title: Anti-inflammatory effect of glucose-mannose binding lectins isolated from Brazilian beans.
abstract: Selectins are essential for leukocyte recruitment in inflammation. Because of a lectin domain present in the selectin structure, we investigated the anti-inflammtory activity of six mannose-glucose binding lectins from brazilian beans: Dioclea guianensis-DguiL; D. grandiflora-DgL; Cratylia floribunda-CfL; D. violacea-D.vL; D. virgata-DvirL and Canavalia brasiliensis-ConBr. The lectins were injected intravenously (i.v.) into rats (0.1 and 1.0 mg/kg; 30 min before irritants) and its activities compared to E. coli endotoxin (LPS,30 mug/kg i.v.). Three lectins (DvL, CfL and DguiL), although less intense than LPS, inhibited the neutrophil migration induced by carrageenan (Cg, 300 mug) in a dose-dependent manner (0.1 and 1.0 mg/kg). DvL activity was reversed by 0.1 M alpha-D-methyl-mannoside (alpha-CH3), but not by 0.1 M alpha-D-galactose. The fMLP (44 ng)-induced neutrophil migration was also reduced by these lectins. Endotoxin contamination of lectin samples could be excluded since alpha-CH3 treatment reversed the DvL effect, but did not modify LPS inhibitory activity. Carrageenan (300 mug)-induced paw oedema was also reduced by LPS or lectin treatments. Conversely, none of the tested lectins inhibited dextran (Dex, 300 mug)-induced paw oedema, a classical leukocyte independent model, or zymosan (Zy, 1.0 mg)-induced peritonitis and paw oedema. LPS showed no effect upon Dex-induced paw oedema and barely reduced (25%) the oedematogenic effects of zymosan. As proposed for LPS, the lectin inhibitory activity was better observed on neutrophil-mediated inflammatory reactions. We speculate that the plant lectin antiinflammatory activity is probably due to a competitive blockage of a common leukocyte and/or endothelial selectin carbohydrate ligand.
authors.affiliation: Department of Physiology and Pharmacology Federal University of Ceara PO Box 3157 Rua Coronel Nunes de Melo, 1127 Fortaleza CE 60.430-270 Brazil.
authors.forename: A M
authors.initials: AM
authors.lastname: Assreuy
authors.forename: M D
authors.initials: MD
authors.lastname: Shibuya
authors.forename: G J
authors.initials: GJ
authors.lastname: Martins
authors.forename: M L
authors.initials: ML
authors.lastname: De Souza
authors.forename: B S
authors.initials: BS
authors.lastname: Cavada
authors.forename: R A
authors.initials: RA
authors.lastname: Moreira
authors.forename: J T
authors.initials: JT
authors.lastname: Oliveira
authors.forename: R A
authors.initials: RA
authors.lastname: Ribeiro
authors.forename: C A
authors.initials: CA
authors.lastname: Flores