Thermodynamic and computational analyses reveal the functional roles of the galloyl group of tea catechins in molecular recognition

Takahashi, Tomoya; Nagatoishi, Satoru; Kuroda, Daisuke; Tsumoto, Kouhei

doi:10.1371/journal.pone.0204856

Cited by 16 publications

(14 citation statements)

References 44 publications

(51 reference statements)

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“…These results suggest that SEA and EGCG can maintain their interaction after absorption from the intestinal tract, even in the presence of serum albumin. The strength of interaction between human serum albumin (HSA) having high homology to BSA and EGCG or a methylated EGCG was in the order of (−)-3 -Me-EGCG > (−)-4 -Me-EGCG > EGCG [26]. In previous studies, the strength of interaction between SEA and EGCG or a methylated EGCG was in the order of EGCG ≥ (−)-4 -Me-EGCG > (−)-3 -Me-EGCG [18].…”

Section: Discussionmentioning

confidence: 99%

Effect of (−)-Epigallocatechin Gallate to Staphylococcal Enterotoxin A on Toxin Activity

et al. 2020

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Staphylococcal enterotoxin A (SEA) functions both as superantigens that stimulate non-specific T cell proliferation as well as potent gastrointestinal toxins. We previously reported that (−)-epigallocatechin gallate (EGCG) binds to SEA. Therefore, the ability of EGCG to inhibit SEA toxin activity was examined. As a result, EGCG significantly decreased SEA-induced expression and production of interferon gamma (IFN-γ). In addition, EGCG inhibited SEA-induced spleen cell proliferation. To investigate the role of the galloyl group in EGCG on SEA cytotoxicity in more detail, the effect of the binding of a hydroxyl group at position 3 of the galloyl group in EGCG to SEA on SEA cytotoxicity was examined using two methylated EGCG. SEA cytotoxicity was significantly controlled in both (−)-3′′-Me-EGCG and (−)-4′′-Me-EGCG. These results suggest that EGCG inhibits toxic activity via direct interaction with SEA or without any interaction with SEA. The binding affinity between SEA and EGCG under in vivo conditions was examined using a model solution. Although after treatment under acidic and alkaline conditions, the presence of protein and the digestive tract model solution, EGCG still interacted with SEA. Our studies are the first to demonstrate the effect of the binding of EGCG to SEA on toxin activity.

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Section: Discussionmentioning

confidence: 99%

Effect of (−)-Epigallocatechin Gallate to Staphylococcal Enterotoxin A on Toxin Activity

et al. 2020

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“…In certain cases, it can even be used to obtain the additional kinetic parameters (k on , k off ) simultaneously [3][4][5][6]. The modern isothermal titration calorimeter designed with power compensation possesses very low detection limits [2,7] and is widely used in biomolecular interaction studies, supramolecular chemistry, drug research, nanomaterials science, and other fields [8][9][10][11][12][13]. Thermodynamic information is key in drug design, discovery and optimization [14][15][16], because it provides details about the balance of driving forces that cannot be obtained solely from current structural and computational methods [17,18].…”

Section: Introductionmentioning

confidence: 99%

Estimation of non-constant variance in isothermal titration calorimetry using an ITC measurement model

Chen

et al. 2020

PLoS ONE

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Isothermal titration calorimetry (ITC) is the gold standard for accurate measurement of thermodynamic parameters in solution reactions. In the data processing of ITC, the non-constant variance of the heat requires special consideration. The variance function approach has been successfully applied in previous studies, but is found to fail under certain conditions in this work. Here, an explicit ITC measurement model consisting of main thermal effects and error components has been proposed to quantitatively evaluate and predict the non-constant variance of the heat data under various conditions. Monte Carlo simulation shows that the ITC measurement model provides higher accuracy and flexibility than variance function in high c-value reactions or with additional error components, for example, originated from the fluctuation of the concentrations or other properties of the solutions. The experimental design of basic error evaluation is optimized accordingly and verified by both Monte Carlo simulation and experiments. An easy-to-run Python source code is provided to illustrate the establishment of the ITC measurement model and the estimation of heat variances. The accurate and reliable non-constant variance of heat is helpful to the application of weighted least squares regression, the proper evaluation or selection of the reaction model.

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“…Проведен сравнительный анализ ИК-спектров проантоцианидинов, выделенных из коры пихты (рис. 2, 3), и проантоцианидинов из коры сосны обыкновенной [8], а также спектров проантоцианидинов, описанных в работах [11,12]. В ИК-спектре проантоцианидинов из коры пихты присутствуют все полосы поглощения, характерные для проантоцианидинов коры сосны, в области 3400-3385, 1612-1607, 1522-1514, 11 Рис.1.…”

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“…4. Структура проантоцианидинов чая, R 1 = H, R 2 = H -процианидины; R 1 = OH, R 2 = H, -продельфинидины; R 2 = галлоил -галлаты проантоцианидинов [11,12]. Fig.4.…”

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Isolation and Study of Abies Bark Proanthocyanidins

Levdansky

Kondrasenko

Levdansky

et al. 2019

Journal of Siberian Federal University. Chemistry

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The process of proanthocyanidins isolation from abies bark by water and water-alcohol solutions containing 5, 10, 15 and 20 % ethanol was studied for the first time. The optimal conditions providing the maximum yield of proanthocyanidins were determined experimentally. It was shown that the use of 15-20 % water-alcohol solutions allows to increase the yield of proanthocyanidins from 0.33 to 0.38 %. The composition of the obtained proanthocyanidins was studied by UV, IR, and 13C NMR spectroscopy. The obtained proanthocyanidins were transformed into colored anthocyanidins in ethanol medium in the presence of hydrochloric acid. The flavonoids cyanidin and delphinidin were isolated and identified. It was established that the obtained proanthocyanidins mainly consist of procyanidin and prodelphinidin. It was shown that proanthocyanidins obtained from abies bark, in contrast to the proanthocyanidins isolated from pine bark described in the literature, contain gallic acid residues, which is typical for proanthocyanidins isolated from various types of tea

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Thermodynamic and computational analyses reveal the functional roles of the galloyl group of tea catechins in molecular recognition

Cited by 16 publications

References 44 publications

Effect of (−)-Epigallocatechin Gallate to Staphylococcal Enterotoxin A on Toxin Activity

Effect of (−)-Epigallocatechin Gallate to Staphylococcal Enterotoxin A on Toxin Activity

Estimation of non-constant variance in isothermal titration calorimetry using an ITC measurement model

Isolation and Study of Abies Bark Proanthocyanidins

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