title: Oral administration of Polypodium leucotomos delays skin tumor development and increases epidermal p53 expression and the anti-oxidant status of UV-irradiated hairless mice.
abstract: Chronic exposure to ultraviolet radiation (UVR) induces skin tumors in hairless mice. Daily oral administration of a Polypodium leucotomos (PL) extract significantly delayed tumor development in PL-treated versus non-PL-treated mice. UVR and/or PL treatment modified several oxidative stress markers. In all irradiated mice, erythrocytic glutathione S-transferase (GST) activity and glutathione disulphide (GSSG) content increased and in all PL-treated mice GSSG content decreased, specially in non-irradiated animals, and total plasma anti-oxidant capacity (ORAC) increased. In dorsolateral non-tumoral skin of all irradiated mice, glutathione reductase (GR) and glutathione peroxidase (GPx) activities increased and GSSG decreased in non-irradiated PL-treated animals. UVR induced a steep increase of p53 expression in epidermal cells. In non-tumoral skin, this increase was significantly higher in PL-treated animals than in non-treated mice and can contribute in delaying tumor development, either by repairing the damaged DNA or by increasing apoptosis. These results reinforce the usefulness of PL as systemic photoprotective agent, especially in patients highly sensitive to UVR.
authors.affiliation: Department of Pharmacology, School of Medicine, Reus, Spain.
authors.forename: Esperanza
authors.initials: E
authors.lastname: Rodríguez-Yanes
authors.forename: Jesús
authors.initials: J
authors.lastname: Cuevas
authors.forename: Salvador
authors.initials: S
authors.lastname: González
authors.forename: Jordi
authors.initials: J
authors.lastname: Mallol
mesh_terms: D000284:Administration, Oral; D000818:Animals; D000975:Antioxidants / Q000378:metabolism; D017209:Apoptosis; D005260:Female; D019803:Glutathione Disulfide / Q000378:metabolism; D005979:Glutathione Peroxidase / Q000378:metabolism; D005982:Glutathione Transferase / Q000378:metabolism; D007165:Immunosuppression Therapy; D055623:Keratosis, Actinic / Q000188:drug therapy; D008027:Light; D051379:Mice; D009381:Neoplasms, Radiation-Induced / Q000517:prevention & control; D018384:Oxidative Stress; D010936:Plant Extracts / Q000008:administration & dosage*; D032494:Polypodium / Q000737:chemistry*; D012867:Skin / Q000528:radiation effects; D012878:Skin Neoplasms / Q000517:prevention & control* / Q000628:therapy*; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism*; D014466:Ultraviolet Rays
chemical_list: D000975:Antioxidants; D010936:Plant Extracts; D016159:Tumor Suppressor Protein p53; D005979:Glutathione Peroxidase; D005982:Glutathione Transferase; D019803:Glutathione Disulfide
keywords: Anti-oxidant; Polypodium leucotomos; natural plant extract; p53; photoprotection