Free radicals and aging of the skin

Protective Effect of Panax notoginseng Extract Fermented by Four Different Saccharomyces cerevisiae Strains on H2O2 Induced Oxidative Stress in Skin Fibroblasts

Purpose

To produce Panax notoginseng extract as a cosmetic ingredient through Saccharomyces cerevisiae fermentation.

Methods

We first compared the total sugar content, polysaccharide content, reducing sugar content, total phenolic content, total saponin content, DPPH free radical, ABTS free radical, hydroxyl free radical scavenging ability and ferric reducing antioxidant power (FRAP) of Panax notoginseng fermented extract (pnFE) and unfermented extract (pnWE). Their potential correlations were analyzed by Pearson's correlation analysis. Then, the oxidative stress model of H2O2-induced MSFs was used to evaluate the effects of different pnFE on MSF viability, reactive oxygen species (ROS), malondialdehyde (MDA), and the activities of catalase (CAT), glutathione peroxidase (GSH-Px) and superoxide dismutase (SOD) to explore their protective effects on MSFs subjected to H2O2-induced cellular oxidative damage. Finally, their safety and stability were evaluated by using the red blood cell (RBC) test and hen's egg test-chorioallantoic membrane (HET-CAM) assay, and changes in pH and content of soluble solids, respectively.

Results

Compared with pnWE, pnFE has more active substances and stronger antioxidant capacity. In addition, pnFE has a protective effect on H2O2-induced oxidative stress in MSFs with appropriate safety and stability.

Conclusion

PnFE has broad application prospects in the field of cosmetics.

Anti-Melanogenic and Antioxidant Effects of Cell-Free Supernatant from Lactobacillus gasseri BNR17

In recent years, there has been considerable interest in the use of cell-free supernatant of probiotics culture for nutritional and functional applications. In this study, we investigated the effect of the cell-free supernatant from Lactobacillus gasseri BNR17 (CFS) on anti-melanogenesis and reducing oxidative stress in B16-F10 murine melanoma cells and HaCaT human keratinocytes. Treatment with CFS significantly inhibited the production of extracellular and intracellular melanin without cytotoxicity during melanogenesis induced by the α-MSH in B16-F10 cells. The CFS dramatically reduced tyrosinase activity and the melanogenesis-related gene expression. Further, it showed antioxidative effects in a dose-dependent manner in DPPH (2,2-diphenyl-1-picryl-hydrazyl-hydrate) assays and significantly increased the mRNA levels of HO-1 and CAT in HaCaT cells. Furthermore, the CFS increased HO-1 and anti-oxidative-related gene expression during H2O2-induced oxidative stress in HaCaT cells. Together, this study suggests that the CFS reduces hyperpigmentation and inhibits oxidative stress, and thus can be used as a potential skincare product in the future.

Frog Skin Derived Peptides With Potential Protective Effects on Ultraviolet B-Induced Cutaneous Photodamage

Hyla annectans is a tree frog living in the southwestern plateau area of China where there is strong ultraviolet radiation and long duration of sunshine. So their naked skin may possess chemical defense components that protect it from acute photo-damage. However, no such peptide or components has been identified till to date. In the current work, two novel peptides (FW-1, FWPLI-NH2 and FW-2, FWPMI-NH2) were identified from the skin of the tree frog. Five copies of FW-1 and four copies of FW-2 are encoded by an identical gene and released from the same protein precursor, which possess 167 amino acid residues. FW-1 and -2 can exert significant anti-inflammatory functions by directly inhibiting Ultraviolet B irradiation (UVB)-induced secretion of inflammatory cytokines such as tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6). They may achieve this function by modulating the UV-induced stress signaling pathways such as Mitogen-activated protein kinases (MAPK) and Nuclear Factor Kappa B (NF-κB). Besides, FW-1 and -2 showed potential antioxidant effects on epidermis by attenuating the UVB-induced reactive oxygen species (ROS) production through an unknown mechanism. Considering small peptides' easy production, storage, and potential photo-protective activity, FW-1/2 might be exciting leading compounds or templates for the development of novel pharmacological agents for the suppression of UVB-induced skin inflammation. Moreover, this study might expand our knowledge on skin defensive mechanism of tree frog upon UVB irradiation.

Phoenix dactylifera L. Seed Extract Exhibits Antioxidant Effects and Attenuates Melanogenesis in B16F10 Murine Melanoma Cells by Downregulating PKA Signaling

Background: The mode of action of Phoenix dactylifera seed extract in skin care has never been explored. Methods: P. dactylifera L. seeds were extracted by ultrasonic extraction. The antioxidant characteristics of the extract were determined by 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2′-azino-di-(3-ethylbenzthiazoline sulfonic acid) (ABTS⁺) assays and scavenging methods. The total phenolic content, reducing capacity, iron (II) ion-chelation, and intracellular reactive oxygen species (ROS)-scavenging capacities were also investigated. The effects of P. dactylifera L. seed extract on melanogenesis were evaluated spectrophotometrically by a mushroom tyrosinase activity assay, determination of intracellular tyrosinase activity, and melanin content. The expression levels of melanogenesis-related proteins were analyzed by Western blotting. Results: The results revealed that the P. dactylifera L. seed extract exerted apparent antioxidant capacity and significantly decreased intracellular ROS content at concentrations of 0.245 and 0.49 (mg/mL). Furthermore, the extract decreased the expression of melanocortin 1 receptor (MC1R), microphthalmia-associated transcription factor (MITF), tyrosinase, tyrosinase-related protein-1 (TRP1), and tyrosinase-related protein-2 (TRP2), and inhibited melanogenesis in B16F10 cells. Conclusions: Our results revealed that P. dactylifera L. seed extract attenuated melanogenesis in B16F10 cells by downregulating protein kinase A (PKA) signaling pathways. Hence, the extract could be used as a type of skin-whitening agent in skin care products.

Germinated Riceberry Rice Enhanced Protocatechuic Acid and Vanillic Acid to Suppress Melanogenesis through Cellular Oxidant-Related Tyrosinase Activity in B16 Cells

The anti-melanogenic bioactivities of phytophenolic compounds have been well recognized. Riceberry rice contains a rich source of phenolic compounds that act as melanin inhibitors through their antioxidant and anti-tyrosinase properties. Germination has been shown to be an effective process to improve targeted phenolic compounds. In this study, germinated riceberry rice extract was tested for antioxidant activity. Total phenolic content was determined while the tyrosinase inhibitory effect was screened by the in vitro mushroom tyrosinase assay. Cytotoxicity of germinated riceberry rice extract was investigated in B16 cells before evaluating its activities on cellular tyrosinase, melanogenesis, melanin excretion, morphological appearance, and cellular oxidants. Germinated riceberry rice extract showed increased potency of antioxidants and was also twice as effective for mushroom tyrosinase inhibition when compared with ungerminated riceberry rice extract. In B16 cells, the extract inhibited cellular tyrosinase, melanogenesis, and cellular oxidants in a dose-dependent manner when compared with untreated cells. Germinated riceberry rice extract also displayed an effect on B16 cells morphology by reducing the number of melanin- containing cells and their dendriticity. Additionally, the germination of riceberry rice dominantly enhanced two phenolic acids, protocatechuic acid and vanillic acid, which have the potential for antioxidant-associated hyperpigmentation control. Thus, the restricted germination of riceberry rice tended to promote protocatechuic acid and vanillic acid, which dominantly displayed antioxidants and tyrosinase-related melanogenic inhibition.

Relation of Redox and Structural Alterations of Rat Skin in the Function of Chronological Aging

Accumulation of oxidative insults on molecular and supramolecular levels could compromise renewal potency and architecture in the aging skin. To examine and compare morphological and ultrastructural changes with redox alterations during chronological skin aging, activities of antioxidant defense (AD) enzymes, superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px), glutathione reductase (GR), thioredoxin reductase (TR), and methionine sulfoxide reductase A (MsrA), and the markers of oxidative damage of biomolecules—4-hydroxynonenal (HNE) and 8-oxoguanine (8-oxoG)—were examined in the rat skin during life (from 3 days to 21 months). As compared to adult 3-month-old skin, higher activities of CAT, GSH-Px, and GR and a decline in expression of MsrA are found in 21-month-old skin. These changes correspond to degenerative changes at structural and ultrastructural levels in epidermal and dermal compartments, low proliferation capacity, and higher levels of HNE-modified protein aldehydes (particularly in basal lamina) and 8-oxoG positivity in nuclei and mitochondria in the sebaceous glands and root sheath. In 3-day-old skin, higher activities of AD enzymes (SOD, CAT, GR, and TR) and MsrA expression correspond to intensive postnatal development and proliferation. In contrast to 21-month-old skin, a high level of HNE in young skin is not accompanied by 8-oxoG positivity or any morphological disturbances. Observed results indicate that increased activity of AD enzymes in elderly rat skin represents the compensatory response to accumulated oxidative damage of DNA and proteins, accompanied by attenuated repair and proliferative capacity, but in young rats the redox changes are necessary and inherent with processes which occur during postnatal skin development. Мorphological and ultrastructurаl changes are in line with the redox profile in the skin of young and old rats.

Analysis of Floral Volatile Components and Antioxidant Activity of Different Varieties of Chrysanthemum morifolium

This study investigated the volatile flavor compounds and antioxidant properties of the essential oil of chrysanthemums that was extracted from the fresh flowers of 10 taxa of Chrysanthemum morifolium from three species; namely Dendranthema morifolium (Ramat.) Yellow, Dendranthema morifolium (Ramat.) Red, Dendranthema morifolium (Ramat.) Pink, Dendranthema morifolium (Ramat.) White, Pericallis hybrid Blue, Pericallis hybrid Pink, Pericallis hybrid Purple, Bellis perennis Pink, Bellis perennis Yellow, and Bellis perennis White. The antioxidant capacity of the essential oil was assayed by spectrophotometric analysis. The volatile flavor compounds from the fresh flowers were collected using dynamic headspace collection, analyzed using auto thermal desorber–gas chromatography/mass spectrometry, and identified with quantification using the external standard method. The antioxidant activities of Chrysanthemum morifolium were evaluated by DPPH and FRAP assays, and the results showed that the antioxidant activity of each sample was not the same. The different varieties of fresh Chrysanthemum morifolium flowers were distinguished and classified by fingerprint similarity evaluation, principle component analysis (PCA), and cluster analysis. The results showed that the floral volatile component profiles were significantly different among the different Chrysanthemum morifolium varieties. A total of 36 volatile flavor compounds were identified with eight functional groups: hydrocarbons, terpenoids, aromatic compounds, alcohols, ketones, ethers, aldehydes, and esters. Moreover, the variability among Chrysanthemum morifolium in basis to the data, and the first three principal components (PC1, PC2, and PC3) accounted for 96.509% of the total variance (55.802%, 30.599%, and 10.108%, respectively). PCA indicated that there were marked differences among Chrysanthemum morifolium varieties. The cluster analysis confirmed the results of the PCA analysis. In conclusion, the results of this study provide a basis for breeding Chrysanthemum cultivars with desirable floral scents, and they further support the view that some plants are promising sources of natural antioxidants.

Tiron Inhibits UVB-Induced AP-1 Binding Sites Transcriptional Activation on MMP-1 and MMP-3 Promoters by MAPK Signaling Pathway in Human Dermal Fibroblasts

Recent research found that Tiron was an effective antioxidant that could act as the intracellular reactive oxygen species (ROS) scavenger or alleviate the acute toxic metal overload in vivo. In this study, we investigated the inhibitory effect of Tiron on matrix metalloproteinase (MMP)-1 and MMP-3 expression in human dermal fibroblast cells. Western blot and ELISA analysis revealed that Tiron inhibited ultraviolet B (UVB)-induced protein expression of MMP-1 and MMP-3. Real-time quantitative PCR confirmed that Tiron could inhibit UVB-induced mRNA expression of MMP-1 and MMP-3. Furthermore, Tiron significantly blocked UVB-induced activation of the MAPK signaling pathway and activator protein (AP)-1 in the downstream of this transduction pathway in fibroblasts. Through the AP-1 binding site mutation, it was found that Tiron could inhibit AP-1-induced upregulation of MMP-1 and MMP-3 expression through blocking AP-1 binding to the AP-1 binding sites in the MMP-1 and MMP-3 promoter region. In conclusion, Tiron may be a novel antioxidant for preventing and treating skin photoaging UV-induced.

Oxidative Stress Biomarkers and Adenosine Deaminase over the Alopecic Area of the Patients with Alopecia Areata

BACKGROUND

Alopecia areata (AA) is an autoimmune, T-cell mediated, and chronic inflammatory disorder. The pathological mechanisms of disease are unclear, but oxidative stress may be involved. To our knowledge, no studies have examined the oxidative stress levels or biomarkers within the lesional area and skin surface in patients with AA. Similarly, adenosine deaminase (ADA) has not been characterized in AA.

AIMS

Therefore, we aimed to define ADA levels and the factors involved in oxidative stress from scalp-scrapes of patients with AA.

STUDY DESIGN

Case-control study.

METHOD

A total of 60 patients (30 diagnosed AA patients and 30 healthy controls) were included in the study. ADA as well as oxidative stress factors, including malondialdehyde (MDA), reduced glutathione (GSH), superoxide dismutase (SOD) and catalase (CAT) were analyzed from scalp-scrapes in both groups and quantified by spectrophotometry.

RESULTS

Activities of SOD (p=0.000), CAT (p=0.033), and ADA (p=0.004) as well as levels of GSH (p=0.000) and MDA (p=0.032) in patients with AA were higher than the controls statistically significant.

CONCLUSION

Based on these results, factors associated with oxidative stress were elevated in AA patient scalp-scrapes compared to controls and may have a defined role the disease pathogenesis. Alterations in the activities of antioxidant enzymes from AA patient scraping samples may be a local effect of elevated oxidative stress levels. In this disease, oxidative stress may affect not only hair follicle but also any layers of the skin.

Investigation of the Anti-Melanogenic and Antioxidant Characteristics of Eucalyptus camaldulensis Flower Essential Oil and Determination of Its Chemical Composition

The effects of essential oil from Eucalyptus camaldulensis flowers oil on melanogenesis and the oil’s antioxidant characteristics were investigated. Assays of mushroom and cellular tyrosinase activities and melanin content of mouse melanoma cells were performed spectrophotometrically, and the expression of melanogenesis-related proteins was determined by Western blotting. The possible signaling pathways involved in essential oil-mediated depigmentation were also investigated using specific protein kinase inhibitors. The results revealed that E. camaldulensis flower essential oil effectively suppresses intracellular tyrosinase activity and decreases melanin amount in B16F10 mouse melanoma cells. The essential oil also exhibits antioxidant properties and effectively decreases intracellular reactive oxygen species (ROS) levels. The volatile chemical composition of the essential oil was analyzed with gas chromatography–mass spectrometry (GC/MS). The chemical constituents in the essential oil are predominately oxygenated monoterpenes (34.9%), followed by oxygenated sesquiterpenes (31.8%), monoterpene hydrocarbons (29.0%) and sesquiterpene hydrocarbons (4.3%). Our results indicated that E. camaldulensis flower essential oil inhibits melanogenesis through its antioxidant properties and by down-regulating both mitogen-activated protein kinases (MAPK) and protein kinase A (PKA) signaling pathways. The present study indicates that the essential oil has the potential to be developed into a skin care product.

Inhibitory effects of adlay extract on melanin production and cellular oxygen stress in B16F10 melanoma cells

The aim of this study was to determine the effects of adlay extract on melanin production and the antioxidant characteristics of the extract. The seeds were extracted by the supercritical fluid CO₂ extraction (SFE) method. The effect of adlay extract on melanin production was evaluated using mushroom tyrosinase activity assay, intracellular tyrosinase activity, antioxidant properties and melanin content. Those assays were performed spectrophotometrically. In addition, the expression of melanogenesis-related proteins was determined by western blotting. The results revealed that the adlay extract suppressed intracellular tyrosinase activity and decreased the amount of melanin in B16F10 cells. The adlay extract decreased the expression of microphthalmia-associated transcription factor (MITF), tyrosinase, tyrosinase related protein-1 (TRP-1) and tyrosinase related protein-2 (TRP-2). The extract also exhibited antioxidant characteristics such as free radical scavenging capacity and reducing power. It effectively decreased intracellular reactive oxygen species (ROS) levels in B16F10 cells. We concluded that the adlay extract inhibits melanin production by down-regulation of MITF, tyrosinase, TRP-1 and TRP-2. The antioxidant properties of the extract may also contribute to the inhibition of melanogenesis. The adlay extract can therefore be applied as an inhibitor of melanogenesis and could also act as a natural antioxidant in skin care products.

Supercritical fluid extract of Lycium chinense Miller root inhibition of melanin production and its potential mechanisms of action

Background

The mode of action of Lycium chinense Miller root extract in skin care has never been explored. In the present study, Lycium chinense Miller root was extracted by the supercritical fluid CO₂ extraction method.

Methods

In the present study, the components of the root extract were analyzed by HPLC. The effects of the extract on tyrosinase activity and melanin content were determined spectrophotometrically; the expression of melanogenesis-related proteins was determined by Western blotting; the possible signaling pathways involved in the root extract-mediated depigmentation were also investigated using specific inhibitors.

Results

The results revealed that the SFE of Lycium chinense Miller root (2.37-7.11 mg/mL) effectively suppressed intracellular tyrosinase activity and decreased the melanin content in B16F10 cells. The root extract also effectively decreased intracellular reactive oxygen species (ROS) levels. Furthermore, the root extract decreased the expression of melanocortin 1 receptor (MC1R), microphthalmia-associated transcription factor (MITF), tyrosinase and tyrosinase-related protein-1 (TRP-1) and then inhibited melanogenesis in B16F10 cells. The root extract also showed antioxidant capacities and depleted cellular ROS.

Conclusions

Our results indicate that the SFE of Lycium chinense Miller root inhibited melanogenesis in B16F10 cells by down-regulation of both mitogen-activated protein kinases (MAPK) and protein kinase A (PKA) signaling pathways or through its antioxidant properties.

Fucoxanthin Protects Cultured Human Keratinocytes against Oxidative Stress by Blocking Free Radicals and Inhibiting Apoptosis

Fucoxanthin is an important carotenoid derived from edible brown seaweeds and is used in indigenous herbal medicines. The aim of the present study was to examine the cytoprotective effects of fucoxanthin against hydrogen peroxide-induced cell damage. Fucoxanthin decreased the level of intracellular reactive oxygen species, as assessed by fluorescence spectrometry performed after staining cultured human HaCaT keratinocytes with 2',7'-dichlorodihydrofl uorescein diacetate. In addition, electron spin resonance spectrometry showed that fucoxanthin scavenged hydroxyl radical generated by the Fenton reaction in a cell-free system. Fucoxanthin also inhibited comet tail formation and phospho-histone H2A.X expression, suggesting that it prevents hydrogen peroxideinduced cellular DNA damage. Furthermore, the compound reduced the number of apoptotic bodies stained with Hoechst 33342, indicating that it protected keratinocytes against hydrogen peroxide-induced apoptotic cell death. Finally, fucoxanthin prevented the loss of mitochondrial membrane potential. These protective actions were accompanied by the down-regulation of apoptosispromoting mediators (i.e., B-cell lymphoma-2-associated x protein, caspase-9, and caspase-3) and the up-regulation of an apoptosis inhibitor (B-cell lymphoma-2). Taken together, the results of this study suggest that fucoxanthin defends keratinocytes against oxidative damage by scavenging ROS and inhibiting apoptosis.

Dual bioactivities of essential oil extracted from the leaves of Artemisia argyi as an antimelanogenic versus antioxidant agent and chemical composition analysis by GC/MS

The study was aimed at investigating the antimelanogenic and antioxidant properties of essential oil when extracted from the leaves of Artemisia argyi, then analyzing the chemical composition of the essential oil. The inhibitory effect of the essential oil on melanogenesis was evaluated by a mushroom tyrosinase activity assay and B16F10 melanoma cell model. The antioxidant capacity of the essential oil was assayed by spectrophotometric analysis, and the volatile chemical composition of the essential oil was analyzed with gas chromatography-mass spectrometry (GC/MS). The results revealed that the essential oil significantly inhibits mushroom tyrosinase activity (IC₅₀ = 19.16 mg/mL), down-regulates B16F10 intracellular tyrosinase activity and decreases the amount of melanin content in a dose-dependent pattern. Furthermore, the essential oil significantly scavenged 2,2-diphenyl-1-picryl-hydrazyl (DPPH) and 2,2′-azino-bis (3-ethylbenzthiazoline- 6-sulphonic acid) ABTS radicals, showed an apparent reduction power as compared with metal-ion chelating activities. The chemicals constituents in the essential oil are ether (23.66%), alcohols (16.72%), sesquiterpenes (15.21%), esters (11.78%), monoterpenes (11.63%), ketones (6.09%), aromatic compounds (5.01%), and account for a 90.10% analysis of its chemical composition. It is predicted that eucalyptol and the other constituents, except for alcohols, in the essential oil may contribute to its antioxidant activities. The results indicated that essential oil extracted from A. argyi leaves decreased melanin production in B16F10 cells and showed potent antioxidant activity. The essential oil can thereby be applied as an inhibitor of melanogenesis and could also act as a natural antioxidant in skin care products.

Antioxidative properties and inhibitory effect of Bifidobacterium adolescentis on melanogenesis

Melanin is a dark pigment produced by melanocytes. Tyrosinase is a key enzyme which catalyzes the rate-limiting step of melanogenesis. However, accumulation of melanin leads to various skin hyperpigmentation disorders. To find a novel skin-whitening agent, the antioxidant capacity of Bifidobacterium adolescentis culture filtrate and inhibitory effect on melanogenesis were investigated. The antioxidant effects of B. adolescentis culture filtrate include 2,2-diphenyl-1-picryl-hydrazyl (DPPH) radical scavenging capacity, 2,2'-azino-bis (3-ethylbenzthiazoline-6-sulphonic acid)(ABTS) radical cation scavenging activity and reducing power were measured spectrophotometrically. The reducing power is a useful index for the evaluation of potential antioxidants which carry out reduction of ferricyanide to ferrocyanide. Furthermore, the inhibitory effects of the bacterial culture filtrate on mushroom tyrosinase, B16F10 intracellular tyrosinase activity and melanin content were also determined. The results revealed that B. adolescentis culture filtrate (2.5, 5.0 and 7.5 %; v/v) effectively scavenged DPPH and ABTS radicals, and lower concentrations of the bacterial culture filtrates (0.5, 1.0 and 1.5 %; v/v) showed potent reducing power in a dose-dependent pattern. Additionally, the bacterial culture filtrate suppressed murine tyrosinase activity and decreased the amount of melanin in a dose-dependent manner. Our results demonstrated that B. adolescentis culture filtrate decreases the melanogenesis process of melanoma cells by inhibiting tyrosinase activity, which we suggest may be mediated through its antioxidant activity.

Inhibition of melanogenesis and antioxidant properties of Magnolia grandiflora L. flower extract

Background

Magnolia grandiflora L. flower is wildly used in Asian as a traditional herbal medication. The purpose of the study was to investigate the antimelanogenic and antioxidant properties of Magnolia grandiflora L. flower extract. In the study, the inhibitory effects of M. grandiflora L. flower extract on mushroom tyrosinase, B16F10 intracellular tyrosinase activity and melanin content were determined spectrophotometrically. Meanwhile, the antioxidative capacity of the flower extract was also investigated.

Results

Our results revealed that M. grandiflora L. flower extract inhibit mushroom tyrosinase activity (IC₅₀ =11.1%; v/v), the flower extract also effectively suppressed intracellular tyrosinase activity (IC₅₀ = 13.6%; v/v) and decreased the amount of melanin (IC₅₀ = 25.6%; v/v) in a dose-dependent manner in B16F10 cells. Protein expression level of tyrosinase and tyrosinase-related protein 1 (TRP-1) were also decreased by the flower extract. Additionally, antioxidant capacities such as ABTS⁺ free radical scavenging activity, reducing capacity and total phenolic content of the flower extract were increased in a dose-dependent pattern.

Conclusions

Our results concluded that M. grandiflora L. flower extract decreased the expression of tyrosinase and TRP-1, and then inhibited melanogenesis in B16F10 cells. The flower extract also show antioxidant capacities and depleted cellular reactive oxygen species (ROS). Hence, M. grandiflora L. flower extract could be applied as a type of dermatological whitening agent in skin care products.

Inhibition of melanogenesis versus antioxidant properties of essential oil extracted from leaves of Vitex negundo Linn and chemical composition analysis by GC-MS

This study was aimed at investigating the antimelanogenic and antioxidative properties of the essential oil extracted from leaves of V. negundo Linn and the analysis of the chemical composition of this essential oil. The efficacy of the essential oil was evaluated spectrophotometrically, whereas the volatile chemical compounds in the essential oil were analyzed by gas chromatography-mass spectrometry (GC-MS). The results revealed that the essential oil effectively suppresses murine B16F10 tyrosinase activity and decreases the amount of melanin in a dose-dependent manner. Additionally, the essential oil significantly scavenged 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulphonic acid) (ABTS) radicals, and showed potent reducing power versus metal-ion chelating properties in a dose-dependent pattern. The chemical constituents in the essential oil are sesquiterpenes (44.41%), monoterpenes (19.25%), esters (14.77%), alcohols (8.53%), aromatic compound (5.90%), ketone (4.96%), ethers (0.4%) that together account for 98.22% of its chemical composition. It is predicted that the aromatic compound in the essential oil may contribute to its antioxidant activities. The results indicated that essential oil extracted from V. negundo Linn leaves decreased melanin production in B16F10 melanoma cells and showed potent antioxidant activities. The essential oil can thereby serve as an inhibitor of melanin synthesis and could also act as a natural antioxidant.

Dermal benefits of topical D-ribose

Our aging skin undergoes changes with reductions in collagenous and elastic fibers, fibroblasts, mast cells, and macrophages with free radical production, which can result in reduced skin tone and wrinkle formation. Fibroblasts are important for dermal integrity and function with a decrease in function producing less skin tone, thinning, and wrinkle formation. Dermal levels of adenosine triphosphate (ATP) decline with aging, potentially altering dermal function. Supplemental D-ribose, a natural occurring carbohydrate, enhances ATP regeneration. D-ribose-based studies demonstrated benefits in both cell culture fibroblastic activities and a subsequent clinical study in women with decreased skin tone with wrinkles. Supplemental D-ribose may offer this needed cellular benefit.

Melatonin maintains mitochondrial membrane potential and attenuates activation of initiator (casp-9) and effector caspases (casp-3/casp-7) and PARP in UVR-exposed HaCaT keratinocytes

Melatonin is a recognized antioxidant with high potential as a protective agent in many conditions related to oxidative stress such as neurodegenerative diseases, ischemia/reperfusion syndromes, sepsis and aging. These processes may be favorably affected by melatonin through its radical scavenging properties and/or antiapoptotic activity. Also, there is increasing evidence that these effects of melatonin could be relevant in keratinocytes, the main cell population of the skin where it would contribute to protection against damage induced by ultraviolet radiation (UVR). We therefore investigated the kinetics of UVR-induced apoptosis in cultured keratinocytes characterizing the morphological and mitochondrial changes, the caspases-dependent apoptotic pathways and involvement of poly(ADP-ribose) polymerase (PARP) activation as well as the protective effects of melatonin. When irradiated with UVB radiation (50 mJ/cm(2)), melatonin treated, cultured keratinocytes were more confluent, showed less cell blebbing, more uniform shape and less nuclear condensation as compared to irradiated, nonmelatonin-treated controls. Preincubation with melatonin also led to normalization of the decreased UVR-induced mitochondrial membrane potential. These melatonin effects were followed by suppression of the activation of mitochondrial pathway-related initiator caspase 9 (casp-9), but not of death receptor-dependent casp-8 between 24 and 48 hr after UVR exposure. Melatonin down-regulated effector caspases (casp-3/casp-7) at 24-48 hr post-UV irradiation and reduced PARP activation at 24 hr. Thus, melatonin is particularly active in UV-irradiated keratinocytes maintaining the mitochondrial membrane potential, inhibiting the consecutive activation of the intrinsic apoptotic pathway and reducing PARP activation. In conclusion, these data provide detailed evidence for specific antiapoptotic mechanisms of melatonin in UVR-induced damage of human keratinocytes.

Epidermal localization and protective effects of topically applied superoxide dismutase

Data from the literature, as well as our previous work, indicate a protective effect of superoxide dismutase (SOD) in topical application against UV-induced cutaneous damage. In the present article we show that pre-treatment of the skin with SOD protects against PUVA-induced inflammatory reactions not only in murine, but also in human skin. Using fluorescently labelled Cu,Zn SOD, epifluorescence microscopy and digital image processing, we demonstrate that the FITC fluorescence localizes in the stratum corneum and upper granulosa, as well as in the epidermal cell layer surrounding the lumina of the hair follicles. These findings were similar for murine and human skin. Since autofluorescence was eliminated by a special filter, it can be ascertained that the fluorescence observed in the tissues was due to FITC-labelled SOD.

Aggregation of collagen exposed to UVA in the presence of riboflavin: a plausible role of tyrosine modification

Riboflavin-sensitized photodynamic modification of collagen led to significant formation of cross-linked molecules. Sodium azide or 1,4-diazabicyclo(2,2,2)octane, which are known to be singlet oxygen quenchers, and catalase could not inhibit the modification. Surprisingly, the collagen modification was accelerated in the presence of superoxide dismutase. The aggregation was accompanied by the loss of tyrosine and histidine residues in the collagen. An inhibitory effect of dissolved oxygen on the modification of collagen was observed. Similarly, the loss of tyrosine residues in the irradiated collagen was inhibited in the presence of dissolved oxygen. Dityrosine formation was also observed with the loss of tyrosine. These results indicate that photodynamic modification of tyrosine probably contributes to the riboflavin-sensitized cross-linking of collagen through the formation of dityrosine.