title: Treatment of green tea polyphenols in hydrophilic cream prevents UVB-induced oxidation of lipids and proteins, depletion of antioxidant enzymes and phosphorylation of MAPK proteins in SKH-1 hairless mouse skin.
abstract: The use of botanical supplements has received immense interest in recent years to protect human skin from adverse biological effects of solar ultraviolet (UV) radiation. The polyphenols from green tea are one of them and have been shown to prevent photocarcinogenesis in animal models but their mechanism of photoprotection is not well understood. To determine the mechanism of photoprotection in in vivo mouse model, topical treatment of polyphenols from green tea (GTP) or its most chemopreventive constituent (-)-epigallocatechin-3-gallate (EGCG) (1 mg/cm(2) skin area) in hydrophilic ointment USP before single (180 mJ/cm(2)) or multiple UVB exposures (180 mJ/cm(2), daily for 10 days) resulted in significant prevention of UVB-induced depletion of antioxidant enzymes such as glutathione peroxidase (78-100%, P < 0.005-0.001), catalase (51-92%, P < 0.001) and glutathione level (87-100%, P < 0.005). Treatment of EGCG or GTP also inhibited UVB-induced oxidative stress when measured in terms of lipid peroxidation (76-95%, P < 0.001), and protein oxidation (67-75%, P > 0.001). Further, to delineate the inhibition of UVB-induced oxidative stress with cell signaling pathways, treatment of EGCG to mouse skin resulted in marked inhibition of a single UVB irradiation-induced phosphorylation of ERK1/2 (16-95%), JNK (46-100%) and p38 (100%) proteins of MAPK family in a time-dependent manner. Identical photoprotective effects of EGCG or GTP were also observed against multiple UVB irradiation-induced phosphorylation of the proteins of MAPK family in vivo mouse skin. Photoprotective efficacy of GTP given in drinking water (d.w.) (0.2%, w/v) was also determined and compared with that of topical treatment of EGCG and GTP. Treatment of GTP in d.w. also significantly prevented single or multiple UVB irradiation-induced depletion of antioxidant enzymes (44-61%, P < 0.01-0.001), oxidative stress (33-71%, P < 0.01) and phosphorylation of ERK1/2, JNK and p38 proteins of MAPK family but the photoprotective efficacy was comparatively less than that of topical treatments of EGCG and GTP. Lesser photoprotective efficacy of GTP in d.w. in comparison with topical application may be due to its less bioavailability in skin target cells. Together, for the first time a cream based formulation of green tea polyphenols was tested in this study to explore the possibility of its use for the humans, and the data obtained from this in vivo study further suggest that GTP could be useful in attenuation of solar UVB light-induced oxidative stress-mediated and MAPK-caused skin disorders in humans.
authors.affiliation: Department of Dermatology, University of Alabama at Birmingham, 1670 University Blvd, Volker Hall 557, 35294, USA.
authors.forename: Praveen K
authors.initials: PK
authors.lastname: Vayalil
authors.forename: Craig A
authors.initials: CA
authors.lastname: Elmets
authors.forename: Santosh K
authors.initials: SK
authors.lastname: Katiyar
mesh_terms: D000818:Animals; D015153:Blotting, Western; D002374:Catalase / Q000378:metabolism; D002392:Catechin / Q000031:analogs & derivatives* / Q000627:therapeutic use*; D005260:Female; D005978:Glutathione / Q000378:metabolism; D005979:Glutathione Peroxidase / Q000378:metabolism; D048031:JNK Mitogen-Activated Protein Kinases; D050356:Lipid Metabolism; D015227:Lipid Peroxidation; D048670:MAP Kinase Kinase 4; D020935:MAP Kinase Signaling System / Q000187:drug effects*; D051379:Mice; D008812:Mice, Hairless; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3; D020929:Mitogen-Activated Protein Kinase Kinases / Q000378:metabolism; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D009824:Ointments; D018384:Oxidative Stress / Q000187:drug effects; D010088:Oxidoreductases / Q000378:metabolism*; D010766:Phosphorylation; D011506:Proteins / Q000378:metabolism*; D011837:Radiation-Protective Agents / Q000627:therapeutic use*; D012867:Skin / Q000187:drug effects* / Q000378:metabolism / Q000528:radiation effects; D013662:Tea; D014466:Ultraviolet Rays; D048051:p38 Mitogen-Activated Protein Kinases
chemical_list: D009824:Ointments; D011506:Proteins; D011837:Radiation-Protective Agents; D013662:Tea; D002392:Catechin; C045651:epigallocatechin gallate; D010088:Oxidoreductases; D002374:Catalase; D005979:Glutathione Peroxidase; D048031:JNK Mitogen-Activated Protein Kinases; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases; D048670:MAP Kinase Kinase 4; D020929:Mitogen-Activated Protein Kinase Kinases; D005978:Glutathione