title: Comparison of the inhibitory effects of monomeric, dimeric, and trimeric procyanidins on the biochemical markers of skin tumor promotion in mouse epidermis in vivo.
abstract: Several procyanidin dimers and an epicatechin trimer purified from Douglas fir bark tannins were compared with their monomer components (+)-catechin and (-)-epicatechin for their abilities to inhibit the biochemical effects of the potent tumor promoter 12-O-tetradecanoylphorbol 13-acetate (TPA) in mouse epidermis in vivo. Topical applications of the procyanidins, 15 min before the tumor promoter, inhibit TPA-induced ornithine decarboxylase (ODC) activity and this inhibition increases with the degree of polymerization (trimer > dimer > monomer). At a dose of 10 mumol, all procyanidin dimers inhibit the ODC response to TPA to a greater degree than 20 mumol of epicatechin and 10 mumol of epicatechin and/or catechin. Under similar conditions, catechin and epicatechin fail to inhibit the hydroperoxide (HPx) response to TPA whereas the procyanidin dimers inhibit this response by almost 40%. At a dose of 10 mumol, the epicatechin trimer also inhibits TPA-induced ODC activity and HPx production to a greater degree than 10-30 mumol of epicatechin. However, these various treatments with monomeric, dimeric, and trimeric procyanidins do not differ significantly in their abilities to inhibit TPA-stimulated DNA synthesis. These results suggest that some of the antitumor-promoting effects of procyanidins might increase at the biflavanoid and triflavanoid levels.
authors.affiliation: Division of Biology, Kansas State University, Manhattan 66506-4901.
authors.forename: H U
authors.initials: HU
authors.lastname: Gali
authors.forename: E M
authors.initials: EM
authors.lastname: Perchellet
authors.forename: X M
authors.initials: XM
authors.lastname: Gao
authors.forename: J J
authors.initials: JJ
authors.lastname: Karchesy
authors.forename: J P
authors.initials: JP
authors.lastname: Perchellet
mesh_terms: D000818:Animals; D016588:Anticarcinogenic Agents / Q000494:pharmacology*; D014408:Biomarkers, Tumor / Q000037:antagonists & inhibitors*; D004817:Epidermis / Q000187:drug effects*; D005260:Female; D051379:Mice; D011108:Polymers / Q000494:pharmacology*; D012878:Skin Neoplasms / Q000517:prevention & control*
chemical_list: D016588:Anticarcinogenic Agents; D014408:Biomarkers, Tumor; D011108:Polymers