Tannic acid and quercetin display a therapeutic effect in atopic dermatitis via suppression of angiogenesis and TARC expression in Nc/Nga mice

Discovery of a C-S lyase inhibitor for the prevention of human body malodor formation: tannic acid inhibits the thioalcohol production in Staphylococcus hominis

Human body odor is a result of the bacterial biotransformation of odorless precursor molecules secreted by the underarm sweat glands. In the human axilla, Staphylococcus hominis is the predominant bacterial species responsible for the biotransformation process of the odorless precursor molecule into the malodorous 3M3SH by two enzymes, a dipeptidase and a specific C-S lyase. The current solutions for malodor, such as deodorants and antiperspirants are known to block the apocrine glands or disrupt the skin microbiota. Additionally, these chemicals endanger both the environment and human health, and their long-term use can influence the function of sweat glands. Therefore, there is a need for the development of alternative, environmentally friendly, and natural solutions for the prevention of human body malodor. In this study, a library of secondary metabolites from various plants was screened to inhibit the C-S lyase, which metabolizes the odorless precursor sweat molecules, through molecular docking and molecular dynamics (MD) simulation. In silico studies revealed that tannic acid had the strongest affinity towards C-S lyase and was stably maintained in the binding pocket of the enzyme during 100-ns MD simulation. We found in the in vitro biotransformation assays that 1 mM tannic acid not only exhibited a significant reduction in malodor formation but also had quite low growth inhibition in S. hominis, indicating the minimum inhibitory effect of tannic acid on the skin microflora. This study paved the way for the development of a promising natural C-S lyase inhibitor to eliminate human body odor and can be used as a natural deodorizing molecule after further in vivo analysis.

Development of Olive Oil Containing Phytosomal Nanocomplex for Improving Skin Delivery of Quercetin: Formulation Design Optimization, In Vitro and Ex Vivo Appraisals

The objective of the current work was to fabricate, optimize and assess olive oil/phytosomal nanocarriers to improve quercetin skin delivery. Olive oil/phytosomal nanocarriers, prepared by a solvent evaporation/anti-solvent precipitation technique, were optimized using a Box–Behnken design, and the optimized formulation was appraised for in vitro physicochemical characteristics and stability. The optimized formulation was assessed for skin permeation and histological alterations. The optimized formulation (with an olive oil/PC ratio of 0.166, a QC/PC ratio of 1.95 and a surfactant concentration of 1.6%), and with a particle diameter of 206.7 nm, a zeta potential of −26.3 and an encapsulation efficiency of 85.3%, was selected using a Box–Behnken design. The optimized formulation showed better stability at ambient temperature when compared to refrigerating temperature (4 °C). The optimized formulation showed significantly higher skin permeation of quercetin when compared to an olive-oil/surfactant-free formulation and the control (~1.3-fold and 1.9-fold, respectively). It also showed alteration to skin barriers without remarkable toxicity aspects. Conclusively, this study demonstrated the use of olive oil/phytosomal nanocarriers as potential carriers for quercetin—a natural bioactive agent—to improve its skin delivery.

Molecular Mechanisms of Luteolin Against Atopic Dermatitis Based on Network Pharmacology and in vivo Experimental Validation

PURPOSE

To undercover the underlying mechanisms of luteolin against atopic dermatitis (AD), clinically characterized by recurrent eczematous lesions and intense itching, based on network pharmacology, molecular docking and in vivo experimental validation.

METHODS

TCMSP, STITCH and SwissTargetPrediction databases were utilized to screen the corresponding targets of luteolin. Targets related to AD were collected from DisGeNET, GeneCards and TTD databases. PPI network of intersection targets was constructed through STRING 11.0 database and Cytoscape 3.9.0 software. GO and KEGG enrichment analysis were performed to investigate the critical pathways of luteolin against AD. Further, the therapeutic effects and candidate targets/signaling pathways predicted from network pharmacology analysis were experimentally validated in a mouse model of AD induced by 2, 4-dinitrofluorobenzene (DNFB).

RESULTS

A total of 31 intersection targets were obtained by matching 151 targets of luteolin with 553 targets of AD. Among all, 20 core targets were identified by PPI network topology analysis, including IL-6, TNF, IL-10, VEGFA, IL-4, etc., and molecular docking indicated that luteolin binds strongly to these core targets. KEGG pathway enrichment analysis suggested that the intersected targets were significantly enriched in IL-17 signaling pathway, Th17 cell differentiation, Th1 and Th2 cell differentiation, JAK/STAT signaling pathway, etc. The in vivo experiment validated that luteolin could alleviate AD-like skin symptoms, as evidenced by the lower SCORAD score, the reduced infiltration of mast cells and the recovery of skin barrier function. Furthermore, luteolin restored immune balance by regulating the production of Th1/Th2/Th17-mediated cytokines, which were both the predicted core targets. Moreover, luteolin inhibited the phosphorylation of JAK2 and STAT3 in the lesional skin.

CONCLUSION

Together, the present study systematically clarifies the ameliorative effects and possible molecular mechanisms of luteolin against AD through the combination of network pharmacology and experimental validation, shedding light on the future development and clinical application of luteolin.

Pharmacological effects and mechanisms of tannic acid

In recent years, increasing attention has been paid to the pharmacological efficacy of tannins. Tannic acid (TA), the simplest hydrolysable tannin that has been approved by the FDA as a safe food additive, is one of the most important components of these traditional medicines. Studies have shown that TA displays a wide range of pharmacological activities, such as anti-inflammatory, neuroprotective, antitumor, cardioprotective, and anti-pathogenic effects. Here, we summarize the known pharmacological effects and associated mechanisms of TA. We focus on the effect and mechanism of TA in various animal models of inflammatory disease and organ, brain, and cardiovascular injury. Moreover, we discuss the possible molecular targets and signaling pathways of TA, in addition to the pharmacological effects of TA-based nanoparticles and TA in combination with chemotherapeutic drugs.

Potential Natural Biomolecules Targeting JAK/STAT/SOCS Signaling in the Management of Atopic Dermatitis

Atopic dermatitis (AD) is a chronic inflammatory skin disease caused by the dysregulation of cytokines and other immune mediators. JAK/STAT is a classical signal transduction pathway involved in various biological processes, and its dysregulation contributes to the key aspects of AD pathogenesis. Suppressor of cytokine signaling (SOCS) proteins negatively regulate the immune-related inflammatory responses mediated by the JAK/STAT pathway. JAK/STAT-mediated production of cytokines including IL-4, IL-13, IL-31, and TSLP inhibits the expression of important skin barrier proteins and triggers pruritus in AD. The expression of SOCS proteins regulates the JAK-mediated cytokines and facilitates maintaining the skin barrier disruptions seen in AD. STATs are crucial in dendritic-cell-activated Th2 cell differentiation in the skin, releasing inflammatory cytokines, indicating that AD is a Th2-mediated skin disorder. SOCS proteins aid in balancing Th1/Th2 cells and, moreover, regulate the onset and maintenance of Th2-mediated allergic responses by reducing the Th2 cell activation and differentiation. SOCS proteins play a pivotal role in inflammatory cytokine-signaling events that act via the JAK/STAT pathway. Therapies relying on natural products and derived biomolecules have proven beneficial in AD when compared with the synthetic regimen. In this review, we focused on the available literature on the potential natural-product-derived biomolecules targeting JAK/STAT/SOCS signaling, mainly emphasizing the SOCS family of proteins (SOCS1, SOCS3, and SOCS5) acting as negative regulators in modulating JAK/STAT-mediated responses in AD pathogenesis and other inflammatory disorders.

Keratinocytes: An Enigmatic Factor in Atopic Dermatitis

Atopic dermatitis (AD), characterized by rashes, itching, and pruritus, is a chronic inflammatory condition of the skin with a marked infiltration of inflammatory cells into the lesion. It usually commences in early childhood and coexists with other atopic diseases such as allergic rhinitis, bronchial asthma, allergic conjunctivitis, etc. With a prevalence rate of 1–20% in adults and children worldwide, AD is gradually becoming a major health concern. Immunological aspects have been frequently focused on in the pathogenesis of AD, including the role of the epidermal barrier and the consequent abnormal cytokine expressions. Disrupted epidermal barriers, as well as allergic triggers (food allergy), contact allergens, irritants, microbes, aggravating factors, and ultraviolet light directly initiate the inflammatory response by inducing epidermal keratinocytes, resulting in the abnormal release of various pro-inflammatory mediators, inflammatory cytokines, and chemokines from keratinocytes. In addition, abnormal proteinases, gene mutations, or single nucleotide polymorphisms (SNP) affecting the function of the epidermal barrier can also contribute towards disease pathophysiology. Apart from this, imbalances in cholinergic or adrenergic responses in the epidermis or the role played by immune cells in the epidermis such as Langerhans cells or antigen-presenting cells can also aggravate pathophysiology. The dearth of specific biomarkers for proper diagnosis and the lack of a permanent cure for AD necessitate investigation in this area. In this context, the widespread role played by keratinocytes in the pathogenesis of AD will be reviewed in this article to facilitate the opening up of new avenues of treatment for AD.

Co-Application with Tannic Acid Prevents Transdermal Sensitization to Ovalbumin in Mice

Transdermal sensitization to allergens is of great concern as a sensitization route for food allergies. This skin-mediated invasion and sensitization to allergens is involved in skin barrier breakdown and inflammation, followed by the production of several kinds of cytokines. Cytokines such as thymic stromal lymphopoietin and thymus and activation-regulated chemokine are also involved. In this study, we investigated the suppressive effect of tannic acid (TA) on transdermal sensitization using ovalbumin (OVA), a major egg-white allergen. We also analyzed the mechanisms associated with the inhibitory effects of TA. The results showed that the co-application with TA prevents transdermal sensitization to OVA. As possible mechanisms, its anti-inflammatory and astringent effect on the skin and binding ability with the protein were considered. These results indicate that TA could be applied to cosmetics and lotions, which could suppress the transdermal sensitization to allergens.

Alleviation effects of Rubus coreanus Miquel root extract on skin symptoms and inflammation in chronic atopic dermatitis

Atopic dermatitis (AD) is an inflammatory skin disease characterized by chronic inflammatory dermatitis with immunological manifestations. The aim of this study was to investigate the effects of polyphenol-containing Rubus coreanus Miquel root extract on skin allergy and AD. The protective effects of R. coreanus root ethanol extract against AD were investigated using the human keratinocyte cell line HaCaT, human mast cell line HMC-1, and the 2,4-dinitrochlorobenzene (DNCB)-induced AD-like skin NC/Nga mouse model. Treatment with R. coreanus root ethanol extracts reduced β-hexosaminidase and histamine release from HMC-1 cells stimulated with compound 48/80 compared to treatment with R. coreanus fruit ethanol extract. Furthermore, topical application of R. coreanus root ethanol extract dramatically reduced the severity of skin symptoms and the thickening and swelling of the dorsal skin and ear in DNCB-treated NC/Nga mice. The protein and mRNA expression of several cytokines (IL-4, IL-5, IL-12, IFN-γ, TNF-α, and TARC) and IgE was significantly lowered upon application of the R. coreanus root ethanol extract. The promising candidate for the active ingredient of R. coreanus root polyphenols was revealed to be ellagic acid. These findings clearly indicate that the R. coreanus root polyphenols show strong anti-allergic effects and suppress the symptoms of AD. Therefore, polyphenol-containing R. coreanus root ethanol extract could be a novel therapeutic candidate for the treatment of allergy and AD.

Promising Natural Products in New Drug Design, Development, and Therapy for Skin Disorders: An Overview of Scientific Evidence and Understanding Their Mechanism of Action

The skin is the largest organ in the human body, composed of the epidermis and the dermis. It provides protection and acts as a barrier against external menaces like allergens, chemicals, systemic toxicity, and infectious organisms. Skin disorders like cancer, dermatitis, psoriasis, wounds, skin aging, acne, and skin infection occur frequently and can impact human life. According to a growing body of evidence, several studies have reported that natural products have the potential for treating skin disorders. Building on this information, this review provides brief information about the action of the most important in vitro and in vivo research on the use of ten selected natural products in inflammatory, neoplastic, and infectious skin disorders and their mechanisms that have been reported to date. The related studies and articles were searched from several databases, including PubMed, Google, Google Scholar, and ScienceDirect. Ten natural products that have been reported widely on skin disorders were reviewed in this study, with most showing anti-inflammatory, antioxidant, anti-microbial, and anti-cancer effects as the main therapeutic actions. Overall, most of the natural products reported in this review can reduce and suppress inflammatory markers, like tumor necrosis factor-alpha (TNF-α), scavenge reactive oxygen species (ROS), induce cancer cell death through apoptosis, and prevent bacteria, fungal, and virus infections indicating their potentials. This review also highlighted the challenges and opportunities of natural products in transdermal/topical delivery systems and their safety considerations for skin disorders. Our findings indicated that natural products might be a low-cost, well-tolerated, and safe treatment for skin diseases. However, a larger number of clinical trials are required to validate these findings. Natural products in combination with modern drugs, as well as the development of novel delivery mechanisms, represent a very promising area for future drug discovery of these natural leads against skin disorders.

Bioadhesive metal-phenolic nanoparticles for enhanced NIR imaging-guided locoregional photothermal/antiangiogenic therapy

Locoregional drug delivery has emerged as a promising solution to the problems associated with intravenously administered antitumor agents, such as systemic toxicity and insufficient drug accumulation at tumor sites. Herein, we have developed an adhesive nanoparticle (NP)-based drug delivery system, using natural bioadhesive tannic acid (TA) and metal ions (Fe3+), for locoregional photothermal and antiangiogenic synergistic cancer therapy. In this study, a new near-infrared (NIR) photothermal agent indocyanine green (IR820) and an antiangiogenic agent sorafenib (SRF) were co-encapsulated in a TA-Fe complex (SIF@TA-Fe). The SIF@TA-Fe NPs exhibited super adhesion, antiangiogenesis, and efficient cellular uptake. Moreover, SIF@TA-Fe NPs showed a synergistic antitumor effect in vivo, including high tumor inhibition rate, excellent survival extension, and low risk of recurrence, resulting from the prolonged retention of the NPs in the tumor. Thus, this adhesive SIF@TA-Fe NP-based therapeutic system provides a promising approach for locoregional drug delivery of combined cancer therapy.

A comprehensive review of natural products against atopic dermatitis: Flavonoids, alkaloids, terpenes, glycosides and other compounds

Atopic dermatitis (AD) is considered a great challenge for human communities and imposes both physiological and mental burdens on patients. Natural products have widely been used to treat a wide range of diseases, including cancer, gastrointestinal diseases, asthma, neurological disorders, and infections. To seek potential natural products against AD, in the current review, we searched the terms "atopic dermatitis" and "natural product" in Pubmed, Medline, Web of Science，Science Direct, Embase, EBSCO, CINAHL, ACS. The results show that many natural products, especially puerarin, ferulic acid and ginsenosides, cound protect against AD. Meanwhile, we discussed the therapeutic mechanisms and showed that the natural products exert their anti-inflammatory effects by suppressing the quantity and activity of many inflammatory cell types and cytokines, including neutrophils, monocytes, lymphocytes, Langerhans cells, interleukins (ILs, including IL-1α, IL-1β, IL-4), TNF-α, and TSLP, IgE. via inhibition of JAK/STAT, MAPKs and NF-κB signaling pathways, thereby, halting the inflammatory cascade. Future investigations should focus on studies with more reflective of the clinical characteristics and demographics, so as to develop natural products that will be hopefully available for the treatment of human AD disease.

Screening of chemical libraries in pursuit of kallikrein-5 specific inhibitors for the treatment of inflammatory dermatoses

Background Aberrant kallikrein activity is observed in a number of inflammatory dermatoses. Up-regulation of kallikrein-5 (KLK5) activity leads to uncontrolled skin desquamation and cleavage of proteinase-activated receptor-2 (PAR2), causing the release of pro-inflammatory cytokines and disruption of epidermal barrier function. This study aimed to identify KLK5-specific small molecule inhibitors which can serve as the foundation of a novel therapeutic for inflammatory skin disorders. Methods Five chemical libraries (13,569 compounds total) were screened against recombinant KLK5 using a fluorogenic enzymatic assay. Secondary validation was performed on the top 22 primary hits. All hits were docked in the KLK5 crystal structure to rationalize their potential interactions with the protein. Results A naturally occurring compound derived from the wood of Caesalpinia sappan (Brazilin) was identified as a novel KLK5 inhibitor (IC50: 20 μM, Ki: 6.4 μM). Docking suggests that the phenolic moiety of Brazilin binds in the S1-pocket of KLK5 and forms a H-bond with S195 side chain. KLK14 was also found to be susceptible to inhibition by Brazilin with a calculated IC50 value of 14.6 μM. Conclusions Natural KLK5 small molecule inhibitors such as Brazilin, are ideal for topical skin disease drug design and remain a promising therapeutic for severe cases of inflammatory skin disorders. Optimized KLK inhibitors may have increased efficacy as therapeutics and warrant further investigation.

Quercetin Downregulates Cyclooxygenase-2 Expression and HIF-1α/VEGF Signaling-Related Angiogenesis in a Mouse Model of Abdominal Aortic Aneurysm

Objective

Abdominal aortic aneurysm (AAA) development has been characterized by increased expression of vascular endothelial growth factor (VEGF), which contributes to angiogenesis via cyclooxygenase-2 (COX-2). Quercetin, one of the most common and well-researched flavonoids and abundant in vegetables and fruits, has beneficial effects in inhibiting angiogenesis. This study investigated the antiangiogenic effects of quercetin on experimental aneurysms.

Methods

We utilized the in vivo AAA mouse model induced by the periaortic application of CaCl₂ to examine the effectiveness of quercetin in blocking angiogenesis. Quercetin was administered at 60 mg/kg once daily on the day of the AAA induction and then continued for 6 weeks. Celecoxib, a selective COX-2 inhibitor, was used as the positive control.

Results

Our results demonstrated that quercetin significantly attenuated aneurysm growth in AAA mice and medial neovascularization. Accordingly, quercetin decreased the expression of proangiogenic mediators, including VEGF-A, intercellular adhesion molecule-1, vascular cell adhesion molecule 1, and vascular endothelial cadherin. Quercetin treatment also inhibited the expression of COX-2 and hypoxia-inducible factor 1α (HIF-1α). It was also found that quercetin-3-glucuronide, a major quercetin metabolite, downregulated the expression of COX-2, HIF-1α, VEGF-A, and matrix metalloproteinase activities in aortic vascular smooth muscle cells isolated from AAA mice.

Conclusion

Quercetin attenuates neovascularization during AAA growth, and this effect is mediated via the inhibition of COX-2, which decreases HIF-1α/VEGF signaling-related angiogenesis.

Quercetin Improves Inflammation, Oxidative Stress, and Impaired Wound Healing in Atopic Dermatitis Model of Human Keratinocytes

Background: Atopic dermatitis (AD) is a common inflammatory skin disease with complex pathogenesis. Natural flavonoids exhibit strong anti-inflammatory and antioxidant properties in many human diseases. In this study, the potential bioactive effect of quercetin, a polyphenolic plant-derived flavonoid, on the AD model of human keratinocytes was evaluated. Methods: Immortalized human HaCaT keratinocytes were treated with interleukin (IL) -4, -13, and tumor necrosis factor-α to mimic AD features in vitro. Then effects of quercetin on inflammation, oxidative stress, and wound healing were assessed. Results: Pretreatment of the cells with 1.5 μM of quercetin significantly reduced the expression of AD-induced IL-1β, IL-6, IL-8, and thymic stromal lymphopoietin, while it strongly enhanced the expression of superoxide dismutase-1 (SOD1), SOD2, catalase, glutathione peroxidase, and IL-10. Quercetin promoted wound healing by inducing epithelial-mesenchymal transition, which was supported by the upregulation of Twist and Snail mRNA expression. Unexpectedly, quercetin pretreatment of AD-induced cells upregulated the mRNA expression of occludin and E-cadherin, while downregulating matrix metalloproteinase 1 (MMP1), MMP2, and MMP9 expression. The pretreatment inhibited AD-induced phosphorylation of extracellular signal-regulated kinase 1/2/mitogen-activated protein kinase (ERK1/2 MAPK) and the expression of nuclear factor-kappa B (NF-κB), but it did not alter signal transducer and activator of transcription 6 (STAT6) phosphorylation. Conclusion: Quercetin may serve as a potential bioactive substance for atopic dermatitis-related symptoms through anti-inflammatory and antioxidant activities along with its acceleration of wound healing via ERK1/2 MAPK and NF-κB pathways.

Quercetin with the potential effect on allergic diseases

Quercetin is a naturally occurring polyphenol flavonoid which is rich in antioxidants. It has anti-allergic functions that are known for inhibiting histamine production and pro-inflammatory mediators. Quercetin can regulate the Th1/Th2 stability, and decrease the antigen-specific IgE antibody releasing by B cells. Quercetin has a main role in anti-inflammatory and immunomodulatory function which makes it proper for the management of different diseases. Allergic diseases are a big concern and have high health care costs. In addition, the use of current therapies such as ß2-agonists and corticosteroids has been limited for long term use due to their numerous side effects. Since the effect of quercetin on allergic diseases has been widely studied, in the current article, we review the effect of quercetin on allergic diseases, such as allergic asthma, allergic rhinitis (AR), and atopic dermatitis (AD).

Polymer- and Hybrid-Based Biomaterials for Interstitial, Connective, Vascular, Nerve, Visceral and Musculoskeletal Tissue Engineering

In this review, materials based on polymers and hybrids possessing both organic and inorganic contents for repairing or facilitating cell growth in tissue engineering are discussed. Pure polymer based biomaterials are predominantly used to target soft tissues. Stipulated by possibilities of tuning the composition and concentration of their inorganic content, hybrid materials allow to mimic properties of various types of harder tissues. That leads to the concept of "one-matches-all" referring to materials possessing the same polymeric base, but different inorganic content to enable tissue growth and repair, proliferation of cells, and the formation of the ECM (extra cellular matrix). Furthermore, adding drug delivery carriers to coatings and scaffolds designed with such materials brings additional functionality by encapsulating active molecules, antibacterial agents, and growth factors. We discuss here materials and methods of their assembly from a general perspective together with their applications in various tissue engineering sub-areas: interstitial, connective, vascular, nervous, visceral and musculoskeletal tissues. The overall aims of this review are two-fold: (a) to describe the needs and opportunities in the field of bio-medicine, which should be useful for material scientists, and (b) to present capabilities and resources available in the area of materials, which should be of interest for biologists and medical doctors.

Effect of the topical application of an ethanol extract of quince seeds on the development of atopic dermatitis-like symptoms in NC/Nga mice

Background

Quince (Cydonia oblonga Miller) is a deciduous shrub belonging to the Rosaceae family. Quince seed extract has long been used as a cosmetic ingredient for its moisturizing effect. However, little is known about whether quince seed extract has therapeutic effects on keratinocyte-associated skin inflammation.

Methods

In the present study, we investigated the effect of the topical application of ethanol extract of quince seeds (QSEtE) on atopic dermatitis (AD) symptoms in NC/Nga mice. The direct effect of QSEtE on keratinocytes was evaluated using the human keratinocyte cell line HaCaT.

Results

The preliminary application of QSEtE markedly reduced house dust mite allergen-induced skin lesions. The expression of thymus- and activation-regulated chemokine (TARC) in dorsal skin was downregulated. QSEtE directly suppressed the expression and production of TARC in HaCaT cells.

Conclusions

The results suggest that the topical application of QSEtE is effective in preventing the onset of and ameliorating the atopic symptoms of keratinocyte-associated skin inflammation by suppressing TARC production in keratinocytes.

The Localization of Phenolic Compounds in Liposomal Bilayers and Their Effects on Surface Characteristics and Colloidal Stability

The interactions with and effects of five chemically distinct, bioactive phenolic compounds on the lipid bilayers of model dipalmitoylphosphatidylcholine (DPPC) liposomes were investigated. Complementary analytical techniques, including differential scanning calorimetry (DSC) and phosphorus and proton nuclear magnetic resonance spectroscopy (NMR), were employed in order to determine the location of the compounds within the bilayer and to correlate location with their effects on bilayer characteristics and liposomal stability. As compared to the phenolic compounds localized in the glycerol region of the DPPC head group within the bilayer, which enhanced the colloidal stability of the liposomes, compounds located closer to the center of the bilayer reduced vesicle stability as a function of time. Molecules present in the upper region of liposomal DPPC acyl chains (C₁-C₁₀) inhibited liposomal aggregation and size increase, perhaps due to tighter packing of adjoining DPPC molecules and increased surface exposure of DPPC phosphate head groups. These data may be useful for designing liposomal systems containing hydrophobic phenols and other small molecules, selecting appropriate analytical methods for determining their location within liposomal bilayers, and predicting their effects on liposome characteristics early in the liposome formulation development process.

Suppression of neuropeptide production by quercetin in allergic rhinitis model rats

Background

Quercetin, a dietary flavonoid found in many fruits, red wine and onion, among others, has been reported to have potent anti-oxidant, anti-viral and anti-cancer effects. Although quercetin is also reported to have anti-inflammatory and anti-allergic effects, the precise mechanisms by which quercetin favorably modify the clinical conditions of allergic diseases such as allergic rhinitis (AR). The present study was designed to examine the influence of quercetin on the development of AR by using AR model rats.

Methods

Sprague-Dawley (SD) rats were sensitized with toluene 2,4-diisocyanate (TDI) by intranasal instillation of a 10 % TDI in ethyl acetate in a volume of 5 μl once a day for 5 consecutive days. This sensitization procedure was repeated after a 2-day interval. After 5 days of the second sensitization, rats were treated with various doses of quercetin once a day for 2 to 7 days. Nasal allergy-like symptoms, which were induced by bilateral application of 5 μl of 10 % TDI in ethyl acetate, were assessed by counting sneezing and nasal rubbing behaviors for 10 min just after TDI nasal challenge. The levels of substance P (SP), calcitonin gene-related peptide (CGRP) and nerve growth factor (NGF) in nasal lavage fluids obtained 6 h after TDI nasal challenge was examined by ELISA.

Results

Oral administration of quercetin for 5 and 7 days, but not 2 and 3 days, could inhibit sneezing and nasal rubbing movements, which were increased by TDI nasal challenge. The minimum dose that caused significant inhibition was 25 mg/kg. Oral administration of quercetin at more than 25 mg/kg for 5 days significantly inhibited the increase in SP, CGRP and NGF contents in nasal lavage fluids induced by TDI nasal challenge.

Conclusion

The present results strongly suggested that quercetin will be a good candidate for the supplement on the management and treatment of allergic diseases, especially AR.

Molecular targets of quercetin with anti-inflammatory properties in atopic dermatitis

Atopic dermatitis (AD) is an inflammatory skin disease. Over the past few decades, AD has become more prevalent worldwide. Quercetin, a naturally occurring polyphenol, shows antioxidant, anti-inflammatory, and antiallergic activities. Several recent clinical and preclinical findings suggest quercetin as a promising natural treatment for inflammatory skin diseases. Significant progress in elucidating the molecular mechanisms underlying the anti-AD properties of quercetin has been achieved in the recent years. Here, we discuss the use of quercetin as treatment for AD, with a particular focus on the molecular basis of its effect. We also briefly discuss the approaches to improve the bioavailability of quercetin.

The Potential of Plant Phenolics in Prevention and Therapy of Skin Disorders

Phenolic compounds constitute a group of secondary metabolites which have important functions in plants. Besides the beneficial effects on the plant host, phenolic metabolites (polyphenols) exhibit a series of biological properties that influence the human in a health-promoting manner. Evidence suggests that people can benefit from plant phenolics obtained either by the diet or through skin application, because they can alleviate symptoms and inhibit the development of various skin disorders. Due to their natural origin and low toxicity, phenolic compounds are a promising tool in eliminating the causes and effects of skin aging, skin diseases, and skin damage, including wounds and burns. Polyphenols also act protectively and help prevent or attenuate the progression of certain skin disorders, both embarrassing minor problems (e.g., wrinkles, acne) or serious, potentially life-threatening diseases such as cancer. This paper reviews the latest reports on the potential therapy of skin disorders through treatment with phenolic compounds, considering mostly a single specific compound or a combination of compounds in a plant extract.

Induction of cellular and molecular immunomodulatory pathways by vitamin A and flavonoids

INTRODUCTION

A detailed study of reports on the immunomodulatory properties of vitamin A and select flavonoids may pave the way for using these natural compounds or compounds with similar structures in novel drug and vaccine designs against infectious and autoimmune diseases and cancers.

AREAS COVERED

Intracellular transduction pathways, cellular differentiation and functional immunomodulatory responses have been reviewed. The reported studies encompass in vitro, in vivo preclinical and clinical studies that address the role of vitamin A and select flavonoids in induction of innate and adaptive B- and T-cell responses, including TH1, TH2 and regulatory T cells (Treg).

EXPERT OPINION

While the immunomodulatory role of vitamin A, and related compounds, is well-established in many preclinical studies, its role in humans has begun to gain wider acceptance. In contrast, the role of flavonoids is mostly controversial in clinical trials, due to the diversity of the various classes of these compounds, and possibly due to the purity and the selected doses of the compounds. However, current preclinical and clinical studies warrant further detailed studies of these promising immunomodulatory compounds.

Angiogenesis and lymphangiogenesis in inflammatory skin disorders

Angiogenesis, the growth of new blood vessels from pre-existing vessels, occurs physiologically in wound healing, during inflammatory diseases, and in tumor growth. Lymphangiogenesis can be activated in inflammation and tumor metastasis. The family of vascular endothelial growth factors (VEGFs) and angiopoietins are essential for angiogenesis and lymphangiogenesis. The angiogenic process is tightly regulated by VEGFs, angiopoietins, and endogenous inhibitors. VEGFs and angiopoietins exert their effects by activating specific receptors present on blood and lymphatic endothelial cells. There is now compelling evidence that cells of innate and adaptive immunity (macrophages, mast cells, neutrophils, eosinophils, lymphocytes) are a major source of angiogenic and lymphangiogenic factors. Chronic inflammatory skin diseases such as psoriasis and atopic dermatitis are characterized by altered angiogenesis, lymphangiogenesis, or both. Also such acute inflammatory skin disorders as urticaria, ultraviolet B-induced damage, and angioedema are associated with changes in angiogenic factors. In systemic sclerosis there is a switch from proangiogenic to antiangiogenic factors that play a role in the defective vascular process of this disorder. As yet, there are no clinical trials showing that canonical VEGF/VEGF receptor-targeted strategies can modulate inflammatory skin diseases. Novel strategies targeting other angiogenic/lymphangiogenic pathways should also be investigated.

Modulation of HMGB1 translocation and RAGE/NFκB cascade by quercetin treatment mitigates atopic dermatitis in NC/Nga transgenic mice

Quercetin, glycosylated form of flavonoid compound, has potent antioxidant and anti-inflammatory properties. In this study, we have investigated the effects of quercetin on skin lesion, high-mobility group box (HMGB)1 cascade signalling and inflammation in atopic dermatitis (AD) mouse model. AD-like lesion was induced by the application of house dust mite extract to the dorsal skin of NC/Nga transgenic mouse. After AD induction, quercetin (50 mg/kg, p.o) was administered daily for 2 weeks. We evaluated dermatitis severity, histopathological changes and changes in protein expression by Western blotting for HMGB1, receptor for advanced glycation end products (RAGE), toll-like receptor (TLR)4, nuclear factor (NF)κB, nuclear factor erythroid-2-related factor (Nrf)2, kelch-like ECH-associated protein (Keap)1, extracellular signal-regulated kinase (ERK)1/2, cyclooxygenase (COX)2, tumor necrosis factor (TNF)α, interleukin (IL)-1β, IL-2Rα and other inflammatory markers in the skin of AD mice. In addition, serum levels of T helper (Th) cytokines (interferon (IFN)γ, IL-4) were measured by enzyme-linked immunosorbent assay. Quercetin treatment attenuated the development of AD-like skin lesions. Histological analysis showed that quercetin inhibited hyperkeratosis, parakeratosis, acanthosis, mast cells and infiltration of inflammatory cells. Furthermore, quercetin treatment downregulated cytoplasmic HMGB1, RAGE, nuclear p-NFκB, p-ERK1/2, COX2, TNFα, IL-1β, IL-2Rα, IFNγ and IL-4 and upregulated nuclear Nrf2. Our data demonstrated that the HMGB1/RAGE/NFκB signalling might play an important role in skin inflammation, and quercetin treatment could be a promising agent for AD by modulating the HMGB1/RAGE/NFκB signalling and induction of Nrf2 protein.

Effect of topical application of quercetin-3-O-(2″-gallate)-α-l-rhamnopyranoside on atopic dermatitis in NC/Nga mice

BACKGROUND

Quercetin-3-O-(2″-gallate)-α-l-rhamnopyranoside (QGR) is a new quercetin derivative which is isolated from the leaves of Acer ginnala Maxim, a native plant of Korea. Quercetin has several biological effects including antioxidative, anti-inflammatory, and anti-allergic effects. However, the topical effect of QGR on atopic dermatitis (AD) like skin lesion in NC/Nga mice has not been studied.

OBJECTIVE

To evaluate the anti-inflammatory and anti-allergic effect of QGR in a murine model of atopic dermatitis.

METHODS

We measured inducible nitric oxide synthase (iNOS) and cyclooxygenase -2(COX-2) level in RAW264.7 cell with QGR treatment. And after induction of AD like skin lesions with Dermatophagoides farina (Df) ointment, mice were treated with QGR and control drugs. Clinical scores, interleukin (IL) 4, 5, and 13, serum IgE, eosinophil levels, iNOS and COX-2 level were evaluated.

RESULTS

Results show that mRNA level of iNOS and COX-2 in vitro were decreased after QGR treatment. Topical QGR markedly decreased the iNOS and COX-2 mRNA expressions in the skin. QGR also significantly suppressed the increase in the level of total plasma IgE and eosinophils. In addition, topical application of QGR down-regulated the expressions of the cytokines, IL-4,5 and 13, which were induced by Df ointment stimulation.

CONCLUSIONS

In the present study, we showed that topical application of QGR ameliorated Df-induced AD-like inflammatory responses in NC/Nga mice. These results demonstrate that QGR might be beneficial in the treatment of AD.

Efficient immuno-modulation of TH1/TH2 biomarkers in 2,4-dinitrofluorobenzene-induced atopic dermatitis: nanocarrier-mediated transcutaneous co-delivery of anti-inflammatory and antioxidant drugs

The present study was conducted with the aim to investigate the immuno-modulatory and histological stabilization effects of nanocarrier-based transcutaneous co-delivery of hydrocortisone (HC) and hydroxytyrosol (HT). In this investigation, the clinical and pharmacological efficacies of nanoparticle (NP)-based formulation to alleviate 2,4-dinitrofluorobenzene (DNFB)-induced atopic dermatitis (AD) was explored by using an NC/Nga mouse model. Ex vivo visual examination of AD induction in experimental mice indicated remarkable control of NP-based formulations in reducing pathological severity of AD-like skin lesions. Therapeutic effectiveness of NP-based formulations was also evaluated by comparing skin thickness of AD-induced NP-treated mice (456±27 µm) with that of atopic mice (916±37 µm). Analysis of the immuno-spectrum of AD also revealed the dominance of NP-based formulations in restraining immunoglobulin-E (IgE), histamine, prostaglandin-E2 (PGE2), vascular endothelial growth factor-α (VEGF-α), and T-helper cells (TH1/TH2) producing cytokines in serum and skin biopsies of tested mice. These anti-AD data were further supported by histological findings that revealed alleviated pathological features, including collagen fiber deposition, fibroblasts infiltration, and fragmentation of elastic fibers in experimental mice. Thus, NP-mediated transcutaneous co-delivery of HC and HT can be considered as a promising therapy for managing immunological and histological spectra associated with AD.

Downregulation of immunological mediators in 2,4-dinitrofluorobenzene-induced atopic dermatitis-like skin lesions by hydrocortisone-loaded chitosan nanoparticles

Background

Atopic dermatitis is a chronic, noncontiguous, and exudative disorder accompanied by perivascular infiltration of immune mediators, including T-helper (Type 1 helper/Type 2 helper) cells, mast cells, and immunoglobulin E. The current study explores the immunomodulatory and histological effects of nanoparticle (NP)-based transcutaneous delivery of hydrocortisone (HC).

Methods

In this study, HC, the least potent topical glucocorticoid, was administered transcutaneously as chitosan NPs. The pharmacological and immunological effects of the NP-based HC delivery on the alleviation of 2,4-dinitrofluorobenzene-induced atopic dermatitis (AD)-like skin lesions were evaluated using the NC/Nga mouse model.

Results

In vivo Dino-Lite^® microscopic assessment revealed that the NP-based formulation displayed a remarkable ability to reduce the severity of the pathological features of AD (dermatitis index, 3.0). The AD suppressive activity of the NP-based topical formulation was expected owing to the interruption of a series of immunopathological events, including the production of immunoglobulin E, release of histamine, and expression of prostaglandin-E₂ and vascular endothelial growth factor-α in the sera and skin of the tested animals. Analysis of the cytokine expression in AD-like skin lesions further revealed that the NP-based formulation inhibited the pathological expression of interleukin (IL)-4, IL-5, IL-6, IL-13, IL-12p70, interferon-γ, and tumor necrosis factor-α in serum and skin homogenates of NC/Nga mice. Further, our histological findings indicated that the NP-based formulation inhibited fibroblast infiltration and fragmentation of elastic fibers, further supporting the clinical importance of these formulations in maintaining the integrity of elastic connective tissues.

Conclusion

The current investigation suggests that NP-mediated transcutaneous delivery of HC could be considered an effective therapeutic approach to manage dermatitis.

Immunosuppressive effects of fisetin against dinitrofluorobenzene-induced atopic dermatitis-like symptoms in NC/Nga mice

Atopic dermatitis (AD) is a multifactorial chronic skin disorder that is increasing in prevalence globally. In NC/Nga mice, repetitive epicutaneous applications of 2-4-dinitrofluorobenzene (DNFB) induces AD-like clinical symptoms. Bioflanonol fisetin (3,7,3',4'-tetrahydroxyflavone) is a dietary component found in plants, fruits and vegetables. Fisetin has various physiological effects that include anti-oxidation, anti-angiogenesis, anti-carcinogenesis and anti-inflammation. In this study, we investigated whether fisetin relieves AD-like clinical symptoms induced by repeated DNFB treatment in NC/Nga mice. Fisetin significantly inhibited infiltration of inflammatory cells including eosinophils, mast cells and CD4(+) T and CD8(+) T cells, and suppressed the expressions of cytokines and chemokines associated with dermal infiltrates in AD-like skin lesions. Total serum immunoglobulin E (IgE) levels and the ratio of phospho-NF-κB p65 to total NF-κB p65 were markedly reduced by fisetin. Fisetin also reduced the production of interferon-gamma and interleukin-4 by activated CD4(+) T cells in a dose-dependent manner, whereas the anti-inflammatory cytokine, interleukin-10 was increased. These results implicate fisetin as a potential therapeutic for AD.

Inulae Flos and Its Compounds Inhibit TNF-α- and IFN-γ-Induced Chemokine Production in HaCaT Human Keratinocytes

The present study is to investigate which kinds of solvent extracts of Inulae Flos inhibit the chemokine productions in HaCaT cell and whether the inhibitory capacity of Inulae Flos is related with constitutional compounds. The 70% methanol extract showed comparatively higher inhibition of thymus and activation-regulated chemokine (TARC/CCL17) in HaCaT cells, therefore this extract was further partitioned with n-hexane, chloroform, ethyl acetate, butanol, and water. The ethyl acetate fraction inhibited TARC, macrophage-derived chemokine (MDC/CCL22), and regulated on activation of normal T-cell-expressed and -secreted (RANTES/CCL5) production in HaCaT cells better than the other fractions. The compounds of Inulae Flos, such as 1,5-dicaffeoylquinic acid and luteolin, inhibited TARC, MDC, and RANTES production in HaCaT cells. 1,5-Dicaffeoylquinic acid was contained at the highest concentrations both in the 70% methanol extract and ethyl acetate fraction and inhibited the secretion of chemokines dose-dependently more than the other compounds. Luteolin also represented dose-dependent inhibition on chemokine productions although it was contained at lower levels in 70% methanol extract and solvent fractions. These results suggest that the inhibitory effects of Inulae Flos on chemokine production in HaCaT cell could be related with constituent compounds contained, especially 1,5-dicaffeoylquinic acid and luteolin.

Tannic acid suppresses ultraviolet B-induced inflammatory signaling and complement factor B on human retinal pigment epithelial cells

Ultraviolet B (UVB) radiation may cause the inflammation of retinal pigment epithelium (RPE) cells and play a role in development of age-related macular degeneration (AMD). The activation of the complement factor B (CFB) gene has been shown to be involved in formation of AMD. Here our results revealed that UVB induces IL-6/STAT3 signaling activation and the UVB-induced STAT3 is able to regulate the CFB expression in ARPE-19 cells. Tannic acid (TA) is a kind of water-soluble polyphenol and may have anti-inflammation effects. We also found that TA attenuates the UVB-induced IL-6 protein production, the STAT3 phosphorylation and the CFB expression. Taken together, these findings suggest UVB-induced inflammation of RPE can be mediated through the IL-6/STAT3/CFB pathway, and TA has a protected effect via the inhibition to the inflammatory response.

Effect of Alnus japonica extract on a model of atopic dermatitis in NC/Nga mice

AIM OF THE STUDY

The bark of Alnus species has long been used in traditional oriental medicine in the treatment of many pathological conditions, including fever, hemorrhage, diarrhea, alcoholism, various skin diseases (e.g. chronic herpes, eczema and prurigo), and inflammation. In order to assess the immunomodulatory efficacy of a novel herbal medicine in treating atopic dermatitis, we measured serum levels of several allergic and inflammatory biomarkers in NC/Nga mice before and after treatment with this experimental agent.

MATERIALS AND METHODS

Gene and protein expression analyses of iNOS and COX-2 were quantified by real time PCR and Western blot analysis and serum levels of IL-4, -5 and -13 were also measured by ELISA, all of which were reduced after treatment with the experimental agent. Additionally, serum concentrations of IgE and blood eosinophil counts were reduced in treated mice.

RESULTS

The topical application of leaf and bark extract from Alnus japonica suppressed the development of AD-like skin lesions. The percent of blood eosinophils was decreased after treatment with leaf and bark extract from Alnus japonica. The serum IgE and Th2-related cytokine levels were decreased after treatment with leaf and bark extract from Alnus japonica compared with those treated with base cream (vehicle treated AD group). The IL-4, IL-5 and IL-13 were lower than those of vehicle treated AD group.

CONCLUSIONS

We contend that leaf and bark extract from Alnus japonica may prove useful in the treatment of atopic dermatitis and other allergic skin diseases, although more in-depth clinical studies are necessary before clinical implementation.

Detection of allergenic compounds using an IL-4/luciferase/CNS-1 transgenic mice model

The interleukin-4 (IL-4) signaling cascade has been identified as a potentially important pathway in the development of allergies. The principal objective of this study was to produce novel transgenic (Tg) mice harboring the luciferase gene under the control of the human IL-4 promoter and the enhancer of IL-4 (CNS-1), in an effort to evaluate three types of allergens including a respiratory sensitizer, vaccine additives, and crude extracts of natural allergens in vivo. A new lineage of Tg mice was generated by the microinjection of pIL-4/Luc/CNS-1 constructs into a fertilized mice egg. The luciferase activity was successfully regulated by the IL-4 promoter in splenocytes cultured from IL-4/Luc/CNS-1 Tg mice. From the first five founder lines, one (#57) evidencing a profound response to ovalbumin was selected for use in evaluating the allergens. Additionally, the lungs, thymus, and lymph nodes of IL-4/Luc/CNS-1 Tg mice evidenced high luciferase activity in response to allergens such as phthalic anhydride (PA), trimellitic anhydride, ovalbumin, gelatin, Dermatophagoides pteronyssinus extracts, and Japanese cedar pollen, whereas key allergy-related indicators including ear thickness, Immunoglobulin E concentration, and the infiltration of inflammatory leukocytes in response to PA were unaltered in the Tg mice relative to the non-Tg mice. Furthermore, the expression levels of endogenous type 2 helper T cells cytokines and proinflammatory cytokines were similarly increased in these organs of IL-4/Luc/CNS-1 Tg mice in response to allergens. These results indicate that IL-4/Luc/CNS-1 Tg mice may be used as an animal model for the evaluation and prediction of the human body response to a variety of allergens originating from the environment and from certain industrial products.