Elucidation of structural difference in theaflavins for modulation of starch digestion

Miao, Ming; Jiang, Huan; Jiang, Bo; Li, Yungao; Cui, Steve W.; Jin, Zhengyu

doi:10.1016/j.jff.2013.09.021

Cited by 50 publications

(31 citation statements)

References 22 publications

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“…In previous studies, polyphenols have been reported to interact with polysaccharides through a combination of hydrogen bonds and hydrophobic interactions (Le Bourvellec & Renard, 2012;Renard, Watrelot, & Le Bourvellec, 2017). Polyphenols can bind with both a-amylase and polysaccharides (two different macromolecules) (Miao et al, 2013;Renard et al, 2017), and there is a competitive relationship between the two binding interactions (Soares et al, 2012;Soares et al, 2009). The interaction equilibrium among polysaccharides, polyphenols and PPA (Fig.…”

Section: Discussionmentioning

confidence: 99%

“…The inhibition of a-amylase by polyphenols arises as a result of hydrogen bonding between the hydroxyl groups of the phenolic compounds and the catalytic sites of amylase and hydrophobic interactions between the aromatic moieties of polyphenols and the enzyme (Miao et al, 2013). To characterize the mechanism of interactions (binding) between polyphenols and porcine pancreatic a-amylase (PPA), a range of methods have been employed, including half inhibition concentration (IC 50 ) value, inhibition kinetics and fluorescence quenching (Fei et al, 2014;Rawel, Frey, Meidtner, Kroll, & Schweigert, 2006;Sun, Warren, Netzel, & Gidley, 2016).…”

Section: Introductionmentioning

confidence: 99%

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Soluble polysaccharides reduce binding and inhibitory activity of tea polyphenols against porcine pancreatic α-amylase

2018

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Mixed linkage b-glucan Kinetics of inhibition Fluorescence quenching a b s t r a c tThe effects of three soluble polysaccharides on the inhibitory activity of tea polyphenols against porcine pancreatic a-amylase (PPA) were studied through PPA inhibition, half inhibition concentration (IC 50 ), inhibition kinetics and fluorescence quenching. The results show that citrus pectin, wheat arabinoxylan and oat b-glucan could each increase the IC 50 values and competitive inhibition constants (K ic ), and decrease the fluorescence quenching constants (K FQ ) of tea polyphenols interacting with PPA. The data show a competitive interaction equilibrium among polysaccharides, polyphenols and PPA. For individual polyphenols, there were negative linear correlations between both the values of 1/K ic and K FQ and that of IC 50 with and without polysaccharides, indicating that the decreased inhibitory activity of polyphenols induced by the polysaccharides was caused by the reduced binding of polyphenols with PPA. Additionally, the slopes of the linear relationship between IC 50 and K ic and that between K FQ and 1/K ic remained stable with and without polysaccharides, suggesting that these constants may be combined to characterize the effects of soluble polysaccharides on the PPA inhibition by polyphenols.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Soluble polysaccharides reduce binding and inhibitory activity of tea polyphenols against porcine pancreatic α-amylase

2018

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“…2.1B (Qian, Haser, & Payan, 1993). Notably, amino acid residues at the active site of α-amylase are proposed to be in positions where the interactions between inhibitors and α-amylase are thought to occur (Miao, Jiang, Jiang, Li, Cui, & Jin, 2013).…”

Section: 1mentioning

confidence: 99%

“…Catechin (C), epicatechin (EC), epigallocatechin (EGC), epigallocatechin gallate (EGCG), epicatechin gallate (ECG), theaflavin, theaflavin-3'-gallate (TF1), theaflavin-3, 3'-digallate (TF2) are the prominent polyphenols in aqueous green, oolong or black tea extracts (Serpen, Pelvan, Alasalvar, Mogol, Yavuz, Gokmen, et al, 2012). The inhibitory activities of the tea polyphenols against α-amylase have been studied, and the results showed that polyphenols with a galloyl moiety in the molecular structures showed greater enzyme inhibition than those without galloyl moiety, indicated by IC 50 values (Hara & Honda, 1990) (Miao, Jiang, Jiang, Li, Cui, & Jin, 2013;Miao, Jiang, Jiang, Zhang, & Li, 2015). Therefore, 3 or 3'-galloyl groups on the C or C' ring ( Fig.…”

Section: Galloyl Moietymentioning

confidence: 99%

“…The total binding energy (kJ/mol) of polyphenol with α-amylase can be obtained from the docking study as well. It was found that the order of the binding energy for four theaflavin compounds was opposite to that of IC 50 , indicating that more binding of theaflavins with α-amylase corresponded to higher inhibitory activity (Miao, Jiang, Jiang, Li, Cui, & Jin, 2013). In addition, as the binding energy can also reflect the binding of polyphenols with the enzyme, it may be combined with 1/K ic , K FQ and K itc to more completely characterize the binding interactions.…”

Section: Molecular Dockingmentioning

confidence: 99%

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Studying the interactions between tea polyphenols and α-amylase

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Dixon, Cornish-Bowden and Lineweaver-Burk plot analyses were applied to study the detailed kinetics of inhibition of porcine pancreatic α-amylase (PPA) by tea polyphenols.Fluorescence quenching (FQ), differential scanning calorimetry (DSC) and isothermal titration calorimetry (ITC) were combined with the kinetics of inhibition to elucidate the mechanism of binding interactions of tea polyphenols and PPA. Then, the reciprocal of competitive inhibition constant (1/K ic ), fluorescence quenching constant (K FQ ) and binding constant (K itc ) obtained from these measurements were compared and correlated to analyse the relations between PPA inhibition and binding behaviour. The role of the galloyl moiety in binding of catechins and theaflavins with PPA was highlighted as well. In addition, the effects of three soluble polysaccharides (citrus pectin (CP), wheat arabinoxylan (WAX) and oat β-glucan (OBG)) on the inhibition of PPA by tea polyphenols were studied through PPA inhibition, IC 50 value, inhibition kinetics and fluorescence quenching methods. Furthermore, the effects of tea polyphenols on binding of PPA with normal maize starch granules were studied in terms of binding ratio, dissociation constant (K d ) and binding rate. Then, the association constant (1/K d ), 1/K ic and K FQ of tea polyphenols were correlated to analyse the effects of PPA inhibition on the binding of the enzyme with starch.The results show that green, oolong and black tea extracts, epigallocatechin gallate, theaflavin-3, 3'-digallate and tannic acid were competitive inhibitors of PPA, whereas epicatechin gallate, theaflavin-3'-gallate and theaflavin were mixed-type inhibitors with both competitive and uncompetitive inhibitory characteristics. Only catechins with a galloyl substituent at the 3-position showed measurable inhibition. K ic values were lower for theaflavins than catechins, with the lowest value for theaflavin-3, 3'-digallate. The lower K ic than the uncompetitive inhibition constant for the mixed-type inhibitors suggests that they bind more tightly with free PPA than with the PPA-starch complex. A 3 and/or 3'-galloyl moiety in catechin and theaflavin structures was consistently found to increase inhibition of PPA through enhanced association with the enzyme active site. A higher quenching effect of polyphenols corresponded to a stronger inhibitory activity against PPA. The red-shift of maximum emission wavelength of PPA bound with some polyphenols indicated a potential IV

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The inhibitory effects of free and bound phenolics from Phyllanthus emblica Linn. on α‐amylase: a comparison study

Xing,

Xie,

Wang

et al. 2024

J Sci Food Agric

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BACKGROUNDPhyllanthus emblica Linn. (PE) is rich in polyphenols, which can be categorized into free and bound phenolics (PEFP and PEBP). This study evaluated the inhibitory effect of PEFB and PEBP on α‐amylase for the first time. The mechanism of the inhibition effect of PEFP and PEBP on α‐amylase was investigated by enzyme inhibition kinetics, multispectral analysis, thermodynamics, and molecular docking.RESULTSFree and bound phenolics inhibited α‐amylase activity effectively in a mixed type of inhibition. Fluorescence quenching and thermodynamic analyses showed that the binding of PEFP and PEBP to α‐amylase occurred through a static quenching process (Kq = 6.94 × 10¹² and 5.74 × 10¹² L mol−1 s−1), which was accompanied by a redshift (λem from 343 to 347 nm), leading to a change in the microenvironment. This process was found to be a spontaneous exothermic reaction (ΔG < 0). Circular dichroism (CD) analysis confirms that the secondary structure of α‐amylase was altered, in particular a decrease in α‐helixes and an increase in random coils. Molecular docking studies showed that PEFP and PEBP interacted with α‐amylase through hydrogen bonding and hydrophobic interactions.CONCLUSIONThe present study provides valuable insights into the mechanism of action of PEFP and PEBP on α‐amylase, which will provide a theoretical basis for their possible use as novel natural α‐amylase inhibitors. © 2024 Society of Chemical Industry.

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Elucidation of structural difference in theaflavins for modulation of starch digestion

Cited by 50 publications

References 22 publications

Soluble polysaccharides reduce binding and inhibitory activity of tea polyphenols against porcine pancreatic α-amylase

Soluble polysaccharides reduce binding and inhibitory activity of tea polyphenols against porcine pancreatic α-amylase

Studying the interactions between tea polyphenols and α-amylase

The inhibitory effects of free and bound phenolics from Phyllanthus emblica Linn. on α‐amylase: a comparison study

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