Table 1.

Exogenous antioxidants with photoprotective or damage protective effects.

Antioxidants	Outcome of the study	Study
Ascorbic acid	Topical vitamin C 5% cream applied for six months led to clinical improvement in the appearance of photoaged skin
	Topical vitamin C stimulates the collagen-producing activity of the dermis
	Magnesium ascorbyl phosphate administration immediately after exposure in hairless mice significantly delayed skin tumor formation and hyperplasia induced by chronic exposure to UV radiation	Elmore, 2005 [51]
	Ascorbic acid was a photoprotectant when applied to mice and pig skin before exposure to ultraviolet (UV) radiation	Elmore, 2005 [51]
Vitamin E	UV-induced vitamin E depletion	Packer and Valacchi, 2002 [52]
	The interaction of vitamin E with the eicosanoid system may result in an anti-inflammatory effect and thereby complement the photoprotective effects of other antioxidants in the skin	Boelsma et al., 2001 [53]
	Vitamin E has skin barrier-stabilizing properties	Packer et al., 2001 [54]
Lycopene	UV light decreased skin lycopene concentrations more so than skin β-carotene concentrations	Ribaya-Mercadoet al., 1995 [55]
	Lycopene protects against UV-induced erythema in humans
Carotenoids (carotene, β-carotene, and carotenoid mix)	Carotenoids are efficient in photoprotection, scavenging singlet oxygen, and peroxyl radicals. Supplements or a carotenoid-rich diet decreased sensitivity against UV-induced erythema	Sies and Stahl, 2004 [56]
	Supplementation with carotenoids contributes to basal protection of the skin but is not sufficient to obtain complete protection against severe UV irradiation	Stahl and Krutmann, 2006 [57]
	Dietary beta-carotene has effect on wrinkles and elasticity, procollagen gene expression, and ultraviolet (UV)-induced DNA damage in human skin	Cho et al., 2010 [58]
	Erythema-protective effect of a carotenoid mix inhibited serum lipid peroxidation	Heinrich et al., 1998 [59] Heinrich et al., 2003 [60] Lee et al., 2000 [61]
	Presupplementation with β-carotene before and during sunlight exposure provides protection against sunburn	Gollnick et al., 1996 [62]
	Inhibition of UV-induced epidermal damage and tumor formation in mouse models	Mathews-Roth and Krinsky, 1987 [63]
Tretinoin	Topical tretinoin ameliorates the clinical signs of photoaging	Cordero, 1983 [64] Kligman et al., 1986 [65]
	The treatment of photodamaged skin with tretinoin increased collagen I formation.	Griffiths et al., 1993 [66]
	Topical tretinoin is safe and effective in the treatment of photodamage	Gilchrest, 1997 [67]
	Improvement in photodamaged skin	Weinstein et al., 1991 [68]
	Topical tretinoin reduced the effects of photoaging	Voorhees, 1990 [69]
	Topical tretinoin in combination with sun protection as a useful approach to the treatment of sun-damaged skin	Leyden, 1998 [70]
Coenzyme Q10 (CoQ10)	Topical application of CoQ10 has the beneficial effect of preventing photoaging	Hoppe et al., 1999 [71]
	Coenzyme Q10 protects against oxidative stress-induced cell death and enhances the synthesis of basement membrane components in dermal and epidermal cells	Muta-Takada et al., 2009 [72]
	CoQ10 was shown to reduce UVA-induced MMPs in cultured human dermal fibroblasts	Inui et al., 2008 [73]
Glutathione	Glutathione is a photoprotective agent in skin cells	Connor and Wheeler, 1987 [74]
Zinc	Zn-treated fibroblasts were more resistant to UVR than cells grown in normal medium	Richard et al., 1993 [75]
	Zn can positively influence the effects of oxidative stress on cultured human retinal pigment epithelial (RPE) cells	Tate et al., 1999 [76]
Resveratrol	Application of resveratrol to the skin of hairless mice effectively prevented the UVB-induced increase in skin thickness and the development of the skin edema	Afaq and Mukhtar, 2002 [77]
Green tea	Green tea polyphenols were shown to reduce UV light-induced oxidative stress and immunosuppression	Katiyar et al., 2000 [78]
	Topical treatment or oral consumption of green tea polyphenols (GTP) inhibits chemical carcinogen- or UV radiation-induced skin carcinogenesis in different laboratory animal models	Katiyar, 2003 [79]
Green tea or caffeine	Oral administration of green tea or caffeine in amounts equivalent to three or five cups of coffee per day to UVB-exposed mice increased levels of p53, slowed cell cycling, and increased apoptotic sun burn cells in the epidermis	Lu et al., 2008 [80]
Sylimarin	Silymarin strongly prevents both photocarcinogenesis and skin tumor promotion in mice	Singh and Agarwal, 2002 [81]
	Skin cancer chemopreventive effects	Ahmad et al., 1998 [82]
Genistein	Antioxidant and anticarcinogenic effects on skin	Wei et al., 1995 [83]
Cocoa	Dietary flavanols from cocoa contribute to endogenous photoprotection, improve dermal blood circulation, and affect cosmetically relevant skin surface and hydration variables	Heinrich et al., 2006 [84]
	Photoprotection against UV-induced erythema	Heinrich et al., 2006 [84]