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. Author manuscript; available in PMC: 2008 Mar 18.
Published in final edited form as: Proc Soc Exp Biol Med. 1999 Apr;220(4):239–243. doi: 10.1046/j.1525-1373.1999.d01-41.x

Table II.

Summary of Possible Inhibitory Mechanisms of Green Tea and Black Tea Against Cooked-Meat Heterocyclic Amines

Mechanism Green tea Black tea
(1) Enzyme induction Increase in CYP1A2 and CYP1A1; increase in UDP-glucuronosyl transferase Slight increase in CYP1A2 and UDP-glucuronosyl transferase
(2) Enzyme inhibition Inhibition of NADPH-cytochrome P450 reductase and acetyltransferases Slight inhibition of NADPH-cytochrome P450 reductase
(3) Complex formation Weak Weak
(4) Mutagen degradation No effect on N-hydroxylated metabolites No effect on N-hydroxylatred metabolites
(5) Electrophile scavenging Inhibition of aryl nitrenium Inhibition of aryl nitrenium
(6) Free radical scavenging Likely contribution of catechins Possible contribution of catechins, theaflavins, thearubigins??