Rhamnus davurica leaf extract inhibits Fyn activation by antigen in mast cells for anti-allergic activity.

BACKGROUND: Complementary and alternative herbal medicines are recently considered as a promising approach for treating various diseases. We screened approximately 100 plant extracts for anti-allergic activity. Rhamnus davurica leaf extract showed the most potent inhibitory effect on the activation of RBL-2H3 mast cells. Although Rhamnus davurica extract has been used to treat pruritus, dysuresia, and constipation as a traditional herbal medicine in some Asian countries, an anti-allergic effect of Rhamnus davurica has not yet been demonstrated. We aimed to investigate the effect and mechanism of the leaf extract of Rhamnus davurica (LERD) on mast cells in vitro and allergic responses in vivo. METHODS: The effects of LERD on the activation of mast cells and mast cell-mediated passive cutaneous anaphylaxis (PCA) were measured in mice and two types of mast cells, mouse bone marrow-derived mast cells (BMMCs) and RBL-2H3 cells in vitro. A mechanistic study of its inhibitory effect was performed by using degranulation assay, reverse transcriptase-polymerase chain reaction, enzyme-linked immunosorbent assay, and western blotting analysis. RESULTS: LERD reversibly suppressed antigen-stimulated degranulation in BMMCs and RBL-2H3 cells, and also inhibited mRNA expression and secretion of TNF-α and IL-4 in a dose-dependent manner. In a PCA animal model, LERD significantly inhibited antigen-induced allergic response and degranulation of ear tissue mast cells. As for the mechanism of action, LERD inhibited the activation of Syk, which is the pivotal signaling protein for mast cell activation by antigen. Furthermore, LERD also impeded the activations of well-known downstream proteins such as LAT, Akt and three MAP kinases (Erk, p38 and JNK). In an in vitro kinase assay, LERD suppressed the activation of Fyn in antigen-stimulated mast cells. CONCLUSION: This study demonstrated for the first time that LERD has anti-allergic effects through inhibiting the Fyn/Syk pathway in mast cells. Therefore, this study provides scientific evidence for LERD to be used as an herbal medicine or health food for patients with allergic diseases.

Morus bombycis extract suppresses mast cell activation and IgE-mediated allergic reaction in mice.

ETHNOPHARMACOLOGICAL RELEVANCE: Morus bombycis Koidzumi (MB) is widely distributed throughout Korea, where it is used as a traditional folk remedy for the treatment of allergic diseases including asthma. However, the pharmacological effect and the mechanistic study of MB have not been investigated. We aimed to investigate the anti-allergic activity of MB in vitro and in vivo and the mechanism of its action on mast cells. MATERIALS AND METHODS: The anti-allergic activity of MB extract (MBE) was assessed using passive cutaneous anaphylaxis (PCA) in mice and mouse bone marrow-derived mast cells (BMMCs) in vitro. The effects of MBE on mast cell activation were evaluated by using the ß-hexosaminidase release assay, reverse transcriptase-polymerase chain reaction, enzyme-linked immunosorbent assay, and western blotting analysis. RESULTS: MBE reversibly inhibited degranulation and generation of cytokines (TNF-α and IL-4) in antigen-stimulated mast cells. With regard to its mechanism of action, MBE inhibited the activation of Lyn and Syk, which have essential roles in degranulation and the production of various inflammatory cytokines. MBE also inhibited the activating phosphorylation of mitogen-activated protein (MAP) kinases, Erk1/2, p38, JNK, and Akt. In agreement with its in vitro effect, MBE significantly inhibited mast cell-mediated PCA reactions in IgE-sensitized mice. CONCLUSIONS: The present results strongly suggest that MBE exerts an anti-allergic effect, both in vitro and in vivo by inhibiting the Lyn and Syk pathways in mast cells. Therefore, MBE may be useful for the treatment of allergic diseases, including atopic dermatitis and allergic asthma.

Analgesic and anti-inflammatory effects in animal models of an ethanolic extract of Taheebo, the inner bark of Tabebuia avellanedae.

Taheebo, the purple inner bark of the Bignoniaceae tree Tabebuia avellanedae Lorentz ex Griseb, which is found in tropical rain forests in northeastern Brazil, has been used as a traditional medicine for various diseases for more than 1,500 years. In the current study, various animal models were used to demonstrate the analgesic and anti-inflammatory properties of its ethanolic extract, thereby investigating its potential as a therapeutic treatment for diseases with pain and inflammation. In the hot plate and writhing tests for the in vivo analgesic effect test of Taheebo, a 200 mg/kg dose of the extract induced a significant anti-nociceptive effect and increased the pain threshold by approximately 30% compared with the control. In vascular permeability and tetradecanoylphorbol acetate (TPA)­, arachidonic acid- and carrageenan-induced paw edema tests for anti-inflammatory effects, treatment with 200 mg/kg Taheebo led to significant anti-inflammatory effects and inhibited inflammation by 30-50% compared with the control. At 100 mg/kg, the extract decreased the levels of pain and inflammation in all tested models, but the degree of inhibition was not statistically significant. The results suggest that the ethanolic extract of the inner bark of Tabebuia avellanedae has the potential to be developed as a therapeutic or supportive drug against diseases with accompanying pain and inflammation, including osteoarthritis.

A mixture of Trachelospermi caulis and Moutan cortex radicis extracts suppresses collagen-induced arthritis in mice by inhibiting NF-κB and AP-1.

OBJECTIVES: We aimed to determine the anti-arthritis effect and its mechanism of a combination of herbal extracts from Trachelospermi caulis (TC) and Moutan cortex radicis (MC) (TCMC). METHODS: The anti-arthritis activity of TCMC was assessed using a mouse model of type II collagen-induced arthritis (CIA). Reverse transcriptase-polymerase chain reaction (RT-PCR), enzyme-linked immunosorbent assay (ELISA), electrophoretic mobility shift assay (EMSA) and other biological assays were performed. KEY FINDINGS: TCMC significantly ameliorated various inflammatory parameters, such as clinical arthritis index, histological deformation of joints, serum levels of rheumatoid arthritis biomarkers (cartilage oligomeric matrix protein, serum amyloid P and anti-collagen type II IgG antibody), and Th1-related responses (T cell proliferation, and production of Interferon-γ and interleukin (IL)-2 in splenocytes isolated from CIA mice). The production of matrix metalloproteinases (MMPs), pro-inflammatory cytokines (tumour necrosis factor-α, IL-1ß and IL-6) and chemokines (macrophage inflammatory protein-1, monocyte chemoattractant protein-1, and Regulated upon Activation, Normal T-cell Expressed, and Secreted) was suppressed by TCMC in CIA mice. In addition, the number of osteoclasts in the hind tibia was significantly decreased. With regard to the mechanism, TCMC suppressed the activation of the transcription factors nuclear factor (NF)-κB and activator protein (AP)-1. CONCLUSIONS: TCMC exerts an anti-arthritis effect in CIA mice by suppression of the production of various inflammatory factors and the formation of osteoclasts through the inhibition of NF-κB and AP-1 activation.

Dryopteris crassirhizoma has anti-cancer effects through both extrinsic and intrinsic apoptotic pathways and G0/G1 phase arrest in human prostate cancer cells.

AIM OF THE STUDY: The inhibitory effect of Dryopteris crassirhizoma on the proliferation of human metastatic prostate PC3-MM2 cells and the mechanism of action were examined to identify its anti-cancer properties. The effect of the extract on cell cycle progression and its combined cytotoxic effect with tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) on PC3-MM2 cells were also investigated. MATERIALS AND METHODS: The anti-proliferative effects of Dryopteris crassirhizoma were examined by culturing PC3-MM2 cells in the presence or absence of various concentrations of Dryopteris crassirhizoma extract, and the inhibitory effects on cell proliferation were determined by Cell Counting Kit (CCK)-8 analysis. The quantities of apoptosis-inducing proteins were measured by western blotting analysis. Cell cycle progression was analyzed by PI staining using flow cytometry. RESULTS: Dryopteris crassirhizoma (50 and 100 microg/ml) inhibited markedly the proliferation of PC-3 and PC3-MM2 cells without cytotoxicity to normal (spleen) cells from BALB/C mice. Dryopteris crassirhizoma (100 microg/ml) effectively induced apoptosis through the activation of caspase-3, -8, -9, bid, and PARP in PC3-MM2 cells. The cells exposed to Dryopteris crassirhizoma increased significantly the accumulation of the DNA contents in the G0/G1 phase and sub-G1 phase in contrast to the control. The combined cytotoxic effects of Dryopteris crassirhizoma and TRAIL induced the increased activity of 29% in contrast to the sum of the inhibitory effects of each agent alone. CONCLUSIONS: Dryopteris crassirhizoma has anti-cancer properties by inducing cell cycle arrest and apoptosis through the extrinsic and intrinsic pathway in PC3-MM2 cells. The extract also showed a combined effect with TRAIL on the inhibition of proliferation in the cells. These findings suggest that possibly its extract could be used for treating androgen-independent prostate cancer with minimal side effects.

Anti-inflammatory effects of Artemisia princeps in antigen-stimulated T cells and regulatory T cells.

OBJECTIVES: The aim was to investigate the anti-inflammatory effects of Artemisia princeps extract on the activity of anti-CD3/CD28-stimulated CD4(+)CD25(-) T cells and antigen-expanded regulatory T cells. METHODS: CD4(+)CD25(-) T cells were activated with coated anti-CD3 and anti-CD28 and cultured in the presence or absence of various concentrations of A. princeps extract. The cultures were pulsed on Day 6 with [(3)H]thymidine and, after harvesting the cells, [(3)H]thymidine incorporation was measured. For analysis of interleukin-2 and interferon-gamma secreted from CD4(+)CD25(-) T cells, culture supernatants were collected on Days 2 and 6. For the analysis of interleukin-10 secreted from the CD4(+)CD25(-) T cells and expanded regulatory T cells, supernatants were collected after 2 and 7 days, respectively. Cytokine levels were determined using an enzyme-linked immunosorbent assay. Potential medicinal components of the A. princeps extract were determined using gas chromatography-mass spectrometry. KEY FINDINGS: A. princeps (30 microg/ml) effectively suppressed proliferation of CD4(+)CD25(-) T cells that were stimulated with anti-CD3/CD28 without causing cytotoxicity in spleen cells incubated under conditions lacking antigen stimulation. A. princeps inhibited production of the pro-inflammatory cytokines interleukin-2 and interferon-gamma in anti-CD3/CD28-stimulated CD4(+)CD25(-) T cells. Also, the extract slightly increased production of the anti-inflammatory cytokine interleukin-10 in these cells. In regulatory T cells expanded by anti-CD3/CD28, A. princeps increased production of interleukin-10 and Foxp3. CONCLUSIONS: The results suggest that A. princeps may be useful in the treatment of autoimmune diseases and organ transplantation rejection by inhibiting proliferation of inflammatory T cells, suppressing inflammatory processes in antigen-stimulated CD4(+)CD25(-) T cells and increasing activity of expanded regulatory T cells.

Identification of the most active interleukin-32 isoform.

Cytokines are crucial in host defence against pathogens such as bacteria, viruses, fungi and parasites. A newly described cytokine, interleukin-32 (IL-32), induces various proinflammatory cytokines (tumour necrosis factor-alpha, IL-1beta, IL-6) and chemokines in both human and mouse cells through the nuclear factor-kappaB and p38 mitogen-activated protein kinase inflammatory signal pathway. The IL-32 primarily acts on monocytic cells rather than T cells. In an attempt to isolate the IL-32 soluble receptor, we used an IL-32 ligand-affinity column to purify neutrophil proteinase 3, which is a serine proteinase involved in many inflammatory diseases. IL-32 has biological activity associated with Mycobacterium tuberculosis and chronic proinflammatory diseases such as rheumatoid arthritis. IL-32 is transcribed as six alternative splice variants and the biological activity of each individual isoform remains unknown. Here, we cloned the complementary DNA of the four IL-32 isoforms (alpha, beta, gamma and delta) that are the most representative IL-32 transcripts. To produce recombinant protein with a high yield, the amino acids of two cysteine residues were mutated to serine residues, because serine residues are not conserved among different species. The multi-step purified recombinant IL-32 isoform proteins were assessed for their biological activities with different cytokine assays. The gamma isoform of IL-32 was the most active, although all isoforms were biologically active. The present study will provide a specific target to neutralize endogenous IL-32, which may contribute to basic and clinical immunology.

Anti-inflammatory action of Cudrania tricuspidata on spleen cell and T lymphocyte proliferation.

This study examined whether an extract of Cudrania tricuspidata shows anti-proliferative effects in anti-CD3/CD28-mediated spleen and CD4+CD25- T cells and decreases the production of the proinflammatory cytokines interleukin-2 (IL-2) and interferon-gamma (IFN-gamma) in anti-CD3/CD28-mediated CD4+CD25- T cells. The proliferation of anti-CD3/CD28-mediated spleen cells and CD4+CD25- T cells was effectively suppressed by C. tricuspidata. This extract, however, did not show cytotoxicity in spleen cells under conditions where the antigen was not stimulated using CCK-8 analysis. C. tricuspidata also decreased the production of the pro-inflammatory cytokines IL-2 and IFN-gamma by selective inhibition of this extract on proliferating cells in anti-CD3/CD28-mediated CD4+CD25- T cells. These results suggest that C. tricuspidata may be useful in the treatment of autoimmune diseases and organ transplantation through the inhibitory action of T cells in inflammation.

Mast cell-mediated allergic response is suppressed by Sophorae flos: inhibition of SRC-family kinase.

Complementary and alternative medicines are considered as a promising direction for the development of anti-allergic therapies in oriental countries. We screened approximately 100 oriental herbal medicines for anti-allergic activity. Sophorae flos exhibited the most potent effect on degranulation in antigen-stimulated mast cells. We further investigated the effect of Sophorae flos on the IgE-mediated allergic response in vivo and its mechanism of action in mast cells. Sophorae flos exhibited a significant inhibitory effect on degranulation in antigen-stimulated mast cells with IC(50) values of approximately 31.6 microg/mL (RBL-2H3 mast cells) and approximately 47.8 microg/mL (bone marrow-derived mast cells). Sophorae flos also suppressed the expression and secretion of TNF-alpha and IL-4 in the cells and IgE-mediated passive cutaneous anaphylaxis (PCA) in mice. Sophorae flos inhibited the activating phosphorylation of Syk and LAT in mast cells. Further downstream, activating phosphorylation of Akt and the prototypic MAP kinases, namely, p38, ERK1/2, and JNK, were also inhibited. These results suggest that Sophorae flos inhibits the Src family kinase-dependent signaling cascades in mast cells and may thus exert anti-allergic activity.

Korean mistletoe lectin (KML-IIU) and its subchains induce nitric oxide (NO) production in murine macrophage cells.

Synthesis of nitric oxide (NO) is one of the important effector functions of innate immune cells. Although several reports have indicated mistletoe lectins induce immune cells to produce cytokines, studies regarding the activities of the lectins in the production of NO have been very limited. Here, we report on the induction of NO synthesis in a murine macrophage cell line, RAW264.7, by Korean mistletoe lectin (KML-IIU). When the macrophage cells were treated with KML-IIU in the presence of a suboptimal concentration of IFN-gamma, NO production was induced in a concentration-dependent manner. Significantly higher levels of NO were induced by subchains of the KML-IIU (A and B), which have lower toxicities, as compared to the hololectin. Furthermore, expression of the inducible nitric oxide synthase (iNOS) gene was elevated in accordance with the level of NO production. When the synthase was inhibited by iNOS inhibitors (L-NIL and L-NAME), NO production was specifically reduced in a concentration-dependent manner. Our studies demonstrate that the KML-IIU and its subchains induce NO production in murine macrophage cells via activation of the iNOS gene expression, suggesting that the KML-IIU subchains may be used as an immunomodulator to enhance the effector functions of innate immune cells.

Isolation and characterization of two Korean mistletoe lectins.

Two isolectins (KML-IIU and the KML-IIL) were individually isolated from the previously reported Korean mistletoe lectin, KML-C, by using an immunoaffinity column. Molecular weights of the KML-IIU and the KML-IIL were 64 kDa and 60 kDa respectively. Both of the lectins were composed of heterogeneous A and B subunits linked with a disulfide bond, and showed the same carbohydrate-binding specificities for Gal and GalNAc. However, they are different not only in biophysical properties (glycosylation and amino acid compositions) but also bioactivities (cell killing and cytokine induction). The KML-IIL showed 17-145 times stronger in cytotoxicities to various human and mouse cancer cell lines than the KML-IIU. The KML-IIL also induced TNF-alpha secretion from mouse peritoneal macrophages 4.5 times better than the KML-IIU. The results demonstrated isolectins in Korean mistletoe were varied in bioactivities and the KML-IIL may be developed as an anti-cancer agent.

Polygoni cuspidati radix inhibits the activation of Syk kinase in mast cells for antiallergic activity.

The antiallergic activity of Polygoni cuspidati radix (PR) and the mechanism of action by which it functions were investigated in this study. The extract of PR exhibited potent inhibitory activity in mast cells; its IC50 values were 62 +/- 2.1 microg/ml for RBL-2H3 mast cells and 46 +/- 3.2 microg/m for bone marrow-derived mast cells by antigen stimulation, and it also suppressed the expression of tumor necrosis factor-alpha and interleukin-4 in RBL-2H3 cells. According to the in vivo animal allergy model, it inhibited a local allergic reaction, passive cutaneous anaphylaxis, in a dose-dependent manner. With regard to its mechanism of action, PR inhibited the activating phosphorylation of Syk, a key signaling protein for the activation of mast cells. It also suppressed Akt and the mitogen-activated protein kinases ERK1/2, p38, and JNK, which are critical for the production of various inflammatory cytokines in mast cells. The results of the study indicate that the antiallergic activity of PR is mediated through the inhibition of histamine release and allergic cytokine production by the inhibition of Syk activating phosphorylation in mast cells.

Meliae cortex extract exhibits anti-allergic activity through the inhibition of Syk kinase in mast cells.

The anti-allergic action of various Oriental medicinal herbs was investigated using in vitro and in vivo experimental models. Of these extracts, the ethanol extract of Meliae cortex (MC) exhibited the most potent activity in mast cells; its IC(50) values were 29+/-1.5 microg/ml for antigen stimulation and 57+/-3.4 microg/ml for thapsigargin stimulation. It inhibited compound-48/80-induced systemic anaphylaxis by 52.9% at a dose of 300 mg/kg in mice; it also inhibited the expression of the proinflammatory mediator TNF-alpha. With regard to its mechanism of action, MC suppressed the activating phosphorylation of Syk, a key enzyme in mast-cell signaling processes and that of Akt in a dose-dependent manner. It also inhibited the MAP kinase ERK1/2, which is critical for the production of inflammatory cytokines in mast cells, as indicated by the suppression of the activating phosphorylation of ERK1/2. Taken together, these results suggest that the anti-allergic activity of MC may be due to the inhibition of histamine secretion and cytokine expression through the Syk inhibition in mast cells.

In-vitro and in-vivo anti-inflammatory action of the ethanol extract of Trachelospermi caulis.

In this study, we aimed to investigate the anti-inflammatory activity, antinociceptive activity and the action mechanism of Trachelospermi caulis extract. The anti-inflammatory effects were investigated using arachidonic acid, 12-O-tetradecanoylphorbol 13-acetate or carrageenan-induced oedema assays. Antinociceptive activity, using the acetic acid-induced writhing model, was also tested in mice. The extract exhibited dose-dependent and significant (P<0.05 at 100-400 mg kg-1) anti-inflammatory and antinociceptive activity in the animals. To further understand the mechanism of activity, we investigated whether the extract inhibited the expression of inducible nitric oxide synthase (iNOS), the production of nitric oxide (NO) and the expression of TNF-alpha from murine macrophage RAW 264.7 cells. Similar to the in-vivo activity, the iNOS expression, NO production and TNF-alpha expression were found to be dose dependent and significantly suppressed by the extract through the inhibition of the p38 MAP kinase/NF-kappaB pathway. Taken together, the results presented here suggest that T. caulis extract may be useful for the treatment of various inflammatory diseases.

Rubiae Radix suppresses the activation of mast cells through the inhibition of Syk kinase for anti-allergic activity.

The effect of extracts from various Oriental medicinal herbs on mast-cell-mediated allergic reactions was investigated in this study. Of these extracts, the medicinal herb Rubiae Radix exhibited the most potent activity in the cells, with an IC50 value (concentration necessary to obtain 50% inhibition of the response) of approximately 35 +/- 2.1 microg mL(-1), and its inhibition of compound-48/80-induced systemic anaphylaxis by 48.6 +/- 8.5% at 300 mg kg(-1) in mice. It also inhibited the expression of the pro-inflammatory mediator tumour necrosis factor-alpha (TNF-alpha). As for its mechanism of action, Rubiae Radix suppressed the activating phosphorylation of Syk, a key enzyme in mast-cell signalling processes, and that of Akt in a dose-dependent manner. It also inhibited the MAP kinase ERK1/2, which is critical for the production of inflammatory cytokines in mast cells, as indicated by the suppression of the activating phosphorylation of ERK1/2. These results suggest that Rubiae Radix suppresses the activation of mast cells through the inhibition of Syk for anti-allergic activity.

Inhibitory effects of a fermented ginseng extract, BST204, on the expression of inducible nitric oxide synthase and nitric oxide production in lipopolysaccharide-activated murine macrophages.

In this study, the effects of BST204, a fermented ginseng extract, on the expression of inducible nitric oxide synthase (iNOS) and nitric oxide (NO) production are looked into. Crude ginseng extract was incubated with ginsenoside-beta-glucosidase to prepare BST204. BST204, unlike lipopolysaccharide (LPS) and crude ginseng extract, did not affect the level of iNOS protein and NO production in unstimulated RAW 264.7 cells. However, it suppressed the level of iNOS protein and NO production in LPS-stimulated RAW 264.7 cells but did not manifest the same effect on the iNOS mRNA level. An investigation of the activating phosphorylation of p70 S6 kinase and 4E-BP1, which are important for translation, was conducted to investigate the suppressive mechanism of iNOS protein. LPS increased the phosphorylation of p70 S6 kinase, but not 4E-BP1, in a time-dependent manner, and BST204 inhibited it in a dose-dependent manner. The expression of iNOS protein, however, was partially suppressed by rapamycin, an upstream inhibitor of p70 S6 kinase. Therefore, this paper suggests that the suppression of iNOS protein by BST204 was partially correlated with the inhibition of p70 S6 kinase activation.

Effect of a fermented ginseng extract, BST204, on the expression of cyclooxygenase-2 in murine macrophages.

This paper investigates how BST204, a fermented ginseng extract, affects the expression and mechanism of cyclooxygenase-2 (COX-2). BST204 was prepared by incubating crude ginseng extract with ginsenoside-beta-glucosidase. Unexpectedly, BST204 had no effect on the level of COX-2 protein in unstimulated RAW 264.7 cells, and it suppressed the level of COX-2 protein and PGE(2) production in lipopolysaccharide (LPS)-stimulated RAW 264.7 cells. It did not show any suppressive effect, though, on the COX-2 mRNA level. To investigate the suppressive mechanism of COX-2 protein, the activating phosphorylation of p70 S6 kinase and 4E-BP1, which are important for translation, were measured. The phosphorylation of p70 S6 kinase, not 4E-BP1, was increased by LPS in a time-dependent manner, and was inhibited by BST204 in a dose-dependent manner. The expression of COX-2 protein, however, was partially suppressed by rapamycin, an upstream inhibitor of p70 S6 kinase. Therefore, this paper suggests that the suppression of COX-2 protein by BST204 was partially correlated with the inhibition of p70 S6 kinase activation.

Inhibitory activity of Chrysanthemi sibirici herba extract on RBL-2H3 mast cells and compound 48/80-induced anaphylaxis.

The effects of extracts from various oriental medicinal herbs on mast cell-mediated allergic reaction were investigated. Among them, Chrysanthemi sibirici herba ethanol extract exerted the potent inhibitory activity on antigen-induced degranulation in RBL-2H3 mast cells. Chrysanthemi sibirici herba dose-dependently inhibited DNP-BSA or compound 48/80-induced degranulation in RBL-2H3 mast cells, with IC(50) values of approximately 49 microg/ml and 76 microg/ml, respectively. This extract strongly suppressed compound 48/80-induced systemic anaphylaxis by 48.7% at a dose of 300 mg/kg in mice. Chrysanthemi sibirici herba also inhibited the expression of TNF-alpha and the activation of the MAP kinase, ERK1/2, which is critical for the production of inflammatory cytokines in mast cells, as indicated by the suppression of activating phosphorylation of ERK1/2. These results lead us to conclude that Chrysanthemi sibirici herba may be used clinically to treat various allergic diseases.

In-vitro and in-vivo anti-allergic actions of Arecae semen.

The effects of various extracts from oriental medicinal herbs on mast cell-mediated allergic reactions have been investigated. Among the extracts, Arecae semen was the most potent inhibitor of antigen-induced degranulation in RBL-2H3 mast cells. A. semen inhibited DNP-BSA- and compound 48/80-induced degranulation in RBL-2H3 mast cells with IC(50) values of approximately 53 and 52 microg mL(-1), respectively, and inhibited compound 48/80-induced systemic anaphylaxis by 46% at 300 mg kg(-1) in mice. A. semen also inhibited the expression of TNF-alpha and the activation of mitogen activated protein kinase, ERK1/2, which is critical for the production of inflammatory cytokines in mast cells, as indicated by the suppression of the activating phosphorylation of ERK1/2. These results suggest that A. semen may be useful for the treatment of various immediate and delayed allergic diseases.

Antitumor activity of the Korean mistletoe lectin is attributed to activation of macrophages and NK cells.

Inhibitory effect of the lectins (KML-C) isolated from Korean mistletoe (KM; Viscum album coloratum) on tumor metastases produced by murine tumor cells (B16-BL6 melanoma, colon 26-M3.1 carcinoma and L5178Y-ML25 lymphoma cells) was investigated in syngeneic mice. An intravenous (i.v.) administration of KML-C (20-50 ng/mouse) 2 days before tumor inoculation significantly inhibited lung metastases of both B16-BL6 and colon 26-M3.1 cells. The prophylactic effect of 50 ng/mouse of KML-C on lung metastasis was almost the same with that of 100 microg/mouse of KM. Treatment with KML-C 1 day after tumor inoculation induced a significant inhibition of not only the experimental lung metastasis induced by B16-BL6 and colon 26-M3.1 cells but also the liver and spleen metastasis of L5178Y-ML25 cells. Furthermore, multiple administration of KML-C given at 3 day-intervals after tumor inoculation led to a significant reduction of lung metastasis and suppression of the growth of B16-BL6 melanoma cells in a spontaneous metastasis model. In an assay for natural killer (NK) cell activity, i.v. administration of KML-C (50 ng/mouse) significantly augmented NK cytotoxicity against Yac-1 tumor cells 2 days after KML-C treatment. In addition, treatment with KML-C (50 ng/mouse) induced tumoricidal activity of peritoneal macrophages against B16-BL6 and 3LL cells. These results suggest that KML-C has an immunomodulating activity to enhance the host defense system against tumors, and that its prophylactic and therapeutic effect on tumor metastasis is associated with the activation of NK cells and macrophages.