The inhibitory activities against DNA polymerases (pols) of catechin derivatives (i.e., flavan-3-ols) such as (+)-catechin, (-)-epicatechin, (-)-gallocatechin, (-)-epigallocatechin, (+)-catechin gallate, (-)-epicatechin gallate, (-)-gallocatechin gallate, and (-)epigallocatechin gallate (EGCg) were investigated. Among the eight catechins, some catechins inhibited mammalian pols, with EGCg being the strongest inhibitor of pol alpha and lambda with IC50 values of 5.1 and 3.8 mu M, respectively. EGCg did not influence the activities of plant (cauliflower) pot and beta or prokaryotic pols, and further had no effect on the activities of DNA metabolic enzymes such as calf terminal deoxynucleotidyl transferase, T7 RNA polymerase, and bovine deoxyribonuclease I. EGCg-induced inhibition of pot a and k, was competitive with respect to the DNA template-primer and non-competitive with respect to the dNTP (2'-deoxyribonucleotide 5'-triphosphate) substrate. Tea catechins also suppressed TPA (12-O-tetradecanoylphorbol-13-acetate)-induced inflammation, and the tendency of the pot inhibitory activity was the same as that of anti-inflammation. EGCg at 250 Pg was the strongest suppressor of inflammation (65.6% inhibition) among the compounds tested. The relationship between the structure of tea catechins and the inhibition of mammalian pols and inflammation was discussed. (c) 2005 Elsevier Inc. All rights reserved.