Dictamnine Ameliorates DNFB-Induced Atopic Dermatitis Like Skin Lesions in Mice by Inhibiting M1 Macrophage Polarization and Promoting Autophagy.

Autophagy and M1 macrophage polarization play important roles in the regulation of inflammation in atopic dermatitis (AD). Dictamnine is one of the main ingredients in Cortex Dictamni, a widely used traditional Chinese medicine for the treatment of dermatitis. In the present study, we investigated the anti-inflammatory effects of dictamnine on AD like skin lesions and M1 macrophage polarization. A 2,4-dinitrofluorobenzene (DNFB) triggered AD like skin lesions models in mice was established to identify the ameliorative effects of dictamnine on AD in vivo. In addition, an M1 macrophage polarization model was co-stimulated by lipopolysaccharide (LPS) and interferon-γ (IFN-γ) using phorbol myristate acetate (PMA) differentiated THP-1 cells, to investigate the effect of dictamnine on promoting autophagy and inhibiting inflammatory factor release. Dictamnine suppressed DNFB-induced skin inflammation by inhibiting M1 macrophage polarization, up-regulating the expression of microtubule-associated protein 1A/1B-light chain 3 (LC3) expression, and promoting macrophage autophagy at inflammatory sites. Dictamnine also could reduce the release of interleukin-1ß (IL-1ß), tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), monocyte chemotactic protein-1 (MCP-1), and interleukin-8 (IL-8), and down-regulate the mRNA expression of these genes in LPS-IFN-γ triggered M1 polarized macrophages. Dictamnine ameliorates AD like skin lesions by inhibiting M1 macrophage polarization and promoting autophagy. Hence, dictamnine is expected to be a potential therapeutic candidate for AD.

Exploration of hapten-induced atopic dermatitis murine models for non-clinical pharmacodynamics study of drugs / 药学学报

Atopic dermatitis (AD) is a chronic, relapsing, inflammatory dermatosis with a variety of clinical manifestations and difficult to cure. Currently, many AD drug candidates have entered the research and development pipeline. In order to provide technical specifications for the clinical development of AD drugs, the Center for Drug Evaluation of National Medical Products Administration released the "Technical Guidelines for Clinical Trials of Drugs for AD Treatment" (Draft for Comments) in November 2022. Non-clinical pharmacodynamics evaluation is an important research before the drug enters clinical trials. Oxazolone (OXA)- and 2,4-dinitro-fluorobenzene (DNFB)-induced models are the most popular classical hapten-induced AD murine models, but variations of modeling are existing in the methods from different studies, including sensitization sites, haptens' dosages, the period of challenges, and the skin lesions severity evaluation as well. In this study, the investigation of OXA- and DNFB-induced AD murine models with various conditions of modeling was performed to compare the characteristics of hapten-induced AD murine models in the pathological process and severity according to the appearance of AD patients, and the guidance of pharmacodynamics evaluation of AD-therapeutic drugs in clinical trials as well, which may provide a proposal for AD treatment drug candidates in the non-clinical pharmacodynamics evaluation. All animal experiments were approved by the Animal Care & Welfare Committee of Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College (approval No.: 00007782 and 00007784).

Synthesis of N-(2,4-dinitrophenyl) derivatives of D-ribosylamines; unexpected reaction and hydrolysis products.

Reaction of 2,3-O-isopropylidene-d-ribofuranosylamine with 2,4-dinitrofluorobenzene afforded the crystalline 2,3-O-isopropylidene-N-(2,4-dinitrophenyl)-ß-d-ribofuranosylamine (3) and a 1:1 crystalline complex of 2,3-O-isopropylidene-N-(2,4-dinitrophenyl-α-d-ribofuranosylamine and 2,3-O-isopropylidene-ß-d-ribofuranose; controlled acidic hydrolysis of 3 afforded N-(2,4-dinitrophenyl-α-d-ribopyranosylamine and not the expected ß-d-furanosylamine derivative. The structures of the new compounds were confirmed by NMR spectroscopy and X-ray crystallography.

Animal Models of Contact Dermatitis: 2,4-Dinitrofluorobenzene-Induced Contact Hypersensitivity.

Allergic contact dermatitis (ACD) is a common skin disease with high prevalence in work environments. Human allergic contact dermatitis is triggered by the exposure to haptens that leads to an initial phase known as sensitization. During this phase, hapten-protein complexes presented by antigen-presenting cells activate a T-cell-mediated response, leading to the generation of memory cells against the hapten. Upon re-exposure to the same hapten, the elicitation phase is initiated. This phase is characterized by a quicker acute inflammatory response involving activation and/or infiltration of a variety of immune cell populations. Human ACD can be studied through the use of animal models of contact hypersensitivity (CHS). The 2,4-dinitrofluorobenzene (DNFB)-induced CHS model is a commonly used mouse model that has been helpful in the study of the mechanisms as well as potential therapeutic interventions of ACD. In this chapter I will provide a detailed protocol to develop acute DNFB-induced CHS in mice in a period of 7 days. In addition, I will discuss several key considerations for experimental design including best controls, potential expected outcomes, and sample collection.

Conjugated linoleic acid attenuates 2,4-dinitrofluorobenzene-induced atopic dermatitis in mice through dual inhibition of COX-2/5-LOX and TLR4/NF-κB signaling.

Conjugated linoleic acid (CLA), commonly found in beef, lamb and dairy products, has been reported to exhibit anti-inflammatory and antipruritus effects and to inhibit the release of chemical mediators such as histamine and eicosanoid in laboratory rodents. The chief objective of the study is to assess the efficacy of CLA on atopic dermatitis (AD) in mice and to explore possible mechanisms with CLA treatments. To develop a new therapy for AD, the anti-AD potential of CLA was investigated by inducing AD-like skin lesions in mice using 2,4-dinitrofluorobenzene. We evaluated dermatitis severity; histopathological changes; serum levels of T helper (Th) cytokines (interferon-γ, interleukin-4); changes in protein expression by western blotting and immunohistochemistry staining for cyclooxygenase-2 (COX-2), 5-lipoxygenase (5-LOX), toll like receptor 4 (TLR-4), myeloid differentiation factor 88 (MyD88), nuclear factor-κB (NF-κB) and tumor necrosis factor α (TNF-α); and production of the proinflammatory lipid mediators, such as prostaglandin E2 and leukotriene B4, in the skin lesions. Treatment with CLA ameliorated the development of AD-like clinical symptoms and effectively inhibited epidermal hyperplasia and infiltration of mast cells and CD4+ T cells in the AD mouse skin. Total serum immunoglobulin E levels and the expression levels of Th1/Th2 cytokines and lipid mediators in dorsal skin were dramatically suppressed by CLA. Furthermore, CLA down-regulated the expressions of COX-2, 5-LOX, TLR4, MyD88, NF-κB and TNF-α. Taken together, our findings demonstrate the potential usefulness of CLA as an anti-inflammatory dietary supplement or drug for the prevention and management of AD skin diseases by modulating the COX-2/5-LOX and TLR4/MyD88/NF-κB signaling pathways.

Regulatory effects of chrysophanol, a bioactive compound of AST2017-01 in a mouse model of 2,4-dinitrofluorobenzene-induced atopic dermatitis.

The aim of this study is to determine whether AST2017-01 which consists of Rumex crispus and Cordyceps militaris would improve atopic dermatitis (AD). We analyzed anti-AD effects of AST2017-01 and chrysophanol, a bioactive compound of AST2017-01, using a 2,4-dinitrofluorobenzene-induced AD murine model. AST2017-01 and chrysophanol relieved clinical severity in AD-like skin lesions and significantly decreased scratching behavior. The thickness of epidermis and infiltration of inflammatory cells in AD-like skin lesions were reduced by AST2017-01 or chrysophanol. AST2017-01 and chrysophanol significantly suppressed the levels of histamine, immunoglobulin E, thymic stromal lymphopoietin (TSLP), interleukin (IL)-4, IL-6, and tumor necrosis factor-α in serum of AD mice. The protein levels of TSLP, intercellular adhesion molecule-1, and macrophage inflammatory protein 2 were significantly inhibited in the skin lesions. The mRNA expressions of TSLP, thymus and activation-regulated chemokine/CCL17, and C-C chemokine receptor 3 were inhibited in the skin lesions by AST2017-01 or chrysophanol. In addition, AST2017-01 and chrysophanol significantly suppressed the expressions and activities of caspase-1 in the skin lesions. Taken together, these results suggest that AST2017-01 has beneficial effects on AD and may be used as a health functional food in AD.

Suppressive effect of ethanol extract from mango (Mangifera indica L.) peel on IgE production in vitro and in vivo.

Immunoglobulin E (IgE) is involved in the onset of allergic reaction, and the suppression of IgE production leads to alleviation of allergic symptoms. We found that mango peel ethanol extract (MPE) significantly suppresses IgE production by human myeloma cell line U266 cells, suggesting that MPE has an anti-allergic effect by inhibiting the production of IgE. Although mangiferin is contained in mango, which suppresses IgE production by U266 cells, it was not contained in MPE. We investigated the suppressive effect of MPE in 2,4-dinitrofluorobenzene (DNFB)-induced allergic contact dermatitis model mice. The elevation of serum IgE level was significantly suppressed by oral administration of MPE. Intake of MPE also suppressed the expression level of IL-4 in the DNFB-challenged ears, suggesting that MPE suppresses the IL-4-mediated maturation into IgE-producing cells. Our findings indicate that MPE has a potential to alleviate the increase in serum IgE level that is feature of type I allergy.

Improved transdermal delivery of morin efficiently inhibits allergic contact dermatitis.

The skin is an important site for local or systemic application of drugs. However, most of the drugs have poor permeability through the skin's outermost layer, stratum corneum. The aim of this study was to develop a method to enable transdermal delivery of morin (3, 5, 7, 2, 4-pentahydroxyflavone), which is a poorly water-soluble drug with anti-inflammatory properties obtained from natural products. Morin phospholipid complex (MPC) was prepared and then loaded in Carbopol 940 hydrogel (MPC-gel), which can significantly increase the transdermal flux of morin based on the in vitro skin penetration data presented in this paper. To further enhance permeation, different compositions of penetration enhancers were dispersed in the gel and screened. After applied onto the mouse skin, MPC-gel showed apparent reduction of ear swelling in 2, 4-dinitrofluorobenzene (DNFB)-induced allergic contact dermatitis (ACD). Further determination of cytokines levels, histopathological analysis and T lymphocytes proliferation indicates that the MPC-gel is potent enough to reduce the inflammatory response mediated by the DNFB in ACD mice model. Collectively, we anticipate that such an approach may provide a new treatment for topical ACD.

Impact of germination on nutritional and physicochemical properties of adlay seed (Coixlachryma-jobi L.).

Adlay has garnered a great deal of research attentions in recent years as a highly nutritious food material and herbal medicine. This study characterized the changes of nutritional and physicochemical properties of adlay seeds during a 60-h germination. The results showed that the 60-h germination brought about a 3.4-fold increase in γ-aminobutyric acid (GABA) and 3.6-fold increase in coixol compared to ungerminated adlay seeds, while the triolein content slightly decreased. Some high molecular proteins were hydrolyzed into smaller proteins, peptides and amino acids after germination. Scanning electron micrographs (SEM) showed that the germination process destroyed the continuous matrix structure of adlay flour and created pits and holes on the surface of some starch granules. Germination resulted to changes in the pasting and gelatinization properties of adlay flour. The results of present study suggest that germination efficiently enhances the nutritional compounds while altering the physicochemical characteristics of adlay seeds.

Development of a pharmaceutical cocrystal with solution crystallization technology: Preparation, characterization, and evaluation of myricetin-proline cocrystals.

Myricetin shows low oral bioavailability (<10%) in rats due to poor aqueous solubility, although it has demonstrated various pharmacological activities such as those related to anticancer, anti-diabetes, and hepatic protection. To overcome this issue, in this study, pharmaceutical cocrystals were designed to efficiently deliver myricetin by oral administration. A 1:2 stoichiometric cocrystal of myricetin with proline was prepared successfully by solution crystallization based on the ternary phase diagram (TPD) principle, and it is presented as a new sphericity-like crystalline phase characterized by differential scanning calorimetry (DSC), powder X-ray diffraction (PXRD), and scanning electron microscopy (SEM). The formation of myricetin-proline cocrystals was a spontaneous and exothermic process, probably due to the supramolecular interactions between themselves, which were determined by Fourier transform-infrared spectroscopy (FT-IR). Consequently, the dissolution efficiency of myricetin from cocrystals was increased 7.69-fold compared with that of coarse myricetin, and the oral bioavailability of myricetin cocrystals in rats was enhanced by approximately 3.03 times compared with that of pure myricetin. The present study provides useful information for the potential application of cocrystal technology for water-insoluble drugs, especially flavonoid compounds.

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.

Effects of intestinal bacteria-derived p-cresyl sulfate on Th1-type immune response in vivo and in vitro.

Protein fermentation by intestinal bacteria generates various compounds that are not synthesized by their hosts. An example is p-cresol, which is produced from tyrosine. Patients with chronic kidney disease (CKD) accumulate high concentrations of intestinal bacteria-derived p-cresyl sulfate (pCS), which is the major metabolite of p-cresol, in their blood, and this accumulation contributes to certain CKD-associated disorders. Immune dysfunction is a CKD-associated disorder that frequently contributes to infectious diseases among CKD patients. Although some studies imply pCS as an etiological factor, the relation between pCS and immune systems is poorly understood. In the present study, we investigated the immunological effects of pCS derived from intestinal bacteria in mice. For this purpose, we fed mice a tyrosine-rich diet that causes the accumulation of pCS in their blood. The mice were shown to exhibit decreased Th1-driven 2, 4-dinitrofluorobenzene-induced contact hypersensitivity response. The concentration of pCS in blood was negatively correlated with the degree of the contact hypersensitivity response. In contrast, the T cell-dependent antibody response was not influenced by the accumulated pCS. We also examined the in vitro cytokine responses by T cells in the presence of pCS. The production of IFN-γ was suppressed by pCS. Further, pCS decreased the percentage of IFN-γ-producing Th1 cells. Our results suggest that intestinal bacteria-derived pCS suppressesTh1-type cellular immune responses.

A novel liquid chromatography/tandem mass spectrometry method for the quantification of glycine as biomarker in brain microdialysis and cerebrospinal fluid samples within 5min.

Glycine is an important amino acid neurotransmitter in the central nervous system (CNS) and a useful biomarker to indicate biological activity of drugs such as glycine reuptake inhibitors (GRI) in the brain. Here, we report how a liquid chromatography/tandem mass spectrometry (LC-MS/MS) method for the fast and reliable analysis of glycine in brain microdialysates and cerebrospinal fluid (CSF) samples has been established. Additionally, we compare this method with the conventional approach of high performance liquid chromatography (HPLC) coupled to fluorescence detection (FD). The present LC-MS/MS method did not require any derivatisation step. Fifteen microliters of sample were injected for analysis. Glycine was detected by a triple quadrupole mass spectrometer in the positive electrospray ionisation (ESI) mode. The total running time was 5min. The limit of quantitation (LOQ) was determined as 100nM, while linearity was given in the range from 100nM to 100µM. In order to demonstrate the feasibility of the LC-MS/MS method, we measured glycine levels in striatal in vivo microdialysates and CSF of rats after administration of the commercially available glycine transporter 1 (GlyT1) inhibitor LY 2365109 (10mg/kg, p.o.). LY 2365109 produced 2-fold and 3-fold elevated glycine concentrations from 1.52µM to 3.6µM in striatal microdialysates and from 10.38µM to 36µM in CSF, respectively. In conclusion, we established a fast and reliable LC-MS/MS method, which can be used for the quantification of glycine in brain microdialysis and CSF samples in biomarker studies.

Antagonistic effect of the inflammasome on thymic stromal lymphopoietin expression in the skin.

BACKGROUND: Innate immune sensors control key cytokines that regulate T-cell priming and T-cell fate. This is particularly evident in allergic reactions, which represent ideal systems to study the interplay of innate and adaptive immunity. In patients with contact dermatitis, inflammasome-mediated IL-1 activation is responsible for a TH1 immune response. Surprisingly, the IL-1 signaling pathway was also proposed to control the activation of thymic stromal lymphopoietin (TSLP), a cytokine implicated in development of the T(H)2 response in patients with atopic dermatitis (AD) and asthma. OBJECTIVES: We sought to assess the effect of the inflammasome on TSLP expression levels and the development of AD. METHODS: We studied the effect of the inflammasome activator 2,4-dinitrofluorobenzene, and IL-1ß on TSLP mRNA expression levels in mouse and human cell lines (in vitro assays), as well as in live mice and on human skin transplants. We also assessed the effect of 2,4-dinitrofluorobenzene on TSLP and the TH2 response in mice in which the inflammasome and IL-1 signaling pathways were blocked, either genetically or pharmacologically, in 2 models of AD. RESULTS: We provide in vitro and in vivo evidence that inflammasome activation has an inhibitory role on TSLP mRNA expression and T(H)2 cell fate in the skin. We also show that solvents influence the activation of TSLP and IL-1ß and direct the T-cell fate to a given hapten. CONCLUSION: Our observations strongly suggest that the TH1 versus TH2 cell fate decision is regulated at multiple levels and starts with innate immune events occurring within peripheral epithelial tissues.

The inhibitory effect of naringenin on atopic dermatitis induced by DNFB in NC/Nga mice.

AIMS: Atopic dermatitis (AD) is a chronic and relapsing inflammatory dermatitis characterized by pruritic and eczematous skin lesions. Here, we investigated the therapeutic effect of the fruit flavonoid naringenin on DNFB induced atopic dermatitis mice model. MAIN METHODS: AD-like skin lesion was induced by repetitive skin contact with DNFB in NC/Nga mice and the effects of the fruit flavonoid naringenin were evaluated on the basis of histopathological findings of skin, ear swelling and cytokine production of CD4(+)T cells. KEY FINDINGS: Intraperitoneal injection of naringenin for one week after DNFB challenge significantly lowered ear swelling and improved back skin lesions. In addition, naringenin significantly suppressed production of interferon-gamma (IFN-γ) by activated CD4(+) T cells and serum IgE level. Furthermore, naringenin reduced DNFB-induced infiltration of eosinophils, mast cells, CD4(+) T cells, and CD8(+) T cells in skin lesions. SIGNIFICANCE: Naringenin may suppress the development of AD-like skin lesions in DNFB-treated NC/Nga mice by reducing IFN-γ production of activated CD4(+) T cells, serum IgE levels and infiltration of immune cells to skin lesion.

Anti-inflammatory activities of Dictamnus dasycarpus Turcz., root bark on allergic contact dermatitis induced by dinitrofluorobenzene in mice.

ETHNOPHARMACOLOGICAL RELEVANCE: The root bark of Dictamnus dasycarpus Turcz. is widely used as a medicinal herb for treatment of skin diseases such as eczema, pruritus and urticaria in China, Japan and Korea. MATERIALS AND METHODS: We investigated the effects of methanol extract of Dictamnus dasycarpus Turcz., root bark (MEDD) on ear thickness, ear weights, histopathological changes such as hyperplasia, edema, spongiosis and immune cell infiltration and cytokine productions in 1-fluoro-2,4-dinitrofluorobenzene (DNFB)-induced contact dermatitis (CD) mice. We also investigated its effects on degranulation of histamine and ß-hexosaminidase and related mechanisms using RBL-2H3 cells. RESULTS: Topical application of MEDD effectively inhibited enlargement of ear thickness and weight (P<0.05). MEDD treatment also inhibited hyperplasia, edema and spongiosis induced by DNFB. Treatment with 300 µg/ear of MEDD suppressed the increase in IFN-γ and TNF-α levels (P<0.05). In addition, treatment with >50 µg/mL MEDD reduced the level of ß-hexosaminidase release, while >100 µg/mL MEDD lowered the level of histamine release in a dose-dependent manner (P<0.05). Finally, MEDD treatment prevented phosphorylation of p38 MAPK induced by phorbol 12-myristate 13-acetate (PMA) and calcium ionophore A23187 in RBL-2H3 cells. CONCLUSIONS: These data indicate that root bark of Dictamnus dasycarpus Turcz. has the potential for use in the treatment of allergic skin diseases. Furthermore, they suggest that root bark of Dictamnus dasycarpus Turcz. is involved in decreasing degranulation of MCs via inhibition of the p38 MAPK pathway as well as in the inhibition of Th1 skewing reactions.

Spectrophotometric Determination of the Antidepressants Sertraline and Paroxetine HCl using 2,4-Dinitrofluorobenzene.

A simple and sensitive spectrophotometric method was developed for the determination of each of sertraline (SER) and paroxetine HCl (PXT) in dosage forms. The method is based upon reaction of PXT and SER with 2,4-dinitrofluorobenzene (DNFB) to form colored products. The absorbance of the products were measured at 375and 390 nm for SER and PXT respectively. The absorbance concentration plots were rectilinear over the concentration rang of 1-10 and 2-20 µg/mL with lower detection limits (LOD) of 0.11 and 0.28 µg/mL and quantification limits (LOQ) of 0.32 and 0.85 µg/mL for SER and PXT, respectively. The developed method was successfully applied for the determination of SER and PXT in dosage forms. The common excipients and additives did not interfere in their determinations. There was no significant difference between the results obtained by the proposed and the reference methods regarding Student t-test and the variance ratio F-test respectively. A proposal of the reaction pathway was postulated.

Determination of the Main Component of Captopril Tablets by Derivative Spectrophotometry / 中国药房

OBJECTIVE:To establish derivative spectrophotometry for the determination of the main component of Captopril tablets.METHODS:Under the alkaline condition of sodium hydroxide,2,4-dinitrofluorobenzene was used as derivatization reagent to react with captopril at 40 ℃ in the water bath.Then UV spectrophotometry was adopted to detect the content of captopril with detection wavelength set at 342 nm.RESULTS:The linear range of captopril was 1.0～14.0 ?g?mL-1(r=0.999 9) with an average recovery of 99.61%(RSD=1.27%,n=9).The RSD of intra-day and inter-day both were less than 2%.CONCLUSION:This method is stable,reliable,rapid and simple for the determination of the main components of Captopril tablets.

Content Determination of Amino Acids in Folium Isatidis by RP-HPLC Precolumn Derivatization Method / 中国药房

OBJECTIVE:To establish a RP-HPLC precolumn derivatization method for the content determination of argi-nine(Arg)and proline(Pro)in Folium Isatidis.METHOD:2,4-dinitro-fluorobenzene was undergone precolumn derivatization and the amino acids was determined directly under alkaline condition with Kromasil C 18 as chromatographic column,the mobile phase was composed of sodium acetate buffer solution(pH=6.4)-acetonitrile(850∶150)with detection wavelength at360nm,the content was calculated by external reference method.RESULTS:The linear ranges for Arg and Pro were0.627?g～5.016?g(r=0.9996)and0.874?g～7.000?g(r=0.9995),respectively.The average recovery was98.2%with RSD at2.3%and2.2%,respectively.CONCLUSION:The method is simple,accurate and reliable,and suitable for the assaying of amino acids in Folium Isatidis.