Photoprotection of Skin

In biological systems, superoxide and H2O2 are formed in small quantities by normal processes and both of these species produce harmful 

The process of photoinduced interaction of melanin with molecular oxygen is accompanied by photobleaching (232), and phaeomelanin has been found to be more photolabile and susceptible to photodegradation on prolonged photolysis (55). 

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Lin F, Lin Y, Gupta RD.Tournas JA, Burch JA, Selim MA, et al. Ferulic acid stabilizes a solution of vitamins C and E and doubles its photoprotection of skin.J Invest Dermatol 2005 125 826-32. 

Wondrak, G. T. Jacobson, M. K. Jacobson, E. L. (2006). Endogenous UVA photosensitizers mediators of skin photodamage and novel targets for skin photoprotection. Photochemical Photohiological Sciences, Vol.5, (nd), (August 2005), pp. 215 - 237, ISSN 1474-905X. 

Greul, A.K. et al., Photoprotection of UV-irradiated human skin an antioxidative combination of vitamins E and C, carotenoids, selenium and proanthocyanidins, Skin Pharmacol. Appl. Skin Physiol., 15, 307, 2002. 

Schallreuter, K. U. et al. Oxybenzone oxidation following solar irradiation of skin—Photoprotection versus antioxidant inactivation. Journal of Investigative Dermatology 706(3) 583-586, 1996. 

Photochemistry and cultural heritage. What is the impact of light on works of art (Romani, dementi, Miliani and Favaro, 39, 256-284) Photoprotection of human skin (Herzog, 40, 245-273)... 

Moreover, the determination of skin colour is also used by dermatologists to monitor changes in freckles or other skin pigmentation disorders, thus it is obviously a very interesting work tool in the scope of photoprotection and cutaneous photobiology (Chardon and Crdtois, 1991 Pidrard and Pidrard-Franchimont, 1993 Wee et al, 1997 Pidrard, 1998 Domelles et al, 2004). 

Kaidbey KH, Agin PP, Sayre RM, Kligman A (1979) Photoprotection by melanin - a comparison of black and Caucasian skin. J Am Acad Dermatol 1 249-260... 

Bissett DL, Chatterjee R, Hannon DP (1990) Photoprotective effect of superoxide-scavenging antioxidants against ultraviolet radiation-induced chronic skin damage in the hairless mouse. Photodermatol Photoimmunol Photomed 7 56-62... 

Offord, EA, JC Gautier, O Avanti et al. 2002. Photoprotective potential of lycopene, beta-carotene, vitamin E, vitamin C and camosic acid in UVA-irradiated human skin fibroblasts. Free Radio Biol Med 32(12) 1293-1303. 

Some adult invertebrates in tropical areas have relatively high MAA concentrations in external surfaces. Holothuroids preferentially accumulate MAAs in the epidermis, giant clams have highest concentrations of MAAs in the outermost layers of siphonal mantle tissue (more than four times the concentrations in subsurface mantle layers), sea hares have high MAA levels in skin, and ascidian tunics have higher MAA concentrations in the surface cells than in basal dermal lay-ers 102,152 154 jn coraiSj e upper exposed surface of colonies can have five-fold higher UV absorption than the less irradiated vertical faces.155 These topical distribution patterns reinforce the premise that MAAs have a photoprotective function. 

A study on the photoprotective effect of the topical application of 2% vitamin E and 5% vitamin C in humans showed no effect with the application of each substance alone, but an enhanced photo-protective effect after applying vitamins E and C combined, which was attributed to the regeneration of vitamin E by vitamin C.20 This enhanced effect has also been shown with the topical application of a combination of 15% ascorbic acid and 1% a-tocopherol to porcine skin.21 The combined systemic supplementation of vitamins C and E was similarly able to reduce sunburn reactions22 and to increase the minimal erythema dose (MED), a measure for individual photosensitivity, more than supplementation with either vitamin E or vitamin C alone.23,24 An oral supplementation with an anti-oxidative combination of carotenoids (P-carotene and lycopene), vitamin C, vitamin E, selenium, and proanthocyanidins (Seresis , Pharmaton SA, Lugano, Switzerland) also reduced the development and grade of UVB-induced erythema 25... 

Gelis C, Girard S, Mavon A, Delverdier M, Paillous N, Vicendo P. Assessment of the skin photoprotective capacities of an organo-mineral broad-spectrum sunblock on two ex vivo skin models. Photodermatol Photoimmunol Photomed 2003 19 242-53. 

Hexahydropyrrolo[l,2-a]thiazolo[3,4-d]pyrazine-3,5,10-trione derivatives, (IV), prepared by Erdelmeier (5) stimulated the intracellular synthesis of glutathione and were effective as photoprotective skin agents. 

Whereas in living organisms alkaloid molecules diffuse to receptor sites, melanosomes, owing to their immobility, are targets for molecules that diffuse toward them. Many biological functions of melanins, such as camouflage and skin photoprotection, depend on the physicochemical properties of the pigment, whose structure is of special interest to physicists with respect to spectroscopic and conductivity characteristics. 

D.L. Fabacher, E.E. Little (1998). Photoprotective substance occurs primarily in outer layers of fish skin. Environ. Sci. Poll. Res., 5,4-6. 

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