title: The inhibition of the mammalian DNA methyltransferase 3a (Dnmt3a) by dietary black tea and coffee polyphenols.
abstract: BACKGROUND
  Black tea is, second only to water, the most consumed beverage globally. Previously, the inhibition of DNA methyltransferase 1 was shown by dietary polyphenols and epi-gallocatechin gallate (EGCG), the main polyphenolic constituent of green tea, and 5-caffeoyl quinic acid, the main phenolic constituent of the green coffee bean.
  
  
  RESULTS
  We studied the inhibition of DNA methyltransferase 3a by a series of dietary polyphenols from black tea such as theaflavins and thearubigins and chlorogenic acid derivatives from coffee. For theaflavin 3,3 digallate and thearubigins IC50 values in the lower micro molar range were observed, which when compared to pharmacokinetic data available, suggest an effect of physiological relevance.
  
  
  CONCLUSIONS
  Since Dnnmt3a has been associated with development, cancer and brain function, these data suggest a biochemical mechanism for the beneficial health effect of black tea and coffee and a possible molecular mechanism for the improvement of brain performance and mental health by dietary polyphenols.
authors.affiliation: Chemistry, Jacobs University Bremen, Campus Ring 1, 28759 Bremen, Germany.
authors.forename: Arumugam
authors.initials: A
authors.lastname: Rajavelu
authors.forename: Zumrad
authors.initials: Z
authors.lastname: Tulyasheva
authors.forename: Rakesh
authors.initials: R
authors.lastname: Jaiswal
authors.forename: Albert
authors.initials: A
authors.lastname: Jeltsch
authors.forename: Nikolai
authors.initials: N
authors.lastname: Kuhnert
mesh_terms: D000818:Animals; D028241:Camellia sinensis / Q000737:chemistry*; D040503:Coffea / Q000737:chemistry*; D004248:DNA (Cytosine-5-)-Methyltransferases / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism; D000090205:DNA Methyltransferase 3A; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D005419:Flavonoids / Q000494:pharmacology*; D051379:Mice; D010636:Phenols / Q000494:pharmacology*; D010936:Plant Extracts / Q000494:pharmacology*; D059808:Polyphenols
chemical_list: C000715535:Dnmt3a protein, mouse; D004791:Enzyme Inhibitors; D005419:Flavonoids; D010636:Phenols; D010936:Plant Extracts; D059808:Polyphenols; D004248:DNA (Cytosine-5-)-Methyltransferases; D000090205:DNA Methyltransferase 3A