Skin cell protection against UVA by Sideroxyl, a new antioxidant complementary to sunscreens

Density Functional Theory Study on Antioxidant Activity of Three Polyphenols

In recent years, research on the antioxidant activity of natural antioxidants has become more and more popular. Polyphenols are a large number of natural antioxidants in plants. This paper selected three common polyphenols to study their antioxidant activity based on quantum chemistry theory. This experiment hopes to provide a theoretical basis for the further development of polyphenol health food with strong antioxidant activity. Three polyphenols resveratrol, liquiritigenin, and isoliquiritigenin were optimized at the level of B3lyp/6-311G (d, p), and the single point energy was calculated with B3lyp/6-311 +  + G (2d, 2p). The phenol hydroxyl bond dissociation enthalpy (BDE), ionization potential (IP), proton dissociation enthalpy (PDE), proton affinity (PA), and electron transfer enthalpy (ETE) were calculated in different phase states study the antioxidant mechanism. Draw the frontier molecular orbital and conduct dynamic simulation analysis scavenging · OH and · OOH to explore the most possible active sites in different phenolic hydroxyl sites. The bond length, dihedral angle, BDE, IP, PDE, PA and ETE were compared to speculate the antioxidant activity: Resveratrol > isoliquiritigenin > liquiritigenin. By analyzing the frontier molecular orbital and dynamic simulation results, it is speculated that the phenolic hydroxyl groups at C4', C4', and C4 are the most likely active sites of resveratrol, liquiritigenin, and isoliquiritigenin, respectively. In different phase states, the three compounds showed the same antioxidant activity, and the phenolic hydroxyl activities of the three compounds were different at different sites.

Fucoxanthin for Topical Administration, a Phototoxic vs. Photoprotective Potential in a Tiered Strategy Assessed by In Vitro Methods

Fucoxanthin possesses a well-described antioxidant activity that might be useful for human skin photoprotection. However, there is a lack of scientific information regarding its properties when applied onto human skin. Thus, the objective of the present study was to assess the photoprotective and phototoxicity potential of fucoxanthin based on its ultraviolet (UVB 280-320 nm; UVA 320-400 nm) and visible (VIS 400-700 nm) absorption, photostability, phototoxicity in 3T3 mouse fibroblast culture vs. full-thickness reconstructed human skin (RHS), and its ability to inhibit reactive oxygen species formation that is induced by UVA on HaCaT keratinocytes. Later, we evaluated the antioxidant properties of the sunscreen formulation plus 0.5% fucoxanthin onto RHS to confirm its bioavailability and antioxidant potential through the skin layers. The compound was isolated from the alga Desmarestia anceps. Fucoxanthin, despite presenting chemical photo-instability (dose 6 J/cm2: 35% UVA and 21% VIS absorbance reduction), showed acceptable photodegradation (dose 27.5 J/cm2: 5.8% UVB and 12.5% UVA absorbance reduction) when it was added to a sunscreen at 0.5% (w/v). In addition, it increased by 72% of the total sunscreen UV absorption spectra, presenting UV-booster properties. Fucoxanthin presented phototoxic potential in 3T3 fibroblasts (mean photo effect 0.917), but it was non-phototoxic in the RHS model due to barrier function that was provided by the stratum corneum. In addition, it showed a significant inhibition of ROS formation at 0.01% (p < 0.001), in HaCat, and in a sunscreen at 0.5% (w/v) (p < 0.001), in RHS. In conclusion, in vitro results showed fucoxanthin protective potential to the skin that might contribute to improving the photoprotective potential of sunscreens in vivo.

A series of in vitro and human studies of a novel lip cream formulation for protecting against environmental triggers of recurrent herpes labialis

Purpose

These studies describe the testing of a novel, daily-use lip cream designed for individuals with lips prone to recurrent herpes labialis (RHL) that protects against environmental triggers.

Subjects and methods

In vitro occlusive and in vitro and in vivo photoprotection analyses, a characterization of normal vs dry lips, and a randomized, evaluator-blinded, clinical trial that assessed the lip cream in healthy subjects with dry lips were conducted. In the clinical trial, subjects applied the lip cream or were untreated and evaluated using transepidermal water loss (TEWL), corneometry, visual assessments of lip dryness, expert photographic evaluations, and subject-rated outcomes.

Results

The lip cream’s in vitro water vapor transmission rate (84.1 g/(m² h)) indicated moderate occlusivity. The lip cream, but not placebo or control (water), reduced ultraviolet A (UVA)- and UVB-induced DNA damage, and tumor necrosis factor-α (EpiDerm^FT) and pros-taglandin E₂ release (EpiDerm^FT and EpiGingival™). The lip cream’s in vivo sun protection factor (SPF) was 12.2 (lower confidence limit, 11.3) and SPF/UVA protection factor ratio was 0.9. The characterization of dry vs normal lips identified differences in moisturization. In the clinical trial, the lip cream significantly decreased TEWL (difference: −7.19 [95% CI: −11.41, −2.98]; P<0.01), increased corneometry (difference: 4.62 [95% CI: 1.05, 8.19]; P<0.05), and reduced visual dryness (difference: −1.48 [95% CI: 2.24, −0.71]; P<0.001) compared to untreated subjects. Significant benefits were also observed on expert photographic assessments of scaling (difference: −0.89 [95% CI: −1.75, −0.03]; P< 0.05), cupping (difference: −1.50 [95% CI: −2.30, −0.70]; P<0.001), and healthy appearance (difference: −1.44 [95% CI: −2.29, −0.58]; P<0.01); differences in overall healthy appearance were not significant (P=0.51). Subject-rated assessments indicated improvements in cracking, dryness, and flaking in the lip cream group but worsening in untreated subjects.

Conclusion

These studies indicate that this novel, daily-use lip cream protects against UV radiation, drying, and chapping, which are established environmental RHL triggers.

Antioxidant action and protective and reparative effects of lentinan on oxidative damage in HaCaT cells

BACKGROUND

Lentinus edodes is one of the largest edible fungi. Lentinan, extracted from its fruiting body has clinically significant anticancer, antibacterial, antiviral, and anticoagulant effects; however, its preventive effects on skin oxidative damage are unclear.

AIMS

We aimed to evaluate the in vitro antioxidation capability of lentinan and its protective and reparative effects on a model of cell oxidative damage.

METHODS

We evaluated the in vitro antioxidant potential of lentinan by assessing its free-radical quenching ability using DPPH and ABTS and superoxide anions. Using the HaCaT cell line as the experimental system, we tested the protective and reparative effects of lentinan on a model of H₂ O₂ -induced cellular oxidative damage through assessment of cell survival rate, malondialdehyde (MDA) content, and superoxide dismutase (SOD) activity.

RESULTS

Lentinan displayed high antioxidant potential: DDPH and ABTS quenching rates were above 60%; superoxide anions, approximately 18%. Furthermore, lentinan could dose-dependently prevent the reduction of activity in HaCaT cells by H₂ O₂ , reduce MDA formation, and increase SOD activity. Moreover, lentinan showed not only a protective effect against oxidative damage but also reparative effects to a certain extent, in HaCaT cells.

CONCLUSIONS

Our findings demonstrated the ability of lentinan to enhance cellular tolerance to oxidative damage, stress resistance, and to have protective and reparative effects on damaged cells. Therefore, with L. edodes as a source for antiaging substances, cosmetics with homology to foods have great potential clinical applications.

The Properties of the Ulcinj Peloid make it Unique Biochemical Laboratory Required for the Treatment of Problematic Skin and Health Care

The aim of this study was to investigate the physicochemical properties of peloid, its mineralogical composition and its antimicrobial activity, including the presence of algae, with the aim of considering its dermo-cosmetic application, such as anti-skin aging and treatment. Physicochemical analysis showed that peloid from Ulcinj coast, contains minerals, necessary for smooth performance of skin functions, as well as, the whole body. A studied peloid sample showed significant antimicrobial activity of Candida albicans strain, and the presence of algae of Bacillariophyta division, known to have a beneficial effect on skin health. Results of examination of peloid from Ulcinj locality, recommended it as a high quality natural substance applicative in dermo-cosmetic preparations for treatment of problematic skin.

Novel double prodrugs of the iron chelator N,N'-bis(2-hydroxybenzyl)ethylenediamine-N,N'-diacetic acid (HBED): Synthesis, characterization, and investigation of activation by chemical hydrolysis and oxidation

The development of iron chelators suitable for the chronic treatment of diseases where iron accumulation and subsequent oxidative stress are implicated in disease pathogenesis is an active area of research. The clinical use of the strong chelator N,N'-bis(2-hydroxybenzyl)ethylenediamine-N,N'-diacetic acid (HBED) and its alkyl ester prodrugs has been hindered by poor oral bioavailability and lack of conversion to the parent chelator, respectively. Here, we present novel double prodrugs of HBED that have the carboxylate and phenolate donors of HBED masked with carboxylate esters and boronic acids/esters, respectively. These double prodrugs were successfully synthesized as free bases (7a-f) or as dimesylate salts (8a-c,e), and were characterized by (1)H, (13)C, and (11)B NMR; MP; MS; and elemental analysis. The crystal structure of 8a was solved. Three of the double prodrugs (8a-c) were selected for further investigation into their abilities to convert to HBED by stepwise hydrolysis and H2O2 oxidation. The serial hydrolysis of the pinacol and methyl esters of N,N'-bis(2-boronic acid pinacol ester benzyl)ethylenediamine-N,N'-diacetic acid methyl ester dimesylate (8a) was verified by LC-MS. The macro half-lives for the hydrolyses of 8a-c, measured by UV, ranged from 3.8 to 26.3 h at 37 °C in pH 7.5 phosphate buffer containing 50% MeOH. 9, the product of hydrolysis of 8a-c and the intermediate in the conversion pathway, showed little-to-no affinity for iron or copper in UV competition experiments. 9 underwent a serial oxidative deboronation by H2O2 in N-methylmorpholine buffer to generate HBED (k = 10.3 M(-1) min(-1)). The requirement of this second step, oxidation, before conversion to the active chelator is complete may confer site specificity when only localized iron chelation is needed. Overall, these results provide proof of principle for the activation of the double prodrugs by chemical hydrolysis and H2O2 oxidation, and merit further investigation into the protective capabilities of the prodrugs against H2O2-induced cell death.

Ellagic acid plays a protective role against UV-B-induced oxidative stress by up-regulating antioxidant components in human dermal fibroblasts

Ellagic acid (EA), an antioxidant polyphenolic constituent of plant origin, has been reported to possess diverse pharmacological properties, including anti-inflammatory, anti-tumor and immunomodulatory activities. This work aimed to clarify the skin anti-photoaging properties of EA in human dermal fibroblasts. The skin anti-photoaging activity was evaluated by analyzing the reactive oxygen species (ROS), matrix metalloproteinase-2 (MMP-2), total glutathione (GSH) and superoxide dismutase (SOD) activity levels as well as cell viability in dermal fibroblasts under UV-B irradiation. When fibroblasts were exposed to EA prior to UV-B irradiation, EA suppressed UV-B-induced ROS and proMMP-2 elevation. However, EA restored total GSH and SOD activity levels diminished in fibroblasts under UV-B irradiation. EA had an up-regulating activity on the UV-B-reduced Nrf2 levels in fibroblasts. EA, at the concentrations used, was unable to interfere with cell viabilities in both non-irradiated and irradiated fibroblasts. In human dermal fibroblasts, EA plays a defensive role against UV-B-induced oxidative stress possibly through an Nrf2-dependent pathway, indicating that this compound has potential skin antiphotoaging properties.

Protective properties of ginsenoside Rb3 against UV-B radiation-induced oxidative stress in HaCaT keratinocytes

This work aimed to evaluate the skin anti-photoaging properties of ginsenoside Rb3 (Rb3), one of the main protopanaxdiol-type ginsenosides from ginseng, in HaCaT keratinocytes. The skin anti-photoaging activity was assessed by analyzing the levels of reactive oxygen species (ROS), pro-matrix metalloproteinase-2 (proMMP-2), pro-matrix metalloproteinase-9 (proMMP-9), total glutathione (GSH), and superoxide dismutase (SOD) activity as well as cell viability in HaCaT keratinocytes under UV-B irradiation. When HaCaT keratinocytes were exposed to Rb3 prior to UV-B irradiation, Rb3 exhibited suppressive activities on UV-B-induced ROS, proMMP-2, and proMMP-9 enhancements. On the contrary, Rb3 displayed enhancing activities on UV-B-reduced total GSH and SOD activity levels. Rb3 could not interfere with cell viabilities in UV-B-irradiated HaCaT keratinocytes. Rb3 plays a protective role against UV-B-induced oxidative stress in human HaCaT keratinocytes, proposing its potential skin anti-photoaging properties.

Skin anti-photoaging properties of ginsenoside Rh2 epimers in UV-B-irradiated human keratinocyte cells

Ginseng, one of the most widely used herbal medicines, has a wide range of therapeutic and pharmacological applications. Ginsenosides are the major bioactive ingredients of ginseng, which are responsible for various pharmacological activities of ginseng. Ginsenoside Rh2, known as an antitumour ginsenoside, exists as two different stereoisomeric forms, 20(S)-ginsenoside Rh2 [20(S)-Rh2] and 20(R)-ginsenoside Rh2 [20(R)-Rh2]. This work aimed to assess and compare skin anti-photoaging activities of 20(S)-Rh2 and 20(R)-Rh2 in UV-B-irradiated HaCat cells. 20(S)-Rh2, but not 20(R)-Rh2, was able to suppress UV-B-induced ROS production in HaCat cells. Both stereoisomeric forms could not modulate cellular survival and NO level in UV-B-irradiated HaCat cells. Both 20(S)-Rh2 and 20(R)-Rh2 exhibited suppressive effects on UV-B-induced MMP-2 activity and expression in HaCat cells. In brief, the two stereoisomers of ginsenoside Rh2, 20(S)-Rh2 and 20(R)-Rh2, possess skin anti-photoaging effects but possibly in different fashions.

Suppressive properties of ginsenoside Rb2, a protopanaxadiol-type ginseng saponin, on reactive oxygen species and matrix metalloproteinase-2 in UV-B-irradiated human dermal keratinocytes

Ginsenosides, also known as ginseng saponins, are the principal bioactive ingredients of ginseng, which are responsible for its diverse pharmacological activities. The present work aimed to assess skin anti-photoaging properties of ginsenoside Rb2 (Rb2), one of the predominant protopanaxadiol-type ginsenosides, in human epidermal keratinocyte HaCaT cells under UV-B irradiation. When the cultured keratinocytes were subjected to Rb2 prior to UV-B irradiation, Rb2 displayed suppressive activities on UV-B-induced reactive oxygen species elevation and matrix metalloproteinase-2 expression and secretion. However, Rb2 at the used concentrations was unable to modulate cellular survivals in the UV-B-irradiated keratinocytes. In brief, Rb2 possesses a protective role against the photoaging of human keratinocyte cells under UV-B irradiation.

A role for human mitochondrial complex II in the production of reactive oxygen species in human skin

The mitochondrial respiratory chain is a major generator of cellular oxidative stress, thought to be an underlying cause of the carcinogenic and ageing process in many tissues including skin. Previous studies of the relative contributions of the respiratory chain (RC) complexes I, II and III towards production of reactive oxygen species (ROS) have focussed on rat tissues and certainly not on human skin which is surprising as this tissue is regularly exposed to UVA in sunlight, a potent generator of cellular oxidative stress. In a novel approach we have used an array of established specific metabolic inhibitors and DHR123 fluorescence to study the relative roles of the mitochondrial RC complexes in cellular ROS production in 2 types of human skin cells. These include additional enhancement of ROS production by exposure to physiological levels of UVA. The effects within epidermal and dermal derived skin cells are compared to other tissue cell types as well as those harbouring a compromised mitochondrial status (Rho-zero A549). The results show that the complex II inhibitor, TTFA, was the only RC inhibitor to significantly increase UVA-induced ROS production in both skin cell types (P<0.05) suggesting that the role of human skin complex II in terms of influencing ROS production is more important than previously thought particularly in comparison to liver cells. Interestingly, two-fold greater maximal activity of complex II enzyme was observed in both skin cell types compared to liver (P<0.001). The activities of RC enzymes appear to decrease with increasing age and telomere length is correlated with ageing. Our study showed that the level of maximal complex II activity was higher in the MRC5/hTERT (human lung fibroblasts transfected with telomerase) cells than the corresponding wild type cells (P=0.0012) which can be considered (in terms of telomerase activity) as models of younger and older cells respectively.

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We examined the influence of mitochondrial complex II on ROS production in human skin.

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Past studies have focussed on ROS production from mitochondrial complexes I and III.

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DHR123 fluorescence was used following individual complex inhibition and UVA exposure.

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Only complex II inhibition significantly increased ROS levels in both skin cell types.

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Complex II had a two-fold greater activity in skin cells compared to liver cells.

Stereoselective skin anti-photoaging properties of ginsenoside Rg3 in UV-B-irradiated keratinocytes

Ginsenosides are major bioactive constituents that are responsible for the diverse pharmacological activities of ginseng. This work aimed to assess the skin anti-photoaging activities of the two stereoisomeric forms of ginsenoside Rg3, 20(S)-Rg3 and 20(R)-Rg3. When the two Rg3 stereoisomers were added to cultured human keratinocyte HaCaT cells prior to irradiation with 70 mJ/cm(2) UV-B, 20(S)-Rg3, but not 20(R)-Rg3, decreased the UV-B-induced intracellular reactive oxygen species (ROS) levels in a concentration-dependent manner, as detected by both fluorometric and confocal microscopic analyses. Likewise, 20(S)-Rg3, but not 20(R)-Rg3, decreased the UV-B-induced ROS levels in human dermal fibroblast cells. Both stereoisomers were unable to modulate the nitric oxide levels in HaCaT cells under UV-B irradiation, and induced no cytotoxicity in cultured keratinocytes and fibroblasts. 20(S)-Rg3 suppressed the UV-B-induced matrix metalloproteinase (MMP)-2 activities in HaCaT cells. Taken together, these results indicate that 20(S)-Rg3 possesses both ROS-scavenging and MMP-2 inhibitory activities, while 20(R)-Rg3 possesses neither activity. These findings imply that ginsenoside Rg3 stereoselectively demonstrates skin anti-photoaging activities.

Effects of UV wavelength on cell damages caused by UV irradiation in PC12 cells

Ultraviolet (UV) radiations present in sunlight are a major etiologic factor for many skin diseases and induce DNA damage through formation of cyclobutane pyrimidine dimer (CPD). This study was conducted to determine the toxicological effects of different wavelengths (250, 270, 290, and 310 nm) and doses of UV radiation on cell viability, DNA structure, and DNA damage repair mechanisms in a PC12 cell system. For this, we evaluated cell viability and CPD formation. Cell survival rate was markedly decreased 24h after UV irradiation in a dose-dependent manner at all wavelengths (except at 310 nm). Cell viability increased with increasing wavelength in the following order: 250<270<290<310 nm. UV radiation at 250 nm showed the highest cell killing ability, with a median lethal dose (LD50) of 120 mJ/cm(2). The LD50 gradually increased with increase in wavelength. Among the 4 wavelengths tested, the highest LD50 (6000 mJ/cm(2)) was obtained for 310 nm. CPD formation decreased substantially with increasing wavelength. Among the 4 wavelengths, the proportion of CPD formation was highest at 250 nm and lowest at 310 nm. On the basis of LD50 values for each wavelength, PC12 cells irradiated with UV radiation of 290 nm showed maximum DNA repair ability, whereas those irradiated with the 310-nm radiation did not show any repair ability. Toxicity of UV radiation varied with wavelengths and exposure doses.

Differential response of normal human epidermal keratinocytes and HaCaT cells to hydrogen peroxide-induced oxidative stress

BACKGROUND

  Normal human epidermal keratinocytes (NHEKs) and HaCaT cells are the most common models used to study the effects of various factors on skin cells. These cell lines share some common characteristics, but little is known about their differences in handling hydrogen peroxide (H(2) O(2) )-induced oxidative stress.

AIM

To investigate the differential response of NHEKs and HaCaT cells to H(2) O(2) -induced oxidative stress.

METHODS

We examined differences in NHEKs and HaCaT cells after H(2) O(2) treatment, assessing changes in cell viability; levels of intracellular reactive oxygen species (ROS), superoxide dismutase (SOD) and caspase-3/7; percentage of cells arrested in G1 phase; number of senescence-associated β-galactosidase (SA-β-Gal)-positive cells and; expression of senescence-related protein Klotho.

RESULTS

The viability of NHEKs and HaCaT cells decreased in a concentration-dependent and time-dependent manner after exposure to H(2) O(2) . The inhibitory effect of 150 μmol/L H(2) O(2) on cell viability was greater in HaCaT cells than in NHEKs (P<0.05). Levels of ROS and caspase-3/7, and the percentage of cells arrested in G1 phase, were higher in HaCaT cells than in NHEKs, whereas intracellular SOD was higher in NHEKs than in HaCaT cells after exposure to 150 μmol/L H(2) O(2) (P < 0.05). SA-β-Gal positive cells increased significantly in NHEKs after treatment with H(2) O(2) (P < 0.05). Klotho was significantly downregulated in both NHEKs and HaCaT cells after H(2) O(2) treatment, but no SA-β-Gal-positive HaCaT cells were seen, even after treatment with H(2) O(2) .

CONCLUSIONS

Normal human epidermal keratinocytes are more resistant than HaCaT cells to H(2) O(2) -induced oxidative stress. HaCaT cells have senescence phenotypes, but do not express β-Gal.

Ellagic acid protects human keratinocyte (HaCaT) cells against UVA-induced oxidative stress and apoptosis through the upregulation of the HO-1 and Nrf-2 antioxidant genes

UV radiation from the sun is a potent environmental risk factor in the pathogenesis of skin damage. Much of the skin damage caused by ultraviolet A (UVA) irradiation from the sun is associated with oxidative stress. The aim of this study was to investigate the protective role of ellagic acid (25-75 μM), a natural antioxidant, against UVA (5-20 J/cm(2))-induced oxidative stress and apoptosis in human keratinocyte (HaCaT) cells and to reveal the possible mechanisms underlying this protective efficacy. Ellagic acid pre-treatment markedly increased HaCaT cell viability and suppressed UVA-induced ROS generation and MDA formation. Moreover, ellagic acid pre-treatment prevented UVA-induced DNA damage as evaluated by the comet assay. Ellagic acid treatment also significantly inhibited the UVA-induced apoptosis of HaCaT cells, as measured by a reduction of DNA fragmentation, mitochondria dysfunction, ER stress, caspase-3 activation, and Bcl-2/Bax deregulation. Notably, the antioxidant potential of ellagic acid was directly correlated with the increased expression of HO-1 and SOD, which was followed by the downregulation of Keap1 and the augmented nuclear translocation and transcriptional activation of Nrf2 with or without UVA irradiation. Nrf2 knockdown diminished the protective effects of ellagic acid. Therefore, ellagic acid may be useful for the treatment of UVA-induced skin damage.