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Antioxidants

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Title: Antioxidants for vitiligo and photoprotection: new insights and possible therapeutic implications. …

Title: Antioxidants for vitiligo and photoprotection: new insights and possible therapeutic implications.
Introduction: It is known that oxidative stress is of main importance in the pathogenesis of vitiligo and in the cutaneous photo-damage. Reactive oxygen species (ROS) can start a pathogenetic cascade that leads to photo-carcinogenesis and photo-aging. Indeed, ROS induce DNA oxidative damage (i.e., strands breaks, nucleic acids oxidations, mutagenic lesions), proteins and lipid peroxidation and dermal accumulation. An imbalance in ROS scavenging systems have been reported in vitiligo patients, and hydrogen peroxide excess is known to induce melanocytes damage. Hence, the use of antioxidants (AOs) in dermatology, both endogenous and exogenous, have been investigated during the last two decades.
Aims & Scope: To evaluate the current knowledge about the use of AOs for increase photo-protection and vitiligo prevention and/or treatment.
Material and Methods: Antioxidants can be administered both topically and orally: the pros and cons of each one of these ways is discussed. 13 AOs have been chosen on the basis of their beneficial effects for photo-protection and vitiligo, and described in details. For each AO agent, the most recent and important studies have been reported. The Exogenous AOs molecules here discussed include: vitamin C, vitamin E, vitamin A, 4 flavoinoids (i.e., resveratrol, quercetin, tea polyphenols and soy isoflavones) Polypodium leucotomos extract, curcumin, capsaicin. Endogenous AOs include: polyunsatured fatty acids, glutathione, melatonin.
Results: Many recent studies on AOs show promising results, in both topical and oral administration of various antioxidants agents, alone or in combination with other AOs, minerals or aminoacids, and with phototherapy (i.e., narrow band UVB or PUVA). However, large part of the last decades’ studies have used in vitro models or animal models (especially mice), while few investigation have involved human beings.
Comments: Further investigations on human model, including randomized double-blind trials on large population groups, are necessary to obtain statistically significant data and to test different treatment modalities (oral vs topical, alone vs combined) of the various AOs molecules.

2 questions with 3 multiple choice:
1) Which of the following AOs have shown to protect against several cancers, beside skin cancer?
A. Vitamin C
B. Cathechins
C. Genstein
2) Which of the following AOs combination has been recently demonstrated toimprove the resistance of cultured cells to oxidative stress, in vitro?
A. Resveratol and capsaicin
B. Curcumin snd capsaicin
C. Curcumin and Polipodyum leucotmos exract
- DISCLAIMER-
This PPT is loaded as student material "as is", from the VRF Vitiligo Master Class Barcelona November 2011; VRF does not endorse or otherwise approve it.

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    PPT Title: Antioxidants for vitiligo and photoprotection: new insights and possible therapeutic implications.
    This PPT is loaded as student material 'as is', from the Vitiligo Master Class Barcelona November 2011; VRF does not endorse or otherwise approve it.
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  • 1. The International School of Vitiligo & Pigmentary Disorders Barcelona, 2-5 November 2011 ‘ ‘ Linda Tognetti, MD Division of Clinical, Preventive and Oncologic Dermatology Department of Critical Care Medicine and Surgery University of Florence (Italy)
  • 2. THE ROLE OF OXIDATIVE STRESS IN CUTANEOUS PHOTO-DAMAGE Photochemic reaction in the skinUV light SKIN CROMOPHORES φ photonbreakdown filaggrin > Urocanic acid 1O singlet oxygen (high concentrations superficially in the epidermis) 2 UV absorption > DNA changes between adjacent pyrimidine basesMutagenic Strand breaks + Reactive oxygen species (ROS) lesions nucleic acids oxidation Proteins and lipids Cell membrane damage Inflammation peroxidation Extracellular accumulation PHOTO-CARCINOGENESIS Melanoma; BCC and SCC Dermal matrix alteration PHOTO-AGING wrinkles, dryness, telangiectasia, pigmentary abnormalities Masaki H. Role of antioxidants in the skin: anti-aging effects. J Dermatol Sci 2010;58(2):85-90. Sander CS et al. Oxidative stress in malignant melanoma and non-melanoma skin cancer. Br J Dermatol 2003;148(5):913-22.
  • 3. THE ROLE OF OXIDATIVE STRESS IN THE PATHOGENESIS OF VITILIGO Significantly lower levels of: - vitamins C Significantly higher levels of - vitamin E indicators of oxidative stress: - superoxidedismutase - glutathione peroxidase malondialdehyde - catalase and xanthine oxidase - total antioxidant ativity in the skin and blood of vitiligo patients, compared Imbalance of ROS scavenging with controls H2O2 transfered from system in vitiligo melanocytes keratinocytes to melanocytes ROS cause lipid peroxidation of cellular membrane of melanocytes ROS alter melanocytes’ specific factors to produce neo-antigens  amplify antigen presentation  promote autoimmune destruction of melanocytesKoca R PV et al. Determination of oxidative stress in vitiligo by measuring superoxide dismutase and catalase levels in 406-9.Sravani et al. Oxidant-antioxidant enzymes and lipid peroxidation in generalized vitiligo. Clin Exp Dermatol 2004; 29(4): vitiliginous and non-vitiliginous Oxidative damage is the initial pathogenic event in melanocyte degenerationskin. Ind J Dermatol Venereol Leprol 2009;75:268–271.Khan R et al. Circulatory levels as antioxidantsreactive oxygen species by transferring hydrogen peroxide to melanocytes. be ArchPelle E et al. Keratinocytesdysregulation, oxidative stress, autoimmunity, and melanocytorrhagy in vitiligo: Can they J Invest Dermatol Res 2009;Namazi MR. Neurogenic act of a source of and lipid peroxidation in Indian patients with generalized and localized vitiligo. interconnected? Pigment301(10):731-72005;124:793–797.Cell Res 2007;20:360-3.Haider N et al. Oxidative Stress and Antioxidant Status in Vitiligo Patients.Dhaka Univ J Pharm Sci 2010; 9(2): 103-8.
  • 4. High metabolic demands SKINEnvironmental factors Increased Depletion of OXIDATIVE(smoking, pollution) oxidative antioxidants reserves DAMAGE stress  Physiologic antioxidant systems are insufficient ANTIOXIDANTS ORAL ADMINISTRATION: TOPICAL Diet, supplementati It may prevent Sunscreen on creams and/or limit photo-damage and vitiligo pathogenesis?Gonzalez S et al. A New Generation of Oral Photoprotectors. The Open Dermatology Journal 2011; 5:6-14.Masaki H. Role of antioxidants in the skin: anti-aging effects. J Dermatol Sci 2010;58(2):85-90.
  • 5. TOPICAL ANTIOXIDANTS TOPICAL AOs are a supplement to the physiological antioxidant protection present in the skin. They augment photoprotection provided by sunscreens lotions/creams. Direct application to the skin has the advantage of targeting a specific skin area needing photoprotection. Once penetrated through the stratum corneum, they may remain active for several days. Topical AOs exert their effect inside the cells: by regenerating each other, they provide an ontioxidants’ reservoir.Pinnell SR. Cutaneous photodamage, oxidative stress, and topical antioxidant protection. J Am Acad Dermatol 2003;48:1-19.Wang SQ et al. Photoprotection: a review of the current and future technologies. Dermatol Ther 2010;23(1):31-47.Gonzalez S et al. Current Trends in Photoprotection - A New Generation of Oral Photoprotectors. Open Dermat J 2011; 5:6-14.
  • 6. ORAL ANTIOXIDANTS Physiologic processes related to absorption, solubility and transport of oral AOs are not fully known, but they seem to limit the quote of oral OAs that can be delivered into the skin. An AO molecule is more stable when incorporated by nutrition in the skin, where it accumulates in a mixture with different AOs molecules, compared with single topically applied AO. Oral AOs increase the basal threshold of systemic AOs, actively collaborating in refreshing skin natural AO systems. Toghether with Topical AOs, Oral AOs can prevent photoaging and photocarcinogenesis, in both animal and human models. Oral AOs administration helps preventing skin alterations, (e.g., uneven skin tone and atopic dermatitis) and correlates with a lower incidence of wrinkles.Namazi MR, et al. Vitiligo and diet: a theoretical molecular approach with practical implications.Indian J Dermatol Venereol Leprol 2009;75(2):116-8.Epstein HA. The effect of diet and nutrition on the skin. Prime 2011;1:4 : 46-51.Gonzalez S, et al. Current Trends in Photoprotection - A New Generation of Oral Photoprotectors. Open Dermatol Journ 2011; 5:6-14.
  • 7. 13 Antioxidants VITAMIN C VITAMIN E VITAMIN A RESVERATROL QUERCETIN Flavonoids TEA POLYPHENOLS SOY ISOFLAVONES Polypodium leucotomos extract POLYUNSATURED FATTY ACIDS CURCUMIN CAPSAICIN GLUTATHIONE MELATONIN
  • 8.  Vitamin C or L-ascorbic acid is the predominant AO in the skin and it is an essential cofactor for collagen synthesis. Topical administration of L-ascorbate and its derivates (with greater SOURCES : cutaneous penetration) augments photo-protection (sunscreen component), papaya strawberry improves epidermal barrier function and provides anti-aging effects orange kale (moisturizing creams component). lemon melon Oral combination of vitamins C and E in high doses provide protection auliflower garlic against UV-induced erythema. grapefruit Ascorbic acid plasma levels are often lowered in patients with vitiligo. raspberry kiwi Oral administration of vit C, in association with vit E/ vit A/ vit B12/ mandarin passion fruit folic acid +/- broadband UVB, has been followed by definite spinach lime repigmentation without side effects in vitiligo patients. mango blackberry potatoDarr D et al. Effectiveness of antioxidants (vitamin C and E) with and without sunscreens as topical photoprotectants. Acta melonDerm Venereol 1996;76(4):264-8. cranberryEberlein-Konig B et al. Protective effect against sunburn of combined systemic ascorbic acid (vitamin C) and d-alpha-tocopherol(vitamin E). J Am Acad Dermatol 1998;38:45-8. tomatoMontes LF, et al. Folic acid and vitamin B12 in vitiligo: a nutritional approach. Cutis 1992;50(1):39-42. blueberryDon P et al.Treatment of vitiligo with broadband ultraviolet B and vitamins. Int J Dermatol. 2006;45(1):63-5. pineapple
  • 9.  Vitamin E exists in 8 forms, 4 tocopherols and 4 tocotrienols, being α-tocopherol the most represented in humans. Topical application of α-tocopherol reduces photo-aging and photo-carcinogenesis, and prevents UV-induced erythema, lipid SOURCES : peroxidation and immunosuppression. wheat germ oil Oral administration of vit E combined with vit C and/or vit A sunflower oil demonstrated to increase protection against UV-induced damage. safflower oil nuts, nut oils Oral 3 months-therapy with α-tocopherol plus ubiquinone, green leafy vegetables selenomethionine, methionine stopped the progression of vitiligo tomato products and induced repigmentation of the most recent lesions. pumpkin sweet potato Oral vit E has shown to increase narrow band-UVB effectiveness rockfish mangoes in vitiligo patients. asparagus broccoli papayasYuen KS, et al. Alpha-tocopherol, an inhibitor of epidermal lipid peroxidation, prevents ultraviolet radiation from suppressing avocadosthe skin immune system. Photochem Photobiol 1997;65:587-92.Lin JY et al. UV photoprotection by combination topical antioxidants vitamin C and vitamin E. J Am Acad Dermatol 2003: 48: 866–874.Picardo M et al. Antioxidant treatment in vitiligo? Pigment Cell Res 1997;10:360.Elgoweini M et al. Response of vitiligo to narrowband ultraviolet B and oral antioxidants. J Clin Pharmacol 2009;49(7):852-5.
  • 10. SOURCES : Liver (beef, pork,  Vitamin A includes retinol and carotenoids (α/β/γ-carotene, chicken, turk lycopene and the xanthophylls lutein and zeaxanthin). ey, fish) carrot broccoli leaf  Vit A is fat-soluble and can be stored in keratinocytes as retinyl esters. sweet potato  Carotenoids are useful to protect against UV-induced damage: butter kale  Lycopene concentration in skin correlates significantly with roughness. spinach  Daily oral β-carotene (30mg) can prevent and repair photoaging pumpkin collard and increases synthesis of procollagen type I. greens cheddar  Topical β-carotene (2mg/cm2) provides protection against ROS in the cheese cantaloupe human skin exposed to infra-red radiation. melon egg  Oral supplementation with vit A plus vit C and vit E, and minerals apricot papaya promoted vitiligo lesion repigmentation in the mice settings. mango pea broccoli milkCamera E et al. Astaxanthin, canthaxanthin and beta-carotene differently affect UVA-induced oxidative damage andexpression of oxidative stress-responsive enzymes. Exp Dermatol 2009; 18:222–231.Cho S et al. Differential effects of low-dose and high-dose beta-carotene supplementation on the signs of photoaging and type Iprocollagen gene expression in human skin in vivo. Dermatology. 2010;221:160-71.Darvin ME et al. Topical beta-carotene protects against infra-red-light-induced free radicals. Exp Dermatol 2011;20:125-9.Jalel A et al. Vitiligo treatment with vitamins, minerals and polyphenol supplementation. Indian J Dermatol 2009;54(4):357-60.
  • 11.  Quercetin is a very potent AO, member of the flavonoids family. Topical quercetin has successfully inhibited UVB- induced skin damage in rodent models. SOURCES : apples Topical application of the quercetin aglycone has been shown to onions (++red onion) prevent UVC-induced liposome peroxidation, UVB-induced red grapes citrus fruit myeloperoxidase activity and glutathione depletion. tomato broccoli leafy green In vitro studies demonstrated that quercetin can efficiently contrast vegetables keratinocytes oxidative damage induced by H2O2 exposure. raspberry whortleberry lingonberry cranberry chokeberry rowanberryVicentini FT et al. Quercetin in w/o microemulsion: in vitro and in vivo skin penetration and efficacy against UVB-induced skin capersdamages evaluated in vivo. Eur J Pharm Biopharm 2008; 69(3): 948-57. lovageCasagrande R et al. Protective effect of topical formulations containing quercetin against UVB-induced oxidative stress in rootshairless mice. J Photochem Photobiol B 2006; 84(1): 21-7. legumesFahlman BM et al. UVA and UVB radiation-induced oxidation products of quercetin. J Photochem Photobiol B. 2009; 97: 123-31.Wang X, et al.Quercetin in combating H2O2 induced early cell apoptosis and mitochondrial damage to normal human keratinocytes Chin Med J2010;123(5):532-536
  • 12.  Green tea polyphenols definition is used to refer to several potent antioxidants that appear in green tea leaves. The most abundant (60-80%) polyphenols contained in green tea leaves are cathechins: epicatechin epicatechin-3-gallate epigallocatechin epigallocatechin-3-gallate (EGCG)  most important molecule As antioxidant, cathehins are more potent than vitamins C and E. Cathechins are able to regenerate oxidized vitamin E.Harbowy ME et al. Tea chemistry. Crit Rev Plant Sci 1997;16:415-80.
  • 13.  EGCG has photo-protective, anti-inflammatory, anti-carcinogenic effects (promotes rapid repair of UVB- induced DNA damage) and can inhibit collagenase activity. Several studies assessed that oral administration of EGCG significantly increases the minimal erythema dose to UV, prevents disruption of the epidermal barrier function, improves microcirculation and modulates skin properties of women. Topical application of EGCG inhibits carcinogenesis and selectively increases apoptosis in UVB-induced skin tumors, in both animal and human model. Oral supplementation of green tea decoction in association with vit A/E/C and minerals (selenium, zinc) has promoted vitiligo lesions repigmentation in mice.Katiyar SK. Green tea prevents non-melanoma skin cancer by enhancing DNA repair. Arch Biochem Biophys. 2011; 508: 152-158.Jeon HY et al. Effects of oral epigallocatechin gallate supplementation on the minimal erythema dose and UV-induced skin damage. Skin PharmacolPhysiol 22; 2009:137–141.Heinrich U, et al. Green tea polyphenols provide photoprotection, increase microcirculation, and modulate skin properties of women. J Nutr 2011; 141:1202-8.Lu YP et al. Topical applications of caffeine or (-)-epigallocatechin gallate (EGCG) inhibit carcinogenesis and selectively increase apoptosis in UVB-induced skin tumors in mice. Proc Natl Acad Sci U S A 2002: 99: 12455–60.Camouse MM et al. Topical application of green and white tea extracts provides protection from solar-simulated ultraviolet light in human skin. ExpDermatol. 2009; 18: 522-526.Jalel A et al. Vitiligo treatment with vitamins, minerals and polyphenol supplementation. Indian J Dermatol 2009;54(4):357-60.
  • 14. TEA POLYPHENOLS QUERCETIN VITAMIN CGreen tea extract, quercetin and vitamin C havedemonstrated strong cytoprotective effects on H202 treatedMel-Ab melanocytes (immortalized mouse melanocyte cellline), preventing H202-induced cell death.Jeong Y-M et al. Cytoprotective Effect of Green Tea Extract and Quercetin against Hydrogen Peroxide-Induced Oxidative Stress. Arch Pharm Res2005; 28(11):1251-56.
  • 15. The triple combination green tea extract/quercetin/folicbeThis suggests that effective combinations of AOs mayacid prevented and cellular damage induced byoffers a aof importance, the that co-treatment with AOs H202 insynergistic manner.possible means of treating vitiligo.Jeong Y-M et al. Cytoprotective Effect of Green Tea Extract and Quercetin against Hydrogen Peroxide-Induced Oxidative Stress. Arch Pharm Res2005; 28(11):1251-56.
  • 16.  Resveratrol is a polyphenolic phytoalexin. Its benifical effects (anti-oxidant, anti-inflammatory, anti-cancer, blood sugar-lowering) are currently a topic of numerous animal and SOURCES : human studies. Grapes/wines Oral resveratrol can prevent UV-induced tumorigenesis, increases (red,rose,white, cell survival and contrast cutaneous inflammatory disorders. pinot noir) peanuts Topical adsorbption of resveratrol has been investigated, mulberries and its topical use on hairless mice before UVB irradiation blueberries decreased erythema, ROS production and inflammation. apples cocoa powder baking chocolate Nichols JA et al. Skin photoprotection by natural polyphenols: anti-inflammatory, antioxidant and DNA repair mechanisms. dark chocolate Arch Dermatol Res 2010; 302(2): 71-83.Ndiaye M et al. Ahmad N. The grape antioxidant resveratrol for skin disorders: promise, prospects, and challenges. Arch Biochem Biophys2011;508(2):164-70.Hung CF et al. Delivery of resveratrol, a red wine polyphenol, from solutions and hydrogels via the skin. Cancer Prev Res 2010;3(2):170-8.Aziz MH et al. Longley BJ, Ahmad N. Chemoprevention of skin cancer by grape constituent resveratrol: relevance to human disease? Faseb J 2005;19(9): 1193-5.
  • 17.  Soybeans and their associated food products are a rich source of flavonoids called isoflavones, the most abundant being genistein. In animal studies, oral soy or genistein protected against several SOURCES : cancers including bladder, breast, colon, liver, lung, prostate and skin. Soy red clover Oral genistein decreases UVB-induced skin photoaging, carcinogenesis, ginkgo biloba inflammation and immunosuppression in a rodent model. Topical genistein reduces erythema and histologic inflammation induced by PUVA in mice. Genistein has collagen-stimulating effects, by increasing collagen (COL1A2) gene expression. A recent study has reported an association between daily ingestion of Ginko biloba with a significant improvement in total VASI (Vitiligo Area Scoring Index) and VETF (Vitiligo European Task Force) staging in vitiligo patients.Barnes S. Effect of genistein on in vitro and in vivo models of cancer. J Nutr 1995;125:S777-83.Wei H et al. Isoflavone genistein: photoprotection and clinical implications in dermatology. J Nutr 2003; 133(11s1): 3811S-3819S.Widyarini S, et al. Isoflavonoid compounds from red clover (Trifolium pratense) protect from inflammation and immune suppression induced by UVradiation. Photochem Photobiol 2001: 74: 465–470.Shyong EQ et al. Effects of the isoflavone 4 ’, 5,7-trihydroxyisoflavone (genistein) on psoralen plus ultraviolet A radiation (PUVA)-inducedphotodamage. Carcinogenesis 2002; 23:317-21.Greenwel P et al. Tyrosine dephosphorylation of nuclear proteins mimics transforming growth factor beta-1 stimulation of alpha-2 (I) collagen geneexpression. Mol Cell Biol 1995;15:6813-9.Szczurko O. Ginkgo biloba for the treatment of vitilgo vulgaris: an open label pilot clinical trial. BMC Complement Altern Med 2011;11:21.
  • 18.  Curcumin, a low-molecular-weight polyphenol derived from Curcuma longa, is an active ingredient in the spice tumeric, to which curcumin gives the yellow color. Curcumin has anti-oxidant (induction of glutathione S- transferase enzymes), anti-proliferative, anti-inflammatory (inhibition on cytokines and  Phototoxic dermatitis  Melanoma prostaglandines synthesis),  Vitiligo antiviral, antibacterial and antifungal properties.  Psoriasis  Morphea It reduces wound-healing time, improves collagen deposition  Chronic inflammatory and increases fibroblast and vascular density in wounds. diseases  Primary cutaneous T-cell Potentially, curcumin could be employed in treatment lymphoma of different skin diseases.  NM skin cancer  CosmeticsRowe DL, et al. Modulation of the BRCA1 Protein and Induction of Apoptosis in Triple Negative Breast Cancer Cell Lines by the PolyphenolicCompound Curcumin. Breast Cancer: Basic and Clinical Research 2009; 3: 61–75.Cho JW et al.. Curcumin attenuates the expression of IL-1beta, IL-6, and TNF-alpha as well as cyclin E in TNF-alpha-treated HaCaT cells; NF-kappaBand MAPKs as potential upstream targets. Int J Mol Med 2007; 19: 469-474.Koeberte A, et al Curcumin blocks prostaglandin E2 biosynthesis through direct inhibition of the microsomal prostaglandin E2 synthase-1.Molecul Cancer Therapeut 2009; 8:2348-2355
  • 19. Phototoxic dermatitis It has been showed that topical pretreatment with curcumin significantly inhibited the pro-inflammatory effect of topically-applied tumor promoter 12-o-tetradecanoylphorbol-13-acetate (TPA) in combination with UVA . Melanoma Curcumin at higher doses induces apoptosis in relatively resistant malignant human melanoma cell lines, and its combination with tamoxifen provides a non-toxic option for combinatorial chemotherapy. Vitiligo A recent clinical trial has demonstrated that the association with topical tetrahydrocurcuminoid cream increases the effectiveness of targeted narrowband UVB phototherapy for induction of repigmentation in vitiligo patients. Ishizaki C et al. Enhancing effect of ultraviolet A on ornithine decarboxylase induction and dermatitis evoked by 12-o-tetradecanoylphorbol-13- acetate and its inhibition by curcumin in mouse skin.Dermatol 1996; 193: 311-317. Chatterjee S et al. Chemo-resistant melanoma sensitized by tamoxifen to low dose Curcumin treatment through induction of apoptosis and autophagy. Cancer Biol Ther 2011; 11: 216-228.Asawanonda P, Klahan S. Tetrahydrocurcuminoid cream plus targeted narrowband UVB phototherapy for vitiligo: a preliminary randomized controlledstudy. Photomed Laser Surg 2010; 28: 679-684.
  • 20. Vitiligo • A recent in vitro study has evaluated the protective effects of combinatorial therapy with curcumin and capsaicin supplementation in cultured cells from lesional, perilesional and healthy skin of selected vitiligo patients. • Total antioxidant capacity and mitochondrial membran depolarization has markers of scavenging activity and mitochondrial integrity have been considered. • The supplement of curcumin and capsaicin can improve the resistance of cultured cells to oxidative stress.Becatti M, Prignano F, et al. The involvment of Smac/DIABLO, p53, NF-kB, and MAPK pathways in apoptosis of keratinocytes from perilesional vitiligoskin: Protective effects of curcumin and capsaicin. Antiox Redox Signal 2010;13(1309-1321.
  • 21.  Capsaicin is a natural irritant of the vanilloid family, and represents the main capsaicinoid of chilli peppers and other capsicum preparations (chilli, cayenne pepper, red pepper) obtained from the fruits of the Solanaceae plants, of the genus Capsicum. Capsaicin is a potent anti-inflammatory agent which has been used for : pain and itch relief, because of its desensitization property (it produces a long-lasting refractory period after the initial excitation of sensory neurons); cancer prevention; cardiovascular diseases; weight reduction. High antioxidant and anti-apoptotic potential of capsaicin have been recently described. Pre-treatment with capsaicin inhibits keratinocytes apoptosis in peri-lesional vitiligo skin, increases cellular total antioxidant capacity, contrasts ROS generation and lipid peroxidation and improves mitochondrial activity and cell metabolism. Oyagbemi AA et al. Capsaicin: A novel chemopreventive molecule and its underlying molecular mechanisms of action. Indian J Cancer 2010;47(1):53-8 Becatti M et al. The involvement of Smac/DIABLO, p53, NF-kB, and MAPK pathways in apoptosis of keratinocytes form perilesional vitiligo skin: protective effects of curcumin and capsaicin. Antioxid Redox Signal 2010;13(9):1309-21.
  • 22.  P. leucotomos (PL) extract is obtained from the fern P. leucotomos. Topical application of PL showed to inhibit UVB- and PUVA therapy- induced erythema, in vivo, and to contrast photocarinogenesis. Oral administration provides photoprotection and significantly decreases Langerhans cells depletion. PL prevents oxidative DNA damage by accelerateing repair of thymine dimers and inhibiting trans-urocanic acid photoinduced isomerization and inactivation. PL can potentiate the endogenous antioxidant response and inhibits photo- immunosupression.Gonzalez S et al. Topical or oral administration with an extract of Polypodium leucotomos prevents acute sunburn and psolaren-inducedphototoxic reactions as well as depletion of Langerhans cells in human skin. Photodermatol. Photoimmunol Photomed 1997; 13: 50-60.Middelkamp-Hup MA et al. Orally administered Polypodium leucotomos extract decreases psoralen-UVA-induced phototoxicity, pigmentation, anddamage of human skin. J. Am. Acad. Dermatol. 2004; 50(1): 41-49.Capote R et al. Polypodium leucotomos extract inhibits trans-urocanic acid photoisomerization and photodecomposition. J Photochem Photobiol B2006; 82(3): 173-9.Brieva A, et al. Immunomodulatory properties of an hydrophilic extract of Polypodium leucotomos. Inflammopharmacol 2002;9:361-71.
  • 23.  Ω -3 polyunsatured fatty acids (PFA) are well-documented antioxidants and inhibitors of pro-inflammatory cytokines (e.g.,TNF-α) and free radicals.  Ω-3 PFA in the presence of AOs supplement appears to exert protection against auto-immunity by enhancing antioxidant enzymes.  The enrichment of cell membranes with Ω-3 PFA has been reported to increase the glutathione (GSH) peroxidase activity. SOURCES: cold water  High doses of Ω-3 PFA have been shown to decrease UVB-induced oily fish (salmon, erythema and flogsis. herring, mackerel,  Moreover, Ω-3 PFA seem to favorably influence the vulnerability and anchovies, outcome in depressive disorders, that affect many patients with vitiligo. sardines) fish oil,  The diet of vitiligo patients should include large use of Ω-3 PFA. flaxseeds, nuts, eggs, Brussel Fernandez G. Dietary lipids and risk of autoimmune disease. Clin Immunol Immunopathol 1994;72:193-7. sprouts,Joulain C . Increased glutathione peroxidase activity in human blood mononuclear cells upon in vitro incubation with n-3 blackfatty acids. Biochem Pharmacol 1994;47:1315-23. raspberry,Rhodes LE et al. Dietary fishoil supplementation in humans reduces UVB-erythemal sensitivity but increases epidermal lipid cowberryperoxidation. J Invest Dermatol 1994; 103(2): 151-4.Logan AC. Omega-3 fatty acids and major depression: A primer for the mental health professional. Lipids Health Dis 2004;3:25.Namazi MR et al. Vitiligo and diet: A theoretical molecular approach with practical implications. Indian J Dermatol Venereol Leprol2009;75:116-8
  • 24.  Glutathione (GSH) is a tripeptide ( γ-L-glutamyl-L-cysteinyl-glycine) and represents one of the major contributor to the functional vitality and morphological integrity of cells, where it controls redox-equilibrium. GSH provides efficient protection against UVB-rays damages, by inactivating different ROS and regulating several genes involved in DNA repair and cell cycle regulation.  Suprabasal keratinocytes employ high GSH quotes to absorb and neutralize UVB radiation, and paracrine GSH secretion might mediate basal cells protection.  GSH paracrine stimulation of basal keratinocytes decreases the rate of cyclobutane dimers formation and p53-positive cells. A severe GSH depletion has been documented inside keratinocytes after UV irradiation. The rationale of GSH supplementation is providing intrinsic wide-spectrum photo protection, cancer prevention and anti-aging effect.Schäfer M et al. Nrf2 establishes a glutathione-mediated gradient of UVB cytoprotection in the epidermis. Genes Dev 2010; 24:1045-58.Zhu M et al. Molecular mechanisms for UV-B irradiation-induced glutathione depletion in cultured human keratinocytes. Photochem Photobiol 2004; 80:191-6.Steenvoorden DP et al.The use of endogenous antioxidants to improve photoprotection. J Photochem Photobiol 1997; 41:1-10.Sekhar RV et al. Deficient synthesis of glutathione underlies oxidative stress in aging and can be corrected by dietary cysteine and glycinesupplementation. Am J Clin Nutr 2011
  • 25.  Various studies assessed low levels of glutathione peroxidase activity and total antioxidant status in vitiligo patients with or without diabetes and thyreopathy. It has been demonstrated that this depletion in antioxidant processes is involved in vitiligo pathogenesis. Reduced erythrocytic or systemic GSH levels constitute a distinctive feature in vitiligo patients regardless of disease activity. Anti-oxidant supplementation with GSH-precursor may be helpful in vitiligo treatment.  Consuming high protein foods, rich in sulphur-containing amino acids can help boost glutathione levels.Jalel A, et al. Study of total antioxidant status and glutathione peroxidase activity in Tunisian vitiligo patients. Indian J Dermatol 2009;54(1):13-6.Haider N et al. Oxidative Stress and Antioxidant Status in Vitiligo Patients.Dhaka Univ J Pharm Sci 2010; 9(2): 103-8.Shin JW et al. Erythrocyte malondialdehyde and glutathione levels in vitiligo patients. Ann Dermatol 2010;22(3):279-83.Khan R et al. Circulatory levels of antioxidants and lipid peroxidation in Indian patients with generalized and localized vitiligo. Arch Dermatol Res 2009;301(10):731-7Lu SC. Regulation of glutathione synthesis. Mol Aspects Med 2009; 30: 42-59.
  • 26.  Melatonin (MN) is one of the most ancient and phylogenetically conserved hormones, occurring in unicellular, plants and animals. MN is a potent scavenger of oxygen (OH, O2−), and NO radicals: it has an higher reduction potential than Vitamin C Direct antioxidant It is fivefold better than glutathione at neutralizing hydroxyl radicals, and twofold more effective than vitamin E at inactivating peroxyl radicals MN enhances gene expression of the main antioxidants enzymes: superoxide dismutase (SOD), catalase, glutathione peroxidase Indirect antioxidant MN contributes to the preservation of the epidermal barrier contrasts solar radiation and other physico-chemical stressors activates the pigmentary system to further prevent solar damage stimulates fibroblasts and endoteliocytes to maintain a functional dermis structure enhances immune system response against pathogens.Tan DX et al.Chemical and physical properties and potential mechanisms: melatonin as a broad spectrum antioxidant and free radical scavenger. CurrTop Med Chem 2002; 2: 181-97.Fischer TW et al. Melatonin as a major skin protectant: from free radical scavenging to DNA damage repair. Exp Dermatol 2008;17:713-30.Dreher F et al. Topical melatonin in combination with vitamins E and C protects skin from ultraviolet-induced erythema: a human study in vivo. Br JDermatol 1998;139:332-9.Bonnefont-Rousselot D et al. Melatonin: action as antioxidant and potential applications in human disease and aging. Toxicology 2010; 278:55-67.
  • 27.  In the skin, MN controls the dispersion and aggregation of melanin throughout melanocytes, causing the skin to change color (these variations follow MN circadian secretion cycle). In the past, overactive melatonin receptor was thought melatonin administration Skin disorders which could benefit from to have a key role in vitiligo pathogenesis. • Melanoma/carcinoma Recent evidences on the prominent antioxidative actions of MN have then suggested a • Aging • Psoriasis vulgaris revision of that hypothesis. • Alopecia • Radioprotection According to these evidences, an insufficient intracutaneous synthesis and buffering of MN • Atopic eczema • Sarcoidosis would lead to development of vitiligo when oxidative stress, cellular ⁄ subcellular or DNA • Diabetic foot syndrome damages occur because of insufficient scavenging erythema • Solar and ⁄ or buffering activity. • Hair greying • Vitiligo • Itching • Wound healingFischer T et al. Melatonin in dermatology. Experimental and clinical aspects. Hautarzt 1999;50:5-11.Slominski A et al. Hypothesis: possible role for the melatonin- receptor in vitiligo: discussion paper. J Royal Soc Med 1989: 82:539–541.Slominski A et al. View point 4: melatonin hypothesis on the vitiligo pathogenesis. Exp Dermatol 2008; 17: 149-52
  • 28. Take home message Benefical effects of AOs molecules have been investigated during last two decades. Large part of these studies have used in vitro models or animal models (mouse setting). Few studies have been performed on human beings, almost all based on limited study group and without adequate controls. Further investigations on human model, including randomized double-blind trials on large population groups, are necessary : > to obtain statistically significant data > to test different treatment modalities (oral vs topical, alone vs combined) of the various AOs molecules. AOs represents a natural tool for contrasting photo-damage(photo-aging and photo-carcinogenesis) and vitiligo patogenesis.
  • 29. Thank you for theattention.

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