title: Toxicological aspects of flavonoid interaction with biomacromolecules.
abstract: OBJECTIVE
  Flavonoids are widely accepted as health promoting phytochemicals, however, some flavonoids show ability of direct interaction with DNA and/or enhance carcinogen activation into DNA modifying agents. Thus, their potential harmful effect on the human body should be examined in detail.
  
  
  METHODS
  Direct interaction of flavonoids (quercetin, rutin) with DNA was examined using square wave voltammetry on carbon paste electrode. Induction effect of selected flavonoids on content of cytochrome P450 1A1, carcinogens activating enzyme, in colon and liver microsomal samples of animals exposed to flavonoids was determined by Western blotting, using anti-cytochrome P450 1A1 specific antibody.
  
  
  RESULTS
  Of the natural flavonoids tested, induction of CYP1A1 was elicited by the typical citrus flavonoid naringenin in the colon, as well as by flavone in the liver. Moreover, synthetic beta-naphthoflavone and naturally occurring chrysin, quercetin and diosmin induced CYP1A1 in both tissues. The oxidation signals of guanine and adenine in the DNA molecule were decreased in the presence of flavonoids.
  
  
  CONCLUSIONS
  Although flavonoids are often considered to be safe because of their "plant origin", ingestion of flavonoids should be taken with caution. Enhanced expression of CYP1A1 in colon tissue might be responsible for increasing incidence of colorectal carcinoma in humans. Electrochemistry can be used to study the interactions of flavonoids and DNA.
authors.affiliation: Department of Biochemistry, Faculty of Science, Charles University, Prague, Czech Republic. hodek@natur.cuni.cz
authors.forename: Petr
authors.initials: P
authors.lastname: Hodek
authors.forename: Pavel
authors.initials: P
authors.lastname: Hanustiak
authors.forename: Jitka
authors.initials: J
authors.lastname: Krízková
authors.forename: Radka
authors.initials: R
authors.lastname: Mikelova
authors.forename: Sona
authors.initials: S
authors.lastname: Krízková
authors.forename: Marie
authors.initials: M
authors.lastname: Stiborová
authors.forename: Libuse
authors.initials: L
authors.lastname: Trnková
authors.forename: Ales
authors.initials: A
authors.lastname: Horna
authors.forename: Miroslava
authors.initials: M
authors.lastname: Beklová
authors.forename: René
authors.initials: R
authors.lastname: Kizek
mesh_terms: D000225:Adenine / Q000378:metabolism; D000818:Animals; D003106:Colon / Q000187:drug effects / Q000378:metabolism; D019363:Cytochrome P-450 CYP1A1 / Q000378:metabolism; D004277:DNA, Single-Stranded / Q000378:metabolism*; D004563:Electrochemistry; D004789:Enzyme Activation / Q000187:drug effects; D005419:Flavonoids / Q000378:metabolism* / Q000494:pharmacology / Q000633:toxicity*; D019791:Guanidine / Q000378:metabolism; D008297:Male; D008862:Microsomes, Liver / Q000187:drug effects / Q000378:metabolism; D008954:Models, Biological; D051381:Rats
chemical_list: D004277:DNA, Single-Stranded; D005419:Flavonoids; D019363:Cytochrome P-450 CYP1A1; D000225:Adenine; D019791:Guanidine