Structural analysis of catechin derivatives as mammalian DNA polymerase inhibitors

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 α and λ with IC50 values of 5.1 and 3.8 μM, respectively. EGCg did not influence the activities of plant (cauliflower) pol α and β 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 pol α and λ 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 pol inhibitory activity was the same as that of anti-inflammation. EGCg at 250 μg 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.