Antitumor-promoting effects of gallotannins, ellagitannins, and flavonoids in mouse skin in vivo

• Published in: ACS symposium series no. 546
• Main Authors: Perchellet, J.P. (Kansas State University, Manhattan, KS.), Gali, H.U, Perchellet, E.M, Laks, P.E, Bottari, V, Hemingway, R.W, Scalbert, A
• Format: Journal Article
• Language: English
• Published: 1994
• Subjects: CARCINOMAS; CARCINOME; CONTROL DE ENFERMEDADES; CONTROLE DE MALADIES; FLAVONOIDE; FLAVONOIDES; INHIBICION; INHIBITION; PEAU; PIEL (ANIMAL); RATON; SOURIS; TANINOS; TANNIN
• ISSN: 0097-6156; 1947-5918

Hydrolyzable (HTs) and condensed tannins (CTs) were tested topically for their ability to inhibit the biochemical and biological effects of 12-O-tetradecanoylphorbol-13-acetate (TPA) in mouse epidermis in vivo. Overall, commercial tannic acid (TA), ellagic acid (EA), and n-propyl gallate (PG) inhibit the promotion of skin papillomas and carcinomas by TPA in relation with their ability to inhibit TPA-induced epidermal ornithine decarboxylase (ODC) activity, hydroperoxide (HPx) production, and DNA synthesis. Pure pentagalloylglucose, castalagin, vescalagin, catechin dialkyl ketals, and epicatechin-4-alkylsulphides or heterogenous sumac leaf TA, Aleppo gall TA, tara pod TA, loblolly pine bark CT, guamuchil bark CT, and southern red oak bark CT also inhibit these biochemical markers of TPA promotion to various degrees. When applied to initiated skin 20 min before each promotion treatment, the different TA samples all remarkably inhibit complete tumor promotion by TPA. Sumac leaf TA is the most effective. The antitumor-promoting activity of a TA pretreatment can be further enhanced by the application of TA 24 h after each promotion treatment with TPA. Commercial TA and Aleppo gall TA inhibit the second stage of tumor promotion by mezerein but not the first stage of tumor promotion by TPA. Therefore, tannins in general might be valuable to prevent and/or inhibit tumor propagation, the only reversible stage of tumorigenesis