title: Inhibitory effects of an ellagic acid glucoside, okicamelliaside, on antigen-mediated degranulation in rat basophilic leukemia RBL-2H3 cells and passive cutaneous anaphylaxis reaction in mice.
abstract: Degranulation inhibitors in plants are widely used for prevention and treatment of immediate-type allergy. We previously isolated a new ellagic acid glucoside, okicamelliaside (OCS), from Camellia japonica leaves for use as a potent degranulation inhibitor. Crude extracts from leaves also suppressed allergic conjunctivitis in rats. In this study, we evaluated the in vivo effect of OCS using a pure sample and performed in vitro experiments to elucidate the mechanism underlying the extraordinary high potency of OCS and its aglycon. The IC(50) values for degranulation of rat basophilic leukemia cells (RBL-2H3) were 14 nM for OCS and 3 μM for aglycon, indicating that the two compounds were approximately 2 to 3 orders of magnitude more potent than the anti-allergic drugs ketotifen fumarate, DSCG, and tranilast (0.17, 3, and >0.3 mM, respectively). Antigen-induced calcium ion (Ca(2+)) elevation was significantly inhibited by OCS and aglycon at all concentrations tested (p<0.05). Upstream of the Ca(2+) elevation in the principle signaling pathway, phosphorylation of Syk (Tyr525/526) and PLCγ-1 (Tyr783 and Ser1248) were inhibited by OCS and aglycon. In DNA microarray-screening test, OCS inhibited expression of proinflammatory cytokines [interleukin (IL)-4 and IL-13], cytokine-producing signaling factors, and prostaglandin-endoperoxidase 2, indicating that OCS broadly inhibits allergic inflammation. During passive cutaneous anaphylaxis in mice, OCS significantly inhibited vascular hyperpermeability by two administration routes: a single intraperitoneal injection at 10 mg/kg and per os at 5 mg/kg for 7 days (p<0.05). These results suggest the potential for OCS to alleviate symptoms of immediate-type allergy.
authors.affiliation: Department of Health Sciences, Faculty of Medicine, University of the Ryukyus, 207 Uehara, Nishihara-cho, Okinawa 903-0215, Japan. kubame93@med.u-ryukyu.ac.jp
authors.forename: Megumi
authors.initials: M
authors.lastname: Kuba-Miyara
authors.forename: Kengo
authors.initials: K
authors.lastname: Agarie
authors.forename: Rina
authors.initials: R
authors.lastname: Sakima
authors.forename: Shihoko
authors.initials: S
authors.lastname: Imamura
authors.forename: Kazuyo
authors.initials: K
authors.lastname: Tsuha
authors.forename: Takeshi
authors.initials: T
authors.lastname: Yasumoto
authors.forename: Shinichi
authors.initials: S
authors.lastname: Gima
authors.forename: Goro
authors.initials: G
authors.lastname: Matsuzaki
authors.forename: Tsuyoshi
authors.initials: T
authors.lastname: Ikehara
mesh_terms: D000818:Animals; D018926:Anti-Allergic Agents / Q000494:pharmacology*; D000941:Antigens / Q000276:immunology; D002118:Calcium / Q000276:immunology; D015550:Cell Degranulation / Q000187:drug effects*; D045744:Cell Line, Tumor; D051546:Cyclooxygenase 2 / Q000235:genetics; D016207:Cytokines / Q000235:genetics; D004136:Dinitrobenzenes / Q000276:immunology; D015536:Down-Regulation; D004610:Ellagic Acid / Q000031:analogs & derivatives* / Q000494:pharmacology; D005786:Gene Expression Regulation / Q000187:drug effects; D005960:Glucosides / Q000494:pharmacology*; D007073:Immunoglobulin E / Q000276:immunology; D047908:Intracellular Signaling Peptides and Proteins / Q000276:immunology; D015471:Leukemia, Basophilic, Acute / Q000276:immunology*; D008297:Male; D051379:Mice; D008813:Mice, Inbred ICR; D020411:Oligonucleotide Array Sequence Analysis; D010323:Passive Cutaneous Anaphylaxis / Q000187:drug effects* / Q000276:immunology; D011505:Protein-Tyrosine Kinases / Q000276:immunology; D051381:Rats; D000072377:Syk Kinase
chemical_list: D018926:Anti-Allergic Agents; D000941:Antigens; D016207:Cytokines; D004136:Dinitrobenzenes; D005960:Glucosides; D047908:Intracellular Signaling Peptides and Proteins; C556914:okicamelliaside; D004610:Ellagic Acid; D007073:Immunoglobulin E; D051546:Cyclooxygenase 2; C489691:Ptgs2 protein, rat; D011505:Protein-Tyrosine Kinases; D000072377:Syk Kinase; C000606897:Syk protein, mouse; C000606898:Syk protein, rat; D002118:Calcium