Effects on UVB-induced

Huang et al. (1997) showed an inhibitory effect of p.o.-administered green and black tea on UVB-induced complete carcinogenesis, but the decaffeinated teas were either inactive at moderate dose levels or they enhanced the tnmorigenic effect of UVB at high dose levels. The oral administration of caffeine was foimd to have an inhibitory effect on UVB-induced complete carcinogenesis. This study concluded that caffeine was a biologically important corrstituent of tea. 

Ranaivo and others (2004) used the 4-hydroxynonenal index to demonstrate that wine polyphenols decrease oxidative stress, whereas Tomaino and others (2006) studied the in vitro protective effect of a wine extract on UVB-induced skin damage. 

Tomaino A, Cristani M, Cimino F, Speciale A, Trombetta D, Bonina F and Saija A. 2006. In vitro protective effect of a Jacquez grapes wine extract on UVB-induced skin damage. Toxicol Vitr 20(8) 1395-1402. 

The inhibitory effects of tea polyphenols on UVB-induced phosphatidylinositol-3-kinase (P13K) activation has been demonstrated in mouse epidermal JB6 Cl 41 cells. Pretreatment of cells with EGCG and TF-3 inhibited UVB-induced PI3K activation. Furthermore, UVB-induced activation of Akt and ribosomal p70S6 kinase (p °S6-K), PI3K downstream effectors, were also attenuated by these tea polyphenols. In addition to LY294002, a PI3K inhibitor, pretreatment with MAP-... 

Gills JJ, Kosmeder J 2nd, Moon RC, Lantvit DD, Pezzuto JM (2005) Effect of deguelin on UVB-induced skin carcinogenesis. J Chemerther 17 297—301... 

Inui M, Ooe M, Fuji K, Matsunaka H, Yoshida M, Ichihashi M (2008) Mechanisms of inhibitory effects of CoQlO on UVB-induced wrinkle formation in vitro and in vivo. Biofactors 32 237-243 Johnson A, Gin P, Marbois BN, Hsieh EJ, Wu M, Banos MH, Qarke CF, Tzagoloff A (2005) COQ9, a new gene required for the biosynthesis of coenzyme Q in Saccharomyces cerevisiae. J Biol Chem 280 31397-31404... 

The Protective Effect of Topical Application of DBM on UVB-induced Sunburn Lesions... 

Huang MT, Xie JG, Wang ZY, Ho CT, Lou YR, Wang CX, Hard GC and Conney AH. 1997. Effects of tea, decaffeinated tea, and caffeine on UVB light-induced complete carcinogenesis in SKH-1 mice demonstration of caffeine as a biologically important constituent of tea. Cancer Res 57(13) 2623-2629. 

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... 

In this chapter we summarize work from our laboratory in which we have tested these predictions. The hairless mouse is our model. Initial experiments utilized excised skin while later studies used an in vivo system. We irradiated these systems with either UVA (320 100 nm), UVB (290-320 nm), or simulated sunlight in a pattern of UVA and UVB which closely matched natural sunlight. We have measured UV-induced changes in antioxidants, lipid peroxidation, and the effects of dietary supplementation with the major chain-breaking lipophilic antioxidant, a-tocopherol, on UV-induced skin damage. 

Interestingly, the levels of all the extractable flavonoids in the leaves of B. napus plants are decreased in a dose-dependent manner in response to UVA exposure. Additionally, the accumulation of the extractable flavonoids was examined by a shift from the photosynthetically active radiation (PAR) + UVA to PAR + UVB to assess whether the preexposure of the UVA affects the UVB-induced flavonoid accumulation. The UVA preexposures inhibited the UVB-induced accumulation of some flavonoids. This down regulation was particularly evident for quercetin-3-O-sophoroside and quercetin-3-O-sophoroside-7-O-glucoside of two anthocyanins. This is very interesting because the induction of quercetin by UVB is correlated with the UVB tolerance in some plant species. The photobiological nature of these UVA-mediated effects on flavonoid accumulation might suggest complex interactions between the UVA and UVB responses [66]. 

EGCG arrested UVB-induced steady-state message and transcriptional activation of the c-fos gene and accumulation of the c-fos protein in human keratinocyte ceU line, Ha-CaT via p38 MAPN (Chen et al. 1999). It also inhibited the stimulatory effect of PDGF-receptor p on the c-fos mRNA expression in cultured vascular smooth muscle cells Ifom rat aorta (Ahn et al. 1999). However, EGCG and other green tea polyphenols induced c-JUN/c-FOS in HT-29 and Caco-2 colon cancer ceU lines (Kim et al. 2004) and epidermal cells (Balasubramanian et al. 2002). Curcumin also inhibited the expression of c-FOS (Lin... 

Microemulsion reduced incidence of histological skin alterations, mainly the connective-tissue damage, induced by exposure to UVB irradiation. Study also demonstrated no toxicity of the microemulsion, by evaluating the cytotoxic effect on L929 cells and histological aspects. 

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