Search Results (411)

Ultraviolet B (UVB), as a major component of solar radiation, is a key factor in inducing skin photoaging. The epidermis serves as the primary defensive barrier of the skin and absorbs the majority of UVB. This study aims to elucidate the protective effect of Alk against UVB-induced photoaging and further uncover its underlying molecular mechanisms. In vitro, Alk-pretreated HaCaT cells were exposed to UVB. Cell viability, ROS, senescence, antioxidant enzymes, and protein expression were analyzed. Mechanisms were examined using CETSA, DARTS, Co-IP, and NRF2 knockout. In vivo, Alk hydrogel was tested in UVB-exposed BALB/c mice, with protection assessed via histology and immunohistochemistry. In vitro, Alk directly binds to Keap1, disrupts Keap1–Nrf2 interaction, promotes nuclear translocation of Nrf2, and upregulates the expression of its downstream target HO-1. Consequently, intracellular ROS generation is reduced, cellular senescence is alleviated, and the expression of inflammatory factors (TNF-$\alpha$, COX-2) and MMP-9 is suppressed. In vivo, topical application of the Alk hydrogel prevented UVB-induced skin thickening and collagen degradation. Alk exerts a preventive effect on UVB-induced photoaging in HaCaT cells and skin, providing strong support for developing Alk as a potential plant-derived active ingredient for preventing skin photoaging. Full article

Hydroxycinnamoyl-CoA shikimate/quinate hydroxycinnamoyl transferase, a key acyltransferase in the phenylpropanoid pathway and a canonical member of the BAHD acyltransferase family (BAHD), catalyzes the formation of pivotal intermediates in the biosynthesis of secondary metabolites such as lignin, chlorogenic acid, and flavonoids. These compounds serve indispensable protective functions in terrestrial plants, underpinning their adaptive responses to abiotic stresses such as drought, ultraviolet (UV) radiation, and oxidative damage. Although the role of HCT/HQT in the core phenylpropanoid pathway has been extensively characterized, its precise functional contributions to the flavonoid biosynthetic branch—particularly with respect to substrate selectivity, kinetic regulation, and metabolic channeling—remain incompletely understood. This review systematically analyzes the structural features, spatial conformation, catalytic mechanism, and substrate promiscuity of HCT/HQT to clarify its molecular determinants of activity and specificity. Furthermore, it highlights regulatory factors influencing HCT/HQT gene expression, such as transcription factors (MYB, bHLH, WRKY), phytohormones (GA₃, Eth, MeJA, 6-BA, MT), and abiotic/biotic stressors (temperature, blue light, nitric oxide, nano-selenium). Collectively, these insights illuminate how plants dynamically fine-tune phenylpropanoid metabolism in coordination with developmental programs and environmental challenges. This work provides a foundation for further research on HCT/HQT and supports efforts to develop improved crop varieties through targeted regulation of this central metabolic node. Full article

Ultraviolet-B (UV-B) radiation plays a pivotal role in plant growth, metabolism, and the accumulation of bioactive compounds, but its effects under greenhouse conditions are highly species- and dose-dependent. This study investigated the responses of eggplant (Solanum melongena L., cv. Lunga Napoletana) and lettuce (Lactuca sativa L., cv. Rosplus) cultivated under greenhouse films transmitting 3–39% of ambient UV-B. Leaf temperature was monitored throughout the growth cycle using infrared thermography, while physiological parameters (chlorophyll, flavonoids, anthocyanins, and nitrogen index) and post-harvest nutritional traits (antioxidant activity, vitamin C, carotenoids, and total chlorophyll) were assessed. Comparative analysis revealed species-specific responses. Eggplant exhibited peak nutraceutical quality at higher UV-B levels (35–39%) with minimal changes in yield, whereas lettuce achieved maximal yield and secondary metabolite accumulation under intermediate UV-B (30–35%). At the highest UV-B transmittance (39%), both species exhibited stable or slightly reduced thermal and physiological parameters, indicating dose-dependent regulatory mechanisms that maintain photoprotection and metabolic activity under elevated UV-B exposure. Results suggest an apparent optimal range of UV-B transmittance in greenhouse systems under the tested experimental conditions, contributing to improved crop productivity and nutritional quality. Full article

Artificial optical radiation, spanning from 100 nm to 1 mm, encompasses ultraviolet (UV) and infrared (IR) light. UV light is well known for its risks on the skin and eyes. Recently, there has been growing interest in light at 405 nm (violet-blue light, VBL) due to its antimicrobial properties and perceived safety for mammalian cells when administered in controlled amounts. This research delved into the impact of 405 nm VBL on corneal and retinal pigment epithelial cell cultures. ARPE-19 and corneal BCE C/D 1b cells were exposed to VBL for varying doses, according at different exposure times, to evaluate cell viability, oxidative stress levels and apoptotic indicators. A 3D printed prototype with 14 LEDs centred at 405 nm wavelength was used to ensure uniform distribution of light during exposure. Cell viability was assessed using the MTT assay, measurement of oxygen species (ROS) production was carried out, and Western blot analysis was employed to study catalase and SOD-1 expression and apoptotic marker activation. Exposure to 405 nm VBL for both term (3 h) and prolonged durations (9 h) led to a weak decrease in cell viability in ARPE-19 cells, whereas the effect on BCE C/D 1b cells was negligible. There was no increase in ROS production, with catalase and SOD-1 expression remaining stable, suggesting no pro-oxidative stress effects in these models. Moreover, no activation of caspase-3 and accumulation of cytochrome C were found. Based on our results, exposure to 405 nm light at regulated levels does not pose a threat to the viability of the tested cell lines and does not lead to oxidative stress and apoptosis under these conditions. These results suggest a favourable cytocompatibility profile for these specific ocular cell models, laying a foundation for further investigations into its ocular safety. Full article

Plants respond to ultraviolet B radiation (280–320 nm) with an integrated reaction that includes the reception of the acting stress factor, followed by the generation of reactive oxygen species and damage to macromolecules and membrane structures, as well as changes in cellular metabolism and the formation of protective systems. However, the involvement of key UV-B–related signalling components such as HY5, SPA1 and BIC1 or BIC2 proteins in physiological, biochemical and molecular responses remains insufficiently understood. The effects of 8, 16 and 24 h of UV-B exposure (within an 8 h photoperiod over three days) on the net photosynthetic rate (Pn), chlorophyll fluorescence parameters Y(II) and F_v/F_m, reflecting the functional state of PSII, nonphotochemical quenching (NPQ), pigment contents (Chl(a+b), carotenoids, anthocyanins and UV-absorbing pigments (UAPs) and the expression of key light-induced genes in wild-type Arabidopsis thaliana and spa1, bic1,2 and hy5 mutants were studied. UV-B irradiation resulted in a gradual reduction in the Pn, Y(II), F_v/F_m values and Chl(a+b) but caused a marked increase in the anthocyanin and UAP contents and only minor changes in the carotenoid content. The hy5 mutant presented the lowest net photosynthetic rate (Pn), chlorophyll fluorescence parameters, and chlorophyll and carotenoid contents under all the UV-B exposures. In addition, the accumulation of anthocyanins and UAPs during UV-B treatment was consistently the lowest in hy5. After any UV-B exposure, the highest accumulation of UAPs and anthocyanins was observed in the spa1 mutant, whereas the highest Pn values were detected after 24 h in bic1,2. One of the reasons for the reduced photosynthetic activity and antioxidant capacity in hy5 may be the lower expression levels of CHS and PAL in this variety than in the other genotypes. Our results indicate that HY5 is required to maintain antioxidant responses and photosynthetic performance under repeated daytime UV-B exposure (16.8 kJ m⁻² per day). In contrast, BIC1, BIC2, and SPA1 also contribute to UV-B tolerance, but through distinct regulatory mechanisms and to a lesser extent. Full article

Growing interest in natural therapies has increased the demand for essential oils; however, the complex interactions within their mixtures that dictate their final efficacy remain poorly understood. This study aimed to optimize a blend of ginger, cinnamon, tea tree, and geranium essential oils to develop an active ingredient, with synergistic multifunctional bioactivities, that was relevant to cutaneous healing. Initially, the composition and cytotoxicity for individual oils were determined; subsequently, a D-optimal mixture design was employed to evaluate three biological responses related to skin recovery: ultraviolet B radiation absorption, red blood cell lysis inhibition, and catalase enzyme activity. GC-FID analysis revealed the following major components (% w/w): cinnamon (cinnamaldehyde, 77.56%), ginger (α-zingiberene, 33.77%), geranium (citronellol, 33.6%), and tea tree (terpinen-4-ol, 38.38%). Dose–response data from essential oils tested against Detroit ATCC 551 skin fibroblasts revealed a clear cytotoxic hierarchy (IC₅₀ µg/mL): cinnamon (21.03) > ginger (25.3) > tea tree (41.67) > geranium (92.51). Cinnamaldehyde content was the primary contributor to photoprotective capacity, with a maximum sun protection factor (SPF) of 4.5. Inhibition against erythrocyte membrane lysis was not attributable to a single component; maximum protection (98.4%) was achieved through synergy between oxygenated monoterpenoids (geranium and tea tree), sesquiterpenes (ginger), and aromatic aldehydes (cinnamon). Highest catalase activity (160.86 kU/g Hb) was reached in mixtures with high cinnamaldehyde and eugenol contents, whereas an antagonistic effect was observed between tea tree and geranium oils. Finally, an optimal formulation (desirability = 0.927) was identified (% w/w): 31.7% ginger, 39.1% cinnamon, 14.5% tea tree, and 14.7% geranium. Experimental validation confirmed no significant difference compared with developed predictive models. This optimized mixture constitutes a bioactive natural component with potential for use in products aimed at promoting skin health, warranting further investigation into direct models of skin healing. Full article

Human rhinovirus (HRV) is one of the common respiratory viral infection agents that triggers airway obstruction and asthma exacerbations, especially during childhood. This project aimed at evaluating the mechanism of ultraviolet (UV) and infrared (IR) radiations to inactivate HRV infection and replication inside and outside infected airway epithelial cells and the resulting impact on interferon responses and epithelial barrier integrity. Hereby, airway epithelial cells were infected with different RV concentrations. Later these cells are exposed to UV and IR light to analyze their impact on the viral immune response of the host by real-time PCR. It was found that RV1B disrupted cell junctions of airway epithelial cell barriers. Moreover, high doses of RV1B activated pattern recognition receptor (TLR3), induced interferon (IFN-β) response and reduced SOCS1, which is a negative regulator of IFN-β. Further, IR lights inhibited rhinovirus post infection in primary nasal epithelial cells (NECs). Finally, UVC exposure significantly inhibited the antiviral effects of the host via SOCS1 inhibition and decreased RV1B within 72 h. Collectively, these findings support the role of UV light as an effective therapeutic approach for acutely eliminating RV but resulting in barrier and antiviral damage, which can have a drawback effect for asthma. Full article

Background/Objectives. Ultraviolet B (UVB) radiation is a key etiological factor for skin cancer, inducing oxidative stress, DNA damage and apoptosis. Nicotinamide (NAM), a NAD⁺ precursor, has shown photoprotective properties, although the mechanisms underlying this effect have not been fully elucidated. This study sought to elucidate the role of NAM in counteracting UVB-induced oxidative damage in HaCaT cells and to assess the contribution of NAD⁺ metabolism to these effects. Methods. HaCaT were exposed to low-dose UVB irradiation (40 mJ/cm²) and treated with NAM (25 μM), alone or in combination with the NAMPT inhibitor FK866 (1 nM) for 4 and 24 h. Oxidative stress, lipid peroxidation and DNA damage were evaluated by DCFDA assay, TBARS assay and comet assay, respectively. Cell proliferation, cell cycle progression and apoptosis were assessed using Ki67 immunofluorescence, flow cytometry analysis and Annexin V/PI staining. Transcriptional activity for oxidative stress- and apoptosis-related markers was analyzed by RT-qPCR. Results. NAM significantly reduced UVB-induced ROS production at both 4 and 24 h post-irradiation in an NAD⁺-dependent manner, as demonstrated by the reversal of its effects following NAMPT inhibition. NAM also decreased oxidative DNA damage accompanied by reduced OGG1 expression, a marker of oxidative stress. Moreover, NAM restored HaCaT proliferation and reduced early apoptosis, particularly at 24 h post-UVB exposure. These protective effects were mediated by NAD⁺. Conclusions. Our results show that NAM confers robust protection to HaCaT cells from UVB-induced oxidative stress and cellular damage, largely mediated by NAD⁺-dependent pathways, supporting its potential role as a systemic photoprotective agent in skin cancer prevention. Full article

Prolonged exposure to ultraviolet (UV) radiation in sunlight is a major extrinsic factor that impairs skin function and accelerates photoaging. In this study, a murine model of ultraviolet B (UVB)-induced photoaging exhibited characteristic symptoms, including skin roughness, erythema, hyperpigmentation, and increased wrinkle formation. Epicatechin gallate (ECG), a natural flavonoid, has demonstrated potential skin-protective properties. However, its specific effects and mechanisms against UVB-induced photoaging are not fully understood. Here, we investigated the protective role and underlying mechanism of ECG against UVB-induced damage in human epidermal keratinocytes (HaCaT cells). Using network pharmacology, p38 mitogen-activated protein kinase (p38 MAPK), specifically the p38α isoform, was identified as a key potential target of ECG. Our experimental results confirmed that ECG significantly attenuated UVB-induced photoaging. Mechanistically, ECG treatment effectively suppressed UVB-triggered phosphorylation of p38α, promoted autophagic flux (as evidenced by increased LC3B conversion and decreased p62 levels), and substantially reduced intracellular reactive oxygen species (ROS) accumulation. Consequently, ECG mitigated mitochondrial dysfunction, restored normal cell cycle progression, and decreased the expression of senescence-associated markers (p53, p16, p21) and inflammatory cytokines (IL6, TNF-α). In summary, our findings demonstrate that ECG protects against UVB-induced photoaging primarily by inhibiting p38α activation, thereby enhancing autophagy and alleviating oxidative stress. This study positions ECG as a promising therapeutic candidate for preventing and treating skin photoaging. Full article

The biological effects of radiofrequency electromagnetic fields (RF-EMFs) remain an unresolved scientific issue with important societal relevance, particularly in the context of the global deployment of fifth-generation (5G) wireless technologies. The skin is continuously exposed to both RF-EMFs and ultraviolet (UV) radiation, a well-established inducer of oxidative stress and DNA damage, making it a relevant model for assessing combined environmental exposures. In this study, we investigated whether post-exposure to 5G RF-EMFs (3.5 and 28 GHz) modulates ultraviolet A (UVA)-induced genotoxic stress in human keratinocytes (HaCaT) and murine melanoma (B16) cells. Post-UV RF-EMF exposure significantly reduced DNA damage markers, including phosphorylated histone H2AX (γH2AX) foci formation (by approximately 30–50%) and comet tail moments (by 60–80%), and suppressed intracellular reactive oxygen species (ROS) accumulation (by 56–93%). These effects were accompanied by selective attenuation of p38 mitogen-activated protein kinase (MAPK) phosphorylation (reduced by 55–85%). The magnitude of molecular protection was comparable to that observed with N-acetylcysteine treatment or pharmacological inhibition of p38 MAPK. In contrast, RF-EMF exposure did not reverse UV-induced reductions in cell viability or alterations in cell cycle distribution, indicating that its protective effects are confined to early molecular stress-response pathways rather than downstream survival outcomes. Together, these findings demonstrate that 5G RF-EMFs can facilitate recovery from UVA-induced molecular damage via redox-sensitive and p38-dependent mechanisms, providing mechanistic insight into the interaction between modern telecommunication frequencies and UV-induced skin stress. Full article

Ultraviolet B radiation is a major cause of skin aging, cellular senescence, and inflammaging, mediated by the excessive production of reactive oxygen species (ROS) and induction of apoptosis. This study evaluated the photo-protective effects of astaxanthin, one of the strongest natural antioxidants, in UVB-treated keratinocytes. The antioxidant capacity of astaxanthin was evaluated using ABTS, DPPH, and NBT/riboflavin/SOD assays. HaCaT cells were exposed to 30 mJ/cm² of UVB radiation. Photoprotective effects and accumulated ROS were evaluated in UVB-irradiated HaCaT cells by MTT and DCFH-DA assays. Nitric oxide levels were quantified using the Griess reagent. Apoptosis was assessed by dual staining using acridine orange/ethidium bromide, lysosomal integrity by acridine orange uptake, and cell migration by scratch assay. Cell adhesion was assessed on ECM-coated Nunc plates. Finally, we formulated a 0.5% astaxanthin-enriched cream. Astaxanthin mitigated UVB-induced damage by reducing intracellular ROS levels by 3.7-fold, decreasing nitric oxide production to 29.8 ± 7.7% at the highest concentration, and maintaining lysosomal integrity. The carotenoid significantly enhanced cell viability, increasing it from 60.64 ± 8.3% in UV-treated cells to 102.1 ± 3.22% at 40 µM. Moreover, treated cells showed a significant reduction (p < 0.001) in the apoptotic rate (37.7 ± 3.1 vs. 87.7 ± 3.8 in UVB-irradiated cells, as evidenced by reduced chromatin condensation and nuclear fragmentation. Astaxanthin also enhanced tissue repair, as evidenced by increased cell migration and adhesion to several extracellular matrix (ECM) proteins (poly-L-lysine, laminin, fibrinogen, vitronectin and collagen I). In silico molecular docking predicted strong binding affinities between astaxanthin and key cellular targets, including JAK2 (−9.9 kcal/mol, highest affinity), STAT3, FAK, COX-2, NF-k-B, MMP2, and MMP9. The formulated cream demonstrated an in vitro SPF of 7.2 ± 2.5. Astaxanthin acts as a multifunctional photoprotective compound, providing a strong rationale for its incorporation into cosmetic and dermatological formulations, as further supported by the successful formulation and in vitro SPF estimation of an astaxanthin-enriched cream. Full article

The genus Dysosma, a group of perennial herbaceous plants with significant medicinal value and a relatively narrow ecological niche, is potentially at risk due to the combined pressures of habitat degradation and climate change. As their habitats continue to degrade, all species of this genus have been included in the National Key Protected Wild Plants List (Category II). Investigating the impacts of climate change on the distribution of Dysosma resources is vital for their sustainable utilization. In this study, the potential distribution dynamics of seven Dysosma species under current and three future climate scenarios (SSP126, SSP245, SSP585) were quantified using 534 occurrence points and 25 environmental variables in a MaxEnt model, accompanied by the ecological niche overlap index (Schoener’s D), dynamic metrics (relative change rate [RCR], change intensity [CI], stability index [SI], spatial displacement rate [SDR]), and centroid migration analysis. The results indicated that (1) areas of high habitat suitability were consistently concentrated in the mountainous and hilly regions of southwestern Guizhou, Chongqing, and Hubei, with the minimum temperature of the coldest month (Bio6) and the mean diurnal temperature range (Bio2) being identified as the primary driving factors. (2) The future suitable habitat areas remained highly stable overall (SI > 97.89%), though dynamic changes varied across scenarios. Under SSP126, only slight fluctuations were observed, with an average CI of approximately 3.78% and RCR ranging from −0.46% to 1.97%. Under the SSP245 scenario, suitable habitat areas showed a continuous, slight expansion (RCR = 0.45% to 1.54%), whereas under the high-emission SSP585 scenario, a typical “mid-term expansion–late-term contraction” pattern was observed, with RCR shifting from positive (1.32%, 1.44%) to negative (−0.92%). The SI reached its lowest value of 97.89% in the late term, and the spatial displacement rate increased, signaling a reorganization of the distribution pattern. (3) High ecological niche differentiation was observed within the genus, with the highest overlap index being only 0.562, and approximately one-third of species pairs exhibiting completely non-overlapping niches. (4) Dysosma tsayuensis, a niche-specialist species, exhibited a distribution that was highly dependent on the annual mean ultraviolet-B radiation (UVB, contribution rate 52.9%), displaying an adaptation strategy markedly different from that of conservative species. (5) Centroid analysis indicated that, although the overall centroid remained stable in Guizhou, the presence of niche-specialist species under the high-emission SSP585 scenario resulted in migration paths opposite to those observed under other scenarios. The findings reveal the potential vulnerability and differential response patterns of Dysosma species under rapid climate warming, thereby providing a scientific basis for targeted conservation, in situ and ex situ conservation strategies, and population restoration. Full article

The synthesis of the melanin pigment in melanocytes plays a crucial role in protecting the body from ultraviolet radiation. Tyrosinase, a key enzyme in melanogenesis, catalyzes the conversion of tyrosine to melanin in the melanosomes of melanocytes. During melanogenesis, Tyrosinase is abundantly synthesized in the lumen of the endoplasmic reticulum (ER) and subsequently transported from the ER to the melanosomes via the Golgi apparatus. In the present study, we demonstrate that Box B-binding factor 2 human homolog on chromosome 7 (BBF2H7), an ER-resident transmembrane transcription factor that functions as an ER stress sensor, is activated by mild ER stress caused by abundant Tyrosinase synthesis. Activated BBF2H7 enhances COPII-mediated anterograde transport by inducing the expression of Sec23a, which is a COPII component and transcriptional target of BBF2H7. Loss of BBF2H7 attenuates the transport of Tyrosinase, leading to its accumulation in the ER lumen and reduced melanin production. Restoration of BBF2H7 or Sec23a expression in Bbf2h7-deficient melanocytes rescues anterograde transport of Tyrosinase from the ER and melanin pigmentation. Collectively, these findings reveal that the BBF2H7-Sec23a axis is essential for the ER-to-melanosome transport of Tyrosinase and subsequent melanin synthesis. Thus, it may be a prospective therapeutic target for disorders related to melanin pigmentation. Full article

The optimization of BiVO₄-based structures significantly contributes to the development of a global system towards clean, renewable, and sustainable energies. Enhanced photocatalytic performance has been reported for numerous doped BiVO₄ materials. Bi³⁺-based compounds can be easily doped with rare earth (RE³⁺) ions due to their equal valence and similar ionic radius. This means that RE³⁺ ions could be regarded as active co-catalysts and dopants to enhance the photocatalytic activity of BiVO₄. In this study, a simple microwave-assisted approach was used for preparing nanostructured Bi_1−xEu_xVO₄ (x = 0, 0.03, 0.06, 0.09, and 0.12) samples. Microwave heating at 170 °C yields a bright yellow powder after 10 min of radiation. The materials are characterized through X-ray diffraction (XRD), transmission electron microscopy (TEM), ultraviolet–visible–near-infrared diffuse reflectance spectroscopy (UV-Vis-NIR DRS), photoluminescence spectroscopy (PL), and micro-Raman techniques. The effects of the different Eu³⁺ ion concentrations incorporated into the BiVO₄ matrix on the formation of the monoclinic scheelite (ms-) or tetragonal zircon-type (tz-) BiVO₄ structure, on the photoluminescent intensity, on the decay dynamics of europium emission, and on photocatalytic efficiency in the degradation of Rhodamine B (RhB) were studied in detail. Additionally, microwave chemistry proved to be beneficial in the synthesis of the tz-BiVO₄ nanostructure and Eu³⁺ ion doping, leading to an enhanced luminescent and photocatalytic performance. Full article

Environmentally friendly materials with superior structural, physical, optical, and shielding capabilities are of great technological importance and are continually being investigated. In this work, novel multicomponent borate glasses with the composition xTiO₂-10BaO-5Al₂O₃-5WO₃-20Bi₂O₃-(60-x) B₂O₃, where 0 ≤ x ≤ 15 mol%, were produced via the melt-quenching technique. The increase in TiO₂ content results in a decrease in molar volume and a corresponding increase in density, indicating the formation of a compact, rigid, and mechanically hard glass network. Elastic constant measurements further confirmed this behavior. FTIR analysis confirms the transformation of BO₃ to BO₄ units, signifying improved network polymerization and structural stability. The prepared glasses exhibit an optical absorption edge in the visible region, demonstrating their strong ultraviolet light blocking capability. Incorporation of TiO₂ leads to an increase in refractive index, optical basicity, and polarizability, and a decrease in the optical band gap and metallization number; all of these suggest enhanced electron density and polarizability of the glass matrix. Radiation shielding properties were evaluated using Phy-X/PSD software. The outcomes illustrate that the Mass Attenuation Coefficient (MAC), Effective Atomic Number (Z_eff), Linear Attenuation Coefficient (LAC) increase, while Mean Free Path (MFP) and Half Value Layer (HVL) decrease with increasing TiO₂ at the expense of B₂O₃, confirming superior gamma-ray attenuation capability. Additionally, both TiO₂-doped and undoped samples show higher fast neutron removal cross sections (FNRCS) compared to several commercial glasses and concrete materials. Overall, the incorporation of TiO₂ significantly enhances the optical performance and radiation-shielding efficiency of the environmentally friendly glass system, making these potential candidates for advanced photonic devices and radiation-shielding applications. Full article