title: Plantagoside, a novel alpha-mannosidase inhibitor isolated from the seeds of Plantago asiatica, suppresses immune response.
abstract: A hot-water extract from the seed of Plantago asiatica showed a potent inhibitory activity against jack bean alpha-mannosidase, and a flavanone glucoside, plantagoside, was isolated as the inhibitor. Plantagoside was a specific inhibitor for jack bean alpha-mannosidase (IC50 at 5 microM) and appeared to be a non-competitive inhibitor of the enzyme. Whereas, negligible or weak inhibitory activities were observed for beta-mannosidase, beta-glucosidase, and sialidase tested. Plantagoside also inhibited alpha-mannosidase activities in mouse liver lysosomal and microsomal fractions, and the enzyme inhibitory activity in microsomal fraction was enhanced in the presence of glucosidase inhibitor, castanospermine. Plantagoside suppressed antibody response to sheep red blood cells and concanavalin A induced lymphocyte proliferation which was measured by [3H]thymidine incorporation.
authors.affiliation: Oriental Medicine Research Center, Kitasato Institute, Tokyo, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Yamada
authors.forename: T
authors.initials: T
authors.lastname: Nagai
authors.forename: N
authors.initials: N
authors.lastname: Takemoto
authors.forename: H
authors.initials: H
authors.lastname: Endoh
authors.forename: H
authors.initials: H
authors.lastname: Kiyohara
authors.forename: H
authors.initials: H
authors.lastname: Kawamura
authors.forename: Y
authors.initials: Y
authors.lastname: Otsuka
mesh_terms: D000818:Animals; D000917:Antibody Formation / Q000187:drug effects; D004247:DNA / Q000096:biosynthesis; D004912:Erythrocytes / Q000276:immunology; D005260:Female; D044950:Flavanones; D005419:Flavonoids / Q000302:isolation & purification / Q000494:pharmacology*; D005960:Glucosides / Q000302:isolation & purification / Q000494:pharmacology*; D006026:Glycoside Hydrolases / Q000037:antagonists & inhibitors; D006027:Glycosides / Q000494:pharmacology*; D007109:Immunity / Q000187:drug effects*; D008099:Liver / Q000648:ultrastructure; D008213:Lymphocyte Activation / Q000187:drug effects; D008247:Lysosomes / Q000201:enzymology; D008361:Mannosidases / Q000037:antagonists & inhibitors*; D051379:Mice; D008807:Mice, Inbred BALB C; D008862:Microsomes, Liver / Q000201:enzymology; D008934:Mitogens / Q000494:pharmacology; D010943:Plantago; D010946:Plants, Medicinal; D012639:Seeds / Q000032:analysis*; D012756:Sheep; D013154:Spleen / Q000166:cytology; D043323:alpha-Mannosidase
chemical_list: D044950:Flavanones; D005419:Flavonoids; D005960:Glucosides; D006027:Glycosides; D008934:Mitogens; C062295:plantagoside; D004247:DNA; D006026:Glycoside Hydrolases; D008361:Mannosidases; D043323:alpha-Mannosidase