High-throughput analysis of catechins and theaflavins by high performance liquid chromatography with diode array detection

Neilson, Andrew P.; Green, Rodney J.; Wood, Karl V.; Ferruzzi, Mario G.

doi:10.1016/j.chroma.2006.07.059

Cited by 81 publications

(63 citation statements)

References 33 publications

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“…Green tea has a much higher content of polyphenols (35% of its dry weight) [21] including catechin (C), epicatechin (EC), epigallocatechin (EGC) and their gallate esters. The difference between the polyphenolic contents of black and green tea is the result of the different processing methods once the tea leaves are picked [22]. Once picked, black tea leaves are exposed to warm dry air where they undergo an oxidation process.…”

Section: Beverages Teamentioning

confidence: 99%

Nutritional recommendations for individuals with Flammer syndrome

et al. 2017

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The Flammer syndrome (FS) describes the phenotype of people with a predisposition for an altered reaction of the blood vessels to stimuli like coldness or emotional stress.The question whether such people should be treated is often discussed. On the one hand, most of these subjects are healthy; on the other hand, FS seems to predispose to certain eye diseases such as normal tension glaucoma or retinitis pigmentosa or systemic diseases such as multiple sclerosis or tinnitus. A compromise between doing nothing and a drug treatment is the adaption of nutrition. But what do we mean by healthy food consumption for subjects with FS? The adaption of nutrition depends on the health condition. Whereas patients with e.g. a metabolic syndrome should reduce their calorie intake, this can be counterproductive for subjects with FS, as most subjects with FS have already a low body mass index (BMI) and the lower the BMI the stronger the FS symptoms. Accordingly, while fasting is healthy e.g. for subjects with metabolic syndrome, fasting can even dangerously aggravate the vascular dysregulation, as it has been nicely demonstrated by the loss of retinal vascular regulation during fasting. To give another example, while reducing salt intake is recommended for subjects with systemic hypertensions, such a salt restriction can aggravate systemic hypotension and thereby indirectly also the vascular regulation in subjects with FS. This clearly demonstrates that such a preventive adaption of nutrition needs to be personalized.

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Section: Beverages Teamentioning

confidence: 99%

Nutritional recommendations for individuals with Flammer syndrome

et al. 2017

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“…Although there are several reported methods for analyzing green tea constituents by RP-HPLC, [20][21][22][23][24][25][26][27] some are not reproducible under the conditions available in our laboratory. The USP recommended method for the analysis of decaffeinated GTE 9 has a running time of 90 min and considers the following chemical markers: GA, CAF, EGCG, and polyphenols (C, EC, GCG, ECG, GC, EGC, EGCG, and GCG).…”

Section: Methods Developmentmentioning

confidence: 99%

“…Reversed-phase high performance liquid chromatography (RP-HPLC) followed by UV detection is considered the gold standard. 5,[20][21][22][23][24][25][26][27] Additional analytical techniques, such as ultra performance liquid chromatography (UPLC), 28,29 gas chromatography, 30 thin layer chromatography (TLC), 31 Fourier transform-near infrared spectroscopy (FT-NIR), 32 capillary zone electrophoresis (CZE), 33 and micellar electrokinetic capillary chromatography (MEKC) 34 have also been used for determining catechins. However, most of the aformentioned methods have been developed for the analysis of vegetable, drug, beverage, and extract samples.…”

Section: Introductionmentioning

confidence: 99%

GREEN TEA IN TRANSDERMAL FORMULATION: HPLC METHOD FOR QUALITY CONTROL ANDIN VITRODRUG RELEASE ASSAYS

Alves¹,

Almeida²,

Polonini³

et al. 2014

Química Nova

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RP-HPLC based analytical method for use in both quality control of green tea in a semisolid formulation and for in vitro drug release assays was developed and validated. The method was precise (CV < 5%), accurate (recovery between 98% and 102%), linear (R 2 > 0.99), robust, and specific for the determination of epigallocatechin 3-gallate (EGCG), caffeine (CAF), and gallic acid (GA). In a diffusion cell chamber, the release rate of EGCG was 8896.01 μg cm −2 . This data showed that EGCG will be able to exert its systemic activity when delivered though the transdermal formulation, due to its good flux rates with the synthetic membrane.

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“…Indeed, it could be beneficial to further improve chromatographic performance in terms of throughput and/or resolution particularly when numerous complex tea extracts have to be analyzed. In this context, a recent study shows the possibility of carrying out a separation of six epicatechin derivatives in 5-10 min using a conventional 100 mm, 3.5 m RPLC material at an elevated flow rate (1.2 mL/min) [18]. Even if the authors claimed that the proposed method is repeatable, sensitive and can be used on a conventional HPLC instrument, the selectivity between the investigated compounds and other analytes contained within a real matrix (tea extract) is obviously too limited, and this makes an unambiguous determination and quantification of epicatechins difficult.…”

Section: Introductionmentioning

confidence: 99%

High throughput qualitative analysis of polyphenols in tea samples by ultra-high pressure liquid chromatography coupled to UV and mass spectrometry detectors

Guillarme

Casetta

Bicchi

et al. 2010

Journal of Chromatography A

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a b s t r a c tThe analysis of polyphenols in tea extracts is important due to their potential health benefits. Therefore, efficient and high throughput analytical methods have been developed for the separation of seven predominant polyphenols, also known as catechin derivatives, present in tea extracts. Columns packed with sub-2-m particles operating at elevated pressure (UHPLC strategy) were selected to improve chromatographic performance. The potential of UHPLC-UV was demonstrated with baseline resolution of all standard catechins in only 30 s using a 50-mm column packed with 1.7-m particles. When dealing with real samples such as tea extracts, however, longer columns of up to 150 mm in length were employed to enhance the separation of catechin derivatives and other constituents within the tea samples while maintaining an acceptable analysis time. Two strategies based on 2-D experiments were proposed to clearly identify catechins. Firstly, a liquid-liquid extraction procedure was added prior to the UHPLC-UV analysis to decrease the complexity of the sample. Secondly, UHPLC was coupled to ESI-MS/MS to attain sufficient sensitivity and selectivity between catechin derivatives and other constituents of tea extract. These two strategies were found extremely promising as a clear discrimination of catechins from the matrix could be attained.

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High-throughput analysis of catechins and theaflavins by high performance liquid chromatography with diode array detection

Cited by 81 publications

References 33 publications

Nutritional recommendations for individuals with Flammer syndrome

Nutritional recommendations for individuals with Flammer syndrome

GREEN TEA IN TRANSDERMAL FORMULATION: HPLC METHOD FOR QUALITY CONTROL ANDIN VITRODRUG RELEASE ASSAYS

High throughput qualitative analysis of polyphenols in tea samples by ultra-high pressure liquid chromatography coupled to UV and mass spectrometry detectors

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