Urtica thunbergiana prevents UVB-induced premature skin aging by regulating the transcription factor NFATc1: An in vitro and in vivo study

Antiphotoaging Effects of Damiana (Turnera diffusa) Leaves Extract via Regulation AP-1 and Nrf2/ARE Signaling Pathways

Damiana (Turnera diffusa), of the family Passifloraceae, has been widely studied for its pharmacological effects, especially for antioxidant and antibacterial actions. However, there are limited scientific findings describing its antiphotoaging effects on the skin. In the present study, the underlying molecular mechanisms of the protective effect of Damiana were investigated in keratinocytes (HaCaTs) and normal human dermal fibroblasts (HDFs) subject to UVB irradiation. The mRNA expression of matrix metalloproteinases (MMPs) and procollagen type I was determined by reverse transcription-polymerase chain reaction. The protein expression of antiphotoaging-related signaling molecules in the activator protein-1 (AP-1) and nuclear factor erythroid 2-related factor 2 (NRF2)/antioxidant response element (ARE) pathways was assessed by Western blotting. We observed that Damiana blocked the upregulated production of reactive oxygen species induced in UVB-irradiated HaCaTs and HDFs in a dose-dependent manner. Treatment with Damiana also significantly ameliorated the mRNA expression of MMPs and procollagen type I. In addition, the phosphorylation level of c-Jun and c-Fos was also decreased through the attenuated expression of p-38, p-ERK, and p-JNK after treatment with Damiana. Furthermore, the treatment of cells with Damiana resulted in the inhibition of Smad-7 expression in the TGF-β/Smad pathway and upregulated the expression of the Nrf2/ARE signaling pathway. Hence, the synthesis of procollagen type I, a precursor of collagen I, was promoted. Collectively, these results provide us with the novel insight that Damiana is a potential source of antiphotoaging compounds.

Urtica dioica-Derived Phytochemicals for Pharmacological and Therapeutic Applications

Urtica dioica belongs to the Urticaceae family and is found in many countries around the world. This plant contains a broad range of phytochemicals, such as phenolic compounds, sterols, fatty acids, alkaloids, terpenoids, flavonoids, and lignans, that have been widely reported for their excellent pharmacological activities, including antiviral, antimicrobial, antihelmintic, anticancer, nephroprotective, hepatoprotective, cardioprotective, antiarthritis, antidiabetic, antiendometriosis, antioxidant, anti-inflammatory, and antiaging effects. In this regard, this review highlights fresh insight into the medicinal use, chemical composition, pharmacological properties, and safety profile of U. dioica to guide future works to thoroughly estimate their clinical value.

Attenuation of UV-induced skin photoaging in rats by walnut protein hydrolysates is linked to the modulation of MAPK/AP-1 and TGF-β/Smad signaling pathways

There is growing evidence that prevention of skin photoaging by oral administration of food-derived proteins hydrolysates is intricately linked to its alleviation against oxidative stress through modulation of the signaling pathway. Previously, walnut protein hydrolysates (WPHs) were prepared by enzymatic hydrolysis by our group and exhibited excellent anti-photoaging effect through regulation of extracellular matrix metabolism and the NF-κB signaling pathway. However, its response to oxidative stress and cascade mechanism remain unknown. In the present study, Sprague-Dawley rats were exposed periodically to UV irradiation and orally administered with WPHs to further examine the effects of WPHs on the redox state, MAPK/AP-1 and TGF-β/Smad signaling pathways, type I procollagen synthesis, and histopathological impairments in photoaging skin. Intervention with WPHs for 18 weeks significantly alleviated the photoaging morphology, enhanced the antioxidant components, and downregulated the phosphorylation levels of extracellular signal-regulated kinase (ERK) and C-Jun N-terminal kinase (JNK and p38 proteins) in photoaging tissues, while significant alterations on the gene expression levels of ERK, JNK and p38 were not observed. Meanwhile, WPHs significantly activated the TGF-β/Smad signaling pathway and type I procollagen production. Furthermore, histopathological analysis illustrated that WPHs predominately attenuated epidermal hyperplasia, reduced inflammatory filtration, and promoted the deposition of collagen fibers in photoaging skin. Altogether, the underlying mechanism of WPHs attenuating skin photoaging might lie in the synergistic modulation by increasing the antioxidant capacity, modulating the MAPK/AP-1/MMP-1 and TGF-β/Smad signaling pathways, stimulating the synthesis of type I procollagen, and restoring the impaired architecture structure. Our findings suggest that WPHs are promising agents for preventing skin photoaging.

Crataegus laevigata Suppresses LPS-Induced Oxidative Stress during Inflammatory Response in Human Keratinocytes by Regulating the MAPKs/AP-1, NFκB, and NFAT Signaling Pathways

Crataegus laevigata belongs to the family Rosaceae, which has been widely investigated for pharmacological effects on the circulatory and digestive systems. However, there is limited understanding about its anti-oxidative stress and anti-inflammatory effects on skin. In this study, 70% ethanol C. laevigata berry extract (CLE) was investigated on lipopolysaccharide (LPS)-stimulated keratinocytes. The LPS-induced overproduction of reactive oxygen species (ROS) was suppressed by the treatment with CLE. In response to ROS induction, the overexpression of inflammatory regulating signaling molecules including mitogen-activated protein kinases (MAPK)/activator protein-1 (AP-1), nuclear factor kappa-light-chain-enhancer of activated B cell (NF-κB), and nuclear factor of activated T-cells (NFAT) were reduced in CLE-treated human keratinocytes. Consequently, CLE significantly suppressed the mRNA levels of pro-inflammatory chemokines and interleukins in LPS-stimulated cells. Our results indicated that CLE has protective effects against LPS-induced injury in an in vitro model and is a potential alternative agent for inflammatory treatment.

Zingiber mioga Extract Improves Moisturization and Depigmentation of Skin and Reduces Wrinkle Formation in UVB-Irradiated HRM-2 Hairless Mice

Here, we investigated the effects of Zingiber mioga extracts (FSH-ZM) on the moisturization and depigmentation of skin as well as wrinkle formation in UVB-irradiated HRM-2 hairless mice. The mice were divided into six groups as follows: normal control (NC), UVB-irradiated control (C), positive control 1 (PC1, L-ascorbic acid 200 mg/kg b.w.), positive control 2 (PC2, Arbutin 200 mg/kg b.w.), Z100 (FSH-ZM 100 mg/kg b.w.), and Z200 (FSH-ZM 200 mg/kg b.w.). The experiment spanned a period of 6 weeks. We found that FSH-ZM led to an increase in the expression of hyaluronan synthase 2, fibrillin-1, and elastin mRNAs, and showed improved skin hydration in HRM-2 hairless mice compared to that in the UVB-irradiated control group. Furthermore, FSH-ZM also inhibited the expression of inflammatory cytokines and wrinkle forming factors generated by UVB and reduced the formation of wrinkles in the test group relative to that in the control group by increasing collagen synthesis. Moreover, we found that FSH-ZM decreased the expression of melanogenesis factors, which improved depigmentation in UVB-irradiated hairless mice. These results suggest that Zingiber mioga can potentially be utilized to develop products aimed at improving skin moisturization and depigmentation and reducing wrinkle formation.

Walnut protein hydrolysates, rich with peptide fragments of WSREEQEREE and ADIYTEEAGR ameliorate UV-induced photoaging through inhibition of the NF-κB/MMP-1 signaling pathway in female rats

Skin photoaging is a complicated pathological process, and the imbalance of inflammatory regulation is associated highly with photoaging progression. Previously, prepared walnut protein hydrolysates (WPH), rich with peptide fragments of WSREEQEREE and ADIYTEEAGR demonstrated desirable photoprotection. However, it remains unclear if the photoprotection is mediated by the targeted inhibition of the NF-κB signaling pathway. Herein, we examined the regulation of WPH on inflammatory cytokine expression, and elucidated the modulation of the NF-κB/MMP-1 signaling pathway by WPH in a photoaging SD rat model. WPH significantly reduced the expression level of inflammatory cytokines IL-1β and IL-6, but significantly increased the level of IL-2 (all P < 0.05). Furthermore, WPH dramatically inhibited the activation of the NF-κB signaling pathway by mitigating the phosphorylation of IκB and p-65 proteins in a dose-dependent manner. The histopathological results indicated that WPH predominately attenuated epidermal hyperplasia, reduced the inflammatory filtration, and promoted collagen deposition in the photoaging skin tissue. Furthermore, WPH significantly stimulated the expression of TGF-β and procollagen type I, and inhibited the MMP-1 activities (all P < 0.05). Overall, the underlying mechanism of WPH ameliorating skin photoaging may be attributed to the synergistic modulation via reversing the inflammatory imbalance, suppressing the activation of the NF-κB signal pathway, stimulating procollagen type I synthesis, and inhibiting MMP-1 activities. According to these results, it can be concluded that WPH has the potential as an anti-photoaging agent in functional foods.

Inhibitory Effects of Urtica thunbergiana Ethanol Extract on Atopic Dermatitis-Induced NC/Nga Mice

Atopic dermatitis (AD) is a chronic, inflammatory skin disease that persists or repeatedly recurs in both childhood and adulthood. Urtica thunbergiana (UT) is an aroma herb with little-known pharmacological effects and anti-inflammatory activities against AD. This study investigated the immunomodulatory efficacy of 50% ethanol-extracted UT in necrosis factor-alpha/interferon-gamma (TNF-α/IFN-γ)-stimulated HaCaT cells in vitro and AD-Biostir-induced NC/Nga mice in vivo. The results showed that UT exhibits a dose-dependent increase in scavenged free radicals, reaching 76.0% ± 1.4% of scavenged 1,1-diphenyl-2-picrylhydrazyl at a concentration of 250 µg/mL. In addition, UT significantly downregulated the mRNA expression of the following pro-inflammatory cytokines and chemokines in TNF-α/IFN-γ-stimulated HaCaT cells: interleukin (IL)-6, IL-8, thymus- and activation-regulated chemokine, macrophage-derived chemokine, and regulated on activation normal T expressed and secreted. UT-treated HaCaT cells showed inhibition of the overexpression of chemokine-regulated signaling molecules, such as nuclear factor-kappa B, inhibitor of kappa B (IκBα), signal transducer and activator of transcription 1, and mitogen-activated protein kinases (MAPKs). UT dietary administration in AD-Biostir-induced NC/Nga mice treated and improved AD-like symptoms, such as scales, epidermal thickening, the dermatitis severity score, high trans-epidermal water loss, reduced skin hydration, increased mast cells, elevated serum immunoglobulin E levels, and an enlarged spleen. UT treatment inhibited the expression of phosphorylated forms of MAPKs, nuclear factor of activated T-cells 1, and regulator IκBα. It also upregulated filaggrin (FLG) production. Therefore, UT shows high anti-AD activity both in vitro and in vivo, and can be a useful anti-AD agent.

Protective effects of hawthorn (Crataegus pinnatifida) polyphenol extract against UVB-induced skin damage by modulating the p53 mitochondrial pathway in vitro and in vivo

This study investigated the effect of a hawthorn polyphenol extract (HPE) on ultraviolet B (UVB)-induced damage in HaCaT cells and mice. High-performance liquid chromatography/electrospray ionization tandem mass spectrometry was used to analyze the phenolic composition of HPE. The protective effects of HPE and its main components were compared in HaCaT cells. An enzyme-linked immunosorbent assay was used to detect DNA damage (8-hydroxydeoxyguanosine levels). Flow cytometry and western blotting were used to measure the extent of apoptosis and the levels of apoptosis-related proteins, respectively. Treatment with HPE or its polyphenol components inhibited the UVB-induced damage by removing an excess of reactive oxygen species (ROS), reducing DNA damage and p53 activation, regulating the protein expression of B-cell lymphoma 2 family members toward antiapoptotic ratios, and reducing caspase activation. Similar effects were observed in a UVB-irradiated mouse skin, as detected using terminal deoxynucleotidyl transferase dUTP nick-end labeling, immunohistochemistry, and western blotting assays. These results suggest that HPE can be used as a natural dietary supplement for the prevention and treatment of UVB radiation-induced skin damage. PRACTICAL APPLICATIONS: Hawthorn (Crataegus pinnatifida) shows antioxidant, anti-inflammatory, and lipid-lowering effects. As natural, healthy, and effective additives, HPEs have been widely used in food and health products. The results of this study reveal the molecular mechanisms underlying HPE effects, showing that HPE reverses the effects of UVB irradiation via removal of an excess of ROS and reduction of DNA damage and p53 expression in vitro and in vivo. Consequently, HPE upregulates the expression of antiapoptotic BCL-2 and downregulates that of proapoptotic BAX, thereby reducing the activation of caspase-3/9 and inhibiting apoptosis. These findings suggest that HPE can be used as the base ingredient for antiphotoaging food products. This study provides both theoretical and experimental background for hawthorn deep processing and utilization.

Ultraviolet light-induced gasdermin C expression is mediated via TRPV1/calcium/calcineurin/NFATc1 signaling

Gasdermin (GSDM)‑C is a member of the GSDM gene family and is expressed in the epithelial cells of various tissue types, including skin. GSDMC expression is induced by ultraviolet (UV) irradiation and contributes to UV‑induced matrix metalloproteinase 1 expression in human skin keratinocytes. However, how UV irradiation induces GSDMC expression remains unclear. The present study aimed to investigate the role of transient receptor potential cation channel subfamily V member 1 (TRPV1) and a calcium/calcineurin‑signaling pathway in UV‑induced GSDMC expression in human skin keratinocytes. Suppression of TRPV1 activity by treatment with the TRPV1 antagonists capsazepine and ruthenium red significantly reduced UV‑induced GSDMC expression, whereas direct activation of TRPV1 by capsaicin, a TRPV1 agonist, increased GSDMC expression. The results demonstrated that extracellular calcium and calcineurin activity may be necessary for UV‑induced GSDMC expression in HaCaT cells. In addition, UV‑induced GSDMC expression was either decreased or increased following knockdown or overexpression of nuclear factor of activated T‑cells, cytoplasmic 1 (NFATc1), respectively. These data suggested that TRPV1 may serve an important role in the induction of GSDMC expression by UV and that UV‑induced GSDMC expression may be mediated via a calcium/calcineurin/NFATc1 pathway.

Hawthorn Polyphenol Extract Inhibits UVB-Induced Skin Photoaging by Regulating MMP Expression and Type I Procollagen Production in Mice

Ultraviolet (UV) B radiation can cause skin aging by increasing matrix metalloproteinase (MMP) production and collagen degradation, leading to the formation of wrinkles. This study investigated whether hawthorn polyphenol extract (HPE) protects against UVB-induced skin photoaging using HaCaT human keratinocytes, normal human dermal fibroblasts (HDFs), and mice. Analysis of the phenol composition of HPE by high-performance liquid chromatography-mass spectrometry showed that chlorogenic acid (13.5%), procyanidin B2 (19.2%), and epicatechin (18.8%) collectively accounted for 51.4% of total phenol content and represent the active ingredients of hawthorn fruit. A cell viability assay revealed that HPE treatment promoted cell proliferation in HaCaT cells and HDFs. On the other hand, MMP-1 and type I procollagen production was decreased and increased, respectively, in UVB-exposed cells treated with HPE as compared with those without treatment, as determined by enzyme-linked immunosorbent assay. Hematoxylin and eosin and Weigert staining of dermal tissue specimens from mice demonstrated that HPE also reversed UVB-induced epidermal thickening and dermal damage. The increase in production of reactive oxygen species and decrease in antioxidant enzyme activity as well as the increase in nuclear factor-κB activation and mitogen-activated protein kinase phosphorylation induced by UVB irradiation were reversed by HPE (100 or 300 mg/kg body weight), which also suppressed MMP expression and stimulated the production of type I procollagen in the dorsal skin of UVB-irradiated mice. These results suggest that HPE is a natural product that can prevent UVB radiation-induced skin photoaging.