Role of Phytochemicals in Skin Photoprotection via Regulation of Nrf2

Aloe Vera Gel and Rind-Derived Nanoparticles Mitigate Skin Photoaging via Activation of Nrf2/ARE Pathway

Background

Skin aging is the primary external manifestation of human aging, and long-term exposure to ultraviolet radiation is the leading cause of photoaging, which can lead to actinic keratosis and skin cancer in severe cases. Traditional treatments may pose safety risks and cause side effects. As an emerging research direction, plant-derived exosome-like nanoparticles (PDNPs) show promise in combating aging. Aloe vera, known for its natural active ingredients that benefit the skin, aloe-derived exosome-like nanoparticles (ADNPs) have not yet been studied for their potential in delaying skin aging.

Methods

In this study, nanoparticles were isolated from two different sites, aloe vera gel and aloe vera rind (gADNPs and rADNPs), and characterized by TEM, SEM, AFM, NTA and BCA. The effects were evaluated by constructing in vitro and in vivo models and using RT-qPCR, immunofluorescence, and histopathological analysis.

Results

The results first revealed the exceptional anti-aging effects of ADNPs. We found that ADNPs promoted the nuclear translocation of Nrf2, alleviated oxidative stress and DNA damage induced by UV exposure, and inhibited the elevation of β-gal and SASP. In vivo, ADNPs reduced MDA and SOD levels in mouse skin tissue and delayed skin photoaging. Moreover, safety assessments confirmed the excellent biocompatibility of ADNPs.

Conclusion

ADNPs delay skin photoaging through the Nrf2/ARE pathway, holding potential clinical application value, and may provide new therapeutic strategies for future medical cosmetology and skin disease prevention.

Nootkatone (NK), a grapefruit-derived sesquiterpenoid, suppresses UVB-induced damage by regulating NRF2-HO-1 and AhR-CYP1A1 signaling pathways in HaCaT cells

Nootkatone (NK), a sesquiterpene naturally derived from citrus species, was investigated for its protective effect against UVB-induced damage in HaCaT cells and its underlying mechanisms. NK effectively suppressed UVB-mediated cell death and significantly modulated expression of skin hydration genes; NK (100 μM) increased mRNA levels of collagen-1 and HAS by 44.6 and 34.7%, respectively, while downregulating HYAL by 46.8%. NK also reduced MMP1/2 expression, key matrix metalloproteinases, but enhanced mRNA levels of skin barrier factors, Filaggrin, Loricrin, and Involucrin by up to 45%. Additionally, NK lowered UVB-induced ROS production and elevated antioxidant levels (NRF2, HO-1, catalase, SOD1, and Gpx), and decrease the protein levels of xenobiotic factors, AhR and CYP1A1. These findings suggest that NK protects skin integrity against UVB-induced photoaging through the modulation of NRF2-HO-1 and AhR-CYP1A1 signaling pathways. NK shows promise as a functional agent, either edible or topical, for protecting against UVB-induced skin damage.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10068-024-01791-x.

Exploiting Paradoxical Activation of Oncogenic MAPK Signaling by Targeting Mitochondria to Sensitize NRAS Mutant-Melanoma to Vemurafenib

Vemurafenib is a BRAF (rapidly accelerated fibrosarcoma B-type)-targeted therapy used to treat patients with advanced, unresectable melanoma. It inhibits the MAPK (mitogen-activated protein kinase)/ERK (extracellular signal-regulated kinase) pathway and tumor proliferation in BRAFV600E-mutated melanoma cells. Resistance to vemurafenib has been reported in melanoma patients due to secondary NRAS (neuroblastoma RAS viral oncogene homolog) mutations, which lead to paradoxical MAPK pathway activation and tumor proliferation. However, the impact of this paradoxical activation on mitochondrial dynamics and function in NRAS-mutated melanoma is unclear. Here, we investigated the effects of vemurafenib on NRASQ61R-mutated melanoma cells, focusing on mitochondrial dynamics and function. As expected, vemurafenib did not exhibit cytotoxicity in SK-MEL-147 NRASQ61R-mutated melanoma cells, even after 72 h of incubation. However, it significantly enhanced the MAPK/ERK signaling through paradoxical activation, accompanied by decreased expression of mitochondrial fusion proteins and activation of the fission protein DRP1 (dynamin-related protein 1), leading to small, rounded mitochondrial morphology. These observations were corroborated by transcriptome data obtained from NRAS-mutated melanoma patients, showing MFN1 (mitofusin 1) and OPA1 (optic atrophy 1) downregulation and DNM1L (DRP1 gene) upregulation. Interestingly, inhibition of mitochondrial fission with mdivi-1 or modulation of oxidative phosphorylation via respiratory chain inhibition or uncoupling significantly sensitized NRASQ61R-mutated melanoma cells to vemurafenib. Despite vemurafenib's low cytotoxicity in NRAS-mutated melanoma, targeting mitochondrial dynamics and/or oxidative phosphorylation may offer a promising strategy for combined therapy.

Cranberry Oil: A Potent Natural Intimate Care Ingredient Displaying Antioxidant and Anti-Inflammatory Effects and Promoting Beneficial Vaginal Lactobacillus

Cranberry oil is known for nutritional benefits, and this work is aimed at studying its soothing properties and potential as an intimate care ingredient. The antioxidant, anti-inflammatory, and anti-irritation properties of cranberry oil were evaluated on epithelial cells and tissues, including the vaginal epithelium. The impact of the oil on vaginal microbiota was assessed in vitro. Cranberry oil reduced oxidative stress in keratinocytes (ROS -43%) and lowered inflammation by lessening the release of cytokines IL-8 (-33%) and TNF-α (-32%). Irritation induced by sodium dodecyl sulfate (SDS) in skin explants was lowered by 24%. Cranberry oil and fruit extract acted synergistically on inflammation, decreasing TNF-α release by 75% (vs. -34% and -16%, respectively). Cranberry oil reduced inflammation on EpiVaginal™ tissue, decreasing IL-6 by 36%. The minimum inhibitory concentration (MIC) of cranberry oil on the pathogenic vaginal microorganisms C. albicans and G. vaginalis was 0.5% and 0.1%, respectively. The oil promoted the growth of commensal L. jensenii (×79 at 0.1%) and favored a high proportion of lactic acid bacteria when co-cultured with C. albicans. Cranberry oil has antioxidant, anti-inflammatory, and soothing properties on skin. Anti-inflammatory activity was confirmed on vaginal epithelium, and initial in vitro evidence indicates that the oil can balance vaginal flora to prevent dysbiosis.

Autophagy-Enhancing Properties of Hedyotis diffusa Extracts in HaCaT Keratinocytes: Potential as an Anti-Photoaging Cosmetic Ingredient

The decline in autophagy disrupts homeostasis in skin cells, leading to oxidative stress, energy deficiency, and inflammation-all key contributors to skin photoaging. Consequently, activating autophagy has become a focal strategy for delaying skin photoaging. Natural plants are rich in functional molecules and widely used in the development of anti-photoaging cosmetics. Hedyotis diffusa (HD), as a medicinal plant, is renowned for its anti-inflammatory and anticancer properties; however, its effects on skin photoaging remain unclear. This study investigates HD's potential to counteract skin photoaging by restoring mitochondrial autophagy in keratinocytes. We used HPLC to detect the main chemical components in HD and, using a UVB-induced photoaging model in HaCaT keratinocytes, examined the effects of HD on reactive oxygen species (ROS) levels, Ca2+ concentration, mitochondrial membrane potential (MMP), apoptosis, and the cell cycle. Cellular respiration was further evaluated with the Seahorse XFp Analyzer, and RT-PCR and Western blotting were used to analyze the impact of HD on mitochondrial autophagy-related gene expression and signaling pathways. Our findings indicate that HD promotes autophagy by modulating the PI3K/AKT/mTOR and PINK/PARK2 pathways, which stabilizes mitochondrial quality, maintains MMP and Ca2+ balance, and reduces cytochrome c release. These effects relieve cell cycle arrest and prevent apoptosis associated with an increased BAX/BCL-2 ratio. Thus, HD holds promise as an effective anti-photoaging ingredient with potential applications in the development of cosmetic products.

Effects of Retinol, Natural Pea Peptide and Antioxidant Blend in a Topical Formulation: In Vitro and Clinical Evidence

INTRODUCTION

Retinol has a long history of treating skin conditions, including photoaging. However, skin irritation with repeated use of retinol is well documented. The present study assessed the effectiveness of a novel topical formulation, referred to as retinol topical formulation (RTF), to improve the quality of skin health. The RTF was composed of a low dose retinol, a synthetic retinoid ester, a pea peptide, and an antioxidant blend.

METHODS

In vitro assessment of RTF on human skin co-cultures (human keratinocytes, melanocytes, and dermal fibroblasts) identified gene expression levels and skin biomarkers after 24 h exposure. An 8-week clinical study was conducted to evaluate once-nightly application of the RTF for short-term and long-term benefits in 30 adult subjects between 35 and 70 years of age (21 female, 9 male). Skin evaluations were conducted via bioinstrumentation (for hydration, transepidermal water loss and elasticity) and at 0, 1-, 2-, 4-, and 8-week self-assessment questionnaires and photo-imaging analysis were performed.

RESULTS

RTF treatment of skin in vitro co-cultures upregulated aquaporin-3, PER1, collagen, and elastin, and downregulated expression of MMP1 and the pigmentation genes TYRP1 and MITF. The clinical assessment significantly improved hydration, transepidermal water loss, and elasticity along with incremental but significant increases in nine skin parameters (hydration, clarity, radiance/glow, smoothness, brightness, texture, appearance of pores, dark spots/hyperpigmentation, and skin tone evenness from baseline) with continuous use over 8 weeks compared to baseline values.

CONCLUSIONS

The RTF in vitro analysis showed significant positive changes for several skin biomarkers, and the clinical assessment showed RTF significantly improved the visible signs of dermal aging, without irritation.

Atractylodin mitigates UVB radiation-induced oxidative stress and photoaging responses by enhancing NrF2 signaling in human epidermal keratinocytes

This study explores the protective role of Atractylodin (ATN) on ultraviolet-B (UVB) radiation-exposed oxidative damage and photoaging responses in human epidermal keratinocytes (HaCaT). In vitro, experiments involved subjecting HaCaT cells to UVB radiation (50 mJ/cm2) for a 24 h incubation period, leading to cell death, increased reactive oxygen species (ROS), and DNA damaged lesion (8-Oxo Gunosine). ATN treatment effectively mitigated cell toxicity, ROS generation, and 8-Oxo Gunosine in UVB-exposed HaCaT cells. Furthermore, ATN demonstrated its ability to counteract UVB radiation-exposed oxidative stress by inhibiting the activation of phosphorylated-extracellular signal-regulated kinase-1 (Erk-1), phosphorylated-c-Jun N-terminal kinase (p-Jnk), and phosphorylated p38 Mitogen-Activated Protein Kinase (p-p38) in HaCaT cells. Nuclear factor erythroid 2-related factor 2 (NrF2), recognized for its antioxidant properties, emerged as a key player in protecting against oxidative damage. ATN was observed to inhibit the depletion of NrF2 expression, thereby preventing the depletion of superoxide dismutase (SOD), and glutathione (GSH) in UVB-exposed HaCaT cells. Additionally, ATN inhibited activator protein-1 (AP-1) and matrix metalloproteinases such as MMP-1 and MMP-9 in UVB-exposed HaCaT cells. In conclusion, our findings highlight that ATN effectively prevents UVB-exposed skin oxidative damage and photoaging by modulating NrF2 expression.

Valorization of Hom Thong Banana Peel (Musa sp., AAA Group) as an Anti-Melanogenic Agent Through Inhibition of Pigmentary Genes and Molecular Docking Study

Prolonged and unprotected exposure to the environment explicitly influences the development of hyperpigmented lesions. The enzyme tyrosinase (TYR) is a key target for regulating melanin synthesis. Several bioactive compounds derived from plant extracts have been found to possess potent anti-melanogenesis properties against TYR. In particular, the potential of banana peels from various varieties has garnered interest due to their application in skin hyperpigmentation treatment. A molecular docking study demonstrated interactions between rosmarinic acid, which is predominantly found in all Hom Thong peel extracts, and the active site of TYR (PDB ID: 2Y9X) at residues HIS263, VAL283, SER282, and MET280, with the lowest binding energy of -5.05 kcal/mol, showing the strongest interaction. Additionally, Hom Thong banana peels are rich in phenolic compounds that could inhibit melanin content and tyrosinase activity in both human and mouse melanoma cells. These effects may be attributed to the suppression of gene expression related to melanogenesis, including the regulator gene MITF and pigmentary genes TYR, TRP-1, and DCT, indicating effects comparable to those of the standard treatment groups with arbutin and kojic acid. Our findings indicated the potential of Hom Thong peel extracts as anti-melanogenic agents.

Molecular mechanisms underlying Tao-Hong-Si-Wu decoction treating hyperpigmentation based on network pharmacology, Mendelian randomization analysis, and experimental verification

CONTEXT

Hyperpigmentation, a common skin condition marked by excessive melanin production, currently has limited effective treatment options.

OBJECTIVE

This study explores the effects of Tao-Hong-Si-Wu decoction (THSWD) on hyperpigmentation and to elucidate the underlying mechanisms.

MATERIALS AND METHODS

We employed network pharmacology, Mendelian randomization, and molecular docking to identify THSWD's hub targets and mechanisms against hyperpigmentation. The Cell Counting Kit-8 (CCK-8) assay determined suitable THSWD treatment concentrations for PIG1 cells. These cells were exposed to graded concentrations of THSWD-containing serum (2.5%, 5%, 10%, 15%, 20%, 30%, 40%, and 50%) and treated with α-MSH (100 nM) to induce an in vitro hyperpigmentation model. Assessments included melanin content, tyrosinase activity, and Western blotting.

RESULTS

ALB, IL6, and MAPK3 emerged as primary targets, while quercetin, apigenin, and luteolin were the core active ingredients. The CCK-8 assay indicated that concentrations between 2.5% and 20% were suitable for PIG1 cells, with a 50% cytotoxicity concentration (CC50) of 32.14%. THSWD treatment significantly reduced melanin content and tyrosinase activity in α-MSH-induced PIG1 cells, along with downregulating MC1R and MITF expression. THSWD increased ALB and p-MAPK3/MAPK3 levels and decreased IL6 expression in the model cells.

DISCUSSION AND CONCLUSION

THSWD mitigates hyperpigmentation by targeting ALB, IL6, and MAPK3. This study paves the way for clinical applications of THSWD as a novel treatment for hyperpigmentation and offers new targeted therapeutic strategies.

Components analysis of San-Bai decoction, and its pharmacodynamics and mechanism on preventing and treating melasma

ETHNOPHARMACOLOGICAL RELEVANCE

San-Bai Decoction (SBD) is a classic whitening prescription originally recorded in the 'Introduction to Medicine' of the Ming Dynasty. SBD has been known for invigorating Qi and blood, promoting spleen and stomach, whitening skin, and fading melasma. However, its pharmacodynamic material basis and specific mechanism remain unclear.

AIM OF THE STUDY

The aim of this study is to clarify the pharmacodynamic material basis of SBD and its mechanism of removing melasma.

MATERIALS AND METHODS

The positive and negative ion mass spectrum data of SBD extract were collected by UHPLC-Q-Exactive Orbitrap MS/MS, imported into Compound Discoverer (CD) 3.1 software, matched through the online database, and manually checked. Finally, the in vitro chemical components of SBD were classified. Similarly, the mass spectrum data of SBD in the serum of normal rats and melasma model rats were also analyzed by CD 3.1 software. The in vitro identified Compound file of SBD was imported into the Expected Compounds and the Generate Expected Compounds project was selected. The SBD compounds were then chosen under the Compound Section. All phase I and II reaction types related to SBD components were selected, and the metabolic platform of CD 3.1 software was utilized to process the results and obtain possible metabolites. The metabolites were scored and products with high scores were subsequently screened. According to literature comparison, the final metabolites of SBD in both normal rats and melasma model rats were determined and comprehensively analyzed. The Melasma model rats were constructed through intramuscular injection of progesterone and ultraviolet radiation B (UVB) irradiation. The preventing and treating effect of SBD on melasma were evaluated by regulating inflammation, epidermal collagen content, and oxidative stress. Additionally, the effect of SBD on the Phosphatidylinositol 3-kinase (PI3K)/Protein kinase B (Akt)/Glycogen synthase kinase 3β (GSK3β) pathway was investigated through Western blot (WB) to explore its underlying mechanism on whitening and removing melasma efficacy.

RESULTS

Ultimately, 94 components were identified in SBD, including 41 flavonoids, 27 organic acids, and 9 glycosides, 3 terpenoids, 2 amides, 2 aldehydes, 1 phenylpropanoid and 9 other compounds. In the blood of normal rat group, a total of 24 prototype components and 61 metabolites were identified. Similarly, there were19 prototype components and 44 metabolites identified from the blood of melasma model rats. Pharmacodynamic experiment results indicated that SBD effectively reduced the incidence of melasma, prevent the loss of epidermal collagen, and elevate the activity of superoxide dismutase and decrease the malondialdehyde content in both liver and skin. Interestingly, the WB results demonstrated that SBD effectively activated PI3K/Akt/GSK3β pathway, and down-regulated the expression of melanin-related proteins.

CONCLUSIONS

For the first time, the components of SBD extracts, and its prototype components and metabolites in the blood of normal rats and melasma model rats were successfully identified by high-resolution liquid chromatography-mass spectrometry with CD software. Additionally, the differences of in vivo components of SBD between normal rats and melasma model rats were analyzed. The preventive and therapeutic effect of SBD on melasma was verified in the melasma model rats induced by progesterone and UVB irradiation, and its mechanism was related to activating PI3K/Akt/GSK3β pathway and downregulating the expression of melanin-related proteins. These results provide an experimental foundation for further research on the pharmacodynamic substance basis and pharmacodynamic mechanism of SBD, as well as developing new anti-melasma formula with SBD.

Tapinarof and its structure-activity relationship for redox chemistry and phototoxicity on human skin keratinocytes

Tapinarof (3,5-dihydroxy-4-isopropylstilbene) is a therapeutic agent used in the treatment of psoriasis (VTAMA®). In this study, we examined the redox behaviour, (photo)stability, (photo)toxicity and (bio)transformation of tapinarof in the context of a structure-activity relationship study. Selected derivatives of the structurally related tapinarof were investigated, namely resveratrol, pterostilbene, pinosylvin and its methyl ether. Tapinarof undergoes electrochemical oxidation in a neutral aqueous medium at a potential of around +0.5 V (vs. Ag|AgCl|3M KCl). The anodic reaction of this substance is a proton-dependent irreversible and adsorption-driven process. The pKa value of tapinarof corresponds to 9.19 or 9.93, based on empirical and QM calculation approach, respectively. The oxidation potentials of tapinarof and its analogues correlate well with their HOMO (highest occupied molecular orbital) energy level. The ability to scavenge the DPPH radical decreased in the order trolox ≥ resveratrol > pterostilbene > tapinarof > pinosylvin ≫ pinosylvin methyl ether. It was also confirmed that tapinarof, being a moderate electron donor, is able to scavenge the ABTS radical and inhibit lipid peroxidation. The 4'-OH group plays a pivotal role in antioxidant action of stilbenols. During the stability studies, it was shown that tapinarof is subject to spontaneous degradation under aqueous conditions, and its degradation is accelerated at elevated temperatures and after exposure to UVA (315-399 nm) radiation. In aqueous media at pH 7.4, we observed an ∼50 % degradation of tapinarof after 48 h at laboratory temperature. The main UVA photodegradation processes include dihydroxylation and hydration. In conclusion, the phototoxic effect of tapinarof on a human keratinocytes cell line (HaCaT) was evaluated. Tapinarof exhibited a clear phototoxic effect, similar to phototoxic standard chlorpromazine. The IC50 values of the cytotoxicity and phototoxic effects of tapinarof correspond to 27.6 and 3.7 μM, respectively. The main HaCaT biotransformation products of tapinarof are sulfates and glucuronides.

Potential skin anti-aging effects of main phenolic compounds, tremulacin and tremuloidin from Salix chaenomeloides leaves on TNF-α-stimulated human dermal fibroblasts

The genus Salix spp. has long been recognized as a healing herb for its use in treating fever, inflammation, and pain relief, as well as a food source for its nutritional value. In this study, we aimed to explore the potential bioactive natural products in the leaves of Salix chaenomeloides, commonly known as Korean pussy willow, for their protective effects against skin damage, including aging. Utilizing LC/MS-guided chemical analysis of the ethanol extract of S. chaenomeloides leaves, with a focus on major compounds, we successfully isolated two main phenolic compounds, tremulacin (1) and tremuloidin (2). Subsequently, we investigated the protective effects of tremulacin (1) and tremuloidin (2) in TNF-α-stimulated human dermal fibroblasts (HDFs). The results revealed that both tremulacin (1) and tremuloidin (2) inhibited TNF-α-stimulation-induced ROS, suppressed matrix metalloproteinase-1 (MMP-1) expression, and enhanced collagen secretion. This implies that both tremulacin (1) and tremuloidin (2) hold promise as preventive agents against photoaging-induced skin aging. Furthermore, we assessed the activity of mitogen-activated protein kinases (MAPKs), cyclooxygenase-2 (COX-2), and heme oxygenase 1 (HO-1) to elucidate the mechanism of photoaging inhibition by tremuloidin (2), which exhibited superior efficacy. We found that tremuloidin (2) inhibited ERK and p38 phosphorylation and notably suppressed COX-2 expression while significantly upregulating HO-1 expression. These findings suggest potent anti-inflammatory and antioxidant properties of tremuloidin (2), positioning it as a potential candidate for combating photoaging-induced skin aging.

Anti-Melanogenic Potential of Malabar Spinach (Basella alba) in Human Melanoma Cells with Oxidative Stress Suppression and Anti-Inflammatory Activities

Basella alba has been used in Thai remedies to treat skin disorders, but scientific evidence supporting its efficacy is currently limited. In this study, we investigated the inhibitory effects of B. alba extracts on melanin production using melanoma cells, as well as their impact on oxidative stress and inflammation in keratinocytes. The results demonstrate that B. alba extracts inhibited melanin content and cellular tyrosinase activity in 3-isobutyl-1-methylxanthine (IBMX)-induced melanoma cells by downregulating MITF and the pigmentary genes TYR, TRP-1, and DCT. Interestingly, the MITF regulator gene was inhibited by both the 50% and 95% ethanolic extracts of B. alba with levels of 0.97 ± 0.19 and 0.92 ± 0.09 of the control, respectively, which are comparable to those observed in the arbutin treatment group at 0.84 ± 0.05 of the control. Moreover, after hydrogen peroxide (H2O2) exposure, pretreatment with B. alba reduced lipid peroxidation byproducts and increased the levels of antioxidant-related genes, including SOD-1, GPX-1, and NRF2. Notably, the suppression of the POMC promoter gene in keratinocytes was observed, which may disrupt melanogenesis in melanocytes involving the MC1R signaling pathway. MC1R mRNA expression decreased in the treatments with 50% and 95% ethanolic extracts of B. alba, with relative levels of 0.97 ± 0.18 and 0.90 ± 0.10 of the control, respectively, similar to the arbutin-treated group (0.88 ± 0.25 of control). A significant reduction in nitric oxide was also observed in the B. alba-treated groups, along with a decrease in genes associated with pro-inflammatory cytokines, including IL-1β, IL-6, and COX-2. These findings suggest that B. alba has potential in the prevention of skin-related problems.

A Mendelian randomization study of genetic liability to cutaneous melanoma and sunburns

Background

Some studies have reported that sunburns and cutaneous melanoma (CM) risk is increasing, but a clear causal link has yet to be established.

Methods

This current study conducted a two-sample Mendelian randomization (MR) approach to clarify the association and causality between sunburn history and CM using large-scale genome-wide association study data.

Results

The inverse-variance weighted method result showed that sunburn might be associated with the risk of CM increasing (p = 2.21 × 10-23, OR = 1.034, 95% CI= 1.027-1.041), causally. The MR-Egger regression, weighted median method, simple mode method, and weighted mode method results showed similar results.

Conclusion

This study offers evidence of sunburn history and increased risk of CM, and it shows that there might be common genetic basics regarding sunburns and CM susceptibility in Caucasian, European, or British ethnic groups.

Salvianolic acid B protects against UVB-induced skin aging via activation of NRF2

BACKGROUND

Prolonged exposure to sun radiation may result in harmful skin photoaging. Therefore, discovering novel anti-photoaging treatment modalities is critical. An active component isolated from Salvia miltiorrhiza (SM), Salvianolic acid B (Sal-B), is a robust antioxidant and anti-inflammatory agent. This investigation aimed to discover the therapeutic impact and pathways of salvianolic acid B for UVB-induced skin photoaging, an area that remains unexplored.

METHODS

We conducted in vitro experiments on human dermal fibroblasts (HDFs) exposed to UVB radiation, assessing cellular senescence, superoxide dismutase (SOD) activity, cell viability, proliferation, migration, levels of reactive oxygen species (ROS), and mitochondrial health. The potential mechanism of Sal-B was analyzed using RNA sequencing, with further validation through Western blotting, PCR, and nuclear factor erythroid 2-related factor 2 (NRF2) silencing methods. In vivo, a model of skin photoaging induced by UVB in nude mice was employed. The collagen fiber levels were assessed utilizing hematoxylin and eosin (H&E), Masson, and Sirus red staining. Additionally, NRF2 and related gene and protein expression levels were identified utilizing PCR and Western blotting.

RESULTS

Sal-B was found to significantly counteract photoaging in UVB-exposed skin fibroblasts, reducing aging-related decline in fibroblast proliferation and an increase in apoptosis. It was observed that Sal-B aids in protecting mitochondria from excessive ROS production by promoting NRF2 nuclear translocation. NRF2 knockdown experiments established its necessity for Sal-B's anti-photoaging effects. The in vivo studies also verified Sal-B's anti-photoaging efficacy, surpassing that of tretinoin (Retino-A). These outcomes offer novel insights into the contribution of Sal-B in developing clinical treatment modalities for UVB-induced photodamage in skin fibroblasts.

CONCLUSION

In this investigation, we identified the Sal-B protective impact on the senescence of dermal fibroblasts and skin photoaging induced by radiation of UVB. The outcomes suggest Sal-B as a potential modulator of the NRF2 signaling pathway.

Rubus urticifolius Compounds with Antioxidant Activity, and Inhibition Potential against Tyrosinase, Melanin, Hyaluronidase, Elastase, and Collagenase

In our study, using chromatographic techniques, we isolated three bioactive compounds, which were structurally elucidated as (E)-2-(3-(3,4-dimethoxyphenyl)acrylamido)-N-methylbenzamide (1), 4-Hydroxyquinoline-2-carboxylic acid (2), and (E)-2-Cyano-3-(4-hydroxyphenyl)acrylic acid (3), using spectroscopic methods. The anti-melanogenic, anti-inflammatory, antioxidant, and anti-aging properties were evaluated in vitro by measuring the activity of pharmacological targets including tyrosinase, melanin, NF-κB, hyaluronidase, elastase, collagenase, and Nrf2. Our results show that compound 1 is the most active with IC50 values of 14.19 μM (tyrosinase inhibition), 22.24 μM (melanin inhibition), 9.82-12.72 μM (NF-κB inhibition), 79.71 μM (hyaluronidase inhibition), 80.13 μM (elastase inhibition), 76.59 μM (collagenase inhibition), and 116-385 nM (Nrf2 activation) in the THP-1, HEK001, WS1, and HMCB cells. These findings underscore the promising profiles of the aqueous extract of R. urticifolius at safe cytotoxic concentrations. Additionally, we report, for the first time, the isolation and characterisation of these nitrogenous compounds in the R. urticifolius species. Finally, compound 1, isolated from R. urticifolius, is a promising candidate for the development of more effective and safer compounds for diseases related to skin pigmentation, protection against inflammation, and oxidative stress.

Inhibitory Effects of Fermented Sprouted Oat Extracts on Oxidative Stress and Melanin Overproduction

Hyperpigmentation occurs due to irregular secretion of melanin pigment in the skin. This can affect quality of life depending on its severity, so prevention and management are essential. Oats (Avena sativa L.), a grain consumed worldwide, are known to offer improved health benefits upon germination and fermentation. This study is aimed to investigate the protective effects of lactobacilli-fermented sprouted oat extracts on oxidative stress and melanin overproduction in vitro. The anti-melanogenic effect was investigated using melanin content and tyrosinase activity assays in B16F10 cells, as well as a mushroom tyrosinase-based enzyme inhibition assay. The results showed that L. casei-fermented oat extracts were the most effective for reducing melanin formation by reducing the mRNA expression of microphthalmia-associated transcription factor, tyrosinase, and tyrosinase-related protein 2. Furthermore, L. casei fermentation was effective in improving the total phenolic, flavonoid, and avenanthramide A contents of sprouted oat extracts. The results also demonstrated the antioxidant effects of L. casei-fermented sprouted oat extracts in promoting DPPH radical-scavenging activity, superoxide dismutase-like activity, and reduction in reactive oxygen species levels. Overall, the findings indicate that fermented sprouted oat extracts are promising candidates for antioxidant and anti-hyperpigmentation treatments.

Myconoside and Calceolarioside E Restrain UV-Induced Skin Photoaging by Activating NRF2-Mediated Defense Mechanisms

Chronic and excessive ultraviolet (UVA/UVB) irradiation exposure is known as a major contributor to premature skin aging, which leads to excessive reactive oxygen species generation, disturbed extracellular matrix homeostasis, DNA damage, and chronic inflammation. Sunscreen products are the major preventive option against UVR-induced photodamage, mostly counteracting the acute skin effects and only mildly counteracting accelerated aging. Therefore, novel anti-photoaging and photopreventive compounds are a subject of increased scientific interest. Our previous investigations revealed that the endemic plant Haberlea rhodopensis Friv. (HRE) activates the antioxidant defense through an NRF2-mediated mechanism in neutrophiles. In the present study, we aimed to investigate the photoprotective potential of HRE and two of its specialized compounds-the phenylethanoid glycosides myconoside (MYC) and calceolarioside E (CAL)-in UVA/UVB-stimulated human keratinocytes in an in vitro model of photoaging. The obtained data demonstrated that the application of HRE, MYC, and CAL significantly reduced intracellular ROS formation in UVR-exposed HaCaT cells. The NRF2/PGC-1α and TGF-1β/Smad/Wnt signaling pathways were pointed out as having a critical role in the observed CAL- and MYC-induced photoprotective effect. Collectively, CAL is worth further evaluation as a potent natural NRF2 activator and a promising photoprotective agent that leads to the prevention of UVA/UVB-induced premature skin aging.

Live-cell imaging Unveils stimulus-specific dynamics of Nrf2 activation in UV-exposed melanoma cells: Implications for antioxidant compound screening

The transcription factor Nuclear factor e2-related factor 2 (Nrf2) is pivotal in orchestrating cellular antioxidant defense mechanisms, particularly in skin cells exposed to ultraviolet (UV) radiation and electrophilic phytochemicals. To comprehensively investigate Nrf2's role in maintaining cellular redox equilibrium following UV-induced stress, we engineered a novel Nrf2 fusion-based reporter system for real-time, live-cell quantification of Nrf2 activity in human melanoma cells. Utilizing live quantitative imaging, we dissected the kinetic profiles of Nrf2 activation in response to an array of stimuli, including UVA and UVB radiation, as well as a broad spectrum of phytochemicals including ferulic acid, gallic acid, hispidulin, p-coumaric acid, quercetin, resveratrol, tannic acid, and vanillic acid as well as well-known Nrf2 inducers, tert-butylhydroquinone (tBHQ) and sulforaphane (SFN). Intriguingly, we observed distinct dynamical patterns of Nrf2 activity contingent on the specific stimuli applied. Sustained activation of Nrf2 was empirically correlated with the increased antioxidant response element (ARE) activity. Our findings demonstrate the nuanced impact of different phenolic compounds on Nrf2 activity and the utility of our Nrf2-CTΔ16-YFP reporter in characterizing the dynamics of Nrf2 translocation in response to diverse stimuli. In summary, our innovative reporter system not only revealed compounds capable of modulating UVA-induced Nrf2 activity but also showcased its utility as a robust tool for future antioxidant compound screening efforts.

Aging in the dermis: Fibroblast senescence and its significance

Skin aging is characterized by changes in its structural, cellular, and molecular components in both the epidermis and dermis. Dermal aging is distinguished by reduced dermal thickness, increased wrinkles, and a sagging appearance. Due to intrinsic or extrinsic factors, accumulation of excessive reactive oxygen species (ROS) triggers a series of aging events, including imbalanced extracellular matrix (ECM) homeostasis, accumulation of senescent fibroblasts, loss of cell identity, and chronic inflammation mediated by senescence-associated secretory phenotype (SASP). These events are regulated by signaling pathways, such as nuclear factor erythroid 2-related factor 2 (Nrf2), mechanistic target of rapamycin (mTOR), transforming growth factor beta (TGF-β), and insulin-like growth factor 1 (IGF-1). Senescent fibroblasts can induce and accelerate age-related dysfunction of other skin cells and may even cause systemic inflammation. In this review, we summarize the role of dermal fibroblasts in cutaneous aging and inflammation. Moreover, the underlying mechanisms by which dermal fibroblasts influence cutaneous aging and inflammation are also discussed.

Role of reactive oxygen species in ultraviolet-induced photodamage of the skin

Reactive oxygen species (ROS), such as superoxides (O2 •-) and hydroxyl groups (OH·), are short-lived molecules containing unpaired electrons. Intracellular ROS are believed to be mainly produced by the mitochondria and NADPH oxidase (NOX) and can be associated with various physiological processes, such as proliferation, cell signaling, and oxygen homeostasis. In recent years, many studies have indicated that ROS play crucial roles in regulating ultraviolet (UV)-induced photodamage of the skin, including exogenous aging, which accounts for 80% of aging. However, to the best of our knowledge, the detailed signaling pathways, especially those related to the mechanisms underlying apoptosis in which ROS are involved have not been reviewed previously. In this review, we elaborate on the biological characteristics of ROS and its role in regulating UV-induced photodamage of the skin.

Tanshinone Alleviates UVA-induced Melanogenesis in Melanocytes via the Nrf2-regulated Antioxidant Defense Signaling Pathway

BACKGROUND

As a complex of natural plant compounds, tanshinone is renowned for its remarkable antioxidant properties. However, the potential impact of tanshinone on melanocyte pigmentation regulation has yet to be elucidated. This study aimed to explore the protective effects of tanshinone I (T-I) and dihydrotanshinone (DHT) on melanogenesis by modulating nuclear factor E2-related factor 2 (Nrf2) signaling and antioxidant defenses in human epidermal melanocyte (HEM) cells.

METHODS

HEM cells and Nrf2 knockdown HEM cells were subjected to ultraviolet A (UVA) and treated with T-I and/or DHT. Then, the anti-melanogenic properties of T-I and DHT were examined by assessing tyrosinase activity, melanogenesis-related proteins, and melanin content in UVA-irradiated HEM cells. Furthermore, the antioxidant activities of T-I and DHT were evaluated by assessing oxidant formation and modulation of Nrf2-related antioxidant defenses, including reactive oxygen species (ROS), glutathione (GSH) content, and the activity and expression of antioxidant enzymes, such as catalase (CAT), heme oxygenase-1 (HO-1), and superoxide dismutase (SOD).

RESULTS

Our findings revealed that T-I and DHT diminished melanogenesis in UVAirradiated HEM cells, activated Nrf2-antioxidant response element signaling, and enhanced antioxidant defenses in the irradiated cells. Furthermore, Nrf2 knockdown by shRNA abolished the anti-melanogenesis effects of T-I and DHT on HEM cells against oxidative damage.

CONCLUSION

These results suggest that T-I and DHT inhibit UVA-induced melanogenesis in HEM cells, possibly through redox mechanisms involving Nrf2 signaling activation and increased antioxidant defenses. This indicates that T-I and DHT have potential as whitening agents in cosmetics and medical treatments for hyperpigmentation disorders.

Main Colonic Metabolites from Coffee Chlorogenic Acid May Counteract Tumor Necrosis Factor-α-Induced Inflammation and Oxidative Stress in 3T3-L1 Cells

Obesity is coupled with an altered redox state and low-level inflammation. Oxidative stress may increase pre-adipocyte proliferation, adipocyte differentiation and mature adipocyte size. Regarding inflammation, the dysregulation of cytokine production by adipose tissue takes place in obesity, which is promoted by oxidative stress. Polyphenols may exert a positive effect on obesity, not only by modulating the redox state, but also due to their anti-inflammatory activity. Coffee, which is one of the most consumed beverages, is very rich in phenolic compounds. Bioavailability studies on coffee phenols have shown that the most abundant group of metabolites in plasma and urine are dihydrocaffeic (DHCA), dihydroferulic (DHFA), and hydroxyhippuric (HHA) acids, the three acids of colonic origin. To better understand the antioxidant and anti-inflammatory properties of DHCA, DHFA, and HHA, an inflammation/oxidation model was set up in the pre-adipocyte 3T3-L1 cell line using tumor necrosis factor-α (TNF-α). After the exposure of 3T3-L1 cells to 0.5, 1, 5, and 10 µM of TNF-α at different times, the cell viability, interleukin (IL)-6 secretion, and the production of reactive oxygen species (ROS) and glutathione (GSH) were determined. Using the TNF-α prooxidant and proinflammatory conditions established (10 µM, 24 h), it was observed that the physiological concentrations (0.5, 1, 5, and 10 µM) of DHCA, DHFA, and HHA induced dose-dependent antioxidant effects according to the ROS, GSH, and antioxidant enzyme (glutathione peroxidase) results. In addition, reductions in the IL-1β, IL-6, and monocyte chemoattractant protein-1 (MCP-1) concentrations were observed to different extents depending on the metabolite (DHFA, HHA, or DHCA) and the concentration used. In conclusion, the main colonic metabolites from coffee chlorogenic acids may counteract TNF-α-induced inflammation and oxidative stress in the 3T3-L1 cell line, and thus, they present antiobesity potential.

Childhood sunburn and risk of melanoma and non-melanoma skin cancer: a Mendelian randomization study

Previous evidence has suggested that childhood sunburn could be a risk factor for cutaneous malignant melanoma (MM) and non-melanoma skin cancer (NMSC). However, existing observational studies could not reveal the causal associations genetically. This study aimed to investigate whether there was a genetic causal relationship between childhood sunburn and skin cancers. Univariable Mendelian randomization (MR) and Causal Analysis Using Summary Effect analysis was carried out for causal estimates and evaluation for the horizontal pleiotropy. Multivariable MR and the mediation effects analysis were used to test whether the causal associations were mediated by potential confounders. A suggestively significant causal association between childhood sunburn and MM was indicated (OR = 4.74; 95% CI: 1.31-17.19; p = 1.79E-02). Genetically predicted childhood sunburn was significantly associated with increased risk of overall melanoma in situ (MIS) (OR = 4.02; 95% CI: 2.00-8.08; p = 9.40E-05), MIS of face (OR = 18.28; 95% CI: 5.28-63.35; p = 4.59E-06), and MIS of trunk (OR = 7.05; 95% CI: 2.06-24.13; p = 1.88E-03). Similar trends were found for childhood sunburn and NMSC (OR = 8.16; 95% CI: 6.07-10.99; p = 1.53E-20), including both basal cell carcinoma (BCC) (OR = 3.76; 95% CI:2.96-4.77; p = 2.19E-08) and squamous cell carcinoma (SCC) (OR = 7.44; 95% CI: 5.09-10.87; p = 2.19E-08). After adjustment for hair and skin color, facial ageing, vitamin D levels, body mass index, alcohol consumption, and smoking status, childhood sunburn showed an independent association with MIS, MIS of face, MIS of trunk, as well as NMSC, including both BCC and SCC. Mediation analysis showed no significant mediation effect. This study demonstrated a causal relationship between childhood sunburn and the risk of both MM and NMSC, which suggested that enhanced screening and prevention for childhood sunburn could contribute to the early detection and decreased risk of MM and NMSC.

Overexpression of SIRT6 regulates NRF2/HO-1 and NF-κB signaling pathways to alleviate UVA-induced photoaging in skin fibroblasts

Skin photoaging, resulting from prolonged exposure to sunlight, especially UVA rays, has been identified as a key contributor to age-related skin degeneration. However, the mechanism by which UVA radiation induces skin cell senescence has not been fully elucidated. In this investigation, bioinformatics technology was employed to identify SIRT6 as the core hub gene involved in the progression of skin photoaging. The study evinced that prolonged exposure of cutaneous fibroblasts to UVA radiation results in a marked reduction in the expression of SIRT6, both in vivo and in vitro. Knockdown of SIRT6 in skin fibroblasts resulted in the upregulation of genes associated with cellular aging, thereby exacerbating the effects of UVA radiation-induced photoaging. Conversely, overexpression of SIRT6 decreased the expression of cell aging-related genes, indicating that SIRT6 plays a role in the regulation of senescence in skin fibroblasts induced by UVA radiation. We proffer substantiation that overexpression of SIRT6 protects skin fibroblasts from UVA-induced oxidative stress by activating the NRF2/HO-1 signaling cascade. Moreover, SIRT6 overexpression also reduced UVA-induced type I collagen degradation by inhibiting NF-κB signaling cascade. In summary, our findings showed that overexpression of SIRT6 inhibits UVA-induced senescence phenotype and type I collagen degradation in skin fibroblasts by modulating the NRF2/HO-1 and NF-κB signaling pathways. And the regulation of these signaling pathways by SIRT6 may be achieved through its deacetylase activity. Therefore, SIRT6 is a novel and promising therapeutic target for skin aging related to age and UV.

Anti-Browning Effect of 2-Mercaptobenzo[d]imidazole Analogs with Antioxidant Activity on Freshly-Cut Apple Slices and Their Highly Potent Tyrosinase Inhibitory Activity

Ten 2-mercaptobenzimidazole (2-MBI) analogs were synthesized as potential tyrosinase inhibitors because mercapto-containing compounds can bind to copper ions at the active site of tyrosinase to inhibit enzyme activity. Nine 2-MBI analogs showed sub-micromolar IC50 values for mushroom tyrosinase monophenolase activity; analog 4 was 280-fold more potent than kojic acid, and in diphenolase activity, 6 was 970-fold more potent than kojic acid. The inhibition mode of the 2-MBI analogs was investigated using kinetic studies supported by docking simulations. Benzimidazoles without the 2-mercapto substituent of the 2-MBI analogs lost their tyrosinase inhibitory activity, implying that the 2-mercapto substituent plays an important role in tyrosinase inhibition. The 2-MBI analogs exerted potent antioxidant effects against 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid (ABTS), 2,2-diphenyl-1-picrylhydrazyl (DPPH), and reactive oxygen species (ROS). The results obtained from apple slices and human embryonic kidney cells (HEK-293) suggest that most 2-MBI analogs are sufficiently safe candidates to delay the browning of apple slices effectively. Thus, these results support the potential use of 2-MBI analogs as anti-browning agents in foods such as mushrooms, vegetables, and fruits.

Reversing Gray Hair: Inspiring the Development of New Therapies Through Research on Hair Pigmentation and Repigmentation Progress

Hair graying is a common and visible sign of aging resulting from decreased or absence of melanogenesis. Although it has been established that gray hair greatly impacts people's mental health and social life, there is no effective countermeasure other than hair dyes. It has long been thought that reversal of gray hair on a large scale is rare. However, a recent study reported that individual gray hair darkening is a common phenomenon, suggesting the possibility of large-scale reversal of gray hair. In this article, we summarize the regulation mechanism of melanogenesis and review existing cases of hair repigmentation caused by several factors, including monoclonal antibodies drugs, tyrosine kinase inhibitors (TKIs), immunomodulators, other drugs, micro-injury, and tumors, and speculate on the mechanisms behind them. This review offers some insights for further research into the modulation of melanogenesis and presents a novel perspective on the development of clinical therapies, with emphasis on topical treatments.

A Review of Classification, Biosynthesis, Biological Activities and Potential Applications of Flavonoids

Flavonoids represent the main class of plant secondary metabolites and occur in the tissues and organs of various plant species. In plants, flavonoids are involved in many biological processes and in response to various environmental stresses. The consumption of flavonoids has been known to reduce the risk of many chronic diseases due to their antioxidant and free radical scavenging properties. In the present review, we summarize the classification, distribution, biosynthesis pathways, and regulatory mechanisms of flavonoids. Moreover, we investigated their biological activities and discuss their applications in food processing and cosmetics, as well as their pharmaceutical and medical uses. Current trends in flavonoid research are also briefly described, including the mining of new functional genes and metabolites through omics research and the engineering of flavonoids using nanotechnology. This review provides a reference for basic and applied research on flavonoid compounds.

Design, Synthesis, In Vitro, and In Silico Insights of 5-(Substituted benzylidene)-2-phenylthiazol-4(5H)-one Derivatives: A Novel Class of Anti-Melanogenic Compounds

(Z)-5-Benzylidene-2-phenylthiazol-4(5H)-one ((Z)-BPT) derivatives were designed by combining the structural characteristics of two tyrosinase inhibitors. The double-bond geometry of trisubstituted alkenes, (Z)-BPTs 1-14, was determined based on the ³J_C,Hβ coupling constant of ¹H-coupled ¹³C NMR spectra. Three (Z)-BPT derivatives (1-3) showed stronger tyrosinase inhibitory activities than kojic acid; in particular, 2 was to be 189-fold more potent than kojic acid. Kinetic analysis using mushroom tyrosinase indicated that 1 and 2 were competitive inhibitors, whereas 3 was a mixed-type inhibitor. The in silico results revealed that 1-3 could strongly bind to the active sites of mushroom and human tyrosinases, supporting the kinetic results. Derivatives 1 and 2 decreased the intracellular melanin contents in a concentration-dependent manner in B16F10 cells, and their anti-melanogenic efficacy exceeded that of kojic acid. The anti-tyrosinase activity of 1 and 2 in B16F10 cells was similar to their anti-melanogenic effects, suggesting that their anti-melanogenic effects were primarily owing to their anti-tyrosinase activity. Western blotting of B16F10 cells revealed that the derivatives 1 and 2 inhibited tyrosinase expression, which partially contributes to their anti-melanogenic ability. Several derivatives, including 2 and 3, exhibited potent antioxidant activities against ABTS cation radicals, DPPH radicals, ROS, and peroxynitrite. These results suggest that (Z)-BPT derivatives 1 and 2 have promising potential as novel anti-melanogenic agents.

The Biochemistry and Effectiveness of Antioxidants in Food, Fruits, and Marine Algae

It is more effective to maintain good health than to regain it after losing it. This work focuses on the biochemical defense mechanisms against free radicals and their role in building and maintaining antioxidant shields, aiming to show how to balance, as much as possible, the situations in which we are exposed to free radicals. To achieve this aim, foods, fruits, and marine algae with a high antioxidant content should constitute the basis of nutritional elements, since natural products are known to have significantly greater assimilation efficiency. This review also gives the perspective in which the use of antioxidants can extend the life of food products, by protecting them from damage caused by oxidation as well as their use as food additives.

The Activation of PPARγ by (2Z,4E,6E)-2-methoxyocta-2,4,6-trienoic Acid Counteracts the Epithelial–Mesenchymal Transition Process in Skin Carcinogenesis

Cutaneous squamous cell carcinoma (cSCC) is the most common UV-induced keratinocyte-derived cancer, and its progression is characterized by the epithelial–mesenchymal transition (EMT) process. We previously demonstrated that PPARγ activation by 2,4,6-octatrienoic acid (Octa) prevents cutaneous UV damage. We investigated the possible role of the PPARγ activators Octa and the new compound (2Z,4E,6E)-2-methoxyocta-2,4,6-trienoic acid (A02) in targeting keratinocyte-derived skin cancer. Like Octa, A02 exerted a protective effect against UVB-induced oxidative stress and DNA damage in NHKs. In the squamous cell carcinoma A431 cells, A02 inhibited cell proliferation and increased differentiation markers’ expression. Moreover, Octa and even more A02 counteracted the TGF-β1-dependent increase in mesenchymal markers, intracellular ROS, the activation of EMT-related signal transduction pathways, and cells’ migratory capacity. Both compounds, especially A02, counterbalanced the TGF-β1-induced cell membrane lipid remodeling and the release of bioactive lipids involved in EMT. In vivo experiments on a murine model useful to study cell proliferation in adult animals showed the reduction of areas characterized by active cell proliferation in response to A02 topical treatment. In conclusion, targeting PPARγ may be useful for the prevention and treatment of keratinocyte-derived skin cancer.

Protein persulfidation: Rewiring the hydrogen sulfide signaling in cell stress response

The past few decades have witnessed significant progress in the discovery of hydrogen sulfide (H₂S) as a ubiquitous gaseous signaling molecule in mammalian physiology, akin to nitric oxide and carbon monoxide. As the third gasotransmitter, H₂S is now known to exert a wide range of physiological and cytoprotective functions in the biological systems. However, endogenous H₂S concentrations are usually low, and its potential biologic mechanisms responsible have not yet been fully clarified. Recently, a growing body of evidence has demonstrated that protein persulfidation, a posttranslational modification of cysteine residues (RSH) to persulfides (RSSH) elicited by H₂S, is a fundamental mechanism of H₂S-mediated signaling pathways. Persulfidation, as a biological switch for protein function, plays an important role in the maintenance of cell homeostasis in response to various internal and external stress stimuli and is also implicated in numerous diseases, such as cardiovascular and neurodegenerative diseases and cancer. In this review, the biological significance of protein persulfidation by H₂S in cell stress response is reviewed providing a framework for understanding the multifaceted roles of H₂S. A mechanism-guided perspective can help open novel avenues for the exploitation of therapeutics based on H₂S-induced persulfidation in the context of diseases.

Anti-Photoaging Effect of Phaseolus angularis L. Extract on UVB-Exposed HaCaT Keratinocytes and Possibilities as Cosmetic Materials

Phaseolus angularis L. is widely cultivated and is considered a superfood because of its nutritious protein and starch contents. Nevertheless, P. angularis's effects on skin photoaging are unknown. The aim of this study was to research the effects of P. angularis seed extract (PASE) on photoaging in human keratinocytes (HaCaT) damaged by UVB radiation so as to find out whether PASE can be used as an effective anti-photoaging ingredient in cosmetic products. The antioxidant activities were assessed using 1,1-diphenyl-2-picrylhydrazyl (DPPH), 2,2'-azino-bis-(3-ethylbenzothiazoline)-6-sulfonic acid (ABTS) radical scavenging, and reactive oxygen species (ROS) assays. Enzyme-linked immunosorbent assay (ELISA) analysis was used to determine the change in matrix metalloproteinase (MMP)-1, and MMP-3. The protein levels of mitogen-activated protein kinase (MAPK)/activator protein (AP)-1, transforming growth factor beta (TGF)-β/suppressor of mothers against decapentaplegic (Smad), and NF-E2-related factor (Nrf)2/antioxidant response element (ARE) were measured by western blot. As a result, PASE increased DPPH and ABTS antioxidant activities in a dose-dependent manner. Additionally, PASE treatment (100 µg/mL) significantly reverted the damage induced by UVB (125 mJ/cm²) irradiation by downregulating ROS, matrix metalloproteinase (MMP)-1, and MMP-3 secretion and expression and increasing procollagen type I production. To suppress MMP-1 and MMP-3 secretion, PASE significantly decreased UVB-induced p38 and JNK phosphorylation and phosphorylated c-Fos and c-Jun nuclear translocation. PASE promoted collagen I production by inhibiting UVB-induced TGF-β activation and Smad7 overexpression; antioxidant properties also arose from the stimulation of the Nrf2-dependent expression of the antioxidant enzymes heme oxygenase (HO)-1 and quinone oxidoreductase (NQO)-1. Our data demonstrated that PASE has the potential to prevent ROS formation induced by UVB exposure by targeting specific pathways. Thus, PASE might be a potent anti-photoaging component to exploit in developing anti-aging products.

Antioxidative and Antimicrobial Evaluation of Bark Extracts from Common European Trees in Light of Dermal Applications

Plant species have developed effective defense strategies for colonizing diverse habitats and protecting themselves from numerous attacks from a wide range of organisms, including insects, vertebrates, fungi, and bacteria. The bark of trees in particular constitutes a number of components that protect against unwanted intruders. This review focuses on the antioxidative, dermal immunomodulatory, and antimicrobial properties of bark extracts from European common temperate trees in light of various skin pathogens, wound healing, and the maintenance of skin health. The sustainability aspect, achieved by utilizing the bark, which is considered a byproduct in the forest industry, is addressed, as are various extraction methods applied to retrieve extracts from bark.

The Role of Selected Flavonoids from Bajakah Tampala (Spatholobus littoralis Hassk.) Stem on Cosmetic Properties: A Review

Cosmetics made from natural ingredients are increasingly popular because they contain bioactive compounds which can provide many health benefits, more environmentally friendly and sustainable. The health benefits obtained from natural-based ingredients include anti-aging, photoprotective, antioxidant, and anti-inflammatory. This article reviewed the potential of selected flavonoids from bajakah tampala (Spatholobus littoralis Hassk.) as the native plant in Indonesia. We present in silico, in vitro, in vivo, and clinical research data on the use of selected flavonoids that have been reported in other extracts.

Ginsenoside Rk1 Prevents UVB Irradiation-Mediated Oxidative Stress, Inflammatory Response, and Collagen Degradation via the PI3K/AKT/NF-κB Pathway In Vitro and In Vivo

Long-term exposure to ultraviolet (UV) irradiation, especially UVB, can trigger destructive intracellular effects, including various types of DNA damage, oxidative stress, and inflammatory responses, leading to accelerated skin aging. Ginsenoside Rk1, a rare ginsenoside pertaining to panaxadiol saponins, has been certified to possess underlying anti-inflammatory effects. Nevertheless, the efficiency of Rk1 against the photoaging of human skin and the latent molecular mechanisms are still unclear. Here, UVB-irradiated HaCaT keratinocytes were used as an in vitro model, and UVB-irradiated BALB/c nude mouse dorsal skin was established as an in vivo model to explore the mechanism by which Rk1 protects skin. Consequently, we found that Rk1 administration significantly attenuated oxidative stress by suppressing reactive oxygen species (ROS) overproduction and strengthening the activities of antioxidant enzymes. The UVB-induced inflammatory response was alleviated by Rk1 application via regulation of the secretion of various proinflammatory cytokines. Additionally, western blot assays illustrated that Rk1 intervention inhibited collagen degradation by reducing the expression of matrix metalloproteinases. Further studies revealed that Rk1 could suppress the PI3K/AKT/NF-κB signaling pathways in vitro and in vivo. Molecular docking results indicated that Rk1 might effectively bind to the active pockets of PI3K, AKT, and NF-κB. The PI3K activator 740 Y-P clearly reversed the effects of Rk1 on oxidative stress, the inflammatory response, and collagen degradation in UVB-irradiated HaCaT cells. Moreover, histological and Masson staining verified that the administration of Rk1 to BALB/c nude mice remarkably ameliorated UVB-induced skin roughness, epidermal thickening, collagen fiber arrangement disorder, and wrinkles. Overall, the evidence provided in this study suggested that Rk1 could be applied for the development of effective natural antiphotoaging agents for skin health.

Amentoflavone-Enriched Selaginella rossii Protects against Ultraviolet- and Oxidative Stress-Induced Aging in Skin Cells

Selaginellaceae plants are used in cosmetics to limit skin aging. This study is the first to investigate the anti-aging effects of Selaginella rossii (SR) on ultraviolet B (UVB)- and oxidative stress-induced skin cells. The 95% ethanol extract of Selaginella rossii (SR95E) contained much higher amounts of amentoflavone (AMF), an active compound, than other Selaginellaceae plants and was more effective in inhibiting matrix metalloproteinase (MMP)-1 expression in CCD-986sk fibroblasts. SR95E significantly decreased UVB-induced MMP-1, MMP-2, MMP-3 and MMP-9 expression and enhanced procollagen type I C-peptide content and mRNA expression of collagen type I alpha (COL1A)1 and COL1A2 in CCD-986sk fibroblasts. In HaCaT keratinocytes, SR95E treatment also dose-dependently decreased UVB-induced MMP-1 concentration and MMP-1, MMP-2, MMP-3 and MMP-9 mRNA expression. Moreover, SR95E treatment markedly inhibited UVB-induced c-Jun N-terminal kinase and p38 mitogen-activated protein kinase signaling and nuclear factor kappa-B signaling in HaCaT cells. Furthermore, SR95E and AMF markedly regulated the 2,2'-azobis(2-amidinopropane) dihydrochloride (AAPH)-induced expression of cellular senescence-related markers, including p16, p21 and LMNB1, in HaCaT cells. Overall, this study indicates that SR may have potential as a functional material on preventing UVB- and AAPH-induced skin aging and wrinkles.

Protective Effects of Fermented Houttuynia cordata Against UVA and H2O2-Induced Oxidative Stress in Human Skin Keratinocytes

The biological activities of Houttuynia cordata (H. cordata) fermented with Aureobasidium pullulans (A. pullulans) was investigated for human skin keratinocyte-induced chemical and photo oxidations. In this research, H₂O₂/UVA-induced HaCaT cell lines were treated with H. cordata water/ethanol extracts (HCW/HCE) and fermented with A. pullulans water/ethanol extracts (HCFW/HCFE). A. pullulans fermented with H. cordata (HCFW) increased in 5.4-folds of total polyphenol (HCFW 46.89 mg GAE/extract g), and 2.3-folds in flavonoids (HCFW 53.80 mg GAE/extract g) compared with water extracts of H. cordata (HCW). Further, no significant cytotoxicity for HaCaT cells showed by all the extracts of H. cordata fermented with A. pullulans. HCFW extracts have significantly lowered inflammation factors such as COX-2 and Hsp70 proteins in oxidative stressed HaCaT cells induced by H₂O₂ and UVA treatments. All H. cordata extracts significantly downregulated gene expression involved in oxidative stress and inflammation factors, including IL-1β, IL-6, COX-2, TNF-α, NF-κB, and MMP-1 in the H₂O₂/UVA-treated HaCaT cells. However, keratin-1 gene expression in the UVA-treated HaCaT cells was increased in twofolds by HCFW extracts. Further, A. pullulans fermented H. cordata extracts (HCFW/HCFE) reduced the genes involved in oxidative stresses more effectively than those of H. cordata extract only. Overall, the polyphenol-rich extracts of H. cordata fermented with A. pullulans showed synergistic protective effects for human epidermal keratinocytes to prevent photoaging and intrinsic aging by anti-oxidation and anti-inflammatory functions.

NRF2, a crucial modulator of skin cells protection against vitiligo, psoriasis, and cancer

The skin represents a physical barrier between the organism and the environment that has evolved to confer protection against biological, chemical, and physical insults. The inner layer, known as dermis, is constituted by connective tissue and different types of immune cells whereas the outer layer, the epidermis, is composed by different layers of keratinocytes and an abundant number of melanocytes, localized in the stratum basale of the epidermis. Oxidative stress is a common alteration of inflammatory skin disorders such as vitiligo, dermatitis, or psoriasis but can also play a causal role in skin carcinogenesis and tumor progression. Nuclear factor (erythroid-derived 2)-like 2 (NRF2) has emerged as a crucial regulator of cell defense mechanisms activating complex transcriptional programs that facilitate reactive oxygen species detoxification, repair oxidative damage and prevent xenobiotic-induced toxicity. Accumulating evidence suggests that the keratinocytes, melanocytes, and other skin cell types express high levels of NRF2, which is known to play a pivotal role in the skin homeostasis, differentiation, and metabolism during normal and pathologic conditions. In the present review, we summarize the current evidence linking NRF2 to skin pathophysiology and we discuss some recent modulators of NRF2 activity that have shown a therapeutic efficacy in skin protection against tumor initiation and common inflammatory skin conditions such as vitiligo or psoriasis, with a particular emphasis on natural compounds.

Effects of tocotrienol on aging skin: A systematic review

The skin is the largest organ of the body that protects from mechanical, thermal, and physical injury. However, the function and appearance of skin visibly degenerates with age due to its frequent exposure to harmful effects of the environment, including ultraviolet irradiation and hazardous substances, in addition to the progression of oxidative stress in aging. These factors result in phenotypic changes in the skin, including wrinkling, pigmentation, reduced elasticity, and hydration during aging. Many natural antioxidant compounds have been studied extensively to reverse the signs of aging skin. Tocotrienols are a subfamily of vitamin E with potent antioxidant activity. Therefore, supplementation with vitamin E in the form of tocotrienol may efficiently protect skin from aging. In this review, the effects of tocotrienol on skin health, including pigmentation, moisture, and wrinkles during aging and UV exposure, were systematically evaluated based on a literature search of the PubMed and Scopus databases. The present data showed that tocotrienols protect the skin from inflammation, UV radiation and melanin accumulation. As the therapeutic value of tocotrienols grows, the potential of these vitamin E analogs to the skin requires further investigation.

Efficacy and Safety of Oral Green Tea Preparations in Skin Ailments: A Systematic Review of Clinical Studies

Green-tea-based products and their polyphenols, especially epigallocatechin-3-gallate, have attracted great attention over the years as possible nutraceuticals, due to their promising bioactivities, especially antioxidant and anti-inflammatory, which could be exploited in several diseases, including skin ailments. In this context, the present study aimed at reviewing clinical evidence about the benefits of the oral administration of green tea preparations and its polyphenols to relieve skin disorders, to point out the current knowledge, and to suggest possible novel strategies to effectively exploit the properties of green tea, also managing safety risks. To this end, a systematic review of the existing literature was carried out, using the PRISMA method. Few studies, including five focused on UV-induced erythema and skin alterations, three on photoaging, two on antioxidant skin defenses, and one on acne and genodermatosis, were retrieved. Despite several benefits, clinical evidence only supports the use of oral green tea preparations to protect skin from damage induced by ultraviolet radiation; in other cases, conflicting results and methodological limits of clinical trials do not allow one to clarify their efficacy. Therefore, their application as adjuvant or alternative sunscreen-protective interventions could be encouraged, in compliance with the safety recommendations.

A Novel Class of Potent Anti-Tyrosinase Compounds with Antioxidant Activity, 2-(Substituted phenyl)-5-(trifluoromethyl)benzo[d]thiazoles: In Vitro and In Silico Insights

Sixteen compounds bearing a benzothiazole moiety were synthesized as potential tyrosinase inhibitors and evaluated for mushroom tyrosinase inhibitory activity. The compound 4-(5-(trifluoromethyl)benzo[d]thiazol-2-yl)benzene-1,3-diol (compound 1b) exhibited the highest tyrosinase activity inhibition, with an IC₅₀ value of 0.2 ± 0.01 μM (a potency 55-fold greater than kojic acid). In silico results using mushroom tyrosinase and human tyrosinase showed that the 2,4-hydroxyl substituents on the phenyl ring of 1b played an important role in the inhibition of both tyrosinases. Kinetic studies on mushroom tyrosinase indicated that 1b is a competitive inhibitor of monophenolase and diphenolase, and this was supported by docking results. In B16F10 murine melanoma cells, 1a and 1b dose-dependently and significantly inhibited melanin production intracellularly, and melanin release into medium more strongly than kojic acid, and these effects were attributed to the inhibition of cellular tyrosinase. Furthermore, the inhibition of melanin production by 1b was found to be partially due to the inhibition of tyrosinase glycosylation and the suppression of melanogenesis-associated genes. Compound 1c, which has a catechol group, exhibited potent antioxidant activities against ROS, DPPH, and ABTS, and 1b also had strong ROS and ABTS radical scavenging activities. These results suggest that 5-(trifluoromethyl)benzothiazole derivatives are promising anti-tyrosinase lead compounds with potent antioxidant effects.