Natural phenolics in the prevention of UV-induced skin damage. A review

The Phototoxic Potential of the Flavonoids, Taxifolin and Quercetin

Quercetin, one of the most abundant polyphenols in the plant kingdom has been shown to be photodegraded on exposure to UV light. Despite the fact, it is a component of several dermatological preparations. Its phototoxic potential has not been evaluated to date. The aim of this study was to assess whether photo-induced degradation of quercetin is linked to phototoxic effects on living cells. Its dihydro derivative, taxifolin, was included in the study. For evaluation, the 3T3 Neutral Red Uptake Phototoxicity Test according to OECD TG 432 was used. To better approximate human skin, HaCaT keratinocytes, normal human epidermal keratinocytes and dermal fibroblasts were used, apart from the Balb/c 3T3 cell line. Quercetin showed a dose-dependent photodegradation in aqueous and organic environments and a phototoxic effect on all used cells. Quercetin pretreatment and following UVA exposure resulted in increased reactive oxygen species production and intracellular glutathione level depletion in human dermal fibroblasts. Taxifolin was found completely nonphototoxic and photostable. As only in vitro methodology was used, further studies using 3D skin models and/or human volunteers are needed to confirm whether exposure to sunlight, tanning sunbeds and/or phototherapy in people using cosmetics containing quercetin is a health risk.

Regenerative and reparative effects of human chorion-derived stem cell conditioned medium on photo-aged epidermal cells

Epidermal cells are an important regenerative source for skin wound healing. Aged epidermal cells have a low ability to renew themselves and repair skin injury. Ultraviolet (UV) radiation, particularly UVB, can cause photo-aging of the skin by suppressing the viability of human epidermal cells. A chorion-derived stem cell conditioned medium (CDSC-CNM) is thought to have regenerative properties. This study aimed to determine the regenerative effects of CDSC-CNM on UVB-induced photo-aged epidermal cells. Epidermal cells were passaged four times and irradiated with quantitative UVB, and non-irradiated cells served as a control group. Cells were then treated with different concentrations of CDSC-CNM. Compared to the non-irradiated group, the proliferation rates and migration rates of UVB-induced photo-aged epidermal cells significantly decreased (p < 0.05) with increasing intracellular radical oxygen species (ROS) generation and DNA damage. After treatment with CDSC-CNM, photo-aged epidermal cells significantly improved their viability, and their ROS generation and DNA damage decreased. The secretory factors in CDSC-CNM, including epidermal growth factor (EGF), transforming growth factor-β (TGF-β), interleukin (IL)-6, and IL-8 and the related signaling pathway protein levels, increased compared to the control medium (CM). The potential regenerative and reparative effects of CDSC-CNM indicate that it may be a candidate material for the treatment of prematurely aged skin. The functions of the secretory factors and the mechanisms of CDSC-CNM therapy deserve further attention.

trans-Chalcone, a flavonoid precursor, inhibits UV-induced skin inflammation and oxidative stress in mice by targeting NADPH oxidase and cytokine production

trans-Chalcone inhibits UV-induced skin inflammation and also indirectly reduces oxidative stress.

Induced oxidative stress management in wounds through phenolic acids engineered fibrous protein: An in vitro assessment using polymorphonuclear (PMN) cells

The present study explores the preparation, characterization and the role of phenolic acid tethered fibrous protein in the management of induced oxidative stress studied under in vitro conditions. In brief, the biomaterial is prepared by engineering the fibrous protein with dihydroxy and trihydroxy phenolic acid moieties and subjected to characterization to ensure the tethering. The resultant biomaterial studied for its efficacy as a free radical scavenger using polymorphonuclear (PMN) cells with induced oxidative stress and also as an agent for cell migration using fibroblasts cells. Results revealed that induced oxidative stress in PMN cells after exposure to UVB radiation managed well with the prepared biomaterial by reducing the levels of superoxide anion, oxygen and hydroxyl radicals. Further, the protein and the phenolic acid interaction supports the cell migration as evidenced from the scratch assay. In conclusion, though phenolic acids are well known for their antimicrobial and antioxidant potential, indenting these acids directly to the wounds is not sensible, but tethering to protein explored the scavenging activity as expected. The present study infers that phenolic acid engineered protein has a significant role in managing the imbalance in the redox state prevailing in wounds and supports the healing at appreciable level.

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.

Efficacy of Pre- and Post-Treatment by Topical Formulations Containing Dissolved and Suspended Silybum marianum against UVB-Induced Oxidative Stress in Guinea Pig and on HaCaT Keratinocytes

Plants with high amounts of antioxidants may be a promising therapy for preventing and curing UV-induced oxidative skin damage. The objective of this study was to verify the efficacy of topical formulations containing dissolved and suspended Silybum marianum extract against UVB-induced oxidative stress in guinea pig and HaCaT keratinocytes. Herbal extract was dissolved in Transcutol HP (TC) and sucrose-esters were incorporated as penetration enhancers in creams. Biocompatibility of compositions was tested on HeLa cells and HaCaT keratinocytes as in vitro models. Transepidermal water loss (TEWL) tests were performed to prove the safety of formulations in vivo. Drug release of different compositions was assessed by Franz diffusion methods. Superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) and lipid peroxidation (MDA) activities were evaluated before and after UVB irradiation in a guinea pig model and HaCaT cells. Heme oxygenase-1 (HO-1) enzyme activity was measured in the epidermis of guinea pigs treated by different creams before and after UVB irradiation. Treatment with compositions containing silymarin powder (SM) dissolved in TC and sucrose stearate SP 50 or SP 70 resulted in increased activities of all reactive oxygen species (ROS) eliminating enzymes in the case of pre- and post-treatment as well. Reduction in the levels of lipid peroxidation end products was also detected after treatment with these two compositions. Post-treatment was more effective as the increase of the activity of antioxidants was higher. Lower HO-1 enzyme levels were measured in the case of pre- and post-treatment groups compared to control groups. Therefore, this study demonstrates the effectiveness of topical formulations containing silymarin in inhibiting UVB irradiation induced oxidative stress of the skin.

Herbal extracts, lichens and biomolecules as natural photo-protection alternatives to synthetic UV filters. A systematic review

Besides the unquestionable positive effects of solar exposure for human health, UV rays have been widely investigated for toxicology aspects related to excessive UVB and UVA doses, which involve sunburns, skin aging, DNA skin damage and tumorigenesis. At present, synthetic and mineral sunscreens are used to protect against these damages but several natural molecules can provide UV protection, including also synergic effect or enhanced photo stability. Although a large number of herbal extracts and plant origin molecules can deserve potential applications, most of the study reported utilizes different method and different strategies of investigation, making thus difficult to understand the real versus claimed potential. This is possibly one of the reasons why, beside the large body of literature there are no officially approved natural commercial sun-filter but a consistent number of commercially available solar products (sunscreen) on the market that contain herbal derivatives. In this review we have evaluated the papers appeared in the last 15years and we have critically collected the most significant data. Several databases, namely Scifinder, Pubmed, Google Scholar, ISI-Web of Science and Scopus, were used as literature sources; excluding patents and symposium or congress papers. Only articles in the English language have been selected. New formulation, new skin delivery systems, skin penetration enhancers and boosters are most likely the next frontier of investigation in order to better understand the role of whole herbal extracts in exerting their photo protective activity.

Protective Effect of Cyanidin-3-O-Glucoside against Ultraviolet B Radiation-Induced Cell Damage in Human HaCaT Keratinocytes

Ultraviolet radiation is the major environmental harmful factor that has emotional impact on human skin. The aim of the present study was to determine the mechanism of protection of cyanidin-3-O-glucoside against ultraviolet B (UVB)-induced damage to human HaCaT keratinocytes. Our results show that cyanidin-3-O-glucoside decreased the levels of intracellular reactive oxygen species generated by UVB treatment. Cyanidin-3-O-glucoside also decreased the UVB-augmented levels of the DNA damage indicators phospho-p53 and phospho-ATM/ATR. In addition, cyanidin-3-O-glucoside protected keratinocytes from UVB-induced injury by overturning the disruption of mitochondrial membrane potential and reversing apoptosis. The expression of anti-apoptotic protein B-cell lymphoma 2 (Bcl-2) was attenuated in UVB-exposed cells but restored in UVB/cyanidin-3-O-glucoside-treated cells. Furthermore, expression of the proapoptotic proteins Bcl-2-associated X (Bax) and the key apoptosis executer cleaved caspase-3 were increased in UVB-irradiated cells and decreased in UVB/cyanidin-3-O-glucoside-treated cells. For these reasons, the results demonstrate that cyanidin-3-O-glucoside protects human keratinocytes against UVB-induced oxidative stress and apoptosis. Our study provides a theoretical basis for the use of cyanidin-3-O-glucoside in the fight against light damage.

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.

Protective effects of polyvinylpyrrolidone-wrapped fullerene against intermittent ultraviolet-A irradiation-induced cell injury in HaCaT cells

To identify compounds that suppress UV irradiation-induced oxidative stress in the skin, various types of antioxidants have been studied. Polyvinylpyrrolidone-entrapped fullerene (C60/PVP) is known as a powerful antioxidant that exerts a cytoprotective effect against UV irradiation-induced cell injury in human skin cells and skin models. However, the effects of the alternate attractive C60/PVP feature, persistent antioxidant ability, on cytoprotection have rarely been ascertained. In this study we therefore investigated the efficacies of C60/PVP using an intermittently repeated UVA irradiation model wherein human keratinocytes were repeatedly exposed to UVA five times every 1h and compared the cytoprotective effects with those provided by ascorbic acid-2-O-phosphate-disodium salt (APS) and α-tocopherol (α-Toc). Our results demonstrated that C60/PVP yielded prominent cytoprotective effects against intermittently repeated UVA irradiation-induced injuries in a dose-dependent manner and suppressed intracellular superoxide anion radical (O2(-)) generation both during and after the repeated UVA irradiation. Additionally, C60/PVP also repressed the intermittent UVA irradiation-induced apoptosis via suppression of chromatin condensation and caspase-3/7 activation. Furthermore, the observed cytoprotective effects were superior to the effects of the typical antioxidants APS and α-Toc. These data suggest that C60/PVP might function as a potent cosmetic antioxidant against the effects of repeated and prolonged UVA irradiation through its persistent antioxidative property.

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.

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.

Paeoniflorin attenuates ultraviolet B-induced apoptosis in human keratinocytes by inhibiting the ROS-p38-p53 pathway

Ultraviolet (UV) light is one of the most harmful environmental factors that contribute to skin damage. Exposure to UV induces extensive generation of reactive oxygen species (ROS), and results in photoaging and skin cancer development. One approach to protecting human skin against UV radiation is the use of antioxidants. In recent years, naturally occurring herbal compounds have gained considerable attention as protective agents for UV exposure. Paeoniflorin (PF) is a novel natural antioxidant, which is isolated from peony root (Radix Paeoniae Alba). The present study evaluated the protective effects of PF on UV‑induced skin damage in vitro, and demonstrated that the effects were mediated via the ROS‑p38‑p53 pathway. The results of the present study demonstrated that treatment with PF (25, 50, and 100 µM) significantly increased the percentage of viable keratinocytes after UV‑B exposure. In addition, cell death analysis indicated that PF treatment markedly reduced UV‑B‑radiation‑induced apoptosis in keratinocytes, which was accompanied by increased procaspase 3 expression and decreased cleaved caspase 3 expression. Treatment with PF markedly reduced the production of ROS, and inhibited the activation of p38 and p53 in human keratinocytes, thus suggesting that the ROS‑p38‑p53 pathway has a role in UV‑B‑induced skin damage. In conclusion, the present study reported that PF was able to attenuate UV‑B‑induced cell damage in human keratinocytes. Notably, these effects were shown to be mediated, at least in part, via inhibition of the ROS-p38-p53 pathway.

An Evaluation of Root Phytochemicals Derived from Althea officinalis (Marshmallow) and Astragalus membranaceus as Potential Natural Components of UV Protecting Dermatological Formulations

As lifetime exposure to ultraviolet (UV) radiation has risen, the deleterious effects have also become more apparent. Numerous sunscreen and skincare products have therefore been developed to help reduce the occurrence of sunburn, photoageing, and skin carcinogenesis. This has stimulated research into identifying new natural sources of effective skin protecting compounds. Alkaline single-cell gel electrophoresis (comet assay) was employed to assess aqueous extracts derived from soil or hydroponically glasshouse-grown roots of Althea officinalis (Marshmallow) and Astragalus membranaceus, compared with commercial, field-grown roots. Hydroponically grown root extracts from both plant species were found to significantly reduce UVA-induced DNA damage in cultured human lung and skin fibroblasts, although initial Astragalus experimentation detected some genotoxic effects, indicating that Althea root extracts may be better suited as potential constituents of dermatological formulations. Glasshouse-grown soil and hydroponic Althea root extracts afforded lung fibroblasts with statistically significant protection against UVA irradiation for a greater period of time than the commercial field-grown roots. No significant reduction in DNA damage was observed when total ultraviolet irradiation (including UVB) was employed (data not shown), indicating that the extracted phytochemicals predominantly protected against indirect UVA-induced oxidative stress. Althea phytochemical root extracts may therefore be useful components in dermatological formulations.

Phenolic Acid-based Poly(anhydride-esters) as Antioxidant Biomaterials

Poly(anhydride-esters) comprised of naturally occurring, non-toxic phenolic acids, namely syringic and vanillic acid, with antioxidant properties were prepared via solution polymerization methods. Polymer and polymer precursor physiochemical properties were characterized, including polymer molecular weight and thermal properties. In vitro release studies illustrated that polymer hydrolytic degradation was influenced by relative hydrophobicity and degree of methoxy substitution of the phenolic acids. Further, the released phenolic acids were found to maintain antioxidant potency relative to free phenolic acid controls as determined by a 2,2-diphenyl-1-picrylhydrazyl assay. Polymer cytotoxicity was assessed with L929 fibroblasts in polymer-containing media; appropriate cell morphology and high fibroblast proliferation were obtained for the polymers at the lower concentrations. These polymers deliver non-cytotoxic levels of naturally occurring antioxidants, which could be efficacious in topical delivery of antioxidant therapies.

Protective Effects of Triphala on Dermal Fibroblasts and Human Keratinocytes

Human skin is body’s vital organ constantly exposed to abiotic oxidative stress. This can have deleterious effects on skin such as darkening, skin damage, and aging. Plant-derived products having skin-protective effects are well-known traditionally. Triphala, a formulation of three fruit products, is one of the most important rasayana drugs used in Ayurveda. Several skin care products based on Triphala are available that claim its protective effects on facial skin. However, the skin protective effects of Triphala extract (TE) and its mechanistic action on skin cells have not been elucidated in vitro. Gallic acid, ellagic acid, and chebulinic acid were deduced by LC-MS as the major constituents of TE. The identified key compounds were docked with skin-related proteins to predict their binding affinity. The IC₅₀ values for TE on human dermal fibroblasts (HDF) and human keratinocytes (HaCaT) were 204.90 ± 7.6 and 239.13 ± 4.3 μg/mL respectively. The antioxidant capacity of TE was 481.33 ± 1.5 mM Trolox equivalents in HaCaT cells. Triphala extract inhibited hydrogen peroxide (H₂O₂) induced RBC haemolysis (IC₅₀ 64.95 μg/mL), nitric oxide production by 48.62 ± 2.2%, and showed high reducing power activity. TE also rescued HDF from H₂O₂-induced damage; inhibited H₂O₂ induced cellular senescence and protected HDF from DNA damage. TE increased collagen-I, involucrin and filaggrin synthesis by 70.72 ± 2.3%, 67.61 ± 2.1% and 51.91 ± 3.5% in HDF or HaCaT cells respectively. TE also exhibited anti-tyrosinase and melanin inhibition properties in a dose-dependent manner. TE increased the mRNA expression of collagen-I, elastin, superoxide dismutase (SOD-2), aquaporin-3 (AQP-3), filaggrin, involucrin, transglutaminase in HDF or HaCaT cells, and decreased the mRNA levels of tyrosinase in B16F10 cells. Thus, Triphala exhibits protective benefits on skin cells in vitro and can be used as a potential ingredient in skin care formulations.

Phloroglucinol Reduces Photodamage in Hairless Mice via Matrix Metalloproteinase Activity Through MAPK Pathway

We investigated the photoprotective activity of phloroglucinol on ultraviolet B (UVB)-induced deleterious effects in hairless mice in vivo. To assess the photoprotective effect of phloroglucinol, phloroglucinol-treated HR-1 hairless male mice were exposed to UVB irradiation. The inhibitory activity of phloroglucinol on wrinkle formation was determined by analysis of skin replicas, epidermal thickness based on histological examination and collagen damage. Matrix metalloproteinase-1 (MMP-1), matrix metalloproteinase-9 (MMP-9) and tissue inhibitor of metalloproteinase (TIMP) mRNA levels were measured by real-time PCR. UVB induced transcription of proinflammatory cytokines, including interleukin-1 beta (IL-1β, IL-6) and IL-8 (IL-8). The protective effects of phloroglucinol on UVB-induced skin photoaging were examined by measuring protein levels of MMPs and mitogen-activated protein (MAP) kinases. The results of these experiments suggest that phloroglucinol has a significant beneficial effect on the barrier function of the skin. In hairless mice, signs of photoaging and photodamage, including coarse wrinkle formation, epidermal thickness and elastic fiber degeneration, were reduced in severity by phloroglucinol application. The phloroglucinol-treated group showed remarkably decreased mRNA levels of MMP-1, MMP-9 and inflammatory cytokines in comparison with those of the UVB-induced group. Oral administration of phloroglucinol attenuated phosphorylation of MAP kinases, including extracellular signal-regulated kinase, c-Jun N-terminal kinase and p38.

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.

Photoprotective Potential of Penta-O-Galloyl-β-DGlucose by Targeting NF-κB and MAPK Signaling in UVB Radiation-Induced Human Dermal Fibroblasts and Mouse Skin

Exposure of the skin to ultraviolet radiation can cause skin damage with various pathological changes including inflammation. In the present study, we identified the skin-protective activity of 1,2,3,4,6-penta-O-galloyl-β-D-glucose (pentagalloyl glucose, PGG) in ultraviolet B (UVB) radiation-induced human dermal fibroblasts and mouse skin. PGG exhibited antioxidant activity with regard to intracellular reactive oxygen species (ROS) generation as well as ROS and reactive nitrogen species (RNS) scavenging. Furthermore, PGG exhibited anti-inflammatory activity, inhibiting the activation of nuclear factor-kappaB (NF-κB) and mitogen-activated protein kinase (MAPK) signaling, resulting in inhibition of the expression of pro-inflammatory mediators. Topical application of PGG followed by chronic exposure to UVB radiation in the dorsal skin of hairless mice resulted in a significant decrease in the progression of inflammatory skin damages, leading to inhibited activation of NF-κB signaling and expression of pro-inflammatory mediators. The present study demonstrated that PGG protected from skin damage induced by UVB radiation, and thus, may be a potential candidate for the prevention of environmental stimuli-induced inflammatory skin damage.

In vitro photoprotection and antioxidant capacity of Sphagnum meridense extracts, a novel source of natural sunscreen from the mountains of Colombia

Excessive ultraviolet radiation can cause skin cancer and related health problems in humans. Traditionally, organic and inorganic sunscreens have been used to minimize these effects. Besides, some phenolic compounds present in plants play an important role as photoprotectors. Sphagnum meridense (L), found in Colombia, is continuously exposed to sunlight on high mountain ecosystems. In this work, we evaluated the potential of S. meridense extracts to be applied as UVA-UVB filter in cosmetic formulations and its antioxidant capacity. The mixture acetone-37% hydrochloric acid (1%, v/v) showed the best polyphenol content and UVA-UVB absorption coefficient. These extracts also exhibited promissory UVAPF values, UVA/UVB ratio, critical wavelength (λc) and antioxidant capacity in vitro, comparable to that of conventional sunscreens.

Spent coffee ground extract suppresses ultraviolet B-induced photoaging in hairless mice

The aim of this study is to evaluate the effect of spent coffee ground (SCG) ethanol extract on UVB-induced skin aging in hairless mice. An ethanol extract of SCG (ESCG) was prepared using the residue remaining after extraction of oil from roasted SCG. High performance liquid chromatography (HPLC) analysis showed that the content of caffeine (41.58 ± 0.54 μg/mg) was higher than that of chlorogenic acid isomers (~9.17 μg/mg) in ESCG. ESCG significantly decreased the UVB-induced intracellular reactive oxygen species in HaCaT cells. UVB-induced wrinkle formation in mice dorsal skin was effectively reduced by ESCG administration; high dose of ESCG (5 g/L) caused the reduction of wrinkle area by 30% compared with UVB-treated control (UVBC). This result correlated with the ESCG-mediated decrease in epidermis thickness (25%). In addition, ESCG administration significantly reduced transdermal water loss (20%) and erythema formation (35%) derived from UVB exposure. Collagen type I (COL-1) level in dorsal skin was effectively recovered by ESCG administration. These results were supported by down-regulation of collagen-degrading matrix metalloproteinase 2 (MMP2) and 9 (MMP9) expressions. Our results indicate that ESCG protects mouse skin from UVB-induced photoaging by suppressing the expression of matrix metalloproteinases. Our study suggests that ESCG may be anti-photoaging agent.

The main potentialities of resveratrol for drug delivery systems

Resveratrol (RSV), a natural polyphenol found in grapes, was found to be effective in the prevention and therapy of several diseases, however, it does have unfavourable physicochemical properties. In this context, an increasing number of studies have aimed at developing novel therapeutic systems for its delivery to overcome these disadvantages. This review focuses on the mechanisms of action and therapeutic applications. Finally, it also describes some tested formulations for RSV administration, controlled release and targeting, developed with the purpose of increasing RSV bioavailability.

Resveratrol prevents cigarette smoke-induced keratinocytes damage

The plant polyphenol, resveratrol (Resv, 3,4,5-trihydroxystilbene), naturally occurring in a number of fruits and other food products, has been extensively studied over the last two decades for its beneficial properties. Recently, its possible topical use in ameliorating skin conditions has also been proposed; however, its role in preventing cigarette smoke (CS)-induced keratinocyte damage has not been investigated yet. Because of its peculiar location, cutaneous tissue is constantly exposed to several environmental stressors, such as CS. Many compounds presented in CS, have been shown to induce, directly or indirectly, cellular oxidative stress (OS) and inflammation via the production of ROS and lipid peroxidation compounds, among which 4HNE has been shown to be one of the most reactive. In this study, we have shown that resveratrol (at a dose of 10 μM) can decrease CS-induced ROS and carbonyl formation in human keratinocytes. In addition, pre-treatment with resveratrol prevented the induction of TRPA1 expression (mRNA and protein levels), a known receptor involved in cellular differentiation and inflammation, which has been recently shown to be activated by 4HNE. Finally, in keratinocytes, resveratrol could increase the expression of MsrA, enzyme involved in cell defence against oxidative protein damage. The present study further confirms the idea that the topical use of resveratrol can provide a good defence against CS-induced skin damage.

Anthocyanin-rich extract from Hibiscus sabdariffa calyx counteracts UVC-caused impairments in rats

CONTEXT

Ultraviolet radiation (UV) was reported to cause oxidative stress. Hibiscus sabdariffa L. (Malvaceae) calyx is commonly used in traditional Asian and African medicines and possesses strong antioxidant capacity due to its anthocyanin (ANTH) content.

OBJECTIVE

This study researched the possible protective role of Hibiscus sabdariffa calyx extract (HSCE) in UVC exposure of rats.

MATERIAL AND METHODS

Levels of serum enzymes, renal function tests, and some oxidant/antioxidant biomarkers of skin, lens, and retina tissues were monitored. Rats were exposed to UVC 4 h daily for 40 d and simultaneously received HSCE containing 2.5, 5, and 10 mg doses of ANTH in drinking water.

RESULTS

Significant (p < 0.05) increases in the levels of serum aminotransferases, lactate dehydrogenase, urea, creatinine, and uric acid were noted after UVC exposure. In skin, lens, and retina tissues, total oxidant status, oxidative stress index, lipid peroxidation, and protein oxidation escalated markedly (p < 0.05) whereas total antioxidant status, reduced glutathione, and superoxide dismutase decreased dramatically (p < 0.05) related to UVC. Co-administration of HSCE with each ANTH dose significantly (p < 0.05) reversed aforementioned parameters (except total oxidant status) almost in all tissues. The LD50 of HSCE in rats was determined to be above 5000 mg/kg.

DISCUSSION AND CONCLUSION

Our data revealed that HSCE has a remarkable potential to counteract UVC-caused impairments, probably through its antioxidant and free radical-defusing effects. Therefore, HSCE could be useful against some cutaneous and ocular diseases in which UV and oxidative stress have a role in the etiopathogenesis.

Protective effect of red orange extract supplementation against UV-induced skin damages: photoaging and solar lentigines

BACKGROUND

Exposure of the skin to solar ultraviolet (UV) radiations causes important oxidative damages that result in clinical and hystopathological changes, contributing to premature skin aging. Hyperpigmented lesions, also known as age spots, are one of the most visible alterations in skin photoaging. Skin is naturally equipped with antioxidant systems against UV-induced ROS generation; however, these antioxidant defenses are not completely efficient during exposure to sunlight. Oral antioxidants are able to counteract the harmful effects of UV radiation and to strengthen the physiological skin antioxidant defenses.

AIMS

The present study was performed to evaluate the in vivo skin photo-protecting and anti-aging effects of a red orange (Citrus sinensis varieties Moro, Tarocco and Sanguinello) extract supplementation. Previous studies showed that red orange extracts possess strong in vitro free radical scavenging/antioxidant activity and photo-protective effects on human skin.

MATERIALS/METHODS

The photo-protective effects of red orange extract intake against UV-induced skin erythema and melanin production in solar lentigo was evaluated on healthy volunteers by an objective instrumental method (reflectance spectrophotometry).

RESULTS

Data obtained from in vivo studies showed that supplementation of red orange extract (100 mg/daily) for 15 days brought a significant reduction in the UV-induced skin erythema degree. Moreover, skin age spots pigmentation (melanin content) decreased from 27% to 7% when subjects were exposed to solar lamp during red orange extract supplementation.

CONCLUSIONS

Red orange extract intake can strengthen physiological antioxidant skin defenses, protecting skin from the damaging processes involved in photo-aging and leading to an improvement in skin appearance and pigmentation.

Preliminary pharmacological evaluation of Martynia annua Linn leaves for wound healing

OBJECTIVE

To evaluate the wound healing potential of fractions from ethanol extract of Martynia annua (M. annua) Linn leaves.

METHODS

Ethanol extract of M. annua Linn leaves was fractionate into three different fractions (MAF-A, MAF-B and MAF-C) which were screened for wound healing potential using two models: excision and incision on rats. The thin layer chromatography (TLC) profile of all fractions were analyzed and TLC of luteolin was also done. The Povidone-Iodine Ointment was used as reference for comparision. Excision and incision wounds were created on dorsal portion of rats for study. Wound contraction, biochemical parameters (protein level and hydroxyproline level) and histopathological study were performed in excision wound model whereas incision model was used for determination of tensile strength.

RESULTS

The wound contraction and tensile strength of skin tissues were observed significantly greater in MAF-C fraction treated group than other two fractions (P<0.01). In excision wound method (on day 18) protein content and hydroxyproline were found significantly higher in MAF-C group than control group (P<0.01). Histopathological study also showed better angiogenesis, matured collagen fibres and fibroblast cells as compared with the control group.

CONCLUSIONS

In conclusion, our findings suggest that fraction MAF-C from ethanol extract of M. annua leaves is found most effective in wound healing.

Spectroscopic (FT-IR, FT-Raman, 1H- and 13C-NMR), theoretical and microbiological study of trans o-coumaric acid and alkali metal o-coumarates

This work is a continuation of research on a correlation between the molecular structure and electronic charge distribution of phenolic compounds and their biological activity. The influence of lithium, sodium, potassium, rubidium and cesium cations on the electronic system of trans o-coumaric (2-hydroxy-cinnamic) acid was studied. We investigated the relationship between the molecular structure of the tested compounds and their antimicrobial activity. Complementary molecular spectroscopic techniques such as infrared (FT-IR), Raman (FT-Raman), ultraviolet-visible (UV-VIS) and nuclear magnetic resonance (¹H- and ¹³C-NMR) were applied. Structures of the molecules were optimized and their structural characteristics were calculated by the density functional theory (DFT) using the B3LYP method with 6-311++G** as a basis set. Geometric and magnetic aromaticity indices, atomic charges, dipole moments and energies were also calculated. Theoretical parameters were compared to the experimental characteristics of investigated compounds. Correlations between certain vibrational bands and some metal parameters, such as electronegativity, ionization energy, atomic and ionic radius, were found. The microbial activity of studied compounds was tested against Escherichia coli, Bacillus subtilis, Pseudomonas aeruginosa, Staphylococcus aureus, Proteus vulgaris and Candida albicans.

Photoprotective effects of oxyresveratrol and Kuwanon O on DNA damage induced by UVA in human epidermal keratinocytes

Ultraviolet A not only plays a major part in photoaging and skin tanning but also induces genetic damage and mutation in the epidermal basal layer of human skin. The photoprotective effect of oxyresveratrol and kuwanon O, two phenolic compounds from the root extract of Morus australis, in human primary epidermal keratinocytes was investigated in this study. Both of them were nontoxic to cells at a concentration less than 10 and 0.5 μM, respectively. After pretreatment at the concentrations of 5 and 10 μM, oxyresveratrol increased cell viability, exhibited significant suppressions on UVA- or H2O2-induced cellular ROS. UVA-enhanced nitrotyrosine was also reduced by post-treatment with oxyresveratrol at theses concentrations. Kuwanon O presented similar inhibitions on cellular ROS and nitrotyrosine with lower concentrations (0.25 and 0.5 μM), but there is no significant protection on cell survival after UVA irradiation. Their photoprotective effects also involved the enhanced repair of 8-hydroxy-2'-deoxyguanosine (8-OHdG) and cyclobutane pyrimidine dimers (CPDs) as mediated by the augment of p53 expression after UVA radiation.

Natural products as photoprotection

The rise in solar ultraviolet radiation on the earth's surface has led to a depletion of stratospheric ozone over recent decades, thus accelerating the need to protect human skin against the harmful effects of UV radiation such as erythema, edema, hyperpigmentation, photoaging, and skin cancer. There are many different ways to protect skin against UV radiation's harmful effects. The most popular way to reduce the amount of UV radiation penetrating the skin is topical application of sunscreen products that contain UV absorbing or reflecting active molecules. Based on their protection mechanism, the active molecules in sunscreens are broadly divided into inorganic and organic agents. Inorganic sunscreens reflect and scatter UV and visible radiation, while organic sunscreens absorb UV radiation and then re-emit energy as heat or light. These synthetic molecules have limited concentration according to regulation concern. Several natural compounds with UV absorption property have been used to substitute for or to reduce the quantity of synthetic sunscreen agents. In addition to UV absorption property, most natural compounds were found to act as antioxidants, anti-inflammatory, and immunomodulatory agents, which provide further protection against the damaging effects of UV radiation exposure. Compounds derived from natural sources have gained considerable attention for use in sunscreen products and have bolstered the market trend toward natural cosmetics. This adds to the importance of there being a wide selection of active molecules in sunscreen formulations. This paper summarizes a number of natural products derived from propolis, plants, algae, and lichens that have shown potential photoprotection properties against UV radiation exposure-induced skin damage.

Magnolol reduces UVB-induced photodamage by regulating matrix metalloproteinase activity

In this study, we evaluated the anti-photoaging activity of magnolol in UV-irradiated hairless mice, and hypothesized that magnolol would prevent photoaging in these animals. The inhibitory effect of magnolol on wrinkle formation was determined by analyzing the skin replica, histologically examining the epidermal thickness, and identifying damage to the collagen fibers. The protective effects of magnolol on UVB-induced skin photoaging were examined by determining the level of MMPs and mitogen-activated protein kinases (MAPKs). Exposure to UVB radiation significantly increased skin thickness and wrinkle grade, but magnolol treatment significantly reduced the average length and depth of wrinkles, and this was correlated with the inhibition of collagen fiber loss. The magnolol-treated group had remarkably decreased activity levels of MMP-1, -9, and -13 compared to the corresponding levels in the vehicle-treated UVB-irradiated group. These results indicate that magnolol prevents skin photoaging in UVB-irradiated hairless mice.

Cork extracts reduce UV-mediated DNA fragmentation and cell death

Cork extracts composed of vescalagin/castalagin, gallic acid and ellagic acid reduce UV-mediated cell damage in fibroblasts.

Protein phosphatase-1 is involved in the maintenance of normal homeostasis and in UVA irradiation-induced pathological alterations in HaCaT cells and in mouse skin

The number of ultraviolet (UV) radiation-induced skin diseases such as melanomas is on the rise. The altered behavior of keratinocytes is often coupled with signaling events in which Ser/Thr specific protein kinases and phosphatases regulate various cellular functions. In the present study the role of protein phosphatase-1 (PP1) was investigated in the response of human keratinocyte (HaCaT) cells and mouse skin to UV radiation. PP1 catalytic subunit (PP1c) isoforms, PP1cα/γ and PP1cδ, are all localized to the cytoskeleton and cytosol of keratinocytes, but PP1cδ was found to be dominant over PP1α/γ in the nucleus. PP1c-silencing in HaCaT cells decreased the phosphatase activity and suppressed the viability of the cells. Exposure to a 10 J/cm(2) UVA dose induced HaCaT cell death and resulted in a 30% decrease of phosphatase activity. PP1c-silencing and UVA irradiation altered the gene expression profile of HaCaT cells and suggested that the expression of 19 genes was regulated by the combined treatments with many of these genes being involved in malignant transformation. Microarray analysis detected altered expression levels of genes coding for melanoma-associated proteins such as keratin 1/10, calcium binding protein S100A8 and histone 1b. Treatment of Balb/c mice with the PP1-specific inhibitor tautomycin (TM) exhibited increased levels of keratin 1/10 and S100A8, and a decreased level of histone 1b proteins following UVA irradiation. Moreover, TM treatment increased pigmentation of the skin which was even more apparent when TM was followed by UVA irradiation. Our data identify PP1 as a regulator of the normal homeostasis of keratinocytes and the UV-response.