Quercetin Prevents LPS-Induced Oxidative Stress and Inflammation by Modulating NOX2/ROS/NF-kB in Lung Epithelial Cells

Oxidative stress caused by the production of reactive oxygen species (ROS) plays a major role in inflammatory processes. We hypothesized that modulation of ROS via quercetin may protect against oxidative stress and inflammation. Thus, this study aimed to investigate the effects of quercetin on oxidative stress and inflammation in lung epithelial A549 cells. The lipopolysaccharide (LPS)-induced elevation of intracellular ROS levels was reduced after quercetin treatment, which also almost completely abolished the mRNA and protein expression of nicotinamide adenine dinucleotide phosphate oxidase 2 (NOX2) induced by LPS stimulation. In addition, quercetin suppressed the nuclear translocation of nuclear factor kappa B (NF-κB) and reduced levels of inflammatory cytokine tumor necrosis factor (TNF)-α, interleukin (IL)-1, and IL-6, which had increased significantly after LPS exposure. Our data demonstrated that quercetin decreased ROS-induced oxidative stress and inflammation by suppressing NOX2 production.     

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.     

Inhibition of UVB-mediated oxidative stress and markers of photoaging in immortalized HaCaT keratinocytes by pomegranate polyphenol extract POMx

In recent years there has been an increase in use of botanicals with antioxidant properties as skin photoprotective agents. Pomegranate (Punica granatum L.) fruit possesses strong antioxidant and antiinflammatory properties. Recently, we have shown that pomegranate-derived products rich in anthocyanidins and ellagitannins inhibit UVB-mediated activation of nuclear factor kappa B and modulate UVA-mediated cell proliferation pathways in normal human epidermal keratinocytes. In this study, we evaluated the effect of polyphenol-rich pomegranate fruit extract (POMx) on UVB-induced oxidative stress and photoaging in human immortalized HaCaT keratinocytes. Our data show that pretreatment of HaCaT cells with POMx (10-40 microg mL(-1)) inhibited UVB (15-30 mJ cm(-2))-mediated (1) decrease in cell viability, (2) decrease in intracellular glutathione content and (3) increase in lipid peroxidation. Employing immunoblot analysis we found that pretreatment of HaCaT cells with POMx inhibited UVB-induced (1) upregulation of MMP-1, -2, -7 and -9, (2) decrease in TIMP-1, (3) phosphorylation of MAPKs and (iv) phosphorylation of c-jun, whereas no effect was observed on UVB-induced c-fos protein levels. These results suggest that POMx protects HaCaT cells against UVB-induced oxidative stress and markers of photoaging and could be a useful supplement in skin care products.     

Protective Effect of Djulis (Chenopodium formosanum) Extract against UV- and AGEs-Induced Skin Aging via Alleviating Oxidative Stress and Collagen Degradation

Skin aging is a complex process involving photoaging and glycation stress, which share some fundamental pathways and have common mediators. They can cause skin damage and collagen degradation by inducing oxidative stress and the accumulation of reactive oxygen species (ROS). Chenopodium formosanum (CF), also known as Djulis, is a traditional cereal in Taiwan. This study investigated the protection mechanisms of CF extract against ultraviolet (UV) radiation and advanced glycation end products (AGEs)-induced stress. The results indicated that CF extract had strong antioxidant and free radical scavenging effects. It could reduce UV-induced intracellular ROS generation and initiate the antioxidant defense system by activating the nuclear factor erythroid 2-related factor 2 (Nrf2)/heme oxygenase-1 (HO-1) signaling pathway in human skin fibroblasts. CF extract modulated mitogen-activated protein kinase (MAPK) and transformed growth factor-beta (TGF-β) signaling pathways to alleviate oxidative stress-induced skin aging. Moreover, the results revealed that CF extract not only promoted collagen synthesis but also improved aging-induced collagen degradation. CF extract attenuated AGEs-induced ROS production and the upregulation of receptor for AGEs (RAGE). The overall results suggest that CF extract provides an effective anti-aging strategy by preventing skin damage from oxidative stress and collagen loss with potent antioxidant, anti-photoaging, and antiglycation activities.     

A Peptide YGDEY from Tilapia Gelatin Hydrolysates Inhibits UVB‐mediated Skin Photoaging by Regulating MMP‐1 and MMP‐9 Expression in HaCaT Cells

In this study, we investigated the protective effects of a peptide (YGDEY, Tyr‐Gly‐Asp‐Glu‐Tyr) isolated from tilapia skin gelatin hydrolysates (TGHs), against UVB‐induced photoaging in human keratinocytes (HaCaT) cells. Results showed that YGDEY significantly decreased levels of intracellular reactive oxygen species (ROS), increased antioxidant factors (Superoxide Dismutase, SOD and Glutathione, GSH) expression and maintained balance between GSH and GSSG in HaCaT cells. Comet assay shows that YGDEY can protect DNA from oxidative damage. Furthermore, it significantly inhibited MMP‐1 (collagenase) and MMP‐9 (gelatinase) expression and increased Type I procollagen production. In addition, the molecular docking study showed that YGDEY may form active sites with MMP‐1 and MMP‐9. Moreover, Western blot analysis was utilized to measure the protein levels of UVB‐induced mitogen‐activated protein kinase (MAPK) and nuclear factor‐kappa B (NF‐κB) signaling pathways. Therefore, these results suggested that YGDEY has a therapeutic effectiveness in prevention of UVB‐induced cellular damage, and it is a candidate worthy of being developed as a potential natural antioxidant and food additive.     

Bioactive Compounds Extracted from Ecklonia cava by Using Enzymatic Hydrolysis Protects High Glucose-Induced Damage in INS-1 Pancreatic β-Cells

Pancreatic ??-cells are very sensitive to oxidative stress and this might play an important role in ??-cell death in diabetes. In the present study, we investigated whether the brown alga Ecklonia cava has protective effects against high glucose-induced damage in INS-1 pancreatic ??-cells. For that purpose, we prepared an enzymatic hydrolysate from E. cava (EHE) by using the carbohydrase, Celluclast. High-glucose (30?mM) treatment induced glucotoxicity, whereas EHE prevented cells from high glucose-induced damage then restoring cell viability was significantly increased. Furthermore, lipid peroxidation, intracellular reactive oxygen species (ROS) and nitric oxide (NO) were overproduced as the result of the treatment by high glucose; however, these lipid peroxidation, ROS and NO generations were effectively inhibited by addition of EHE in a dose-dependent manner. Moreover, EHE treatment increased activities of antioxidant enzymes including catalase (CAT), superoxide dismutase (SOD), and glutathione peroxidase (GSH-px) in high glucose pretreated INS-1 pancreatic ??-cells. EHE slightly reduced the expression of pro-apoptotic protein Bax induced by high glucose but increased the expression of Bcl-2, an anti-apoptotic protein. These findings indicate that EHE might be used as potential nutraceutical agent which will protect the glucotoxicity caused by hyperglycemia-induced oxidative stress associated with diabetes.     

Gomisin M2 Ameliorates Atopic Dermatitis-like Skin Lesions via Inhibition of STAT1 and NF-κB Activation in 2,4-Dinitrochlorobenzene/Dermatophagoides farinae Extract-Induced BALB/c Mice

The extracts of Schisandra chinensis (Turcz.) Baill. (Schisandraceae) have various therapeutic effects, including inflammation and allergy. In this study, gomisin M2 (GM2) was isolated from S. chinensis and its beneficial effects were assessed against atopic dermatitis (AD). We evaluated the therapeutic effects of GM2 on 2,4-dinitrochlorobenzene (DNCB) and Dermatophagoides farinae extract (DFE)-induced AD-like skin lesions with BALB/c mice ears and within the tumor necrosis factor (TNF)-α and interferon (IFN)-γ-stimulated keratinocytes. The oral administration of GM2 resulted in reduced epidermal and dermal thickness, infiltration of tissue eosinophils, mast cells, and helper T cells in AD-like lesions. GM2 suppressed the expression of IL-1β, IL-4, IL-5, IL-6, IL-12a, and TSLP in ear tissue and the expression of IFN-γ, IL-4, and IL-17A in auricular lymph nodes. GM2 also inhibited STAT1 and NF-κB phosphorylation in DNCB/DFE-induced AD-like lesions. The oral administration of GM2 reduced levels of IgE (DFE-specific and total) and IgG2a in the mice sera, as well as protein levels of IL-4, IL-6, and TSLP in ear tissues. In TNF-α/IFN-γ-stimulated keratinocytes, GM2 significantly inhibited IL-1β, IL-6, CXCL8, and CCL22 through the suppression of STAT1 phosphorylation and the nuclear translocation of NF-κB. Taken together, these results indicate that GM2 is a biologically active compound that exhibits inhibitory effects on skin inflammation and suggests that GM2 might serve as a remedy in inflammatory skin diseases, specifically on AD.     

Kushenol C Prevents Tert-Butyl Hydroperoxide and Acetaminophen-Induced Liver Injury

Sophora flavescens, also known as Kushen, has traditionally been used as a herbal medicine. In the present study we evaluated the ameliorative effects of kushenol C (KC) from S. flavescens against tBHP (tert-Butyl hydroperoxide)-induced oxidative stress in hepatocellular carcinoma (HEPG2) cells and acetaminophen (APAP)-induced hepatotoxicity in mice. KC pretreatment protected the HEPG2 cells against oxidative stress by reducing cell death, apoptosis and reactive oxygen species (ROS) generation. KC pretreatment also upregulated pro-caspase 3 and GSH (glutathione) as well as expression of 8-Oxoguanine DNA Glycosylase (OGG1) in the HEPG2 cells. The mechanism of action was partly related by KC’s activation of Akt (Protein kinase B (PKB)) and Nrf2 (Nuclear factor (erythroid-derived 2)-like 2) in the HepG2 cells. In in vivo investigations, coadministration of mice with KC and APAP significantly attenuated APAP-induced hepatotoxicity and liver damage, as the serum enzymatic activity of aspartate aminotransferase and alanine aminotransferase, as well as liver lipid peroxidation and cleaved caspase 3 expression, were reduced in APAP-treated mice. Coadministration with KC also up-regulated antioxidant enzyme expression and prevented the production of proinflammatory mediators in APAP-treated mice. Taken together, these results showed that KC treatment has potential as a therapeutic agent against liver injury through the suppression of oxidative stress.     

Phloroglucinol attenuates ultraviolet B radiation-induced matrix metalloproteinase-1 production in human keratinocytes via inhibitory actions against mitogen-activated protein kinases and activator protein-1

Excessive amounts of reactive oxygen species (ROS) induced by ultraviolet (UV) radiation cause skin aging via basement membrane/extracellular matrix degradation resulting from the action of matrix metalloproteinases (MMPs). Recently, phloroglucinol (1,3,5-trihydroxybenzene) was demonstrated to attenuate the cell damage induced by oxidative stress by quenching ROS and stimulating antioxidant systems. In the current study, the effect of phloroglucinol on UVB-induced photoaging was investigated in human HaCaT keratinocytes. Phloroglucinol significantly inhibited the UVB-induced (1) upregulation of MMP-1 mRNA, protein and activity; (2) augmentation of intracellular Ca(2+) levels; (3) phosphorylation of mitogen-activated protein kinases (MAPKs); (4) expression of c-Fos and phospho c-Jun; and (5) enhancement of activator protein-1 (AP-1) binding to the MMP-1 promoter. In addition, the knockdown of MAPKs significantly inhibited UVB-induced MMP-1 expression. The results of this study suggest that phloroglucinol may be useful as a photoprotective compound for the skin.     

Photo-Protective and Anti-Inflammatory Effects of Antidesma thwaitesianum Müll. Arg. Fruit Extract against UVB-Induced Keratinocyte Cell Damage

The main cause of most skin cancers is damage from UVB from sunlight, which penetrate the skin surface and induce inflammation. For this reason, this study aims to identify natural products with photo-protection properties and their mode of action by using the UVB-irradiated HaCaT keratinocyte model. Antidesma thwaitesianum fruit extracts at 25, 50, and 100 µg/mL recovered cell viability following UVB exposure in a dose-dependent manner. Cell survival was associated with the reduction in intracellular ROS and NO. In addition, we showed that the pre-treatment with the fruit extract lowered the phosphorylation level of two MAPK-signaling pathways: p38 MAPKs and JNKs. The resulting lower MAPK activation decreased their downstream pro-inflammatory cascade through COX-2 expression and subsequently reduced the PGE₂ proinflammatory mediator level. The photoprotective effects of the fruit extract were correlated with the presence of polyphenolic compounds, including cyanidin, ferulic acid, caffeic acid, vanillic acid, and protocatechuic acid, which have been previously described as antioxidant and anti-inflammation. Together, we demonstrated that the pre-treatment with the fruit extract had photo-protection by inhibiting oxidative stress and subsequently lowered stress-induced MAPK responses. Therefore, this fresh fruit is worthy of investigation to be utilized as a skincare ingredient for preventing UVB-induced skin damage.     

AGSE: A Novel Grape Seed Extract Enriched for PP2A Activating Flavonoids That Combats Oxidative Stress and Promotes Skin Health

Environmental stimuli attack the skin daily resulting in the generation of reactive oxygen species (ROS) and inflammation. One pathway that regulates oxidative stress in skin involves Protein Phosphatase 2A (PP2A), a phosphatase which has been previously linked to Alzheimer’s Disease and aging. Oxidative stress decreases PP2A methylation in normal human dermal fibroblasts (NHDFs). Thus, we hypothesize agents that increase PP2A methylation and activity will promote skin health and combat aging. To discover novel inhibitors of PP2A demethylation activity, we screened a library of 32 natural botanical extracts. We discovered Grape Seed Extract (GSE), which has previously been reported to have several benefits for skin, to be the most potent PP2A demethylating extract. Via several fractionation and extraction steps we developed a novel grape seed extract called Activated Grape Seed Extract (AGSE), which is enriched for PP2A activating flavonoids that increase potency in preventing PP2A demethylation when compared to commercial GSE. We then determined that 1% AGSE and 1% commercial GSE exhibit distinct gene expression profiles when topically applied to a 3D human skin model. To begin to characterize AGSE’s activity, we investigated its antioxidant potential and demonstrate it reduces ROS levels in NHDFs and cell-free assays equal to or better than Vitamin C and E. Moreover, AGSE shows anti-inflammatory properties, dose-dependently inhibiting UVA, UVB and chemical-induced inflammation. These results demonstrate AGSE is a novel, multi-functional extract that modulates methylation levels of PP2A and supports the hypothesis of PP2A as a master regulator for oxidative stress signaling and aging in skin.     

Phenolic Extract from Aralia nudicaulis L. Rhizomes Inhibits Cellular Oxidative Stresses

UV-B and IR-A radiation are important inducers of biological changes in skin involving ROS generation. The overloading of antioxidant defense mechanisms by ROS production could lead to photoaging and photocarcinogenesis processes. Various traditional usages are reported for Aralia nudicaulis L. extracts, including treatment of dermatological disorders. Antioxidant and anti-inflammatory properties have already been reported for other Aralia species possibly due to the presence of phenolic compounds. However, the phenolic composition and the potential activity of A. nudicaulis rhizomes extract against oxidative stress and UV/IR damages have not been investigated. The main aims of this study were to prepare a fraction enriched in phenolic compounds (FEPC) from A. nudicaulis rhizomes, to identify its major phenolic compounds and to assess its potential for protective effects against oxidative stress induced by UV-B, IR-A or inflammation. A quantitative LC-MS study of FEPC shows that chlorogenic, caffeic and protocatechuic acids are the main phenolic compounds present, with concentrations of 15.6%, 15.3% and 4.8% of the total composition, respectively. With a validated analytical method, those compounds were quantified over different stages of the growing period. As for biological potential, first this extract demonstrates antioxidant and anti-inflammatory activities. Furthermore, ROS generation induced by IR-A and UV-B were strongly inhibited by A. nudicaulis extract, suggesting that Aralia nudicaulis L. rhizome extract could protect dermal cells against oxidative stress induced by UV-B and IR-A.     

Exogenous Melatonin Activating Nuclear Factor E2-Related Factor 2 (Nrf2) Pathway via Melatonin Receptor to Reduce Oxidative Stress and Apoptosis in Antler Mesenchymal Stem Cells

Antler growth depends on the proliferation and differentiation of mesenchymal stem cells (MSCs), and this process may be adversely affected by oxidative stress. Melatonin (MLT) has antioxidant functions, but its role in Cervidae remains largely unknown. In this article, flow cytometry, reactive oxygen species (ROS) identification, qPCR, and other methods were used to investigate the protective mechanism of MLT in H₂O₂-induced oxidative stress of antler MSCs. The results showed that MLT significantly increases cell viability by relieving the oxidative stress of antler MSCs. MLT inhibits cell apoptosis by protecting mitochondrial function. We blocked the melatonin receptor with luzindole (Luz) and found that the receptor blockade significantly increases H₂O₂-induced hyperoxide levels and causes significant inhibition of mitochondrial function. MLT treatment activates the nuclear factor E2-related factor 2 (Nrf2) antioxidant signaling pathway, up-regulates the expression of NAD(P)H quinone oxidoreductase 1 (NQO1) and other genes and it could inhibit apoptosis. In contrast, the melatonin receptor blockade down-regulates the expression of Nrf2 pathway-related genes, but significantly up-regulates the expression of apoptotic genes. It was indicated that MLT activates the Nrf2 pathway through the melatonin receptor and alleviates H₂O₂-induced oxidative stress and apoptosis in antler MSCs. This study provides a theoretical basis for further studying the oxidative stress and antioxidant process of antler MSCs and, thereby, increasing antler yields.     

Antioxidant, Anti-inflammatory, and Anti-senescence Activities of a Phlorotannin-Rich Natural Extract from Brown Seaweed Ascophyllum nodosum

Aging at the cellular level is characterized by oxidative stress, inflammation, and cell senescence. An extract of the brown seaweed Ascophyllum nodosum rich in phlorotannins has been studied for its inhibitory activity against oxidative stress, inflammation, and senescence. A. nodosum extract at 0.2?% prevented tBHP-induced reactive oxygen species production (evaluated using the H2DCF-DA test in cytofluorometry) in epithelial cells and LPS-induced TNF-?? and IL-6 release (evaluated using ELISA technique) in macrophages. A. nodosum extract also increased nuclear SIRT1 activity in epithelial cells. Altogether, these beneficial cellular effects of phlorotannin-rich A. nodosum extract could be used in topical therapeutic formulations against aging.     

Resatorvid‐based Pharmacological Antagonism of Cutaneous TLR4 Blocks UV‐induced NF‐κB and AP‐1 Signaling in Keratinocytes and Mouse Skin

Cutaneous exposure to solar ultraviolet (UV) radiation is a major causative factor in skin carcinogenesis, and improved molecular strategies for efficacious chemoprevention of nonmelanoma skin cancer (NMSC) are urgently needed. Toll‐like receptor 4 (TLR4) signaling has been shown to drive skin inflammation, photoimmunosuppression, and chemical carcinogenesis. Here we have examined the feasibility of genetic and pharmacological antagonism targeting cutaneous TLR4 for the suppression of UV‐induced NF‐κB and AP‐1 signaling in keratinocytes and mouse skin. Using immunohistochemical and proteomic microarray analysis of human skin, we demonstrate for the first time that a significant increase in expression of TLR4 occurs in keratinocytes during the progression from normal skin to actinic keratosis, also detectible during further progression to squamous cell carcinoma. Next, we demonstrate that siRNA‐based genetic TLR4 inhibition blocks UV‐induced stress signaling in cultured keratinocytes. Importantly, we observed that resatorvid (TAK‐242), a molecularly targeted clinical TLR4 antagonist, blocks UV‐induced NF‐κB and MAP kinase/AP‐1 activity and cytokine expression (Il‐6, Il‐8, and Il‐10) in cultured keratinocytes and in topically treated murine skin. Taken together, our data reveal that pharmacological TLR4 antagonism can suppress UV‐induced cutaneous signaling, and future experiments will explore the potential of TLR4‐directed strategies for prevention of NMSC.     

Grape Pomace Polyphenols as a Source of Compounds for Management of Oxidative Stress and Inflammation—A Possible Alternative for Non-Steroidal Anti-Inflammatory Drugs?

Flavonoids, stilbenes, lignans, and phenolic acids, classes of polyphenols found in grape pomace (GP), were investigated as an important alternative source for active substances that could be used in the management of oxidative stress and inflammation. The benefic antioxidant and anti-inflammatory actions of GP are presented in the literature, but they are derived from a large variety of experimental in vitro and in vivo settings. In these in vitro works, the decrease in reactive oxygen species, malondialdehyde, and thiobarbituric acid reactive substances levels and the increase in glutathione levels show the antioxidant effects. The inhibition of nuclear factor kappa B and prostaglandin E2 inflammatory pathways and the decrease of some inflammatory markers such as interleukin-8 (IL-8) demonstrate the anti-inflammatory actions of GP polyphenols. The in vivo studies further confirmed the antioxidant (increase in catalase, superoxide dismutase and glutathione peroxidase levels and a stimulation of endothelial nitric oxide synthase -eNOS gene expression) and anti-inflammatory (inhibition of IL-1𝛼, IL-1β, IL-6, interferon-𝛾, TNF-α and C-reactive protein release) activities. Grape pomace as a whole extract, but also different individual polyphenols that are contained in GP can modulate the endogenous pathway responsible in reducing oxidative stress and chronic inflammation. The present review analyzed the effects of GP in oxidative stress and inflammation, suggesting that it could become a valuable therapeutic candidate capable to reduce the aforementioned pathological processes. Grape pomace extract could become an adjuvant treatment in the attempt to reduce the side effects of the classical anti-inflammatory medication like non-steroidal anti-inflammatory drugs (NSAIDs).