A tandem mass spectrometry method based on selected ions detects low‐abundance phenolics in black tea – theatridimensins as products of the oxidative cascade

Verloop, Annewieke J.W.; Vincken, Jean‐Paul; Gruppen, Harry

doi:10.1002/rcm.7658

Cited by 11 publications

(21 citation statements)

References 25 publications

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“…Therefore, samples were also analyzed using the MS/MS on selected ions mode, a MS method to specifically screen for selected compounds in low abundance. 13 The resulting chromatograms with the MS/ MS on selected ions method for the TF + xO are shown in Figure 2. The MS information on the compounds, corresponding to the numbered peaks, is shown in Table 2.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

“…An example of the latter is the theatridimensin (T3D) type. 12,13 Both types of oligomers can also undergo intramolecular rearrangements when oxidized, in which the interflavanic configuration is altered. For instance, the theanaphtoquinone (TNQ) configuration 14 and theacoumarin (TCou) configuration 15 are formed from a TF-type interflavanic configuration, whereas DhCs δ AB and γ AB 10 configurations are formed from DhC β AB .…”

Section: ■ Introductionmentioning

confidence: 99%

“… The level of oligomerization can be divided into two types of oligomerization: (i) basic oligomerization types, which can be formed from two subunits in one oxidation step: the theaflavin (TF) type, , the theasinensin (TS) type, − the theacitrin (TC) type, , and the dehydrocatechins (DhCs) β AB and ε AB types, , and (ii) tripartite oligomerization types, which require a preformed basic oligomerization between two catechin subunits serving as a scaffold onto which a third catechin is superimposed. An example of the latter is the theatridimensin (T3D) type. , Both types of oligomers can also undergo intramolecular rearrangements when oxidized, in which the interflavanic configuration is altered. For instance, the theanaphtoquinone (TNQ) configuration and theacoumarin (TCou) configuration are formed from a TF-type interflavanic configuration, whereas DhCs δ AB and γ AB configurations are formed from DhC β AB .…”

Section: Introductionmentioning

confidence: 99%

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Peroxidase Can Perform the Hydroxylation Step in the “Oxidative Cascade” during Oxidation of Tea Catechins

Verloop

Vincken

Gruppen

2016

J. Agric. Food Chem.

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Formation of black tea thearubigins involves at least two of the following oxidation steps: (i) oligomerization, (ii) rearrangement, (iii) hydroxylation. The first two are mainly catalysed by polyphenol oxidase(PPO), whereas the enzyme responsible for hydroxylation has not yet been identified. Two main oxidative activities, peroxidase(POD) and PPO, occur in tea leaves. POD was hypothesized to be responsible for hydroxylation. Model systems with horseradish POD and mushroom tyrosinase were used investigating hydroxylation of theaflavins(TF). POD was found capable of hydroxylation. TFs with up to five extra hydroxyl groups were annotated by their MS2 data. Hydroxylation by POD was also shown for theanaphtoquinones, theatridimensins and dehydrodicatechins. H2O2 concentration influenced the extent of hydroxylation, decreasing it at concentrations above 0.01 mM. TFs with up to five extra hydroxyl groups, and traces of other hydroxylated oligomeric catechins, could be annotated in black tea without any sample pre-treatment, using a selective screening method with RP-UHPLC-MS.

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Section: ■ Results and Discussionmentioning

confidence: 99%

Section: ■ Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Peroxidase Can Perform the Hydroxylation Step in the “Oxidative Cascade” during Oxidation of Tea Catechins

Verloop

Vincken

Gruppen

2016

J. Agric. Food Chem.

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“…Peak 14 (t R 17.54 min) had a molecular ion at m/z 699 [M-H] − with a fragment ion at m/z 427 (loss of 272 amu) and 271 (loss of 427 amu), and it was 152 amu less than that of theaflavate A. These indicate that this compound could be theaflavate B [22, 36, 37]. …”

Section: Resultsmentioning

confidence: 99%

A new method to prepare and redefine black tea thearubigins

Wang

Zhang

et al. 2018

Journal of Chromatography A

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Thearubigins (TRs) are the major components of black tea, which are formed during the fermentation reactions. Although anti-inflammatory and anti-cancer activities of TRs have been reported, the prepared TRs according to the literature methods still contain many floating peaks. It is puzzling whether the observed activities are from TRs or these floating peaks. Thus, it is urgent to develop a method to prepare pure TRs and redefine them. In the present study, we developed a new method, the combination of caffeine precipitation and Sephadex LH-20 column chromatography, to prepare pure TRs. The floating peaks on the hump of the crude TRs were removed, and pure TRs were prepared. The chemical profile of the floating peaks was established using LC/MS, and the major compounds in this fraction were identified as apigenin glycosides, quercetin glycosides, kaempferol glycosides, theaflavins, theasinensin, and galloylglucoses based on the analysis of their tandem mass spectra and in comparison with literature data. This study will pave the way to further study the chemistry and biological activities of TRs and the health effects of black tea consumption.

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“…Além do fio de sutura, outros materiais estão sendo estudados para o reparo perineal, por exemplo, a cola cirúrgica. Esse material apresenta grande potencial para mudanças nas técnicas cirúrgicas, pois apresenta um elevado grau de resistência e facilita o procedimento cirúrgico (Dehne et al, 2012). Feigenberg et al (2014) segundo grau e 0,8% de terceiro ou quarto grau (Abedzadeh-Kalahroudi et al, 2019).…”

Section: Introdução Introduçãounclassified

Avaliação dos resultados das condições perineais após o reparo de trauma perineal com cola cirúrgica ou fio de sutura até 8 meses de pós-parto

Brunelli¹

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Introduction: In literature, there are few studies about the use of surgical glue for perineal repair after delivery. Objectives: To compare the intensity of perineal pain, the occurrence of urinary incontinence (UI), the pelvic floor muscle strength (PFMS), the sexual function (SF) and the satisfaction of women after perineal repair with surgical glue or suture yarn in the first 8 months after delivery. Methodology: Longitudinal study linked to a randomized controlled trial (RCT). The population was consisted of women attending a RCT who had normal delivery, underwent repair of first and/or second-degree perineal lacerations or episiotomy with Glubran 2 ® surgical glue (Experimental Group-EG) or with Vicry l® suture yarn (Control Group-CG) in a maternity hospital located in Itapecerica da Serra, São Paulo, and returned for evaluation or accepted to be evaluated in their homes. The women were followed-up during the first 8 months after delivery in six stages, with the first 3 stages corresponding to the RCT database, stage 4 to a cross-sectional study and stages 5 and 6 data to the current study. Stage 1: soon after normal delivery; stage 2: between 12 and 24 hours; stage 3: between 36 and 48 hours; stage 4: between 10 and 20 days; stage 5: between 50 and 70 days; stage 6: between 6 and 8 months after delivery. This study was approved by the Research Ethics Committee of EEUSP, under registration number 2.44.813. Results: A total of 140 women were evaluated in the first three stages, 110 women between 10 and 20 days after delivery (stage 4), 122 women between 50 and 70 days (stage 5) and 54 women between 6 and 8 months after delivery (stage 6). When comparing the intensity of perineal pain over time in the two types of perineal repair, EG presented better results than CG (p=0.001). However, there was no significance when comparing UI in the first five stages (p=0.699) and the use of ICIQ-SF in the sixth stage (p=0.835). Regarding PFMS, there was a difference of 4.96 points between the means of EG (mean 32.39; SD 14.03) and CG (mean 27.43; SD 12.75), but with no significance (p=0.331). As for SF, it was noticed that the EG women presented higher mean scores in all domains, but there was no significance (p=0.504). EG also presented better means in relation to women's satisfaction with perineal repair, but also with no significance (p=0.068). Conclusion: The use of surgical glue showed significantly lower perineal pain intensity in the first 8 months after delivery and better means related to PFMS, SF and women's satisfaction with perineal repair. Surgical glue may be a viable option to decrease the negative outcomes of perineal repair after normal delivery, as well as to increase women's satisfaction.

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A tandem mass spectrometry method based on selected ions detects low‐abundance phenolics in black tea – theatridimensins as products of the oxidative cascade

Cited by 11 publications

References 25 publications

Peroxidase Can Perform the Hydroxylation Step in the “Oxidative Cascade” during Oxidation of Tea Catechins

Peroxidase Can Perform the Hydroxylation Step in the “Oxidative Cascade” during Oxidation of Tea Catechins

A new method to prepare and redefine black tea thearubigins

Avaliação dos resultados das condições perineais após o reparo de trauma perineal com cola cirúrgica ou fio de sutura até 8 meses de pós-parto

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