivatives, and purine alkaloids.

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Figures

Figure 1
Figure 1
Structures of tea flavonoids, other phenolics and other compounds.
Figure 2
Figure 2
LC chromatograms (350 nm) of the extracts (100 mg/5.0 mL of solvent, 30 μL injected) from five tea groups: (A) T1, (B) T6, (C) T26, (D) T46, and (E) T33. The peaks listed in Table 4, and some of the labeled peaks are much stronger in other tea samples.
Figure 3
Figure 3
LC chromatograms (270 nm) of the extracts (100 mg/5.0 mL of solvent, 30 μL injected) from five tea groups: (A) T1, (B) T6, (C) T26, (D) T46, and (E) T33. The peaks listed in Tables 2 and 3, and some of the labeled peaks are much stronger in other tea samples.
Figure 4
Figure 4
Mass spectrum of kaempferol 3-O-2″-hexosyllrhamnosylglucoside (peak 35 in Figure 2) obtained from the PI 100 V MS chromatogram.
Figure 5
Figure 5
LC chromatograms of (A) T3 and (B) T3 after alkaline hydrolysis. Kaempferol 3-O-glucoside (peak 44) was confirmed to be the parent glycosides of its mono- and di-p-coumaroyl derivatives (peaks 65 and 77).
Figure 6
Figure 6
Mass spectra of apigenin-6-C-glucosyl-8-C-arabinoside (peak 23 in Figure 2C) and apigenin 6-C-arabinosyl-8-C-glucoside (peak 24 in Figure 2C) obtained from the PI 250 V MS chromatogram.
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