Topical antioxidant vitamins C and E prevent UVB-radiation-induced peroxidation of eicosapentaenoic acid in pig skin

Nutrition and nonmelanoma skin cancers

Nonmelanoma skin cancer (NMSC), the most widely diagnosed cancer in the United States, is rising in incidence despite public health and educational campaigns that highlight the importance of sun avoidance. It is,therefore, important to establish other modifiable risk factors that may be contributing to this increase. There is a growing body of evidence in the literature suggesting certain nutrients may have protective or harmful effects on NMSC. We review the current literature on nutrition and its effect on NMSC with a focus on dietary fat, vitamin A, nicotinamide, folate, vitamin C, vitamin D, vitamin E, polyphenols, and selenium.

Determining the effectiveness of vitamin C in skin care by atomic force microscope

This article presents the results of experiments, which examine cell mechanisms with the goal of confirming the effective action of the active ingredients used in anti-aging cosmetics. Skin stiffness measurements with the use of an atomic force microscope on two forms of vitamin C (ascorbyl tetraisopalmitate and l-ascorbic acid) have been presented. The estimated Young's modulus for three types of cells (a control as well as cells treated with two forms of vitamin C) has shown significant differences in the stiffness of the tested cells which was confirmed in the histological staining experiment. The presented results indicate the dependence between collagen synthesis and the stiffness of cells treated with two forms of vitamin C.

The relevance of piroxicam for the prevention and treatment of nonmelanoma skin cancer and its precursors

Piroxicam (PXM), a nonsteroidal anti-inflammatory drug, is an enolic benzothiazine and a potent member of the oxicam series. The drug suppresses the synthesis of proinflammatory enzymes, such as cyclo-oxygenases-1 and -2 (COX-1 and 2), downregulates the production of prostaglandins (PGs) and tromboxanes, and inhibits polyamines production by blocking ornithine decarboxylase induction involved in nonmelanoma skin carcinogenesis. In addition, PXM is able to induce tumor cell apoptosis and suppresses metalloproteinase 2 activities. Skin carcinogenesis is a multistep process in which the accumulation of genetic events leads to a gradually dysplastic cellular expression, deregulation of cell growth, and carcinomatous progression. COX-1 upregulation plays a significant role in PG and vascular epidermal growth factor production supporting tumor growth. Increased level of PGs in premalignant and/or malignant cutaneous tumors is also favored by upregulation of COX-2 and downregulation of the tumor suppressor gene 15-hydroxy-prostaglandin dehydrogenase. Chemoprevention can be a hopeful approach to inhibit carcinoma occurrence before an invasive tumor develops. The chemopreventive effect of nonsteroidal anti-inflammatory drugs on nonmelanoma skin cancers has been established. In this study, we highlighted the different modalities of action of PXM on the pathogenesis of nonmelanoma skin cancer, analyzing and evaluating binding modes and energies between COX-1 or COX-2 and PXM by protein–ligand molecular docking. Our clinical experience about the local use of PXM on actinic keratoses and field cancerization is also reported, confirming its efficacy as target therapy.

Antioxidant and antitumor activities of selenium- and zinc-enriched oyster mushroom in mice

Selenium and zinc are well-known essential trace elements with potent biological functions. However, the possible health benefits of the combined administration of dietary selenium and zinc have not been studied extensively. In this study, we prepared selenium- and zinc-enriched mushrooms (SZMs) containing increased levels of selenium and zinc. The effects of SZMs on antioxidant and antitumor activities were evaluated. Mice were fed with either a control diet or a diet supplemented with SZMs or sodium selenite and zinc sulfate for 6 weeks. Antioxidant capacity was investigated by measuring the activities of antioxidant enzymes and the levels of lipid peroxide products. Results showed that treatment with SZMs significantly increased the activities of glutathione peroxidase (GPx) and superoxide dismutase and decreased the levels of malondialdehyde and lipofuscin. Furthermore, using a mouse model of lung tumors, we found that SZMs significantly decreased the number of tumor nodes with an increase in the activity of GPx. SZMs had a greater effect on the increase in both antioxidant and antitumor activities than did sodium selenite and zinc sulfate. These findings suggest that SZMs may be effective for improving antioxidant capacity and preventing tumors.

Spontaneous ultraweak photon emission imaging of oxidative metabolic processes in human skin: effect of molecular oxygen and antioxidant defense system

All living organisms emit spontaneous ultraweak photon emission as a result of cellular metabolic processes. In this study, the involvement of reactive oxygen species (ROS) formed as the byproduct of oxidative metabolic processes in spontaneous ultraweak photon emission was studied in human hand skin. The effect of molecular oxygen and ROS scavengers on spontaneous ultraweak photon emission from human skin was monitored using a highly sensitive photomultiplier tube and charged coupled device camera. When spontaneous ultraweak photon emission was measured under anaerobic conditions, the photon emission was decreased, whereas under hyperaerobic condition the enhancement in photon emission was observed. Spontaneous ultraweak photon emission measured after topical application of glutathione, α-tocopherol, ascorbate, and coenzyme Q10 was observed to be decreased. These results reveal that ROS formed during the cellular metabolic processes in the epidermal cells play a significant role in the spontaneous ultraweak photon emission. It is proposed that spontaneous ultraweak photon emission can be used as a noninvasive tool for the temporal and spatial monitoring of the oxidative metabolic processes and intrinsic antioxidant system in human skin.

Nutrition and nonmelanoma skin cancers

The incidence of nonmelanoma skin cancer is increasing every year. Basal cell carcinoma and squamous cell carcinoma are the two major types of nonmelanoma skin cancer. Among other factors, understanding the potential role of nutrients in the development, progression, and treatment of nonmelanoma skin cancer is critical. This contribution provides a review of the nutrients that have been more extensively investigated in the literature with regard to nonmelanoma skin cancer, including dietary fats, retinol, carotenoids, vitamin C, vitamin D, vitamin E, selenium, copper, iron, zinc, green tea, and black tea.

Effect of pre-treatment of almond oil on ultraviolet B?induced cutaneous photoaging in mice

BACKGROUND

Ultraviolet (UV) radiation has been implicated in photoaging and various types of skin carcinomas. Although the human skin has evolved several defense mechanisms to survive the insults of actinic damage like keratinization, melanin pigmentation, etc., it is still subjected to the harmful effects of sunlight.

AIMS

In this study, the role of almond oil in reducing the degradative changes induced in skin upon exposure to UV radiation was investigated.

METHODS

Mice were divided in four groups of 20 animals. Group I was the control group. Group II was negative control, which received almond oil treatment alone. Group III was exposed to UV radiation only and Group IV received both UV treatment and almond oil treatment. Visible skin grading assessed the changes based on a rating scale, biochemical tests (glutathione estimation and lipid peroxidation), and histopathologic studies.

RESULTS

Upon exposure of mice to UV radiation, it was found that pronounced visible skin changes were seen after 12 weeks of exposure. The results of the biochemical tests, glutathione estimation, and lipid peroxidation showed that almond oil reduced the effect of UV light-induced photoaging on the skin. Histopathologic studies also indicated a photoprotective effect of almond oil on the skin after UV exposure.

CONCLUSIONS

It was concluded that topical almond oil is capable of preventing the structural damage caused by UV irradiation and it was also found useful in decelerating the photoaging process.

Vitamina C

Vitamin C or ascorbic acid is a hydrosoluble vitamin derived from glucose metabolism. It acts as a reductor agent required for synthesis of collagen fibers through hydroxylation of proline and lysine. It also protects the body against damage caused by the free radicals. Humans cannot synthesize ascorbic acid as they lack an enzyme called gulonolactone oxidase. Concentrations in plasma and leukocytes reflect the levels of the diet and body deposits respectively of this vitamin. Among foods with high vitamin C levels are tomatoes, potatoes, and citrus fruits such as limes, oranges and lemons. The current recommendation of daily intake of vitamin C is 90 mg/d for men and 75 mg/d for women. Patients with chronic diseases such as cancer or diabetes or those who smoke need higher doses in their usual diet. Ascorbic acid deficiency gives rise to the appearance of scurvy. This disease is rarely seen in developed countries. The symptoms develop with plasma levels below 0.15 mg/dL. Scurvy is characterized by the presence of weakness, joint pain or skin lesions in form of petechias, gum bleeding, ease of developing bruises or delay in wound healing. The most characteristic skin manifestations are purpuric perifollicular hyperkeratotic papules and the presence of kinky hair.

A new lipophilic pro-vitamin C, tetra-isopalmitoyl ascorbic acid (VC-IP), prevents UV-induced skin pigmentation through its anti-oxidative properties

BACKGROUND

Vitamin C, which is a strong anti-oxidant, plays an important role in maintaining physiological states. In dermatology, Vitamin C is used for treatment of various skin problems such as de-pigmentation of hyperpigmented spots. However, Vitamin C has limited stability and permeability, and development of a Vitamin C derivative with improved properties is needed.

OBJECTIVE

We evaluated the effect of a lipophilic Vitamin C derivative, tetra-isopalmitoyl ascorbic acid (VC-IP), on ultraviolet (UV)-induced skin pigmentation, to determine its potential as a more effective form of Vitamin C.

METHODS

The release of Vitamin C from VC-IP was examined using a reconstructed skin model following topical application of VC-IP. Anti-oxidative and anti-inflammatory activities of VC-IP were tested in cultured human keratinocytes. Subsequently, clinical test was done to clarify the effect of VC-IP on UVB-induced skin pigmentation.

RESULTS

VC-IP released Vitamin C in physiological conditions and worked as pro-Vitamin C. In subsequent experiments, we found that VC-IP suppressed the elevation of intracellular peroxide after UVB irradiation, and enhanced cellular tolerance against UVB and reactive oxygen species such as hydrogen peroxide and tert-butyl hydroperoxide. Furthermore, VC-IP reduced the production of interleukin-1alpha and prostaglandin E2 in UVB-irradiated keratinocytes and suppressed melanocyte proliferation in conditioned culture medium prepared from UVB-irradiated keratinocytes. Finally, in a clinical study, topical application of a 3% VC-IP cream for 3 weeks suppressed pigmentation after UVB irradiation.

CONCLUSIONS

These results demonstrate that VC-IP is a precursor of Vitamin C, and effectively suppresses UVB-induced skin pigmentation, possibly through its anti-oxidative activity.

Photoprotective effect of sesamol on UVB-radiation induced oxidative stress in human blood lymphocytes in vitro

Normal lymphocytes are highly sensitive to the damaging effect of radiation and undergo cell death. In the present study, the photoprotective effect of sesamol, a constituent of sesame oil, has been examined in the UVB-(280-320nm) irradiated human blood lymphocytes. Lymphocytes pretreated with increasing concentrations of sesamol (1, 5 and 10μg/ml) for 30min, were irradiated and lipid peroxidation and antioxidant defense were examined. UVB-irradiated lymphocytes exhibited increased levels of lipid peroxidation and disturbances in antioxidant defense. Sesamol pretreatment resulted in significant reduction in lipid peroxidation marker, thiobarbituric acid reactive substances (TBARS). Further, antioxidants like reduced glutathione (GSH), superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx) increased, in a dose-dependent manner, in sesamol pretreated and UVB-irradiated lymphocytes. The maximum dose of sesamol (10μg/ml) normalized the UVB induced lipid peroxidation, indicating the photoprotective effect of sesamol in irradiated lymphocytes.

Safety and efficacy of 4% hydroquinone combined with 10% glycolic acid, antioxidants, and sunscreen in the treatment of melasma

BACKGROUND

Melasma, also known as mask of pregnancy, is a common, acquired hypermelanosis seen in women with Fitzpatrick skin types II-V, and is often recalcitrant to treatment with depigmentation agents. Glycolic acid has been added to hydroquinone formulations in the past to enhance their depigmentation effects, but may cause irritation, leading to postinflammatory hyperpigmentation.

AIM

To assess the safety and efficacy of a cream containing 4% hydroquinone, 10% buffered glycolic acid, vitamins C and E, and sunscreen (Glyquin, ICN Pharmaceuticals, Costa Mesa, USA) vs. a cream containing sunscreen alone in the depigmentation of epidermal melasma of the face.

METHODS

Thirty-nine Hispanic women, Fitzpatrick skin types III-V, with bilateral epidermal melasma were enrolled in a randomized controlled trial lasting 12 weeks. Patients underwent twice-daily full-face application with the study cream or with the cream containing sunscreen only. Changes in pigmentation were measured using a mexameter, the melasma area and severity index (MASI), and a global evaluation by the patient and blind investigator. Safety evaluations were performed at each follow-up visit.

RESULTS

Thirty-five patients completed the trial. Irritation was more common with the study cream, but resolved with temporary cessation of cream application and the addition of moisturizers. Mexameter results demonstrated a significant decrease in the degree of pigmentation using the study cream compared with the cream containing sunscreen alone (P < 0.0001). Fifteen of 20 patients (75%) using the study cream improved, whereas only two of 15 patients (13%) improved using sunscreen alone.

CONCLUSIONS

A cream containing 4% hydroquinone, 10% buffered glycolic acid, vitamins C and E, and sunscreen is safe and effective in the treatment of melasma.

Topically applied vitamin C and cysteine derivatives protect against UVA-induced photodegradation of suprofen in ex vivo pigskin

Exposure of the nonsteroidal anti-inflammatory drug suprofen (SUP) to UV-radiation results in the formation of radicals, reactive oxygen species (ROS), photodecarboxylated products and photoadducts with biomacromolecules. Using an ex vivo pigskin explant model, we investigated whether topical coapplication of the water-soluble antioxidants vitamin C (Lascorbic acid, ASC), N-acetyl-L-cysteine (NAC) or L-cysteine ethylester (CYSET) with SUP reduced ultraviolet A (UVA)-induced decomposition of SUP. UVA-induced changes in antioxidant bioavailability in the stratum corneum and epidermis were also studied. Epidermal bioavailability of SUP in sham-irradiated pigskin increased 2.2- to 4.1-fold after the lowest antioxidant doses (P < 0.05). As compared with no applied antioxidant, increasing doses of all tested antioxidants resulted in increased levels of SUP and decreased levels of photoproducts (P < 0.05). A maximal protection against SUP photodegradation of 70% was found after an ASC dose of 1 micromol/cm2; these values were 60% for a NAC dose of 10 micromol/cm2 and 50% for a CYSET dose of 5 micromol/cm2. Skin antioxidant levels increased with increasing applied dose (P < 0.05); the bioavailability of CYSET was approximately three-fold lower than that of ASC and NAC. UVA exposure resulted in 30-50% consumption of the topically applied ASC or NAC in the stratum corneum, whereas CYSET was not consumed. In conclusion, the topically applied water-soluble antioxidants ASC, NAC and CYSET protect against UVA-induced decomposition of SUP by scavenging radicals and ROS. Coapplication of these antioxidants may therefore be an effective way to reduce or prevent the phototoxic effects of SUP in vivo.

Photoprotection by antioxidants against UVB-radiation-induced damage in pig skin organ culture

Topically applied antioxidants constitute an important group of protective agents against skin damage induced by ultraviolet radiation. The current study was performed to investigate whether a recently developed ex vivo pig skin model was suitable for short-term studies of the mechanism(s) of UVB-radiation-induced skin damage; the protective effect of topical application of alpha-tocopherol, l-ascorbic acid, alpha-lipoic acid, glutathione ethylester and N-acetylcysteine was tested. Increasing doses of the antioxidants were applied topically on ex vivo pig skin explants and allowed to penetrate for 60 min. Epidermal antioxidant bioavailability was measured before and 60 min after exposure to an ultraviolet B (UVB) radiation of 7.5 kJ/m2. Cell viability (trypan blue dye exclusion) and apoptosis were measured 48 h later in isolated keratinocytes. UVB-radiation-induced epidermal lipid peroxidation was determined immediately after exposure of the skin to a UVB dose of 28 kJ/m2. All antioxidants tested became bioavailable in pig skin epidermis, and none of them were depleted after UVB-radiation exposure. Increasing doses of the antioxidants tested decreased UVB-radiation-induced cell death and apoptosis. The highest doses of antioxidants prevented UVB-radiation-induced lipid peroxidation; alpha-lipoic acid only tended to decrease lipid peroxidation. In conclusion, a single topical dose of the above antioxidants on ex vivo pig skin can reduce UVB-radiation-induced oxidative stress and lipid peroxidation and thereby reduce apoptotic stimuli and cell death. Furthermore, the ex vivo pig skin model was a useful tool for testing compounds for their antioxidant activity.