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. Mar-Apr 2011;94(2):487-97.

A Non-Targeted Approach to Chemical Discrimination Between Green Tea Dietary Supplements and Green Tea Leaves by HPLC/MS

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Free PMC article

A Non-Targeted Approach to Chemical Discrimination Between Green Tea Dietary Supplements and Green Tea Leaves by HPLC/MS

Jianghao Sun et al. J AOAC Int. .
Free PMC article

Abstract

Green tea-based dietary supplements (GTDSs) have gained popularity in the U.S. market in recent years. This study evaluated the phytochemical composition difference of GTDS in comparison with green tea leaves using an HPLC/MS fingerprinting technique coupled with chemometric analysis. Five components that are most responsible for class separation among samples were identified as (-) epicatechin gallate, strictinin, trigalloylglucose, quercetin-3-O-glucosyl-rhamnosylglucoside, and kaempferol-3-O-galactosyl-rhamnosylglucoside, according to the accurate mass measurements and MS/MS data. The similarity coefficients between the GTDSs in solid form with green tea were 0.55 to 0.91, while for the GTDSs in liquid form they were 0.12 to 0.89, which suggested that chemical composition variance across the GTDSs was significant. Flavonol aglycone concentrations were higher in GTDSs than in tea leaves, indicating the degradation of flavonol glycosides or the oxidation of catechin during the manufacturing and storage processes. In some GTDS samples, compounds were identified that were on the label. The results demonstrate the urgency of QC for GTDS products.

Figures

Figure 1
Figure 1
The UV chromatograms detected at 350 nm of all GTDS and GT samples.
Figure 2
Figure 2
HPLC/ESI-MS total ion chromatograms of all GTDS and GT samples.
Figure 3
Figure 3
Extracted ion chromatograms showing the additives identified in Supplements N, Q, and S (Table 1); constituents from (A) stevia leaves, (B) Luo Han Guo, and (C) fenugreek.
Figure 4
Figure 4
The MS/MS fragmentation of esteviolbioside. The product ion with m/z 317 is the steviol aglycone.
Figure 5
Figure 5
The similarity of GTDS and green tea samples based on the Pearson's correlation coefficient. Green-GTDS in liquid form (samples A–L); Blue- GTDS in solid form (samples M–T).
Figure 6
Figure 6
The cluster dendrogram of 20 GTDS samples. Cluster I (M, N, P, Q, R, S) is composed of mainly liquid GTDS samples. Cluster III is mainly solid GTDS samples that have a chemical composition similar to that of the GT reference. Sample letters are identified in Table 1.
Figure 7
Figure 7
PCA score (A) and loading plot (B) derived from the HPLC/MS dataset of GTDS samples and GT leaves. ▲, GTDS solid form; ◇, GTDS liquid form; □, GT samples.

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