title: Inhibitory effect of aqueous spinach extract on degranulation of RBL-2H3 cells.
abstract: The inhibitory effect of an aqueous extract from spinach on degranulation of RBL-2H3 cells is herein reported. The extract significantly suppressed antigen-induced degranulation in a dose-dependent manner without affecting cell viability. Active substances in the extract were heat-stable and trypsin-resistant with molecular weights ranging from 500 Da to 14 kDa. The extract inhibited elevation of the intracellular Ca(2+) concentration caused by stimulation by antigen, while not suppressing degranulation induced by a calcium ionophore A23187. Immunoblot analysis revealed that the inhibitory effect results from downregulation of phosphorylation of both Syk kinase and phosphatidylinositol 3-kinase in the signalling pathways involved in degranulation caused by the antigen-antibody interaction. Taken together, these findings suggest that aqueous spinach extract has an anti-allergic activity that controls degranulation.
authors.affiliation: Ehime University, Matsuyama, Ehime 790-8566, Japan.
authors.forename: Momoko
authors.initials: M
authors.lastname: Ishida
authors.forename: Kosuke
authors.initials: K
authors.lastname: Nishi
authors.forename: Hisashi
authors.initials: H
authors.lastname: Watanabe
authors.forename: Takuya
authors.initials: T
authors.lastname: Sugahara
mesh_terms: D000818:Animals; D018926:Anti-Allergic Agents / Q000494:pharmacology*; D001491:Basophils / Q000187:drug effects* / Q000276:immunology; D002118:Calcium / Q000276:immunology; D015550:Cell Degranulation / Q000187:drug effects*; D045744:Cell Line, Tumor; D010936:Plant Extracts / Q000494:pharmacology*; D051381:Rats; D018724:Spinacia oleracea / Q000737:chemistry*
chemical_list: D018926:Anti-Allergic Agents; D010936:Plant Extracts; D002118:Calcium