title: Inhibitory effect of 12-O-tetradecanoylphorbol-13-acetate-caused tumor promotion in benzo[a]pyrene-initiated CD-1 mouse skin by baicalein.
abstract: The effects of topical application of baicalein on 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced promotion of skin tumors, hyperplasia, ornithine decarboxylase activity, and inflammation were evaluated in female CD-1 mice. Topical application of baicalein (0.08, 0.16, or 0.2 mumol) with TPA (5 nmol) twice weekly for 24 weeks to mice previously initiated with benzo[a]pyrene inhibited the number of TPA-induced tumors per mouse significantly. Preapplication of the same amount of baicalein also afforded significant protection against TPA-induced hyperplasia in the ear skin. Topical application of baicalein inhibited tumor promoter-caused induction of epidermal ornithine decarboxylase activity by TPA (5 nmol). The topical application of baicalein (0.008, 0.016, or 0.02 mumol) inhibited TPA-induced edema of mouse ears by 88%, 96%, or 97%, respectively. Pretreatment of mouse skin with various amounts of baicalein caused inhibition of H2O2 and myeloperoxidase formation by TPA. These results indicate that baicalein can be a potential cancer-chemopreventive agent against tumor promotion.
authors.affiliation: Institute of Biochemistry, Chung Shan Medical and Dental College Hospital, Taichung, Taiwan.
authors.forename: M J
authors.initials: MJ
authors.lastname: Lee
authors.forename: C J
authors.initials: CJ
authors.lastname: Wang
authors.forename: Y Y
authors.initials: YY
authors.lastname: Tsai
authors.forename: J M
authors.initials: JM
authors.lastname: Hwang
authors.forename: W L
authors.initials: WL
authors.lastname: Lin
authors.forename: T H
authors.initials: TH
authors.lastname: Tseng
authors.forename: C Y
authors.initials: CY
authors.lastname: Chu
mesh_terms: D000818:Animals; D016588:Anticarcinogenic Agents / Q000627:therapeutic use*; D001564:Benzo(a)pyrene / Q000633:toxicity*; D002273:Carcinogens / Q000633:toxicity*; D004354:Drug Screening Assays, Antitumor; D005260:Female; D044950:Flavanones; D005419:Flavonoids / Q000627:therapeutic use*; D051379:Mice; D009195:Peroxidase / Q000096:biosynthesis; D012878:Skin Neoplasms / Q000517:prevention & control*; D013755:Tetradecanoylphorbol Acetate / Q000633:toxicity*
chemical_list: D016588:Anticarcinogenic Agents; D002273:Carcinogens; D044950:Flavanones; D005419:Flavonoids; D001564:Benzo(a)pyrene; C006680:baicalein; D009195:Peroxidase; D013755:Tetradecanoylphorbol Acetate