Sophoricoside from Styphnolobium japonicum improves experimental atopic dermatitis in mice.

BACKGROUND: Abnormal immune responses, specifically excessive differentiation of Th2 cells, are associated with the development of atopic dermatitis (AD). Sophoricoside, the genistein-4'-ß-D-glucoside isolated from Styphnolobium japonicum, has previously demonstrated anti-inflammatory and immunosuppressive effects along with IL-3 and IL-5 inhibitory activities. Therefore, we speculated that sophoricoside could regulate AD by regulating abnormal immune responses. PURPOSE: To investigate the role of sophoricoside on AD-like allergic skin inflammation induced by ovalbumin (OVA) or 2,4,6-trinitrochlorobenzene (TNCB) in mouse models. METHODS: Sophoricoside was isolated from the 70% ethanol extract of S. japonicum dried mature seeds. After being submitted to a purification process, its purity was assessed by high-performance liquid chromatography (HPLC). The effects of sophoricoside were determined in vivo by OVA- and TNCB-induced AD-like allergic skin inflammation in mice. Skin tissues were subjected with hematoxylin-eosin (H&E), Giemsa and toluidine blue staining. In vitro CD4+ T cell differentiation was performed and the levels of serum immunoglobulins, cytokines, and genes related to CD4+ T cell differentiation were determined by enzyme-linked immunosorbent assay (ELISA) and quantitative real-time PCR. Cytokine bioassay, mixed lymphocytes reaction and cell viability assay were performed. RESULTS: Topical application of sophoricoside decreased the symptoms of AD-like allergic skin inflammation, including elevated hypertrophic scars with spongiotic epidermis, epidermal hyperplasia, hyperkeratosis, infiltration of immune, and mast cells, dermal thickness, amounts of immunoglobulins, and pro-inflammatory cytokines, and the mast cell population in the skin. Sophoricoside also decreased T cell antigen receptor (TCR)-mediated immune responses. In particular, sophoricoside suppressed the differentiation of naïve CD4+ T cells into Th cell subsets, including Th1, Th2, and Th17, by inhibiting the expression of their subset-specific master transcription factors, leading to suppression of the expression and production of these cell subset-specific cytokines. CONCLUSION: Sophoricoside can improve AD-like allergic skin diseases mainly by inhibiting pathogenic CD4+ T cell differentiation and immune responses.

Cysteine-type cathepsins promote the effector phase of acute cutaneous delayed-type hypersensitivity reactions.

Cysteine-type cathepsins such as cathepsin B are involved in various steps of inflammatory processes such as antigen processing and angiogenesis. Here, we uncovered the role of cysteine-type cathepsins in the effector phase of T cell-driven cutaneous delayed-type hypersensitivity reactions (DTHR) and the implication of this role on therapeutic cathepsin B-specific inhibition. Methods: Wild-type, cathepsin B-deficient (Ctsb-/-) and cathepsin Z-deficient (Ctsz-/-) mice were sensitized with 2,4,6-trinitrochlorobenzene (TNCB) on the abdomen and challenged with TNCB on the right ear to induce acute and chronic cutaneous DTHR. The severity of cutaneous DTHR was assessed by evaluating ear swelling responses and histopathology. We performed fluorescence microscopy on tissue from inflamed ears and lymph nodes of wild-type mice, as well as on biopsies from psoriasis patients, focusing on cathepsin B expression by T cells, B cells, macrophages, dendritic cells and NK cells. Cathepsin activity was determined noninvasively by optical imaging employing protease-activated substrate-like probes. Cathepsin expression and activity were validated ex vivo by covalent active site labeling of proteases and Western blotting. Results: Noninvasive in vivo optical imaging revealed strong cysteine-type cathepsin activity in inflamed ears and draining lymph nodes in acute and chronic cutaneous DTHR. In inflamed ears and draining lymph nodes, cathepsin B was expressed by neutrophils, dendritic cells, macrophages, B, T and natural killer (NK) cells. Similar expression patterns were found in psoriatic plaques of patients. The biochemical methods confirmed active cathepsin B in tissues of mice with cutaneous DTHR. Topically applied cathepsin B inhibitors significantly reduced ear swelling in acute but not chronic DTHR. Compared with wild-type mice, Ctsb-/- mice exhibited an enhanced ear swelling response during acute DTHR despite a lack of cathepsin B expression. Cathepsin Z, a protease closely related to cathepsin B, revealed compensatory expression in inflamed ears of Ctsb-/- mice, while cathepsin B expression was reciprocally elevated in Ctsz-/- mice. Conclusion: Cathepsin B is actively involved in the effector phase of acute cutaneous DTHR. Thus, topically applied cathepsin B inhibitors might effectively limit DTHR such as contact dermatitis or psoriasis. However, the cathepsin B and Z knockout mouse experiments suggested a complementary role for these two cysteine-type proteases.

Effects of Supplementary Seleno-L-methionine on Atopic Dermatitis-Like Skin Lesions in Mice.

Effects of selenium supplementation on atopic dermatitis (AD) were investigated by administering seleno-L-methionine (SeMet) using a mouse model of AD caused by repeated application of 2,4,6-trinitrochlorobenzene (TNCB). BALB/c mice were sensitized with TNCB to the abdomen on day -7; then, TNCB was applied repeatedly to each ear three times a week from days 0 to 23. SeMet was orally administered to the mice from days 0 to 23. The efficacy of SeMet on AD was assessed by measuring ear thickness, histologic evaluation, serum total immunoglobulin (Ig) E levels, and expression of interleukin (IL)-4 in the ear and superficial parotid lymph node. Ear thickness was remarkably increased by repeated application of TNCB, and SeMet significantly suppressed ear thickness in BALB/c mice. SeMet inhibited epidermal hyperplasia and dense infiltration of inflammatory cells. The number of TNCB-induced mast cells was significantly decreased by SeMet. Serum total IgE levels that increased by the repeated application of TNCB were significantly suppressed by SeMet. Repeated application of TNCB induced expression of IL-4, a T-helper (Th) 2 cytokine, in the ear and superficial parotid lymph node of BALB/c mice and its expression was significantly inhibited by SeMet. These results demonstrated that SeMet supplementation suppresses AD-like skin lesions in BALB/c mice and inhibits the expression of total IgE and IL-4.

Therapeutic Effects of Korean Red Ginseng Extract in a Murine Model of Atopic Dermatitis: Anti-pruritic and Anti-inflammatory Mechanism.

Korean red ginseng (KRG) and ginsenosides exhibit diverse biological effects, including anti-inflammatory and anti-allergic. We aimed to investigate the therapeutic effect of KRG in a murine model of atopic dermatitis (AD) is mediated whether by diminishing the pruritus or by suppressing the inflammation. Thirty NC/Nga mice were randomly divided to 5 groups. AD-like skin lesions were induced by percutaneous challenge with 2,4,6-trinitro-1-chrolobenzene (TNCB) on the ears and backs of NC/Nga mice. KRG extract, evening primrose oil, cyclosporine, and phosphate-buffered saline were administered orally by a gastric tube. Each study group was also divided into scratching-permitted and scratching-restricted subgroups to evaluate the impact of scratching behavior on AD. The effects of KRG and the other agents were assessed by measuring the clinical severity score, ear thickness, extent of transepidermal water loss (TEWL), number of scratching movements, total systemic immunoglobulin E (IgE) and interleukin (IL)-31 levels, histologic changes of cutaneous lesions, and mRNA expression levels of tumor necrosis factor (TNF)-α, interferon (IFN)-γ, thymic stromal lymphopoietin (TSLP), and IL-31. KRG exerts therapeutic effects against AD by inhibiting the T helper 2 (Th2) mediated inflammation as well as by diminishing the itching sensation. Moreover, restricting scratching behavior suppresses the vicious cycle of itching and scratching, thus reducing clinical and systemic inflammation in our murine model of AD.

[Effects of Blending Oil of Lavender and Thyme on Oxidative Stress, Immunity, and Skin Condition in Atopic Dermatitis Induced Mice].

PURPOSE: The purpose of this study was to evaluate the effects of essential oil on oxidative stress, immunity, and skin condition in atopic dermatitis (AD) induced mice. METHODS: This study was a 3×3 factorial design. Factors were oil type (Lavender, Thyme, and 2:1 mixture of lavender and thyme oil [blending oil]) and treatment period (0 day, 7 days, and 21 days). The samples were 45 mice with AD and randomly assigned to nine groups of five mice per group. The dependent variables such as superoxide radical, IgE, degranulated mast cells, and epidermal thickness were measured. Data were collected from February to April in 2014. Descriptive statistics, One-way ANOVA, Two-way ANOVA, and Tukey's HSD test were performed using the SPSS WIN 20.0 program. RESULTS: Dependent variables were not statistically significantly different by the three oil types (p>.05). Essential oils such as lavender, thyme, and blending oil were all effective in reducing AD symptoms and especially 2:1 blending oil were most effective. There were statistically significant differences by the three treatment periods in all dependent variables (p<.001). There were statistically significant interactions between oil types and treatment periods in all dependent variables (p<.01). For decreasing superoxide radical, degranulated mast cells, and epidermal thickness, 2:1 mixed oil should be applied for at least 21 days. Otherwise to reduce IgE, 2:1 mixed oil should be used for at least 7 days. CONCLUSION: These findings provide bases for developing effective interventions for AD patients to manage their AD symptoms.

Effects of Blending Oil of Lavender and Thyme on Oxidative Stress, Immunity, and Skin Condition in Atopic Dermatitis Induced Mice

PURPOSE: The purpose of this study was to evaluate the effects of essential oil on oxidative stress, immunity, and skin condition in atopic dermatitis (AD) induced mice. METHODS: This study was a 3x3 factorial design. Factors were oil type (Lavender, Thyme, and 2:1 mixture of lavender and thyme oil [blending oil]) and treatment period (0 day, 7 days, and 21 days). The samples were 45 mice with AD and randomly assigned to nine groups of five mice per group. The dependent variables such as superoxide radical, IgE, degranulated mast cells, and epidermal thickness were measured. Data were collected from February to April in 2014. Descriptive statistics, One-way ANOVA, Two-way ANOVA, and Tukey's HSD test were performed using the SPSS WIN 20.0 program. RESULTS: Dependent variables were not statistically significantly different by the three oil types (p >.05). Essential oils such as lavender, thyme, and blending oil were all effective in reducing AD symptoms and especially 2:1 blending oil were most effective. There were statistically significant differences by the three treatment periods in all dependent variables (p <.001). There were statistically significant interactions between oil types and treatment periods in all dependent variables (p <.01). For decreasing superoxide radical, degranulated mast cells, and epidermal thickness, 2:1 mixed oil should be applied for at least 21 days. Otherwise to reduce IgE, 2:1 mixed oil should be used for at least 7 days. CONCLUSION: These findings provide bases for developing effective interventions for AD patients to manage their AD symptoms.

Activation of cell-mediated immunity by Morinda citrifolia fruit extract and its constituents.

Morinda citrifolia, commonly known as noni, is a traditional natural medicine in French Polynesia and Hawaii. Functional foods derived from M. citrifolia fruit have been marketed to help prevent diseases and promote good health. The objective of this study was to assess the effects of M. citrifolia fruit on cell-mediated immunity. In the picryl chloride-induced contact dermatitis test, M. citrifolia fruit extract (Noni-ext) inhibited the suppression of cell-mediated immunity by immunosuppressive substances isolated from freeze-dried ascites of Ehrlich carcinoma-bearing mice (EC-sup). In addition, Noni-ext inhibited reduction of IL-2 production in EC-sup-treated mice and activated natural killer cells in normal mice. These results suggest that Noni-ext has multiple effects on the recovery of cell-mediated immunity. Furthermore, we investigated the active principles of Noni-ext and identified an iridoid glycoside, deacetylasperulosidic acid. Oral administration of deacetylasperulosidic acid inhibited the reduction of ear swelling, and also cancelled the suppression of IL-2 production along with the activation of natural killer cells in the same manner as that of Noni-ext.

Effect of the hot water extract of Artocarpus camansi leaves on 2,4,6-trinitrochlorobenzene (TNCB)-induced contact hypersensitivity in mice.

Medicinal plants with reported anti-inflammatory activity could have the potential use as anti-allergens and inhibitors of allergic contact dermatitis reactions produced by allergens and chemicals. Some species from the genus Artocarpus were reported to have anti-inflammatory activity. In the Philippines one local source is Artocarpus camansi BLANCO (Moraceae), which is utilized as an ingredient of their cuisine, and decoction of leaves is used for diabetes and baths of people with rheumatism. The objective of this study was to evaluate the effect of the hot water extract of A. camansi leaves on contact hypersensitivity (CHS) in mice. Contact hypersensitivity was induced using 2,4,6-trinitrochlorobenzene (TNCB). The results showed that the A. camansi hot water extract exhibited significant activity against the swelling produced during 24 h and 48 h post-challenge. The same responses were observed from the mice that received the kamansi ethanol-precipitate (KEP) and kamansi ethanol precipitate water-soluble (KEPWS) fractions. Since the high molecular mass fraction showed the significant activity, we therefore speculate that the compound responsible might be a polysaccharide and/or glycoprotein. In conclusion, our results suggest that the hot water extract of A. camansi leaves might be an effective natural product to treat allergic contact dermatitis. However, further investigations are required to understand the mechanisms involved.

Inhibitory effects of cultured Dendrobium tosaense on atopic dermatitis murine model.

Dendrobium tosaense is one of the most valuable Chinese medicines and well developed health food. Atopic dermatitis (AD) is a chronic skin disease that occurs mainly in childhood. The pathogenesis of atopic dermatitis had been studied in BALB/c mice modeling by skin-inoculated ovalbumin (OVA) with 2,4,6-trinitro-1-chrolobenzene (TNCB). These mice exhibit features of chronic dermatitis, including skin rash, mast cells infiltration, and elevated serum anti-OVA specific IgE and cytokines modulation. In this study, a standardized ethyl acetate extract of D. tosaense (DtE) was used to protect these mice from the OVA/TNCB-induced skin lesions of atopic dermatitis. The results indicated an increased population of natural T regulatory cell was accompanied by immunosuppression in cytokine profiles and anti-OVA IgE level to significantly reduce Th2 polarization. Finally, toluidine blue staining indicated mast cell infiltration and degranulation was reduced in skin lesion. Our results were shed light on the usage of D. tosaense in AD.

Effects of Korean red ginseng extract on the prevention of atopic dermatitis and its mechanism on early lesions in a murine model.

ETHNOPHARMACOLOGICAL RELEVANCE: Korean red ginseng (KRG) has been shown to possess various biological activities including anti-inflammatory properties. AIM OF THE STUDY: We aimed to investigate the effects and mechanism of KRG on the prevention of atopic dermatitis (AD) using a mouse model. MATERIALS AND METHODS: The effect of KRG in trinitrochlorobenzene (TNCB)-treated NC/Nga mice was assessed by measuring ear thickness, transepidermal water loss (TEWL), total serum IgE, histologic changes of lesional skin, mRNA and protein expression of thymic stromal lymphopoietin (TSLP) and tumor necrosis factor (TNF)-α, immunohistochemistry for tissue interleukin (IL)-4, IL-17, and interferon (IFN)-γ. RESULTS: KRG significantly reduced ear thickness. Oral administration of KRG significantly prevented the increase in TEWL induced by TNCB. The serum IgE level was significantly lower in the KRG group. Histologically, lymphocyte infiltration was markedly decreased by KRG. CD1a positive (CD1a+) cells were diminished by KRG. Immunohistochemically, KRG significantly suppressed the protein expression of TSLP and TNF-α. The mRNA expression of TSLP in the lesions was significantly reduced by KRG. These results demonstrate that oral administration of KRG may inhibit the development of AD-like skin lesions in NC/Nga mice by modifying TSLP, DCs, and at least in part, the Th2 response. CONCLUSION: KRG may be a potential therapeutic modality for the prevention of AD.

Anthocyanins, but not anthocyanidins, from bilberry (Vaccinium myrtillus L.) alleviate pruritus via inhibition of mast cell degranulation.

We have previously reported that bilberry anthocyanins exhibit an anti-pruritic effect in a mouse model of allergic contact dermatitis. It has been reported that anthocyanins are particularly sensitive to thermal treatment and are easily hydrolyzed to anthocyanidins when exposed to high temperatures. The objective of this study was to compare the anti-pruritic effect of anthocyanin-rich quality-controlled bilberry extract and anthocyanidin-rich degraded extract using a mouse model of allergic contact dermatitis. BALB/c mice with allergic contact dermatitis induced by 4 weeks of repeated application of 2,4,6-trinitro-1-chlorobenzene (TNCB) were administered Bilberon-25 orally for 4 weeks after sensitization with TNCB. The effect of Bilberon-25 on pruritus was evaluated by measurement of scratching behavior. RBL-2H3 mast cells were used to investigate the effect of Bilberon-25 on degranulation in 48/80-stimulated mast cells. Compared with nonheated Bilberon-25, the proportion of anthocyanins in heated Bilberon-25 decreased, and the proportion of anthocyanidins was increased in heated-time dependent manner. Treatment with non-heated Bilberon-25 significantly attenuated the TNCB-induced increase in scratching behavior, whereas treatment with 2 h-heated Bilberon-25 did not. Moreover, 300 µg/mL nonheated Bilberon-25 showed significant inhibition of degranulation in RBL-2H3 mast cells, whereas 2 h-heated Bilberon-25 had no effect at any concentration studied. It is assumed that the inhibitory effect of bilberry anthocyanins on pruritus might be mediated, at least in part, by its inhibitory effect on mast cell degranulation. In conclusion, the anthocyanin-rich but not anthocyanidin-rich bilberry extract may be a useful dietary supplement for skin diseases involving pruritic symptoms, such as chronic allergic contact dermatitis, atopic dermatitis, and rhinitis.

Relating skin sensitizing potency to chemical reactivity: reactive Michael acceptors inhibit NF-κB signaling and are less sensitizing than S(N)Ar- and S(N)2- reactive chemicals.

The skin sensitization potency of chemicals is partly related to their reactivity to proteins. This can be quantified as the rate constant of the reaction with a model peptide, and a kinetic profiling approach to determine rate constants was previously proposed. A linear relationship between the skin sensitization potency in the local lymph node assay (LLNA) and the rate constant for Michael acceptors was reported, characterized by a relatively flat regression line. Thus, a 10-fold increase of reactivity correlates to an increase of the sensitization potential of only 1.7-fold. Here, we first validate this model by repeating previous data and testing additional Michael acceptors and prove that the model is both reproducible and robust to the addition of new data. Chemicals of different mechanistic applicability domains, namely, S(N)Ar- and S(N)2-reactive sensitizers, were then tested with the same kinetic profiling approach. A linear relationship between sensitization potency in the LLNA and rate constants was also found, yet with a much steeper slope, i.e., for S(N)Ar- and S(N)2-reactive sensitizers, increasing reactivity correlates to a much stronger increase in sensitization potency. On the basis of the well-known inhibitory activity of some Michael acceptors on IKK kinase, it was hypothesized that the difference in the slopes is due to the specific anti-inflammatory potential of Michael acceptor chemicals. Therefore, all chemicals were tested for anti-inflammatory activity in a reporter gene assay for the inhibition of NF-κB activation. Increasingly reactive Michael acceptors have increasing anti-inflammatory potential in this assay, whereas no such biological activity was detected for the S(N)Ar and S(N)2 reactive sensitizers. Thus, the increasing reactivity of Michael acceptors confers both anti-inflammatory and skin sensitizing/pro-inflammatory potential, which may partially neutralize each other. This may be the reason for the relatively weak relationship between the potency in the LLNA and the rate constant of this particular group of chemicals.

Effect of pedunculagin investigated by non-invasive evaluation on atopic-like dermatitis in NC/Nga mice.

BACKGROUND/PURPOSE: Atopic dermatitis (AD) is a chronic relapsing inflammatory skin disorder that is becoming increasingly prevalent. Experimental animal models have been an indispensable tool for studying its pathological mechanisms and for in vivo testing of novel therapeutic approaches. AD-like lesions can be induced experimentally in NC/Nga mice. Pedunculagin, an ellagitannin purified from the Manchurian alder, Alnus hirsuta var. microphylla, Betulaceae, is a novel immunomodulator. To evaluate the effect of pedunculagin for AD-like lesions in NC/Nga mice, using clinical and non-invasive methods. METHODS: AD-like lesions were induced in NC/Nga mice using 2,4,6-trinitrochlorobenzene (TNCB). A cream containing 0.1% or 0.5% pedunculagin was applied to the positive treatment group, and the base cream without pedunculagin was applied to the negative treatment group. The control group did not receive any kind of topical agents. We evaluated the therapeutic efficacy of pedunculagin for AD by statistical evaluation of the clinical severity score using non-invasive biomedical engineering tools before treatment, and 1 day, 3 days, 1 week, 2 weeks and 4 weeks afterwards. RESULTS: An AD-like skin rash was successfully induced using TNCB in NC/Nga mice. The group receiving higher concentrations of pedunculagin showed faster and greater improvement. CONCLUSION: Our results suggest that remedies made from natural materials like pedunculagin are now showing promise for medical applications, and many new studies are expected to explore this potential.

Effects of single and combined administration of fermented barley extract and gamma-aminobutyric acid on the development of atopic dermatitis in NC/Nga mice.

We examined the effects single and combined administration of fermented barley extract P (FBEP), prepared from barley-shochu distillery by-products, and gamma-aminobutyric acid (GABA) on the development of atopic dermatitis (AD)-like skin lesions in NC/Nga mice. Single administration of FBEP and GABA dose-dependently reduced the development of AD-like skin lesions in mice. GABA reduced the development of AD-like skin lesions by suppressing serum immunoglobulin E (IgE) and splenocyte interleukin (IL)-4 production, while FBEP reduced skin lesions without affecting the IgE or cytokine production. However, in mice with induced AD-like skin lesions, combined administration of FBEP and GABA decreased serum IgE levels and splenic cell IL-4 production, and increased splenic cell interferon-gamma production. These results suggest that combined administration of FBEP and GABA alleviated AD-like skin lesions in the NC/Nga mice by adjusting the Th1/Th2 balance to a Th1-predominant immune response.

Inhibitory Effects of Korean Red Ginseng Extract on Atopic Dermatitis in NC/Nga Mice / 한국실험동물학회지

Atopic dermatitis (AD) is a chronic eczematous skin disease attended by pruritus, erythema, edema, excoriation, and dryness. This study was to evaluate the effects of Korean red ginseng (RG) on AD in NC/Nga mice treated with 1-chloro-2,4,6-trinitrobenzene (picryl chloride; PC). Experimental groups were divided into 4 groups; normal control (NC), PC control, and PC-RG (50 and 100 mg/kg). RG was orally administered every day repeatedly during 6 weeks. The skin lesions in severity score, scratching behavior, serum immunoglobulin E (IgE), interleukin-4 (IL-4) and interferon-gamma (IFN-gamma) levels, and histological appearance were examined. AD-like lesions were developed on the NC/Nga mice by topical PC applications. Oral administration of RG (50 and 100 mg/kg) significantly suppressed the development of AD, as analyzed by a modified SCORAD score. The scratching behavior decreased after RG administration. The levels of serum IgE, IL-4 and IFN-gamma were increased by PC stimulation, but treatment with RG (100 mg/kg) suppressed the increment of the serum IgE, IL-4 and IFN-gamma levels. Histologically, RG inhibited dermatitis lesions such as hypertrophy, hyperkeratosis, and infiltration of inflammatory cells into epidermis and dermis. These results suggest that the administration of RG may be effective in alleviating the AD induced by PC.

Inhibitory Effects of Korean Red Ginseng Extract on Atopic Dermatitis in NC/Nga Mice / 한국실험동물학회지

Atopic dermatitis (AD) is a chronic eczematous skin disease attended by pruritus, erythema, edema, excoriation, and dryness. This study was to evaluate the effects of Korean red ginseng (RG) on AD in NC/Nga mice treated with 1-chloro-2,4,6-trinitrobenzene (picryl chloride; PC). Experimental groups were divided into 4 groups; normal control (NC), PC control, and PC-RG (50 and 100 mg/kg). RG was orally administered every day repeatedly during 6 weeks. The skin lesions in severity score, scratching behavior, serum immunoglobulin E (IgE), interleukin-4 (IL-4) and interferon-gamma (IFN-gamma) levels, and histological appearance were examined. AD-like lesions were developed on the NC/Nga mice by topical PC applications. Oral administration of RG (50 and 100 mg/kg) significantly suppressed the development of AD, as analyzed by a modified SCORAD score. The scratching behavior decreased after RG administration. The levels of serum IgE, IL-4 and IFN-gamma were increased by PC stimulation, but treatment with RG (100 mg/kg) suppressed the increment of the serum IgE, IL-4 and IFN-gamma levels. Histologically, RG inhibited dermatitis lesions such as hypertrophy, hyperkeratosis, and infiltration of inflammatory cells into epidermis and dermis. These results suggest that the administration of RG may be effective in alleviating the AD induced by PC.

Antiallergic activity of unripe Citrus hassaku fruits extract and its flavanone glycosides on chemical substance-induced dermatitis in mice.

Oral administration of a 50% ethanolic extract (CH-ext) obtained from unripe Citrus hassaku fruits collected in July exhibited a potent dose-dependent inhibition of IgE (immunoglobulin E)-mediated triphasic cutaneous reaction at 1 h [immediate phase response (IPR)], 24 h [late phase response (LPR)] and 8 days [very late phase response (vLPR)] after dinitrofluorobenzene challenge in mice. Naringin, a major flavanone glycoside component of CH-ext, showed a potent dose-dependent inhibition against IPR, LPR and vLPR. Neohesperidin, another major glycoside component of CH-ext, showed an inhibition against vLPR. The effect of CH-ext on type IV allergic reaction was examined by determining inhibitory activity against ear swelling in mice by using the picryl chloride-induced contact dermatitis (PC-CD) model. Oral administration (p.o.) of CH-ext and subcutaneous administration (s.c.) of prednisolone inhibited ear swelling during the induction phase of PC-CD. The inhibitory activities of combinations of CH-ext (p.o.) and prednisolone (s.c.) against PC-CD in mice were more potent than those of CH-ext alone and prednisolone alone, without enhancing the adverse effects. Other combinations of prednisolone (s.c.) and flavanone glycoside (p.o.) components of CH-ext, i.e. naringin and neohesperidin, exerted similar synergistic effects.

Histamine release inhibitory activity of Piper nigrum leaf.

Oral administration of a methanolic extract of Piper nigrum leaf (PN-ext, 50, 200 and 500 mg/kg) showed a potent dose-dependent inhibition of dinitrofluorobenzene (DNFB)-induced cutaneous reaction at 1 h [immediate phase response (IPR)] after and 24 h [late phase response (LPR)] after DNFB challenge in mice which were passively sensitized with anti-dinitrophenyl (DNP) IgE antibody. Ear swelling inhibitory effect of PN-ext (50, 200 and 500 mg/kg, per os (p.o.)) on very late phase response (vLPR) in the model mice was significant but weaker than that on IPR. Oral administration of PN-ext (50, 200 and 500 mg/kg for 7 d) inhibited picryl chloride (PC)-induced ear swelling in PC sensitized mice. PN-ext exhibited in vitro inhibitory effect on compound 48/80-induced histamine release from rat peritoneal mast cells. Two lignans of PN-ext, (-)-cubebin (1) and (-)-3,4-dimethoxy-3,4-desmethylenedioxycubebin (2), were identified as major active principles having histamine release inhibitory activity.

Anti-inflammatory and immunosuppressive effect of flavones isolated from Artemisia vestita.

AIM OF THE STUDY: Artemisia vestita is a common traditional Tibetan medicinal plant which has been used widely in China for treating various inflammatory diseases. Since little is known about its active components, the purpose of this study was to isolate and identify the immunosuppressive compounds from Artemisia vestita. MATERIALS AND METHODS: A bioassay-guided isolation was performed with picryl chloride-induced contact hypersensitivity in mice. MTT assay and Flow cytometric analysis were used for determining Con A-induced lymphocyte proliferation and CD25 expression in T cells, respectively. RESULTS: The ethanol extract of the Artemisia vestita was found to possess significant inhibitory activity against the picryl chloride-induced contact hypersensitivity in mice. Then 4 fractions were isolated by macroporous adsorption resin and one of these fractions (AV3), which showed the highest activity in in vivo test, was further subjected to column chromatography. Nine known flavones were isolated and identified as pectolinarigenin (1), jaceosidin (2), cirsilineol (3), cirsimaritin (4), hispidulin (5), quercetin (6), 6-methoxytricin (7), acacetin (8), and apigenin (9). The structures of the 9 flavones were elucidated by spectral techniques. All the compounds were evaluated for their inhibitory activity on the proliferation and activation of T cells in vitro. Among the 9 flavones, cirsilineol (3), 6-methoxytricin (7) and apigenin (9) significantly inhibited T cell proliferation and activation in the bioassays. CONCLUSION: The result suggests that cirsilineol, 6-methoxytricin and apigenin are the major active components in Artemisia vestita.

Anti-allergic effect of a combination of Citrus unshiu unripe fruits extract and prednisolone on picryl chloride-induced contact dermatitis in mice.

Effect of 50% ethanolic extract of unripe fruits of Citrus unshiu (CU-ext) on type IV allergic reaction was examined by inhibitory activity of ear swelling of picryl chloride-induced contact dermatitis (PC-CD) in mice. Oral administration of CU-ext and subcutaneous administration of prednisolone showed inhibition of ear swelling during both induction and effector phases of PC-CD. The inhibitory activities of combinations of CU-ext (p.o.) and prednisolone (s.c.) during induction phase of PC-CD were more potent than those of CU-ext alone and prednisolone alone. Successive oral administration of hesperidin, a major flavanone glycoside of CU-ext, inhibited ear swelling during induction phase of PC-CD. The inhibitory activities of combinations of hesperidin (p.o.) and prednisolone (s.c.) were more potent than those of hesperidin alone and prednisolone alone. These results indicated that the combinations of prednisolone and CU-ext or hesperidin exerted a synergistic effect.