Botanical antioxidants in the prevention of photocarcinogenesis and photoaging

Myricetin protects keratinocyte damage induced by UV through IκB/NFκb signaling pathway

OBJECTIVE

The aim of this study was to evaluate the potential molecular mechanism of myricetin that protecting cells from photodamage.

METHODS

Myricetin had broadly chemopreventive effects and anti-inflammatory properties. The effect of myricetin was assessed on HaCaT cells. Cell viability assay was carried out. Reactive oxygen species (ROS) level was measured. The expression of pro-inflammatory factor COX2 was determined by real-time PCR and Western blot. The protein levels of p-IκBa and IκBa were determined by Western blot.

RESULTS

Myricetin attenuated UV-induced keratinocyte death in a dose-dependent manner as determined by cell viability assay. Pretreatment with myricetin also reduced the UV-induced ROS levels. Myricetin suppresses the upregulation of COX2 induced by UV in keratinocyte as demonstrated by real-time PCR and Western blot. Furthermore, signal transduction studies confirmed that myricetin attenuates the upregulation of COX2 induced by UV via suppression of IκB/NFκB pathways.

CONCLUSION

These results showed that antioxidant property of myricetin can effectively attenuate UV-caused cell damage and suppress the expression of COX2 through the IκB/NFκB signaling pathways. Myricetin had potential protective effects on UV-induced skin cell damages, which might be used in cosmetic and pharmaceutical industries.

The effect of mangiferin on skin: Penetration, permeation and inhibition of ECM enzymes

Mangiferin (2-C-β-D-glucopyranosyl-1,3,6,7-tetrahydroxyxanthone) is a polyphenol with strong antioxidant properties. Mangiferin is obtained from the mango tree (Mangifera indica L., Anacardiaceae). It has been proven that mangiferin exhibits many pharmacological activities. The aim of this study was to analyze the penetration of mangiferin into the human skin and through the skin. According to our knowledge, skin penetration and permeation studies of mangiferin have not been analyzed so far. Additionally, the influence of mangiferin on two Extracellular Matrix Enzymes (ECM): collagenase and elastase, was evaluated for the first time. It has been indicated that mangiferin is able to permeate the stratum corneum and penetrate into the epidermis and dermis in comparable amounts. For confirmation of the obtained results, fluorescence microscopy was successfully utilized. The analysis revealed the capability of mangiferin to reversibly inhibit elastase and collagenase activity. The mechanism of mangiferin interaction with both enzymes was estimated as a noncompetitive inhibition.

Meristem Plant Cells as a Sustainable Source of Redox Actives for Skin Rejuvenation

Recently, aggressive advertisement claimed a “magic role” for plant stem cells in human skin rejuvenation. This review aims to shed light on the scientific background suggesting feasibility of using plant cells as a basis of anti-age cosmetics. When meristem cell cultures obtained from medicinal plants are exposed to appropriate elicitors/stressors (ultraviolet, ultrasound ultraviolet (UV), ultrasonic waves, microbial/insect metabolites, heavy metals, organic toxins, nutrient deprivation, etc.), a protective/adaptive response initiates the biosynthesis of secondary metabolites. Highly bioavailable and biocompatible to human cells, low-molecular weight plant secondary metabolites share structural/functional similarities with human non-protein regulatory hormones, neurotransmitters, pigments, polyamines, amino-/fatty acids. Their redox-regulated biosynthesis triggers in turn plant cell antioxidant and detoxification molecular mechanisms resembling human cell pathways. Easily isolated in relatively large quantities from contaminant-free cell cultures, plant metabolites target skin ageing mechanisms, above all redox imbalance. Perfect modulators of cutaneous oxidative state via direct/indirect antioxidant action, free radical scavenging, UV protection, and transition-metal chelation, they are ideal candidates to restore photochemical/redox/immune/metabolic barriers, gradually deteriorating in the ageing skin. The industrial production of plant meristem cell metabolites is toxicologically and ecologically sustainable for fully “biological” anti-age cosmetics.

A Combination of Soybean and Haematococcus Extract Alleviates Ultraviolet B-Induced Photoaging

Soybean-derived isoflavones have been investigated for their preventative effects against UV-induced symptoms of skin damage including wrinkle formation and inflammation. Haematococcus pluvialis is a freshwater species of Chlorophyta that contains high concentrations of the natural carotenoid pigment astaxanthin. Astaxanthin is known to be involved in retinoic acid receptor (RAR) signaling and previously been associated with the inhibition of activator protein (AP)-1 dependent transcription. Based on previous studies, we hypothesized that a combination of soy extract (SE) and Haematococcus extract (HE) may prevent UVB-induced photoaging through specific signaling pathways, as measured by UVB-induced wrinkling on hairless mice skin and expression changes in human dermal fibroblasts (HDFs). The 1:2 ratio of SE and HE mixture (SHM) showed the optimal benefit in vivo. SHM was found to inhibit wrinkle formation via the downregulation of matrix metalloproteinase (MMP)-1 mRNA and protein expression. SHM also inhibited mitogen-activated protein kinase (MAPK) phosphorylation and the transactivation of AP-1 which plays an important role in regulating MMP expression. These results highlight the potential for SHM to be developed as a therapeutic agent to prevent UVB-induced skin wrinkling.

Ganoderma lucidum polysaccharides protect fibroblasts against UVB-induced photoaging

Ganoderma lucidum has featured in traditional Chinese medicine for >1,000 years. Ganoderma polysaccharides (GL-PS), a major active ingredient in Ganoderma, confer immune regulation, antitumor effects and significant antioxidant effects. The aim of the present study was to investigate the efficacy and mechanism of GL‑PS‑associated inhibition of ultraviolet B (UVB)‑induced photoaging in human fibroblasts in vitro. Primary human skin fibroblasts were cultured, and a fibroblast photoaging model was built through exposure to UVB. Cell viability was measured by MTT assay. Aged cells were stained using a senescence‑associated β-galactosidase staining (SA‑β‑gal) kit. ELISA kits were used to analyze matrix metalloproteinase (MMP) ‑1 and C‑telopeptides of Type I collagen (CICP) protein levels in cellular supernatant. ROS levels were quantified by flow cytometry. Cells exposed to UVB had decreased cell viability, increased aged cells, decreased CICP protein expression, increased MMP‑1 protein expression, and increased cellular ROS levels compared with non‑exposed cells. However, cells exposed to UVB and treated with 10, 20 and 40 µg/ml GL‑PS demonstrated increased cell viability, decreased aged cells, increased CICP protein expression, decreased MMP‑1 protein expression, and decreased cellular ROS levels compared with UVB exposed/GL‑PS untreated cells. These results demonstrate that GL‑PS protects fibroblasts against photoaging by eliminating UVB‑induced ROS. This finding indicates GL‑PS treatment may serve as a novel strategy for antiphotoaging.

Dietary Foeniculum vulgare Mill extract attenuated UVB irradiation-induced skin photoaging by activating of Nrf2 and inhibiting MAPK pathways

BACKGROUND

Foeniculum vulgare Mill (FV) has long been prescribed in traditional medicine due to its antioxidant anti-inflammatory properties. However, little research has been done on the use of FV to alleviate changes in UVB-induced photoaging PURPOSE: This study was to investigate the photoprotective effects and mechanism of FV in vitro and in vivo.

METHODS

The anti-photoaging effect of FV was assessed in normal human dermal fibroblasts (NHDFs) in vitro. The secretion of reactive oxygen species (ROS), lactate dehydrogenase (LDH), GSH, matrix metalloproteinases (MMPs), procollagen type I, IL-6 and transforming growth factor-β1 (TGF-β1) were measured by kits. Additionally, the level of nuclear factor (erythroid-derived 2)-like 2 (Nrf2), p-ERK and p38 were evaluated by western blotting. In vivo, H&E and Masson's trichrome staining were employed. The expression of MMP-1, procollagen type I, TGF-β1 and elastin were measured by western blot.

RESULTS

FV significantly increased the production of collagen, elastin and TGF-β1 levels, while blocked matrix metalloproteinases (MMPs) production in UVB irradiation induced hairless mice, which were consistent with the result in NHDFs. Furthermore, FV dose-dependently decreased the production of ROS and LDH by promoting the nuclear amount of Nrf2 and enhancing the expression of cytoprotective antioxidants such as GSH. FV also significantly quenched UVB-induced phosphorylation of ERK and p38 in NHDFs.

CONCLUSION

Our results indicate that FV is a potential botanical agent for the treatment of skin damage induced by UV irradiation.

Lemon balm extract (Melissa officinalis, L.) promotes melanogenesis and prevents UVB-induced oxidative stress and DNA damage in a skin cell model

BACKGROUND

Solar ultraviolet (UV) radiation is one of the main causes of a variety of cutaneous disorders, including photoaging and skin cancer. Its UVB component (280-315nm) leads to oxidative stress and causes inflammation, DNA damage, p53 induction and lipid and protein oxidation. Recently, an increase in the use of plant polyphenols with antioxidant and anti-inflammatory properties has emerged to protect human skin against the deleterious effects of sunlight.

OBJECTIVE

This study evaluates the protective effects of lemon balm extract (LBE) (Melissa Officinalis, L) and its main phenolic compound rosmarinic acid (RA) against UVB-induced damage in human keratinocytes.

METHODS

The LBE composition was determined by HPLC analysis coupled to photodiode array detector and ion trap mass spectrometry with electrospray ionization (HPLC-DAD-ESI-IT-MS/MS). Cell survival, ROS generation and DNA damage were determined upon UVB irradiation in the presence of LBE. The melanogenic capacity of LBE was also determined.

RESULTS

RA and salvianolic acid derivatives were the major compounds, but caffeic acid and luteolin glucuronide were also found in LBE. LBE and RA significantly increased the survival of human keratinocytes upon UVB radiation, but LBE showed a stronger effect. LBE significantly decreased UVB-induced intracellular ROS production. Moreover, LBE reduced UV-induced DNA damage and the DNA damage response (DDR), which were measured as DNA strand breaks in the comet assay and histone H2AX activation, respectively. Finally, LBE promoted melanogenesis in the cell model.

CONCLUSIONS

These results suggest that LBE may be considered as a candidate for the development of oral/topical photoprotective ingredients against UVB-induced skin damage.

Thymus vulgaris alleviates UVB irradiation induced skin damage via inhibition of MAPK/AP-1 and activation of Nrf2-ARE antioxidant system

Solar ultraviolet (UV) radiation-induced reactive oxidative species is mainly responsible for the development of photoageing. Rosmarinic acid was one of the main bioactive components detected in Thymus vulgaris (TV) we extracted. In this study, UVB-induced skin damages have been shown to be ameliorated by treatment with TV in hairless mice (HR-1) skin, demonstrated by decreased matrix metalloproteinases (MMPs) and increased collagen production. However, the underlying molecular mechanism on which TV acted was unclear. We examined the photoprotective effects of TV against UVB and elucidated the molecular mechanism in normal human dermal fibroblasts. Thymus vulgaris remarkably prevented the UVB-induced reactive oxygen species and lactate dehydrogenase. Dose-dependent increase in glutathione, NAD(P)H: quinone oxidoreductase1 and heme oxygenase-1, by TV was confirmed by increased nuclear accumulation of Nrf2. Furthermore, 5-Methoxyindole-2-carboxylic acid was introduced as a specific inhibitor of dihydrolipoyl dehydrogenase (DLD). We demonstrated that Nrf2 expression was regulated by DLD, which was a tricarboxylic acid cycle-associated protein that decreased after UVB exposure. Besides, TV significantly diminished UVB induced phosphorylation of mitogen activated protein kinases pathway, containing extracellular signal-regulated kinase, Jun N-terminal kinase and p38, which consequently reduced phosphorylated c-fos and c-jun. Our results suggest that TV is a potential botanical agent for use against UV radiation-induced oxidative stress mediated skin damages.

Antiinflammatory and Antiphotodamaging Effects of Ergostatrien-3β-ol, Isolated from Antrodia camphorata, on Hairless Mouse Skin

Ergostatrien-3β-ol (EK100), isolated from the submerged whole broth of Antrodia camphorata, has antidiabetic, hyperlipidemic, and hepatoprotective activities. However, the antiphotodamage activity of EK100 has still not been revealed. Inflammation and collagen degradation contribute to skin photodamage and premature aging. In the present study, in vivo experiments were designed to investigate the antiinflammatory and antiphotodamaging activities of EK100 in hairless mice by physiological and histological analysis of the skin. Results indicated that topical application of EK100 (25 and 100 μM) for 10 weeks efficiently inhibited ultraviolet B (UVB)-induced wrinkle formation, erythema, and epidermal thickness in the mice skin. EK100 also restored UVB-induced collagen content reduction in hairless mice skin. In addition, the immunohistochemistry results indicated that EK100 significantly inhibited the UVB-induced expression of matrix metalloproteinase-1 (MMP-1), interleukin-6 (IL-6), inducible nitric oxide synthase (iNOS), and nuclear factor kappaB (NF-κB) in the mouse skin. The expression of these proteins was similar to the Normal group after 100 μM EK100 treatment. EK100 inhibited collagen degradation in the skin through MMP-1 inhibition and antiinflammation. EK100 significantly reduced the transepidermal water loss (TEWL), indicating that EK100 protected skin from UVB-induced damage. Our findings strongly suggest that EK100 has significant beneficial antiinflammatory and antiphotoaging activities and that EK100 can be developed as an antiphotodamaging agent.

The Methoxyflavonoid Isosakuranetin Suppresses UV-B-Induced Matrix Metalloproteinase-1 Expression and Collagen Degradation Relevant for Skin Photoaging

Solar ultraviolet (UV) radiation is a main extrinsic factor for skin aging. Chronic exposure of the skin to UV radiation causes the induction of matrix metalloproteinases (MMPs), such as MMP-1, and consequently results in alterations of the extracellular matrix (ECM) and skin photoaging. Flavonoids are considered as potent anti-photoaging agents due to their UV-absorbing and antioxidant properties and inhibitory activity against UV-mediated MMP induction. To identify anti-photoaging agents, in the present study we examined the preventative effect of methoxyflavonoids, such as sakuranetin, isosakuranetin, homoeriodictyol, genkwanin, chrysoeriol and syringetin, on UV-B-induced skin photo-damage. Of the examined methoxyflavonoids, pretreatment with isosakuranetin strongly suppressed the UV-B-mediated induction of MMP-1 in human keratinocytes in a concentration-dependent manner. Isosakuranetin inhibited UV-B-induced phosphorylation of mitogen-activated protein kinase (MAPK) signaling components, ERK1/2, JNK1/2 and p38 proteins. This result suggests that the ERK1/2 kinase pathways likely contribute to the inhibitory effects of isosakuranetin on UV-induced MMP-1 production in human keratinocytes. Isosakuranetin also prevented UV-B-induced degradation of type-1 collagen in human dermal fibroblast cells. Taken together, our findings suggest that isosakuranetin has the potential for development as a protective agent for skin photoaging through the inhibition of UV-induced MMP-1 production and collagen degradation.

Methanol Extract of Bitter Melon Alleviates UVB-Induced MMPs Expression via MAP Kinase and AP-1 Signaling in Human Dermal Fibroblasts in vitro

Ultraviolet (UV) irradiation leads to photo-damage of the skin, which in turn induces expression of matrix metalloproteinases (MMPs) and reduces type I procollagen. Bitter melon (Momordica charantia L.) has been widely used as a traditional medicine. In this study, we tested the photo-protective effects of methanol extracts of bitter melon pulp (BM) and the mechanism of these effects in normal human dermal fibroblasts (NHDFs). The effects of BM were investigated by measuring the levels of MMP-1, -3 and -9, and type I procollagen following UVB irradiation. We found that BM alleviates UVB-induced MMP-1, -3 and -9 expression at 100 µg/mL (down to 52.0%, 73.5%, and 55.6%, respectively). However, cells treated with 100 µg/mL BM had weakly stimulated type I procollagen expression (up to 130.0%). Moreover, treatment with BM significantly reduced UVB-induced extracellular signal-regulated kinase (ERK), Jun N-terminal kinase (JNK), and p38 phosphorylation, which resulted in decreasing UVB-induced phosphorylation of c-Fos and c-Jun. Therefore, our results suggest that BM is a potential agent for regulating skin photoaging. Copyright © 2016 John Wiley & Sons, Ltd.

Microemulsion Using Polyoxyethylene Sorbitan Trioleate and its Usage for Skin Delivery of Resveratrol to Protect Skin against UV-Induced Damage

We examined the phase behavior of various polyoxyethylene sorbitan fatty acid ester (polysorbates)/ethanol/isopropyl myristate (IPM)/150 mM NaCl solution (NaClaq) systems in order to prepare a microemulsion containing a low ratio of ethanol, which is more suitable for in vivo application. Using polyoxyethylene sorbitan trioleate (Tween 85), which has a large lipophilic moiety, as a surfactant component, single-phase domain of the phase diagram was the largest of all the polysorbates examined, and in particular a large oil-rich single-phase domain was obtained. When the ratio of Tween 85 to ethanol was changed from 1 : 1 to 3 : 1, the oil-rich single-phase domain further expanded, which led to a reduced ethanol concentration in the preparation. Thus, we determined the composition of the microemulsion to be Tween 85 : ethanol : IPM : NaClaq=30 : 10 : 53 : 7, and used it for skin delivery of resveratrol. Microemulsion gel was also prepared by adding 6.5% Aerosil) 200 into the microemulsion for ease of topical application. When applied with each vehicle, delivery of resveratrol into guinea pig skin in vitro was significantly enhanced compared with that by IPM, and resveratrol incorporated into the skin by microemulsion gel decreased lipid peroxidation to 29.5% compared with that of the control. Pretreatment of guinea pig dorsal skin with the microemulsion gel containing resveratrol almost completely prevented UV-B-induced erythema formation in vivo. These findings demonstrate that the microemulsion using Tween 85 containing a minimal concentration of ethanol enhanced the skin delivery of resveratrol and the incorporated resveratrol exhibited a protective effect against UV-induced oxidative damage.

Current application of phytocompound-based nanocosmeceuticals for beauty and skin therapy

Phytocompounds have been used in cosmeceuticals for decades and have shown potential for beauty applications, including sunscreen, moisturizing and antiaging, and skin-based therapy. The major concerns in the usage of phyto-based cosmeceuticals are lower penetration and high compound instability of various cosmetic products for sustained and enhanced compound delivery to the beauty-based skin therapy. To overcome these disadvantages, nanosized delivery technologies are currently in use for sustained and enhanced delivery of phyto-derived bioactive compounds in cosmeceutical sectors and products. Nanosizing of phytocompounds enhances the aseptic feel in various cosmeceutical products with sustained delivery and enhanced skin protecting activities. Solid lipid nanoparticles, transfersomes, ethosomes, nanostructured lipid carriers, fullerenes, and carbon nanotubes are some of the emerging nanotechnologies currently in use for their enhanced delivery of phytocompounds in skin care. Aloe vera, curcumin, resveratrol, quercetin, vitamins C and E, genistein, and green tea catechins were successfully nanosized using various delivery technologies and incorporated in various gels, lotions, and creams for skin, lip, and hair care for their sustained effects. However, certain delivery agents such as carbon nanotubes need to be studied for their roles in toxicity. This review broadly focuses on the usage of phytocompounds in various cosmeceutical products, nanodelivery technologies used in the delivery of phytocompounds to various cosmeceuticals, and various nanosized phytocompounds used in the development of novel nanocosmeceuticals to enhance skin-based therapy.

The effects of Origanum hypericifolium essential oil application and ultraviolet B irradiation on mouse skin: An ultrastructural study

Exposure to UV radiation can cause histopathological and ultrastructural changes in the skin. Origanum hypericifolium, an endemic Turkish plant,essential oil is mainly composed of monoterpenes. The effects of undiluted O. hypericifolium oil on the ultrastructural characteristics of the UVB-irradiated dorsal skin of mice were investigated using transmission electron microscopy. The BALB/c mice were shaved of dorsal hair and randomly housed into 4 groups: 1: control; 2: UVB-irradiated; 3: oil applied; and 4: oil applied and UVB-irradiated. The oil was applied topically to the dorsal skins of the mice on alternate days for 1week prior to UVB exposure. The skins were irradiated for a total dose of 3.5J/cm(2). The sections were stained with hematoxylin and eosin, semithin sections were stained with toluidine blue and ultrathin sections were contrasted with uranyl acetate/lead citrate. There were histopathological changes such as parakeratosis and squamous hyperplasia in the epidermal cell layers (Groups 3 and 4). There were also ultrastructural changes including lacunae formations throughout the stratum corneum layer (Groups 2, 3, and 4), enlargement of intercellular spaces (Groups 2 and 3), reduced desmosomes, narrow and elongated interdigitations, shortened, relatively indistinct and electron dense intermediate keratin filament bundles (Group 3). There were various sizes of cytoplasmic and perinucleolar vacuoles (Groups 3 and 4) and apoptotic bodies phagocytized by keratinocytes (Group 4). I conclude that undiluted oil has side-effects and the potential to inflict injury to the skin. The oil does not ameliorate the negative effects of UVB on epidermal skin cells.

Review of narrowband ultraviolet B radiation in vitiligo

Vitiligo is a common, acquired pigmentary disorder of unknown etiology with great impact on patient’s appearance and quality of life. It presents a therapeutic challenge to many dermatologists. Photochemotherapy using psoralen and ultraviolet A (UVA) therapy, topical and oral immunosuppresants, as well as cosmetic camouflage are also commonly employed with varying clinical efficacy. Phototherapy is a popular treatment option, which includes both of the generalized ultraviolet B (UVB) therapies, broadband UVB and narrowband UVB (NB-UVB). It has been used favorably, both alone as well as in combination with other agents like topical calcineurin inhibitors, vitamin-D analogs. Combination therapies are useful and may provide quicker regimentation and treat vitiligo with an additive mechanism of action than UVB phototherapy. Advances in technology may lead to the continuing use of UVB phototherapy as a treatment for vitiligo through the development of sophisticated devices and delivery systems as well as innovative application methods. These will provide increased therapeutic options for all vitiligo patients, particularly those with refractory disease. In this article, I have reviewed the available data pertaining to efficacy and safety issues for NB-UVB as monotherapy, its comparison with psoralen plus UVA and other modes of phototherapy, combination regimens that have been tried and future prospects of NB-UVB in vitiligo.

Adenophora remotiflora protects human skin keratinocytes against UVB-induced photo-damage by regulating antioxidative activity and MMP-1 expression

BACKGROUND/OBJECTIVES

Chronic ultraviolet (UV) exposure-induced reactive oxygen species (ROS) are commonly involved in the pathogenesis of skin damage by activating the metalloproteinases (MMP) that break down type I collagen. Adenophora remotiflora (AR) is a perennial wild plant that inhabits Korea, China, and Japan. The present study investigated the protective effects of AR against UVB-induced photo-damage in keratinocytes.

MATERIALS/METHODS

An in vitro cell-free system was used to examine the scavenging activity of 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical and nitric oxide (NO). The effect of AR on ROS formation, antioxidant enzymes, elastase, MMP-1 level, and mRNA expression of MMP-1 were determined in UVB-irradiated human keratinocyte HaCaT cells.

RESULTS

AR demonstrated strong DPPH free radical and NO scavenging activity in a cell-free system exhibiting IC₅₀ values of 1.88 mg/mL and 6.77 mg/mL, respectively. AR pretreatment dose-dependently attenuated the production of UVB-induced intracellular ROS, and antioxidant enzymes (catalase and superoxide dismutase) were enhanced in HaCaT cells. Furthermore, pretreatment of AR prevented UVB-induced elastase and collagen degradation by inhibiting the MMP-1 protein level and mRNA expression. Accordingly, AR treatment elevated collagen content in UVB-irradiated HaCaT cells.

CONCLUSION

The present study provides the first evidence of AR inhibiting UVB-induced ROS production and induction of MMP-1 as a result of augmentation of antioxidative activity in HaCaT human keratinocytes. These results suggest that AR might act as an effective inhibitor of UVB-modulated signaling pathways and might serve as a photo-protective agent.

pH-Degradable antioxidant nanoparticles based on hydrogen-bonded tannic acid assembly

Hydrogen-bonded polyphenol-based assemblies have attracted increasing interest for biomedical applications.

Orally administered betaine reduces photodamage caused by UVB irradiation through the regulation of matrix metalloproteinase-9 activity in hairless mice

Betaine is widely distributed in plants, microorganisms, in several types of food and in medical herbs, including Lycium chinense. The administration of 100 mg betaine/kg body weight/day is an effective strategy for preventing ultraviolet irradiation‑induced skin damage. The present study aimed to determine the preventive effects of betaine on ultraviolet B (UVB) irradiation‑induced skin damage in hairless mice. The mice were divided into three groups: Control (n=5), UVB‑treated vehicle (n=5) and UVB‑treated betaine (n=5) groups. The level of irradiation was progressively increased between 60 mJ/cm2 per exposure at week 1 (one minimal erythematous dose = 60 mJ/cm2) and 90 mJ/cm2 per exposure at week 7. The formation of wrinkles significantly increased following UVB exposure in the UVB‑treated vehicle group. However, treatment with betaine suppressed UVB‑induced wrinkle formation, as determined by the mean length, mean depth, number, epidermal thickness and collagen damage. Furthermore, oral administration of betaine also inhibited the UVB‑induced expression of mitogen‑activated protein kinase kinase (MEK), extracellular signal‑regulated kinase (ERK), and matrix metalloproteinase‑9 (MMP‑9). These findings suggested that betaine inhibits UVB‑induced skin damage by suppressing increased expression of MMP‑9 through the inhibition of MEK and ERK.

The Effect of Lycopene Preexposure on UV-B-Irradiated Human Keratinocytes

Lycopene has been reported as the antioxidant most quickly depleted in skin upon UV irradiation, and thus it might play a protective role. Our goal was to investigate the effects of preexposure to lycopene on UV-B-irradiated skin cells. Cells were exposed for 24 h to 10 M lycopene, and subsequently irradiated and left to recover for another 24 h period. Thereafter, several parameters were analyzed by FCM and

RT-PCR

genotoxicity/clastogenicity by assessing the cell cycle distribution; apoptosis by performing the Annexin-V assay and analyzing gene expression of apoptosis biomarkers; and oxidative stress by ROS quantification. Lycopene did not significantly affect the profile of apoptotic, necrotic and viable cells in nonirradiated cells neither showed cytostatic effects. However, irradiated cells previously treated with lycopene showed an increase in both dead and viable subpopulations compared to nonexposed irradiated cells. In irradiated cells, lycopene preexposure resulted in overexpression of BAX gene compared to nonexposed irradiated cells. This was accompanied by a cell cycle delay at S-phase transition and consequent decrease of cells in G0/G1 phase. Thus, lycopene seems to play a corrective role in irradiated cells depending on the level of photodamage. Thus, our findings may have implications for the management of skin cancer.

Enhanced permeability of ferulic acid loaded nanoemulsion based gel through skin against UVA mediated oxidative stress

AIMS

The study was aimed to develop a ferulic acid (FA) loaded nanoemulsion based gel in order to ensure the enhanced permeability and maximum antioxidant activity against UVA induced oxidative stress in rat.

MAIN METHODS

The optimized ferulic acid loaded nanoemulsion 3 (FA-NE3) was prepared by spontaneous nano-emulsification method with an appropriate ratio (20:30:50% w/w) of the oil (isostearyl isostearate), aqueous system and Smix [surfactant (labrasol) and co-surfactant (plurol isostearique)] respectively. FA-NE3 was characterized by measuring their droplet size, zeta potential, refractive index, transmission electron microscopy (TEM), ultraviolet (UV), fourier transform infrared spectroscopy (FTIR) and rheological characteristics. Ex vivo skin permeation and in vivo UVA protection activity of FA-NE3 based nano-gels (FA-NG3) along with placebo were studied through the rat skin.

KEY FINDINGS

FA-NE3 exhibited sustained-release profile, better permeability and ultraviolet A (UVA) protection activity as compared to conventional dosage form. This phenomenon may be attributed towards increased solubility of the drug and enhanced permeability from nanoemulsion. FA-NE3 based nanogel (FA-NG3) could elevate the level of skin marker enzymes against oxidative stress mediated by UVA.

SIGNIFICANCE

The gel formulation exhibited significant (P<0.01) skin permeability and antioxidant activity in the current investigations. The nanogel could be promising nanocarriers for topical delivery of FA in response to better skin protection activity against UVA rays in a sustained manner.

Energy restriction and potential energy restriction mimetics

Energy restriction (ER; also known as caloric restriction) is the only nutritional intervention that has repeatedly been shown to increase lifespan in model organisms and may delay ageing in humans. In the present review we discuss current scientific literature on ER and its molecular, metabolic and hormonal effects. Moreover, criteria for the classification of substances that might induce positive ER-like changes without having to reduce energy intake are summarised. Additionally, the putative ER mimetics (ERM) 2-deoxy-d-glucose, metformin, rapamycin, resveratrol, spermidine and lipoic acid and their suggested molecular targets are discussed. While there are reports on these ERM candidates that describe lifespan extension in model organisms, data on longevity-inducing effects in higher organisms such as mice remain controversial or are missing. Furthermore, some of these candidates produce detrimental side effects such as immunosuppression or lactic acidosis, or have not been tested for safety in long-term studies. Up to now, there are no known ERM that could be recommended without limitations for use in humans.

Genistein prevents ultraviolet B radiation-induced nitrosative skin injury and promotes cell proliferation

Nitric oxide (NO) levels increase considerably after 24h of exposure of skin to ultraviolet B (UVB) radiation, which leads to nitrosative skin injury. In addition, increased NO levels after exposure to UVB radiation are associated with inhibition of cell proliferation. Compared to the UV-control group, UV-genistein at 10 mg/kg (UV-GEN10) group showed tissue protection, decreased lipid peroxide and nitrotyrosine formation, and low CAT activity. Furthermore, NO levels and iNOS labeling remained high. In this group, the reduction in lipid peroxides and nitrotyrosine was accompanied by upregulation of cell proliferation factors (Ki67 and PCNA), which indicated that prevention of nitrosative skin injury promoted cell proliferation and DNA repair. Genistein also prevented nitrosative events, inhibited ONOO(-) formation, which leads to tissue protection and cell proliferation. The UV-GEN15 group did not result in a greater protective effect compared to that with UV-GEN10 group. In the UV-GEN15 group, histological examination of the epidermis showed morphological alterations without efficient protection against lipid peroxide formation, as well as inhibition of Ki67 and PCNA, and VEGF labeling, which suggested inhibition of cell proliferation. These results help to elucidate the mechanisms underlying the photoprotective effect of genistein and reveal the importance of UVB radiation-induced nitrosative damage.

Pine bark extracts: nutraceutical, pharmacological, and toxicological evaluation

Proanthocyanidins are among the most abundant constituents in pine bark extracts (PBEs). This review summarizes medical research on PBEs from Pinus pinaster, Pinus radiata, Pinus massoniana, and other less well characterized species. The precise mechanisms of the important physiologic functions of PBE components remain to be elucidated, but there is evidently great potential for the identification and development of novel antioxidant, anti-inflammatory, cardiovascular, neuroprotective, and anticancer medicines. Although toxicological data for PBEs are limited, no serious adverse effects have been reported. PBEs, therefore, may have potential as nutraceuticals and pharmaceuticals and should be safe for use as food ingredients.

Germacrane sesquiterpenes isolated from the rhizome of Curcuma xanthorrhiza Roxb. inhibit UVB-induced upregulation of MMP-1, -2, and -3 expression in human keratinocytes

Four sesquiterpenes were isolated from the rhizome of Curcuma xanthorrhiza Roxb.: furanodiene (1), germacrone (2), furanodienone (3), and 13-hydroxygermacrone (4). Importantly, this was the first time compounds 1 and 4 were isolated from this plant. The chemical structures of these compounds were determined using 1D- and 2D-nuclear magnetic resonance, infrared spectroscopy, and electron ionization mass spectrometry analyses. Among the isolated compounds, compounds 2 and 4 inhibited UVB-induced upregulation of the mRNA and protein expression levels of MMP-1, MMP-2, and MMP-3 in human keratinocytes (HaCaT). Moreover, this upregulation occurred in a dose-dependent manner over the range of 1-10 μM for each compound.

Effects of Galla chinensis extracts on UVB-irradiated MMP-1 production in hairless mice

Galla chinensis (GAC) is a natural traditional Chinese medicine that has been widely used in folk medicine. Although GAC compounds (mainly gallic acid and methyl gallate) possess strong antiviral, antibacterial, anticancer, and antioxidant activities, there is no report regarding topical or oral administration of GAC compounds on UVB irradiation-induced photoaging in hairless mice (SKH: HR-1). In the present study, we examined cell viability, intracellular reactive oxygen species (ROS), matrix metalloproteinase-1 (MMP-1), and interleukin-6 (IL-6) in skin fibroblasts and keratinocytes induced by UVB in vitro. We also studied skin damage by measuring skin thickness, elasticity, wrinkling and levels of protein MMP-1, elastin, procollagen type I, and transforming growth factor-β1 (TGF-β1) in hairless mouse skin chronically irradiated by UVB in vivo. GAC treatment significantly prevented skin photoaging by reducing the levels of ROS, MMP-1, and IL-6 and promoting production of elastin, procollagen type I, and TGF-β1. According to the results of H&E staining and Masson's trichrome staining, GAC reduced skin thickness and wrinkle formation while it increased skin elasticity. The effects of GAC on UVB-induced skin photoaging may be due to suppressed MMP-1 expression. These findings could be referenced for the development of new agents that target UVB-induced photoaging.

Development of O/W emulsions containing Euterpe oleracea extract and evaluation of photoprotective efficacy

Euterpe oleraceaMart. is a palm tree popularly known as açai, which is primarily found in northern Brazil. The açai's fruits contain anthocyanins, a class of polyphenols to which antioxidant properties have been attributed. The aim of this work was to develop O/W sunscreens emulsions containing açai glycolic extract (AGE) and to evaluate both their physical stability and photoprotective efficacy. Emulsions containing AGE and sunscreens were formulated using different types and concentrations of polymeric surfactant (acrylates/C 10-30 alkyl acrylate crosspolymer and sodium polyacrylate). The influence of two rheology modifiers (polyacrylamide (and) C13-14/isoparaffin (and) Laureth-7 and Carbomer) on the stability was also investigated. Physical stability was evaluated by preliminary and accelerated studies. Emulsions with 1.0% sodium polyacrylate were stable and exhibited non-newtonian pseudoplastic behavior and thixotropy. Photoprotective efficacy was evaluated by in vivo Sun Protection Factor (SPF) and determination of Protection Factor of UVA (PF-UVA). When AGE was added to the sunscreen emulsion, no significant increase in the in vivo SPF value was observed. The emulsion containing AGE showed PF-UVA = 14.97, 1.69 of the SPF/PF-UVA ratio and a critical wavelength value of 378 nm, and may therefore be considered a sunscreen with UVA and UVB protection.

Inhibition of peroxisome proliferator-activated receptor gamma prevents the melanogenesis in murine B16/F10 melanoma cells

The purpose of this study was to investigate if PPARγ plays a role in the melanogenesis. B16/F10 cells were divided into five groups: control, melanin stimulating hormone (α-MSH), α-MSH+retinol, α-MSH+GW9662 (PPARγ antagonist), and GW9662. Cells in the control group were cultured in the Dulbecco's modified Eagle's medium (DMEM) for 48 hrs. To initiate the melanogenesis, cells in all α-MSH groups were cultured in medium containing α-MSH (10 nM) for 48 hrs. Cells were treated simultaneously with retinol (5 μM) in the α-MSH+retinol group. Instead of retinol, GW9662 (10 μM) was cocultured in the α-MSH+GW9662 group. Cells in the final group were cultured in the DMEM with GW9662. All the analyses were carried out 48 hours after treatments. The α-MSH was able to increase cell number, melanin production, and the activity of tyrosinase, the limiting enzyme in melanogenesis. These α-MSH-induced changes were prevented either by retinol or by GW9662. Further analyses of the activities of antioxidant enzymes including glutathione, catalase, and the superoxide dismutase (SOD) showed that α-MSH treatment raised the activity of SOD which was dependent on PPARγ level. According to our results, the α-MSH-induced melanogenesis was PPARγ dependent, which also modulated the expression of SOD.

Influence of vegetable oil on the synthesis of bioactive nanocarriers with broad spectrum photoprotection

Due to their unique features, most nanostructured lipid carriers (NLCs) in association with vegetable oils that exhibit UV filtering properties and bioactivity could be used in many cosmetic formulations. Therefore, in this work, a new application of pomegranate seed oil (PSO) in the cosmetic sector was developed, based on the synthesis of bioactive lipid nanocarriers loaded with various UV filters by the hot high pressure homogenization technique. To get broad spectrum photoprotection, different UVA and UVB filters have been used (Avobenzone — AVO, Octocrylen-OCT, Bemotrizinol — BEMT). The influence of the solid lipids combined with PSO on the particle size, physical stability and entrapment efficiency was investigated using 8 nanocarrier systems. An improved physical stability and an appropriate size were obtained for NLCs prepared with Emulgade, carnauba wax and PSO (e.g. −30.9÷-36.9 mV and 160÷185 nm). NLCs showed an entrapment efficiency above 90% and assured slow release rates of UV filters, especially for BEMT (5%). The developed nanocarriers have been formulated into safe and effective sunscreens containing low amounts of synthetic UV filters coupled with a high percent of natural ingredients. The highest SPF of 34.3 was obtained for a cream comprising of 11% PSO and 3.7% BEMT

Nutritional aspects of β-carotene and resveratrol antioxidant synergism in giant unilamellar vesicles

Giant unilamellar vesicles of soy phosphatidylcholine are found to undergo budding when sensitized with chlorophyll a ([phosphatidylcholine] : [chlorophyll a] = 1500 : 1) under light irradiation (400-440 nm, 16 mW mm(-2)). 'Entropy' as a dimensionless image heterogeneity measurement is found to increase linearly with time during an initial budding process. For β-carotene addition ([phosphatidylcholine] : [β-carotene] = 500 : 1), a lag phase of 23 s is observed, followed by a budding process at an initial rate lowered by a factor of 3.8, whereas resveratrol ([phosphatidylcholine] : [resveratrol] = 500 : 1) has little if any protective effect against budding. However, resveratrol, when combined with β-carotene, is found to further reduce the initial budding rate by a total factor of 4.7, exhibiting synergistic antioxidation effects. It is also interesting that β-carotene alone determines the lag phase for the initiation of budding, while resveratrol supports β-carotene in reducing the rate of the budding process following the lag phase; however, it alone has no observable effect on the lag phase. Resveratrol is suggested to regenerate β-carotene following its sacrificial protection of unsaturated lipids from oxidative stress, modeling the synergistic effects in cell membranes by combinations of dietary antioxidants.

Protective effect of trehalose-loaded liposomes against UVB-induced photodamage in human keratinocytes

Trehalose, a naturally occurring non-reducing disaccharide, is known to act as a major protein stabilizer that can reduce ultraviolet B (UVB)-induced corneal damage when topically applied to the eye. However, due to the low skin permeability of trehalose, which makes the development of topical formulations difficult, its use as a skin photoprotective agent has been limited. Previous findings demonstrated that liposomes may significantly improve the intracellular delivery of trehalose. Therefore, the present study aimed to assess the protective effects of trehalose-loaded liposomes against UVB-induced photodamage using the immortalized human keratinocyte cell line, HaCaT. The effects were also compared to those of the common skin photoprotective compounds, including L-carnosine, L-(+)-ergothioneine, L-ascorbic acid and DL-α-tocopherol. The levels of cyclobutane pyrimidine dimers, 8-hydroxy-2'-deoxyguanosine and protein carbonylation in HaCaT cells were used as biological markers of UVB-induced damage. Compared to other compounds, trehalose-loaded liposomes showed the highest efficacy in reducing the levels of the three markers following UVB irradiation of HaCaT cells (all P<0.001 when compared to each of the four other photoprotective compounds). Therefore, these findings indicate that there may be a clinical application for trehalose-loaded liposomes, and further studies should be performed to assess the potential usefulness in skin photoprotection and the prevention of non-melanoma skin cancer.

The protective effects of fucosterol against skin damage in UVB-irradiated human dermal fibroblasts

Exposure to ultraviolet (UV) light causes matrix metalloproteinase (MMP) overexpression and extracellular matrix depletion, leading to skin photoaging. The activation of MMP is related to increased interlukin-6 (IL-6) and type I procollagen production, which is regulated by transforming growth factor-β1 (TGF-β1). Activator protein-1 (AP-1) activation induces MMP-1 production and reduces type I procollagen secretion. Fucosterol, which is extracted and purified from the brown algae Hizikia fusiformis, is a phytosterol. We assessed the effects of fucosterol on photodamage and investigated its molecular mechanism of action in UVB-irradiated normal human dermal fibroblasts by using enzyme-linked immunosorbent assay, Western blot analysis, and reverse transcription-polymerase chain reaction. Our results showed that fucosterol significantly decreased the UVB-induced expression of MMP-1, IL-6, p-c-Jun, and p-c-Fos. Additionally, fucosterol markedly increased the UVB-induced production of type I procollagen and TGF-β1. Our results indicate that fucosterol regulates MMP-1 and type I procollagen expression by modulating AP-1 and TGF-β1 signaling and that MMP-1 activation is correlated with IL-6. These data suggest that fucosterol is a promising botanical agent to protect against skin photodamage.

Topical retinoids in skin ageing: a focused update with reference to sun-induced epidermal vitamin A deficiency

Vitamin A is an important constituent of the epidermis, where it plays a crucial role in epidermal turnover. A deficiency of epidermal vitamin A may be the consequence of nutritional vitamin A deficiency, exposure to sunlight or any UV source, oxidative stress or chronological ageing. As a consequence, any treatment aiming at increasing epidermal vitamin A would exert a protective effect against these deleterious conditions. Retinoids may counteract some deleterious actions of UV radiation by physical and biological mechanisms. Topical natural retinoic acid precursors such as retinaldehyde or retinol are less irritant than acidic retinoids and may prevent epidermal vitamin A deficiency due to nutritional deficiency, exposure to sunlight or any condition leading to free radical production. Retinoids may be combined with other compounds with complementary actions against ageing, nutritional deficiency and cancer, such as antioxidants, to potentiate their beneficial effects in the skin.

Daidzein stimulates collagen synthesis by activating the TGF-β/smad signal pathway

BACKGROUND/OBJECTIVES

The objective of this study was to investigate the effects of daidzein on collagen metabolism and its underlying mechanism in cultured skin fibroblast and nude mouse skin.

METHODS

Skin fibroblasts were exposed to different concentrations of daidzein (0.5-50 μg/mL) for 24 h or 48 h, respectively. Female nude mice were treated topically with 200 μg/mL daidzein once a day for 6 weeks. Cell viability and cell cycle were determined by MTT and flow cytometer. The transcriptional activity of collagen type I was evaluated and the expression of procollagen, matrix metalloproteinase-1 (MMP1) and MMP2 were measured by real-time polymerase chain reaction. A Western blot analysis was applied to detect the levels of phosphorylated-Smad2 and Smad3.

RESULTS

In the daidzein-treated cells the expression of type I procollagen increased markedly while the expressions of MMP1, and MMP2 was significantly inhibited. Additionally, the mouse skin showed more collagen deposition after daidzein treatment. The levels of transforming growth factor (TGF)-β, phosphorylated-smad2 and smad3 were also higher in the daidzein treated skin fibroblasts than in the controls.

CONCLUSIONS

The results showed that daidzein treatment can increase skin collagen synthesis and inhibit collagen degradation in vitro and in vivo. It seems that TGF-β/smad signalling pathways play an important role in daidzein-induced collagen accumulation.

Gardenia jasminoides Extract Attenuates the UVB-Induced Expressions of Cytokines in Keratinocytes and Indirectly Inhibits Matrix Metalloproteinase-1 Expression in Human Dermal Fibroblasts

Ultraviolet radiation (UV) is a major cause of photoaging, which also involves inflammatory cytokines and matrix metalloproteinases (MMP). The present study was undertaken to examine the UVB-protecting effects of yellow-colored plant extracts in cell-based assays. HaCaT keratinocytes were exposed to UVB in the absence or presence of plant extracts, and resulting changes in cell viability and inflammatory cytokine expression were measured. Of the plant extracts tested, Gardenia jasminoides extract showed the lowest cytotoxicity and dose-dependently enhanced the viabilities of UVB-exposed cells. Gardenia jasminoides extract also attenuated the mRNA expressions of interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α) in HaCaT cells stimulated by UVB. Conditioned medium from UVB-exposed HaCaT cells was observed to stimulate MMP-1 protein expression in human dermal fibroblasts, and this effect was much smaller for the conditioned medium of HaCaT cells exposed to UVB in the presence of Gardenia jasminoides extract. Gardenia jasminoides extract also exhibited antioxidative and antiapoptotic effects in HaCaT cells exposed to UVB. These results indicated that UVB-induced injury and inflammatory responses of skin cells can be attenuated by yellow-colored plant extracts, such as Gardenia jasminoides extract.

MicroRNAs in skin response to UV radiation

Solar ultraviolet (UV) radiation, an ubiquitous environmental carcinogen, is classified depending on the wavelength, into three regions; short-wave UVC (200-280 nm), mid-wave UVB (280-320 nm), and long-wave UVA (320- 400 nm). The human skin, constantly exposed to UV radiation, particularly the UVB and UVA components, is vulnerable to its various deleterious effects such as erythema, photoaging, immunosuppression and cancer. To counteract these and for the maintenance of genomic integrity, cells have developed several protective mechanisms including DNA repair, cell cycle arrest and apoptosis. The network of damage sensors, signal transducers, mediators, and various effector proteins is regulated through changes in gene expression. MicroRNAs (miRNAs), a group of small non-coding RNAs, act as posttranscriptional regulators through binding to complementary sequences in the 3´-untranslated region of their target genes, resulting in either translational repression or target degradation. Recent studies show that miRNAs add an additional layer of complexity to the intricately controlled cellular responses to UV radiation. This review summarizes our current knowledge of the role of miRNAs in the regulation of the human skin response upon exposure to UV radiation.

The Effects of Brazilian Green Propolis against Excessive Light-Induced Cell Damage in Retina and Fibroblast Cells

Background. We investigated the effects of Brazilian green propolis and its constituents against white light- or UVA-induced cell damage in mouse retinal cone-cell line 661W or human skin-derived fibroblast cells (NB1-RGB). Methods. Cell damage was induced by 3,000lx white light for 24 h or 4/10 J/cm² UVA exposure. Cell viability was assessed by Hoechst33342 and propidium iodide staining or by tetrazolium salt (WST-8) cell viability assay. The radical scavenging activity of propolis induced by UVA irradiation in NB1-RGB cells was measured using a reactive-oxygen-species- (ROS-) sensitive probe CM-H₂DCFDA. Moreover, the effects of propolis on the UVA-induced activation of p38 and extracellular signal-regulated kinase (ERK) were examined by immunoblotting. Results. Treatment with propolis and two dicaffeoylquinic acids significantly inhibited the decrease in cell viability induced by white light in 661W. Propolis and its constituents inhibited the decrease in cell viability induced by UVA in NB1-RGB. Moreover, propolis suppressed the intracellular ROS production by UVA irradiation. Propolis also inhibited the levels of phosphorylated-p38 and ERK by UVA irradiation. Conclusion. Brazilian green propolis may become a major therapeutic candidate for the treatment of AMD and skin damage induced by UV irradiation.

Effect of Microalgal Extracts of Tetraselmis suecica against UVB-Induced Photoaging in Human Skin Fibroblasts

Exposure of cells to ultraviolet B (UVB) radiation can induce production of free radicals and reactive oxygen species (ROS), which damage cellular components. In addition, these agents can stimulate the expression of matrix metalloproteinase (MMP) and decrease collagen synthesis in human skin cells. In this study, we examined the anti-photoaging effects of extracts of Tetraselmis suecica (W-TS). W-TS showed the strongest scavenging activity against 2,2-difenyl-1-picrylhydrazyl (DPPH) and peroxyl radicals, followed by superoxide anions from the xanthine/xanthine oxidase system. We observed that the levels of both intracellular ROS and lipid peroxidation significantly increased in UVB-irradiated human skin fibroblast cells. Furthermore, the activities of enzymatic antioxidants (e.g., superoxide dismutase) and the levels of non-enzymatic antioxidants (e.g., glutathione) significantly decreased in cells. However, W-TS pretreatment, at the maximum tested concentration, significantly decreased intracellular ROS and malondialdehyde (MDA) levels, and increased superoxide dismutase and glutathione levels in the cells. At this same concentration, W-TS did not show cytotoxicity. Type 1 procollagen and MMP-1 released were quantified using RT-PCR techniques. The results showed that W-TS protected type 1 procollagen against UVBinduced depletion in fibroblast cells in a dose-dependent manner via inhibition of UVB-induced MMP-1. Taken together, the results of the study suggest that W-TS effectively inhibits UVB-induced photoaging in skin fibroblasts by its strong anti-oxidant ability.

The Nrf2-inducers tanshinone I and dihydrotanshinone protect human skin cells and reconstructed human skin against solar simulated UV

Exposure to solar ultraviolet (UV) radiation is a causative factor in skin photocarcinogenesis and photoaging, and an urgent need exists for improved strategies for skin photoprotection. The redox-sensitive transcription factor Nrf2 (nuclear factor-E2-related factor 2), a master regulator of the cellular antioxidant defense against environmental electrophilic insult, has recently emerged as an important determinant of cutaneous damage from solar UV, and the concept of pharmacological activation of Nrf2 has attracted considerable attention as a novel approach to skin photoprotection. In this study, we examined feasibility of using tanshinones, a novel class of phenanthrenequinone-based cytoprotective Nrf2 inducers derived from the medicinal plant Salvia miltiorrhiza, for protection of cultured human skin cells and reconstructed human skin against solar simulated UV. Using a dual luciferase reporter assay in human Hs27 dermal fibroblasts pronounced transcriptional activation of Nrf2 by four major tanshinones [tanshinone I (T-I), dihydrotanshinone (DHT), tanshinone IIA (T-II-A) and cryptotanshinone (CT)] was detected. In fibroblasts, the more potent tanshinones T-I and DHT caused a significant increase in Nrf2 protein half-life via blockage of ubiquitination, ultimately resulting in upregulated expression of cytoprotective Nrf2 target genes (GCLC, NQO1) with the elevation of cellular glutathione levels. Similar tanshinone-induced changes were also observed in HaCaT keratinocytes. T-I and DHT pretreatment caused significant suppression of skin cell death induced by solar simulated UV and riboflavin-sensitized UVA. Moreover, feasibility of tanshinone-based cutaneous photoprotection was tested employing a human skin reconstruct exposed to solar simulated UV (80 mJ/cm² UVB; 1.53 J/cm² UVA). The occurrence of markers of epidermal solar insult (cleaved procaspase 3, pycnotic nuclei, eosinophilic cytoplasm, acellular cavities) was significantly attenuated in DHT-treated reconstructs that displayed increased immunohistochemical staining for Nrf2 and γ-GCS together with the elevation of total glutathione levels. Taken together, our data suggest the feasibility of achieving tanshinone-based cutaneous Nrf2-activation and photoprotection.

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Tanshinones are phenanthrenequinone-based Nrf2 inducers active in human skin cells.

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Tanshinones upregulate Nrf2 target gene expression with the elevation of glutathione.

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Dihydrotanshinone protects cultured human skin cells against solar simulated UV.

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Dihydrotanshinone protects reconstructed human skin against acute photodamage.

In vitro bactericidal effects of 625, 525, and 425 nm wavelength (red, green, and blue) light-emitting diode irradiation

OBJECTIVE

The purpose of this study was to evaluate the relationship of 625, 525, and 425 nm wavelengths, providing average power output and effects on three common pathogenic bacteria.

BACKGROUND DATA

Ultraviolet (UV) light kills bacteria, but the bactericidal effects of UV may not be unique, as 425 nm produces a similar effect. The bactericidal effects of light-emitting diode (LED) wavelengths such as 625 and 525 nm have not been described. Before conducting clinical trials, the appropriate wavelength with reasonable dose and exposure time should be established.

MATERIALS AND METHODS

The bactericidal effects of 625, 525, and 425 nm wavelength LED irradiation were investigated in vitro for the anaerobic bacterium Porphyromonas gingivalis and two aerobes (Staphylococcus aureus and Escherichia coli DH5α). Average power output was 6 mW/cm(2) for 1 h. The bacteria were exposed to LED irradiation for 1, 2, 4, and 8 h (21.6, 43.2, 86.4, and 172.8 J/cm(2), respectively). LED irradiation was performed during growth on agar and in broth. Control bacteria were incubated without LED irradiation. Bacterial growth was expressed in colony-forming units (CFU) and at an optical density at 600 nm in agar and broth.

RESULTS

The bactericidal effect of LED phototherapy depended upon wavelength, power density, bacterial viable number, and bacteria species. The bactericidal effect of 425 and 525 nm irradiation varied depending upon the bacterial inoculation, compared with unirradiated samples and samples irradiated with red light. Especially, P. gingivalis and E. coli DH5α were killed by 425 nm, and S. aureus growth was inhibited by 525 nm. However, the wavelength of 625 nm was not bactericidal for P. gingivalis, E. coli DH5α, or S. aureus.

CONCLUSIONS

Irradiation at 625 nm light was not bactericidal to S. aureus, E. coli, and P. gingivalis, whereas wavelengths of 425 and 525 nm had bactericidal effects. S. aureus was also killed at 525 nm.

Artocarpin attenuates ultraviolet B-induced skin damage in hairless mice by antioxidant and anti-inflammatory effect

Artocarpin, a prenylated flavonoid isolated from an agricultural plant Artocarpus communis, has been documented to possess anti-inflammation and anticancer activities. As oxidative stress and inflammation promote the development of ultraviolet B (UVB) irradiation-induced photodamage, the aim of the present study was to evaluate the photoprotective effect of artocarpin on UVB-induced skin damage in hairless mice. Artocarpin at a topical dose of 0.05% and 0.1% showed a significant photoprotective effect by decreasing histopathological changes, such as desquamation, epidermal thicken and sunburn cell formation, but 0.1% of artocarpin administration did not show better effect. Regarding the antioxidant activities, artocarpin exhibited a significant effect (P<0.05) by decreasing levels of reactive species oxygen and lipid peroxidation. In addition, artocarpin can significant decrease the level of tumor necrosis factor-α and interleukin-1β for downregulating the inflammation protein, including the synthesis of cytosolic phospholipase A2 and cyclooxygenase-2 (P<0.05). In conclusion, these data suggest that artocarpin can prevent skin damage from UVB irradiation-induced photodamage in hairless mice and this is likely mediated through its antioxidant and anti-inflammation mechanisms. Therefore, we suggested that artocarpin could be a useful photoprotective agent in medicine and/or cosmetics.