Inhibition of mast cell-dependent anaphylactic reactions by the pigment of Polygonum tinctorium (Chung-Dae) in rats

Indigo Pulverata Levis (Chung-Dae, Persicaria tinctoria) Alleviates Atopic Dermatitis-like Inflammatory Responses In Vivo and In Vitro

Atopic dermatitis (AD) is a chronic inflammatory skin disease associated with a type 2 T helper cell (Th2) immune response. The IndigoPulverata Levis extract (CHD) is used in traditional Southeast Asian medicine; however, its beneficial effects on AD remain uninvestigated. Therefore, we investigated the therapeutic effects of CHD in 2,4-dinitrochlorobenzene (DNCB)-induced BALB/c mice and tumor necrosis factor (TNF)-α- and interferon gamma (IFN)-γ-stimulated HaCaT cells. We evaluated immune cell infiltration, skin thickness, and the serum IgE and TNF-α levels in DNCB-induced AD mice. Moreover, we measured the expression levels of pro-inflammatory cytokines, mitogen-activated protein kinase (MAPK), and the nuclear factor-kappa B (NF-κB) in the mice dorsal skin. We also studied the effect of CHD on the translocation of NF-κB p65 and inflammatory chemokines in HaCaT cells. Our in vivo results revealed that CHD reduced the dermis and epidermis thicknesses and inhibited immune cell infiltration. Furthermore, it suppressed the proinflammatory cytokine expression and MAPK and NF-κB phosphorylations in the skin tissue and decreased serum IgE and TNF-α levels. In vitro results indicated that CHD downregulated inflammatory chemokines and blocked NF-κB p65 translocation. Thus, we deduced that CHD is a potential drug candidate for AD treatment.

The Pathogenetic Effect of Natural and Bacterial Toxins on Atopic Dermatitis

Atopic dermatitis (AD) is a common allergic skin disease that is associated with chronic, recurrent eczematous and pruritic lesions at the flexural folds caused by interacting factors related to environmental and immune system changes. AD results in dry skin, and immunoglobulin E-mediated allergic reactions to foods and environmental allergens. While steroids and anti-histamines temporarily relieve the symptoms of AD, the possibility of side effects from pharmacological interventions remains. Despite intensive research, the underlying mechanisms for AD have not been clarified. A study of Staphylococcus aureus (S. aureus) established the role of its toxins in the pathogenesis of AD. Approximately 90% of patients with AD experience S. aureus colonization and up to 50%–60% of the colonizing S. aureus is toxin-producing. Any damage to the protective skin barrier allows for the entry of invading allergens and pathogens that further drive the pathogenesis of AD. Some natural toxins (or their components) that have therapeutic effects on AD have been studied. In addition, recent studies on inflammasomes as one component of the innate immune system have been carried out. Additionally, studies on the close relationship between the activation of inflammasomes and toxins in AD have been reported. This review highlights the literature that discusses the pathogenesis of AD, the role of toxins in AD, and the positive and negative effects of toxins on AD. Lastly, suggestions are made regarding the role of inflammasomes in AD.

Genuine traditional Korean medicine, Naju Jjok (Chung-Dae, Polygonum tinctorium) improves 2,4-dinitrofluorobenzene-induced atopic dermatitis-like lesional skin

PURPOSE

Naju Jjok (NJJ, Polygonum tinctorium) is a clear heat and release toxin medicinal. It has been used to treat various inflammatory diseases and as a dye in clothing in traditional Korean medicine. However, the effect of NJJ on atopic dermatitis (AD) has not been elucidated. Therefore, we examined whether NJJ would have an inhibitory effect on AD using the mimic AD murine model and in vitro model.

METHODS

We treated NJJ on 2,4-dinitrofluorobenzene (DNFB)-induced AD-like skin lesions in NC/Nga mice, phorbol myristate acetate/calcium ionophore A23187-stimulated human mast cell line (HMC-1) cells, and anti-CD3/anti-CD28-stimulated splenocytes. Histological analysis, ELISA, PCR, and Western blot analysis were performed.

RESULTS

The oral administration with NJJ suppressed the total clinical severity in DNFB-induced AD-like lesional skin. NJJ significantly suppressed the levels of inflammatory mRNA and protein in AD-like lesional skin. NJJ significantly suppressed the levels of IgE and interleukin-4 in the serum of DNFB-induced AD mice. The expression of mast cells-derived caspase-1 was suppressed by NJJ in AD-like lesional skin. In addition, topical application with NJJ improved clinical symptoms in DNFB-induced AD mice. The topical application with NJJ significantly suppressed the levels of IgE and histamine in the serum of DNFB-induced AD mice. NJJ suppressed the production and mRNA expression of TSLP by blockade of caspase-1 signal pathway in the activated HMC-1 cells. Furthermore, NJJ significantly decreased the production of tumor necrosis factor-α from the stimulated splenocytes.

CONCLUSIONS

In conclusion, these results propose curative potential of natural dye, NJJ by showing the scientific evidence on anti-AD effect of NJJ which has been used traditionally.

Inhibition of IL-32 and TSLP production through the attenuation of caspase-1 activation in an animal model of allergic rhinitis by Naju Jjok (Polygonum tinctorium)

In this study, we investigated the effects of Naju Jjok (Polygonum tinctorium Lour., NJJ) on interleukin (IL)-32 and thymic stromal lymphopoietin (TSLP) levels associated with allergic rhinitis (AR). Using female BALB/c mice, we created an animal model of ovalbumin (OVA)-induced AR. Prior to the callenge with OVA, the mice were administered, either nasally or orally with NJJ. In addition, we also used the eosinophilic cells line, Eol-1, stimulated with granulocyte‑macrophage colony-stimulation factor (GM-CSF). The mRNA and protein levels of inflammatory cytokines and markers [interleukin (IL)-32, IL-4, macrophage-inflammatory protein-2 (MIP-2), intercellular adhesion molecule-1 (ICAM-1), and cyclooxygenase-2 (COX-2)] were measured by RT-PCR and western blot analysis, respectively and serum levels were measured by ELISA. The increased levels of IL-32 in the mice with AR and in the stimulated eosinophilic cell line, Eol-1, were significantly reduced by NJJ. TSLP levels were also decreased following the oral administration of NJJ. Mice orally administered NJJ showed markedly alleviated clinical symptoms, such as a reduced number of nasal rubs, decreased spleen weight, decreased serum immunoglobulin E (IgE) levels and decreased serum histamine levels. The oral administration of NJJ significantly decreased the IL-4 levels, while increasing the interferon-γ levels in the spleen. The increased number of eosinophils and mast cells infiltrating the nasal mucosal tissue of the mice with AR were decreased following the oral administration of NJJ. NJJ effectively attenuated caspase-1 activity in the mice with AR and in the stimulated Eol-1 cells. The oral administration of NJJ significantly reduced the levels of inflammatory markers, such as MIP-2, ICAM-1 and COX-2. Furthermore, the intranasal administration of NJJ significantly reduced the early phase response to allergen exposure, such as nasal rubs, IgE production and histamine release, as well as the late phase responses, such as the expression of inflammatory markers. In conclusion, these data demonstrate that NJJ may play a regulatory role in nasal inflammation.

Subchronic toxicity study of water pepper extract in F344 rats

A subchronic toxicity study of water pepper extract (WPE) from Polygonum hydropiper L. was conducted in groups of 10 male and 10 female F344 rats fed powdered diets containing 0, 62.5, 250, 1000 or 4000 ppm concentrations for 13 weeks. Suppression of body weight gain due to decreased food consumption was observed in both sexes at 4000 ppm, and at autopsy, increase of relative weights was observed for the brain, liver, spleen, kidneys, and testes in these animals, suggestive of the reflection of the reduced body weights. At this dose, slight increases of blood urea nitrogen in both sexes and serum alanine aminotransferase, Na and Cl in females, were observed, suggestive of weak hepatic and renal toxicity, at least in females. The same females also exhibited slight decrease of red blood cells and haematocrit, slight increase of mean corpuscular volume and mean corpuscular haemoglobin, and minimal increase of splenic haemosiderin deposition, providing evidence of slight haemolytic anemia. On the other hand, enhanced accumulation of mast cells was observed in the mesenteric lymph nodes at 4000 ppm in males and 1000 and 4000 ppm in females. Considering the anti-anaphylactic properties of polygodial, a major constituent of WPE, the mast cell accumulation was concluded to be an adaptive change in response to the subchronic oral administration of WPE. Based on the present toxicity data, 1000 ppm was determined to be the no-observed-adverse-effect level, translating into 57.4 and 62.9 mg/kg/day for male and female rats, respectively.

Highly potent anti-HIV-1 activity isolated from fermented Polygonum tinctorium Aiton

A water-soluble extract of fermented Polygonum tinctorium Aiton (Polygonaceae) called Sukumo, exhibited a potent inhibitory activity against HIV type 1 in vitro. The extract potently suppressed acute HIV-1 (III_B) infection in MT-4 cells with EC₅₀ values of 0.5 μg/ml but exhibited low cytotoxicity to MT-4 cells even at a high concentration (CC₅₀ > 1000 μg/ml). It also inhibited giant cell formation in co-cultures of HIV-infected cells and uninfected Molt-4 cells. Sukumo extract was found to interact with both the viral envelope glycoprotein and cellular receptors, thus blocking virus-cell binding and virus-induced syncytium formation. There was a good correlation between the extract's anti-HIV-1 activity and its inhibitory effects on HIV-1 binding. It also suppressed replication of herpes simplex virus type 1 in Vero cells with an EC₅₀ of 11.56 μg/ml. On the other hand, there was no appreciable activity against influenza A virus, poliovirus or SARS corona virus when tested at concentrations ranging from 3.2–400 μg/ml as shown by microscopic image analysis for cytopathic effect (CPE). Physico-chemical studies revealed that the anti-HIV activity in the extract was essentially maintained after boiling at 100 °C in 1N HCl or 1N NaOH, and after treatment with 100 mM NaIO₄. The inhibitory activity of the extract was also not reduced after pronase digestion. The active factor in the extract is likely to be a novel compound(s) having a polyanionic substructure and a molecular weight of 10,000–50,000.

Effect of disodium cromoglycate on mast cell-mediated immediate-type allergic reactions

We investigated the effect of disodium cromoglycate (DSCG) on mast cell-mediated immediate-type hypersensitivity. DSCG inhibited systemic allergic reaction induced by compound 48/80 dose-dependently. Passive cutaneous anaphylaxis was inhibited by 71.6% by oral administration of DSCG (1 g/kg). When DSCG was pretreated at concentration rang from 0.01-1000 g/kg, the serum histamine levels were reduced in a dose dependent manner. DSCG also significantly inhibited histamine release from rat peritoneal mast cell (RPMC) by compound 48/80. We confirmed that DSCG inhibited compound 48/80-induced degranulation of RPMC by alcian blue/nuclear fast red staining. In addition, DSCG showed a significant inhibitory effect on anti-dinitrophenyl IgE-mediated tumor necrosis factor-alpha production. These results indicate that DSCG inhibits mast cell-mediated immediate-type allergic reaction.

Inhibitory effects of Xanthii fructus extract on mast cell-mediated allergic reaction in murine model

The effect of aqueous extract of Xanthii fructus (XF) on mast cell-mediated allergic reaction has been investigated. XF inhibited compound 48/80-induced systemic anaphylaxis in mouse. This dose-dependently inhibited histamine release from rat peritoneal mast cells (RPMC) by compound 48/80. Additionally, XF inhibited local immunoglobulin E (IgE)-mediated passive cutaneous anaphylatic reaction. When XF (0.1mg/ml) was added, the secretion of tumor necrosis factor-alpha (TNF-alpha) from anti-dinitrophenyl (DNP) IgE antibody-stimulated mast cells was inhibited by 56%. Our studies provide evidence that XF may be beneficial in the treatment of various types allergic diseases.