ABSTRACT
Oenanthe javanica is a vegetable grown in East Asia and Australia in which the roots and aerial parts are boiled together to make certain traditional dishes. Nineteen compounds (1-19) were isolated from O. javanica roots and the chemical structures of 2 new norlignans were determined. The inhibitory effects of the compounds on hyaluronidase and degranulation in RBL-2H3 cells were evaluated to determine antiallergic and antiinflammation activities. Saponins (2-4) and the new norlignan seric acid G (12) were among the active compounds identified. Seric acid G (12), a methoxy derivative of seric acid F (11), was obtained as an interconverting mixture of 3:1 trans-cis isomers. Seric acids F and G (11, 12) were derived from seric acids C (10) and E, respectively, by decarboxylation and dehydration reactions that occurred during heating. It was confirmed by HPLC analysis that all eleven of the O. javanica cultivars contained seric acid C (10).
Subject(s)
Enzyme Inhibitors/chemistry , Enzyme Inhibitors/pharmacology , Hot Temperature , Hyaluronoglucosaminidase/antagonists & inhibitors , Oenanthe/chemistry , Plant Roots/chemistry , Propanols/chemistry , Cell Line , Quinic Acid/chemistry , Saponins/chemistryABSTRACT
Two diacyldaucic acids (1 and 2), an α,ß-unsaturated γ-lactone-type lignan (3) and its derivatives (4-6), and 12 known compounds were isolated from a traditional East Asian vegetable, Oenanthe javanica. The absolute configuration of 1 was validated by obtaining (+)-osbeckic acid through acid hydrolysis. The absolute configurations of 3-5 were determined by comparing their experimental and computed ECD data. The conclusion was supported by applying the phenylglycine methyl ester method to 3. Compound 6 was obtained as an interconverting mixture of isomers in a 3:1 trans- cis ratio. Several water-soluble components (1, 3, and 6) showed concentration-dependent inhibitory effects on antigen-stimulated degranulation in RBL-2H3 cells without producing any direct cytotoxicity against RBL-2H3 or HeLa cells.
Subject(s)
Dicarboxylic Acids/pharmacology , Lactones/pharmacology , Lignans/pharmacology , Mast Cells/drug effects , Oenanthe/chemistry , Phenylpropionates/antagonists & inhibitors , Phenylpropionates/pharmacology , Sugar Acids/pharmacology , Animals , Dicarboxylic Acids/chemistry , Dicarboxylic Acids/isolation & purification , HeLa Cells , Humans , Lactones/chemistry , Lignans/chemistry , Lignans/isolation & purification , Mast Cells/chemistry , Phenylpropionates/chemistry , Sugar Acids/chemistry , Sugar Acids/isolation & purificationABSTRACT
Antigen-IgE-mediated mucosal mast-cell activation is critical in the development of food allergies. Cinnamaldehyde, a major constituent of Cinnamomi cortex, dose-dependently inhibited the antigen-IgE-induced degranulation of mucosal-type bone-marrow derived mast cells (mBMMCs) and RBL-2H3 cells. Cinnamaldehyde also suppressed the elevation of the intracellular Ca(2+) level that is induced by the extracellular Ca(2+) influx in antigen-IgE-stimulated mBMMCs. Furthermore, tyrosine phosphorylation of phospholipase C (PLC) γ1, which is a crucial activation switch for the intracellular Ca(2+) mobilization in mast cells, was attenuated by cinnamaldehyde. Together, our results demonstrated that cinnamaldehyde suppressed the intracellular Ca(2+) mobilization and the degranulation of mucosal mast cells by inhibiting the activity of the IgE receptor-PLCγ-Ca(2+) influx pathway. These findings suggest that cinnamaldehyde may have therapeutic potential in mucosal mast cell-related allergic diseases, such as food allergies.
Subject(s)
Acrolein/analogs & derivatives , Antineoplastic Agents, Phytogenic/pharmacology , Calcium/antagonists & inhibitors , Cell Degranulation/drug effects , Cinnamomum/chemistry , Mast Cells/drug effects , Phospholipase C gamma/metabolism , Acrolein/pharmacology , Animals , Antigens/immunology , Bone Marrow Cells/drug effects , Bone Marrow Cells/immunology , Calcium/metabolism , Cells, Cultured , Mast Cells/immunology , Mice , Mice, Mutant Strains , Mucous Membrane/cytology , Mucous Membrane/immunology , Phosphorylation/drug effectsABSTRACT
Mast cell activation by immunoglobulin E (IgE)-mediated stimuli is a central event in the pathogenesis of allergic disorders. The present report shows that treatment with pentagalloylglucose (PGG) resulted in a down-regulation of FcepsilonRI surface expression on mucosal-type murine bone marrow-derived mast cells (mBMMCs), which correlated with a reduction in IgE-mediated activation of mBMMCs. Furthermore, PGG prevented development of allergic diarrhea in a food-allergy mouse model and suppressed the up-regulated FcepsilonRI surface expression on mast cells derived from the food-allergy mouse colon. These findings on PGG suggest its therapeutic potential for allergic diseases through suppressing the FcepsilonRI surface expression.
Subject(s)
Diarrhea/immunology , Food Hypersensitivity/immunology , Hydrolyzable Tannins/pharmacology , Mast Cells/drug effects , Receptors, IgE/antagonists & inhibitors , Animals , Cell Degranulation/drug effects , Cell Membrane/drug effects , Cell Membrane/immunology , Cells, Cultured , Diarrhea/pathology , Disease Models, Animal , Down-Regulation , Drugs, Chinese Herbal/pharmacology , Food Hypersensitivity/pathology , Immunoglobulin E/immunology , Male , Mast Cells/immunology , Mice , Mice, Inbred BALB C , Paeonia/chemistry , Receptors, IgE/immunologyABSTRACT
CD45 is a key protein tyrosine phosphatase regulating Src-family protein tyrosine kinases (Src-PTKs) in lymphocytes; precisely how it exerts its effect remains controversial, however. We previously demonstrated that CD45 negatively regulates Lyn in the WEHI-231 B-cell line. Here we show that negative regulation by CD45 is physiologically significant in B cells and that some CD45 is constitutively associated with glycolipid-enriched microdomains (GEMs), where it inhibits Src-PTKs by dephosphorylating both the negative and the positive regulatory sites. Upon B-cell receptor (BCR) ligation, however, CD45 dissociates from GEMs within 30 seconds, inducing phosphorylation of 2 regulatory sites and activation of Src-PTKs, but subsequently reassociates with the GEMs within 15 minutes. Disruption of GEMs with methyl-beta-cyclodextrin results in abrogation of BCR-induced apoptosis in WEHI-231 cells, suggesting GEMs are critical to signals leading to the fate determination. We propose that the primary function of CD45 is inhibition of Src-PTKs and that the level of Src-PTK activation and the B-cell fate are determined in part by dynamic behavior of CD45 with respect to GEMs.
Subject(s)
B-Lymphocytes/enzymology , Leukocyte Common Antigens/genetics , Leukocyte Common Antigens/metabolism , src-Family Kinases/metabolism , Animals , Apoptosis/immunology , B-Lymphocytes/cytology , Cell Line , Membrane Microdomains , Membrane Proteins/metabolism , Mice , Mice, Inbred C57BL , Mice, Knockout , Phosphoproteins/metabolism , Receptors, Antigen, B-Cell/metabolism , Spleen/cytology , Spleen/immunologyABSTRACT
Src homology region 2 domain-containing phosphatase 1 (SHP-1) is a key mediator in lymphocyte differentiation, proliferation, and activation. We previously showed that B cell linker protein (BLNK) is a physiological substrate of SHP-1 and that B cell receptor (BCR)-induced activation of c-Jun NH(2)-terminal kinase (JNK) is significantly enhanced in cells expressing a form of SHP-1 lacking phosphatase activity (SHP-1-C/S). In this study, we confirmed that SHP-1 also exerts negative regulatory effects on JNK activation in splenic B cells. To further clarify the role of SHP-1 in B cells, we examined how dephosphorylation of BLNK by SHP-1 affects downstream signaling events. When a BLNK mutant (BLNK Delta N) lacking the NH(2)-terminal region, which contains four tyrosine residues, was introduced in SHP-1-C/S-expressing WEHI-231 cells, the enhanced JNK activation was inhibited. Among candidate proteins likely to regulate JNK activation through BLNK, Nck adaptor protein was found to associate with tyrosine-phosphorylated BLNK and this association was more pronounced in SHP-1-C/S-expressing cells. Furthermore, expression of dominant-negative forms of Nck inhibited BCR-induced JNK activation. Finally, BCR-induced apoptosis was suppressed in SHP-1-C/S-expressing cells and coexpression of Nck SH2 mutants or a dominant-negative form of SEK1 reversed this phenotype. Collectively, these results suggest that SHP-1 acts on BLNK, modulating its association with Nck, which in turn negatively regulates JNK activation but exerts a positive effect on apoptosis.