Photodamage attenuating potential of Nectandra hihua against UVB-induced oxidative stress in L929 fibroblasts

Syringic acid protective role: Combatting oxidative stress induced by UVB radiation in L-929 fibroblasts

Neglecting proper skin care and repeated exposure to ultraviolet (UV) radiation can have serious consequences, including skin burns, photoaging and even the development of skin cancer. UV radiation-induced damage is mediated by highly unstable and reactive molecules, named reactive oxygen species (ROS). To counteract ROS, the skin has an endogenous antioxidant system. Considering that, many sunscreens incorporate antioxidant substances to ensure additional photochemioprotective action in the formulation. Syringic acid (SA) is classified as a phenolic acid derived from hydroxybenzoic acid. It has antioxidant properties, which can reduce oxidative stress, and has shown potential to prevent skin cancer. The aim of this study was to assess the ability of SA to protect L-929 fibroblasts from UVB radiation by evaluating oxidative stress biomarkers. As a result, we demonstrated the antioxidant activity of SA through four methodologies, and confirmed the photochemioprotective activity of SA by attenuating the cytotoxicity of UVB radiation in L-929 fibroblasts. The mechanisms involved in the photoprotection of SA include a significant reduction in total ROS, maintenance of mitochondrial membrane potential, decrease in lipid peroxidation, preservation of endogenous antioxidant system enzymes and reduced glutathione (GSH) levels, thereby mitigating the ultrastructural damage caused by UVB. Additionally, SA showed promising results in wound healing. Considering such properties, SA emerges as a strong candidate for incorporation into photoprotective and multifunctional formulations.

Design of solid lipid nanoparticles for skin photoprotection through the topical delivery of caffeic acid-phthalimide

Exposure of the skin to ultraviolet (UV) radiation is associated with many pathological conditions such as premature aging and skin cancer. Furthermore, members of Nicotinamide Adenine Dinucleotide Phosphate-oxidase (NADPH oxidase or NOX) enzyme family can produce UV-induced reactive oxygen species (ROS), even after cessation of radiation exposure. The caffeic acid-phthalimide (CF) compound is a potent antioxidant, which reduces the generation of ROS. However, its high lipophilicity may hamper its permeation through the skin. Solid lipid nanoparticles (SLNs) can ensure close contact and increase the amount of drug absorbed into the skin. The present work aims to develop and optimize SLNs containing CF to achieve enhanced skin photoprotection along with antioxidant and anti-aging effects. SLNs were prepared by the hot homogenization method using Compritol 888 ATO as lipid matrix, and Tween 80 and Pluronic® F-127 as surfactants to stabilize the nanoparticle dispersion. The particles had high stability for at least 30 days. Physicochemical characterizations of the selected SLNs formulations showed sizes in the range 150-180 nm, polydispersity index (PDI) of 0.2, and a negative zeta potential (≅ -25  mV). The SLNs had high CF entrapment efficiency (96-97 %) and showed a controlled drug-release profile. The in vitro study revealed low cytotoxic properties of CF-loaded SLNs towards fibroblasts and a photoprotective effect, reflected from the increased viability of UVB-irradiated fibroblasts treated with CF-SLNs. Moreover, the CF-SLNs induced fibroblast migration and closure, showing that these nanosystems offer not only biological photoprotection, but also stimulate wound healing.

Neuroprotective Effects of Ethanol Extract Polyscias guilfoylei (EEPG) Against Glutamate Induced Neurotoxicity in HT22 Cells

Oxidative stress induced by glutamate is a significant contributor to neuronal cell damage and can lead to neurodegenerative diseases such as Alzheimer's, Huntington's, and ischemic brain injury. At the cellular level, oxidative stress increases Ca2+ ion influx and reactive oxygen species (ROS), which activate the MAPK signaling pathway. Additionally, the generation of ROS causes mitochondrial dysfunction, triggering apoptosis by promoting the translocation of AIF to the nucleus from the mitochondria. The neuroprotective potential of Polyscias guilfoylei has not yet been reported. Therefore, in this study, the ethanol extract of Polyscias guilfoylei (EEPG) was examined for its protective effect against oxidative cell damage caused by glutamate in neuronal cells. EEPG treatment increased the viability of HT22 cells exposed to high concentrations of glutamate. Cellular Ca2+ ion influx and ROS generation decreased with EEPG treatment in glutamate-treated HT22 cells. EEPG treatment inhibited MAPK activation and AIF nuclear translocation. In an in vivo study, EEPG attenuated brain cell death in an ischemic brain injury rat model. This study demonstrates the potential therapeutic effects of Polyscias guilfoylei in the treatment of ischemic brain injury.

Exosomes from hypoxic pretreated ADSCs attenuate ultraviolet light-induced skin injury via GLRX5 delivery and ferroptosis inhibition

Accumulation studies have found that adipose-derived stem cell (ADSC) exosomes have anti-oxidant and anti-inflammatory characteristics. The current study verified their therapeutic potential to elucidate mechanisms of ADSC exosome actions in ultraviolet B (UVB) light-induced skin injury. Exosomes were isolated from ADSCs and hypoxic pretreated ADSCs. Next-generation sequencing (NGS) was applied to characterize differential mRNA expression. A UV-induced mice skin injury model was generated to investigate therapeutic effects regarding the exosomes via immunofluorescence and ELISA analysis. Regulatory mechanisms were illustrated using luciferase report analysis and in vitro experiments. The results demonstrated that exosomes from hypoxic pretreated ADSCs (HExos) inhibited UVB light-induced vascular injury by reversing reactive oxygen species, inflammatory factor expression and excessive collagen degradation. NGS showed that HExos inhibits UV-induced skin damage via GLRX5 delivery, while GLRX5 downregulation inhibited the therapeutic effect of HExos on UV-induced skin damage. GLRX5 upregulation increased the protective Exo effect on UV-induced skin and EPC damage by inhibiting ferroptosis, inflammatory cytokine expression and excessive collagen degradation. Therefore, the data indicate that HExos attenuate UV light-induced skin injury via GLRX5 delivery and ferroptosis inhibition.

Photoprotective effects of Sargassum thunbergii on ultraviolet B-induced mouse L929 fibroblasts and zebrafish

BACKGROUND

Chronic exposure to ultraviolet B (UVB) causes a series of adverse skin reactions, such as erythema, sunburn, photoaging, and cancer, by altering signaling pathways related to inflammation, oxidative stress, and DNA damage. Marine algae have abundant amounts and varieties of bioactive compounds that possess antioxidant and anti-inflammatory properties. Thus, the objective of this study was to investigate the photoprotective effects of an ethanol extract of Sargassum thunbergii.

METHODS

Sargassum thunbergii phenolic-rich extract (STPE) was prepared, and its activity against UVB damage was evaluated using L929 fibroblast cells and zebrafish. STPE was extracted and purified by 40% ethanol and macroporous resin XDA-7. Reactive oxygen species (ROS) and antioxidant markers, such as superoxide dismutase (SOD), catalase (CAT) activities, and malondialdehyde (MDA) content were analyzed. The effect of STPE on UVB-induced inflammation was determined by inflammatory cytokine gene and protein expression. The expression of signaling molecules in the Nuclear Factor KappaB (NF-κB) pathway was determined by western blotting. DNA condensation was analyzed and visualized by Hoechst 33342 staining. In vivo evaluation was performed by tail fin area and ROS measurement using the zebrafish model.

RESULTS

The total polyphenol content of STPE was 72%. STPE reduced ROS content in L929 cells, improved SOD and CAT activities, and significantly reduced MDA content, thereby effectively alleviating UVB radiation-induced oxidative damage. STPE inhibited the mRNA and protein expression of TNF-α, IL-6, and IL-1α. STPE reversed DNA condensation at concentrations of 20 and 40 μg/mL compared with the UVB control. Moreover, STPE inhibited NF-κB signaling pathway activation and alleviated DNA agglutination in L929 cells after UVB irradiation. Additionally, 1.67 μg/mL STPE significantly increased the tail fin area in zebrafish, and 0.8-1.6 μg/mL STPE effectively eliminated excessive ROS after UVB radiation.

CONCLUSIONS

STPE inhibited UVB-induced oxidative stress, inflammatory cytokine expression, and DNA condensation via the downregulation of the NF-κB signaling pathway, suggesting that it prevents UVB-induced photodamage, and has potential for clinical development for skin disease treatment.

Health Benefits of Avicularin in the Medicine Against Cancerous Disorders and other Complications: Biological Importance, Therapeutic Benefit and Analytical Aspects

Background:

Herbal drugs and their derived phytochemicals have been used in medicine for the preparation of different types of pharmaceutical products. Pure phytochemicals including flavonoids, alkaloids and terpenoids have been used in medicine for the treatment of different types of human disorders including cancerous disorders. Flavonoids have been well known in medicine for their anti-viral, anti-bacterial, anti-inflammatory, anti-diabetic, anti-cancer, anti-aging and cardioprotective potential. Avicularin, also called quercetin-3-α-l-arabino furanoside, is a pure flavonoid, a class of phytochemicals, found to be present in Lindera erythrocarpa and Lespedeza cuneata. Avicularin has been well known in medicine for its anti-cancer properties.

Methods:

In the present work, scientific data of avicularin have been collected from different databases such as Google, PubMed, Science Direct, Google Scholar and Scopus and summarized with reference to medicinal importance, pharmacological activities and analytical aspects of avicularin. The present review summarized the health beneficial properties of avicularin in medicine through data analysis of various scientific research works. Further analytical progress in medicine for the qualitative and quantitative analysis of avicularin in medicine has been also discussed in the present work.

Results:

Scientific data analysis of different literature work revealed the biological importance of flavonoid class of phytochemical ‘avicularin’ in medicine. Scientific data analysis revealed that avicularin was found to be present in the Lindera erythrocarpa, Lespedeza cuneata, Rhododendron schlipenbachii and Psidium guajava. Avicularin has been well known in medicine for its anti-inflammatory, anti-allergic, anti-oxidant, anti-tumor and hepatoprotective activities. Avicularin protects cardiomyocytes and hepatocytes against oxidative stress-induced apoptosis and induces cytotoxicity in cancer lines and tumor tissues. Avicularin has positive influence on human hepatocellular carcinoma and inhibits intracellular lipid accumulation. The role of avicularin in rheumatoid arthritis has been also established with its underlying molecular mechanisms in the scientific work. Recent interest in avicularin has focused on pharmacological investigations for its anti-cancer activity in the medicine.

Conclusion:

The present work signified the biological importance of avicularin in medicine through its medicinal uses, pharmacological activities and analytical aspects in the biological system.

Comparative Study of Three Raspberry Cultivar (Rubus idaeus L.) Leaves Metabolites: Metabolome Profiling and Antioxidant Activities

Raspberry (Rubus idaeus L.), known as one of the famous healthy fruits an d are consumed fresh or processed products all over the world. The antioxidation activity of raspberry fruits as well as leaves have been widely investigated. To better understand the metabolite accumulation mechanisms and to develop different functional cultivars, we performed a non-targeted metabolomics analysis using LC-MS/MS to investigate the contents of existing components from three raspberry cultivars, Autumn Britten, Autumn Bliss, and Red Autumn leaves, respectively. The results show multiple differentially accumulated metabolites among three cultivars, especially for the lipids (α-linolenic acid and eicosatetraenoic acid), amino acids and their derivatives (L-cysteine, Phenylalanine), flavonoids (Kaempferol 3-O-rhamnoside-7-O-glucoside, Quercetin 3-glucoside), and vitamins (Biotin, Thiamine, Vitamin K2), etc. The in vitro cellular antioxidant activities of three raspberry cultivars leaves ethanol extracts (RLEE) were also characterized. Through comparison the superoxide dismutase (SOD), glutathione (GSH), catalase (CAT), and reactive oxygen species (ROS) levels before or after RLEE protection of L929 fibroblast cells upon excessive UVB exposure, we evaluated the antioxidation potentials for all three cultivar RLEEs. It turns out the raspberry Autumn Britten leaf extract holds the greatest potential for protecting the L929 fibroblast cells from UVB induced damage. Our study provides theoretical support for screening of active metabolites from three raspberry cultivars leaves, spanning metabolites’ accumulation to cell damage protection, which could be used to refine bioactivity assessment for different raspberry cultivars suitable for antioxidant products extraction.

The phenolic acids from Oplopanax elatus Nakai stems and their potential photo-damage prevention activity

25 phenolic acids, including four new isolates, eurylophenosides A-D (1-4) and 21 known ones (5-25) were isolated and identified from the stems of Oplopanax elatus Nakai. Among the known compounds 5-9, 11-13, 16, 18-25 were isolated from the genus for the first time; 17 was first obtained from the plant; and the NMR data of 22 was reported here first. Meanwhile, the UVB-induced photodamage model of HaCaT cells was used to study the prevent-photodamage abilities of compounds 1-2, 4-8, 11-13 and 15-25 with a nontoxic concentration at 50 μM. Moreover, a dose-dependent experiment was conducted for active compounds at the concentration of 10, 25, and 50 µM, respectively. Consequently, pretreatment with compounds 1, 16, 17, 19, 20, 22, 24 and 25 could suppress the cell viability decreasing induced by UVB irradiation in a concentration-dependent manner. These results indicated that phenolic acids were one kind of material basis with prevent-photodamage activity of O. elatus.

Antioxidant Properties of Plant-Derived Phenolic Compounds and Their Effect on Skin Fibroblast Cells

Plants are rich sources of a diverse range of chemicals, many of which have significant metabolic activity. One large group of secondary compounds are the phenolics, which act as inter alia potent reactive oxygen scavengers in cells, including fibroblasts. These common dermis residue cells play a crucial role in the production of extracellular matrix components, such as collagen, and maintaining the integrity of connective tissue. Chronic wounds or skin exposure to UV-irradiation disrupt fibroblast function by the generation of reactive oxygen species, which may damage cell components and modify various signaling pathways. The resulting imbalance may be reversed by the antioxidant activity of plant-derived phenolic compounds. This paper reviews the current state of knowledge on the impact of phenolics on fibroblast functionality under oxidative stress conditions. It examines a range of compounds in extracts from various species, as well as single specific plant-derived compounds. Phenolics are a good candidate for eliminating the causes of skin damage including wounds and aging and acting as skin care agents.

Photochemoprotective Potential of the Ethyl Acetate Fraction from Eugenia hiemalis Leaves and Its 2,6-Di-O-galloylarbutin Isolate Against UVB-Induced Photodamage

Intense and constant exposure to UVB radiation can lead to inflammation and oxidative stress, which are associated with many cutaneous disorders, including photoaging and skin cancer. Antioxidant plant materials that are rich in polyphenols, such as the ethyl acetate fraction (EAF) from Eugenia hiemalis leaves, and phenolic compounds represent a promising approach to protect the skin against UVB-induced damage. The present study evaluated the photochemoprotective potential of the EAF and its 2,6-di-O-galloylarbutin (1) isolate. The EAF and the phenolic antioxidant (1) reduced UVB-induced L929 fibroblast death. The EAF prevented UVB-induced damage in fibroblasts by inhibiting the intracellular production of reactive oxygen species and lipid peroxidation, especially in pretreated cells. Topical treatment with an emulsion with 1% EAF prevented/attenuated UVB-induced inflammation and oxidative stress in the skin in hairless mice by controlling the increase in myeloperoxidase activity, reducing superoxide anion production, maintaining radical-scavenging ability and ferric reducing power, and controlling the depletion of reduced glutathione and catalase levels. The EAF also inhibited the increase in epidermal thickness, mast cell infiltration, the number of sunburn cells and collagen fiber destruction that were triggered by UVB. The in vitro and in vivo results indicated that the EAF is a bioactive agent that is able to protect the skin against the harmful effects of UVB.

2-acetylphenothiazine protects L929 fibroblasts against UVB-induced oxidative damage

Ultraviolet B (UVB) light corresponds to 5% of ultraviolet radiation. It is more genotoxic and mutagenic than UVA and causes direct and indirect cellular damage through the generation of reactive oxygen species (ROS). Even after radiation, ROS generation may continue through activation of the nicotinamide adenine dinucleotide phosphate (NADPH) oxidase (NOX) enzyme. Long-term exposure can progress to premature skin aging and photocarcinogenesis. To prevent damage that is caused by UVB radiation, several studies have focused on the topical administration of compounds that have antioxidant properties. 2-Acetylphenothiazine (ML171) is a potent and selective inhibitor of NOX1. The present study investigated the antioxidant potential and photoprotective ability of ML171 in UVB-irradiated L929 fibroblasts. ML171 had considerable antioxidant activity in both the DPPH^• and xanthine/luminol/xanthine oxidase assays. ML171 did not induce cytotoxicity in L929 fibroblasts and increased the viability of UVB-irradiated cells. ML171 also inhibited ROS production, the enzymatic activity of NOX, depolarization of the mitochondrial membrane, and DNA damage. Additionally, ML171 protected cell membrane integrity and induced fibroblast migration. These results suggest that the incorporation of ML171 in topical administration systems may be a promising strategy to mitigate UVB-induced oxidative damage in L929 fibroblasts.

Photoprotective Activity of Buddleja cordata Cell Culture Methanolic Extract on UVB-irradiated 3T3-Swiss Albino Fibroblasts

The research on compounds exhibiting photoprotection against ultraviolet radiation (UVR) is a matter of increasing interest. The methanolic extract of a cell culture of Buddleja cordata has potential photoprotective effects as these cells produce phenolic secondary metabolites (SMs). These metabolites are attributed with biological activities capable of counteracting the harmful effects caused by UVR on skin. In the present work, the methanolic extract (310–2500 µg/mL) of B. cordata cell culture showed a photoprotective effect on UVB-irradiated 3T3-Swiss albino fibroblasts with a significant increase in cell viability. The greatest photoprotective effect (75%) of the extract was observed at 2500 µg/mL, which was statistically comparable with that of 250 µg/mL verbascoside, used as positive control. In addition, concentrations of the extract higher than 2500 µg/mL resulted in decreased cell viability (≤83%) after 24 h of exposure. Phytochemical analysis of the extract allowed us to determine that it was characterized by high concentrations of total phenol and total phenolic acid contents (138 ± 4.7 mg gallic acid equivalents and 44.01 ± 1.33 mg verbascoside equivalents per gram of extract, respectively) as well as absorption of UV light (first and second bands peaking at 294 and 330 nm, respectively). Some phenylethanoid glycosides were identified from the extract.

Nectandra cuspidata fraction and the isolated polyphenols protect fibroblasts and hairless mice skin from UVB-induced inflammation and oxidative stress

Excessive exposure to UVB radiation can lead to oxidative and inflammatory damage that compromises the cutaneous integrity. The application on the skin of photochemoprotective products is considered a relevant approach for the prevention of oxidative damage. In this study the in vitro and in vivo photochemoprotective effects of antioxidant plant materials obtained from the leaves of Nectandra cuspidata Nees following UVB irradiation were evaluated. The cytoprotective effect, reactive oxygen species (ROS) production and lipid peroxidation (LPO) were assessed in L-929 fibroblasts treated with the ethyl acetate fraction (EAF) or isolated compounds (epicatechin, isovitexin and vitexin) before or after irradiation with UVB (500 mJ/cm²). EAF substantially reduced the dead of cells and inhibited the UVB-induced ROS production and LPO in both treatments, compared with the irradiated untreated fibroblasts, presenting effects similar or better than pure compounds. The in vivo photochemoprotective effects of a topical emulsion containing 1% EAF (F2) were evaluated in hairless mice exposed to UVB. F2 improved all evaluated parameters in the skin of animals, inhibited ROS production, increased antioxidant defenses by decreasing reduced glutathione (GSH) and catalase depletion, reduced the activities of metalloproteinases (MMP-2 and MMP-9) and myeloperoxidase, decreased epidermal thickness and skin edema, and inhibited the appearance of sunburn cells as well as the recruitment of neutrophils and mast cell inflammatory infiltrates. These findings show that EAF presents high photochemoprotective effects, and that a topical formulation containing it may have potential for skin care.

The Bioprotective Effects of Polyphenols on Metabolic Syndrome against Oxidative Stress: Evidences and Perspectives

Polyphenols are the general designation of various kinds of phytochemicals, mainly classified as flavonoids and nonflavonoids. Polyphenolic compounds have been confirmed to exhibit numerous bioactivities and potential health benefits both in vivo and in vitro. Dietary polyphenols have been shown to significantly alleviate several manifestations of metabolic syndrome, namely, central obesity, hypertension, dyslipidemia, and high blood sugar. This review is aimed at discussing the bioprotective effects and related molecular mechanisms of polyphenols, mainly by increasing antioxidant capacity or oxygen scavenging capacity. Polyphenols can exert their antioxidative activity by balancing the organic oxidoreductase enzyme system, regulating antioxidant responsive signaling pathways, and restoring mitochondrial function. These data are helpful for providing new insights into the potential biological effects of polyphenolic compounds and the development of future antioxidant therapeutics.

Nrf2 Overexpression for the Protective Effect of Skin-Derived Precursors against UV-Induced Damage: Evidence from a Three-Dimensional Skin Model

Background

Skin photodamage is associated with ultraviolet- (UV-) induced reactive oxygen species (ROS) overproduction and nuclear factor erythroid 2-related factor 2 (Nrf2) inactivation. In our previous study, skin-derived precursors (SKPs) were shown to ameliorate a UV-induced damage in mice, probably through Nrf2 activation and ROS scavenging.

Objective

To clarify the mechanism underlying the photoprotective effect of SKPs against UV-induced damage in a three-dimensional (3D) skin model.

Methods

The Nrf2 gene in SKPs was modified using lentiviral infection, and 3D skin models were reconstructed with keratinocytes and fibroblasts on the basis of type I collagen. Subsequently, these models were divided into the following six groups: normal, model, overexpressed, control, silenced, and negative control groups. Prior to irradiation, respective SKPs were injected into the last four groups. Next, all groups except the normal group were exposed to UVA+UVB. Lastly, the pathological and molecular-biological techniques were employed to determine the parameters. Additionally, LY294002, a PI3K inhibitor, was used to investigate the roles of PI3K/Akt and Nrf2/hemeoxygenase-1 (HO-1) in SKP photoprotection.

Results

Normal 3D skin models appeared as milky-white analogs with a clear, well-arranged histological structure. After the skin was exposed to irradiation, it exhibited cell swelling and a disorganized structure and developed nuclear condensation with numerous apoptotic cells. The expressions of cellular protective genes and Nrf2/HO-1/PI3K/Akt proteins remarkably decreased, which were accompanied by increased oxidative stress and decreased antioxidants (P < 0.05). However, these phenomena were reversed by nrf2-overexpressing SKPs. The 3D skin in the overexpressed group showed mild swelling, neatly arranged cells, and few apoptotic cells. Cellular protective genes and Nrf2/HO-1/PI3K/Akt proteins were highly expressed, and the oxidative biomarkers were remarkably ameliorated (P < 0.05). Nevertheless, the expression of these proteins decreased after LY294002 pretreatment regardless of SKP treatment or not. Meanwhile, there were increases in both UV-induced apoptotic cells and ROS level accompanied with SOD and GPX decrease in the presence of LY294002.

Conclusions

Evidence from the 3D skin model demonstrates that the protection of SKPs against UV-mediated damage is primarily via the PI3K/Akt-mediated activation of the Nrf2/HO-1 pathway, indicating that SKPs may be a promising candidate for the treatment of photodermatoses.

ATRA protects skin fibroblasts against UV‑induced oxidative damage through inhibition of E3 ligase Hrd1

All-trans retinoic acid (ATRA) can protect fibroblasts against ultraviolet (UV)-induced oxidative damage, however, its underlying molecular mechanism is still unclear. The present study aimed to investigate the role of 3-hydroxy-3-methylglutaryl reductase degradation (Hrd1) in the protective effect of ATRA on human skin fibroblasts exposed to UV. The expression of Hrd1 in human or mice skin was assessed by immunohistochemistry (IHC) staining and western blot analysis. Hrd1 siRNA (si-Hrd1) and Hrd1 recombinant adenoviruses (Ad-Hrd1) were used to downregulate and upregulate Hrd1 expression in fibroblasts, respectively. The interaction between Hrd1 and NF-E2-related factor 2 (Nrf2) was assessed by co-immunoprecipitation (co-IP) and immunofluorescence analysis. The results revealed that Hrd1 expression was increased but Nrf2 expression was decreased in UV-exposed human skin fibroblasts. In addition, ATRA could reverse the increase of Hrd1 expression induced by UV radiation in vivo and in vitro. ATRA or knockdown of Hrd1 could increase Nrf2 expression in fibroblasts exposed to UV radiation, and Hrd1 could directly interact with Nrf2 in skin fibroblasts. Notably, overexpression of Hrd1 abolished the protective effect of ATRA on the UV-induced decrease of Nrf2 expression, the production of reactive oxygen species (ROS) and the decrease of cell viability. In conclusion, the present data demonstrated that ATRA protected skin fibroblasts against UV-induced oxidative damage through inhibition of E3 ligase Hrd1.

Dihydrocaffeic Acid Prevents UVB-Induced Oxidative Stress Leading to the Inhibition of Apoptosis and MMP-1 Expression via p38 Signaling Pathway

Chronic UVB exposure promotes oxidative stress, directly causes molecular damage, and induces aging-related signal transduction, leading to skin photoaging. Dihydrocaffeic acid (DHCA) is a phenolic compound with potential antioxidant capacity and is thus a promising compound for the prevention of UVB-induced skin photodamage. The aim of this study was to evaluate the antioxidant and protective effect of DHCA against oxidative stress, apoptosis, and matrix metalloproteinase (MMP) expression via the mitogen-activated protein kinase (MAPK) signaling pathway on L929 fibroblasts irradiated with UVB. DHCA exhibited high antioxidant capacity on 2,2-diphenyl-1-picrylhydrazyl (DPPH^•), 2,2-azinobis-3-ethylbenzothiazoline-6-sulphonic acid (ABTS^•+), and xanthine/luminol/xanthine oxidase (XOD) assays and reduced UVB-induced cell death in the neutral red assay. DHCA also modulated oxidative stress by decreasing intracellular reactive oxygen species (ROS) and extracellular hydrogen peroxide (H₂O₂) production, enhancing catalase (CAT) and superoxide dismutase (SOD) activities and reduced glutathione (GSH) levels. Hence, cellular damage was attenuated by DHCA, including lipid peroxidation, apoptosis/necrosis and its markers (loss of mitochondria membrane potential, DNA condensation, and cleaved caspase 9 expression), and MMP-1 expression. Furthermore, DHCA reduced the phosphorylation of MAPK p38. These findings suggest that DHCA can be used in the development of skin care products to prevent UVB-induced skin damage.