Skin aging and photoaging: An outlook

Inhibition of ultraviolet B-mediated activation of nuclear factor κB in normal human epidermal keratinocytes by green tea Constituent (-)-epigallocatechin-3-gallate

“…These ROS cause modifications of protein that results in functional changes of enzymatic proteins (Stadtman, 1992;Katiyar et al 2001b). ROS are responsible for photoxidative damage on nucleic acids, lipids, and activation of transcription factors that control the expression of genes involved in tumor promotion (Goihman-Yahr, 1996;Naylor, 1997;Griffiths et al, 1998). UV radiation in the keratinocytes is directly involved in cyclobutane pyrimidine dimer formation, which is implicated in photocarcinogenesis (Kripke et al, 1992;Burren et al, 1998).…”

“…Our data suggest that EGCG protects against the adverse effects of UV radiation via modulaIntroduction Solar ultraviolet (UV) radiation, particularly its UVB (290-320 nm) spectrum, is the primary cause of skin cancer and other cutaneous pathologies in the human population, more so in Caucasian individuals (Mukhtar and Elmets, 1996;Greenlee et al, 2000). Experimental studies have shown that solar UV radiation elicits many adverse biological effects in the skin, including hyperpigmentation, erythema, photoaging, immunosuppression, and cancer (Goihman-Yahr, 1996;Ananthaswamy et al, 1997;DeGruijil, 1999;Afaq and Mukhtar, 2001). UV radiation to mammalian skin is known to alter cellular function via DNA damage (Eller et al, 1997;Vink et al, 1997;Katiyar et al, 2000), generation of reactive oxygen species (ROS) (Morita et al, 1997;Scharffetter-Kochanek et al, 1997;Katiyar et al, 2001a, b), and the resultant alterations in a variety of signaling events (Gilchrest et al, 1996;Knebel et al, 1996;Rosette and Karin, 1996;Iordanov et al, 1997;Chen et al, 1999;Lefort et al, 2001;Pfundt et al, 2001).…”

Natural phenolics in the prevention of UV-induced skin damage. A review

“…Chronic exposure of mammalian skin to UV radiation induces a number of biological responses, including development of erythema, edema, sunburn cell formation, hyperplasia, immune suppression, DNA damage, photoaging and melanogenesis. These alterations are directly or indirectly involved in the development of skin cancer [1][2][3] . UV radiation is a very potent initiator of photochemical reactions through excitation of electrons and this can result in energy transfer or chemical modification of the exposed molecule.…”

Superoxide Dismutase Enhanced the Formation of Hydroxyl Radicals in a Reaction Mixture Containing Xanthone under UVA Irradiation

“…3,4) Chronic exposure of mammalian skin to solar UV irradiation induces a number of biological responses, including erythema, edema, sunburn cell formation, hyperplastic responses, photoaging, and skin-cancer development. [5][6][7][8][9][10] The skin damage is not caused entirely by UVB. UVA appears to participate greatly in the damage.…”