title: [Adsorption kinetic study of the interaction between human salivary alpha-amylase and the polyphenoles from the black/green tea].
abstract: OBJECTIVE
  To explore the driving force of the oral astringency produced by the interaction of theaflavin (TF) and epigallocatechin-3-gallate (EGCG) to human salivary a-amylase(HSA).
  
  
  METHODS
  The constants of the rate, equilibrium of reaction (k(a), k(d), K(A), and K(D)) and Langmuir, Freundlich adsorption isotherm (K(L), K(f), and Mm) were determined by surface plasmon resonance (SPR) technique and adsorption kinetics.
  
  
  RESULTS
  Both of Langmuir and Freundlich models could be used for describing the binding processes of TF and EGCG onto HSA surfaces, and there were no significant differences of the correlation coefficient of determination between these two models (P > 0.05). The constants of adsorption isotherm, the rate and equilibrium constants of the association for TF were higher than those of EGCG (P < 0.05). The rate and equilibrium constants of the dissociation for TF were lower than those of EGCG (P < 0.05). The affinity of TF to HSA was higher than that of EGCG.
  
  
  CONCLUSIONS
  The sorely oral astringency is much easily produced by TF from the black tea rather than EGCG from the green tea. The driving force of the oral astringency is attributed to the hydrogen bonds of hydroxyl groups and hydrophobic interaction of galloyl groups in polyphenolic structures.
authors.affiliation: Dept. of Prosthodontics, Dentistry Hospital of Xiamen City, Xiamen 361003, China.
authors.forename: Feng
authors.initials: F
authors.lastname: Lin
authors.forename: Jiang-wu
authors.initials: JW
authors.lastname: Yao
mesh_terms: D000327:Adsorption; D000818:Animals; D000975:Antioxidants; D044946:Biflavonoids; D002392:Catechin / Q000031:analogs & derivatives; D002522:Chlorocebus aethiops; D006801:Humans; D055291:Salivary alpha-Amylases; D013662:Tea; D000516:alpha-Amylases
chemical_list: D000975:Antioxidants; D044946:Biflavonoids; D013662:Tea; C056068:theaflavin; D002392:Catechin; C045651:epigallocatechin gallate; D055291:Salivary alpha-Amylases; D000516:alpha-Amylases