title: Effect of Rheedia longifolia leaf extract and fractions on the P2X₇ receptor in vitro: novel antagonists?
abstract: Recently, the P2X(7) receptor has been reported to be associated with chronic inflammatory and neuropathic pain. Because Rheedia longifolia extract has analgesic and anti-inflammatory activity, we evaluated the in vitro inhibitory potential of methanol extract and fractions from its leaves on the P2X(7) purinergic receptor. The activity of P2X(7) was studied with a dye uptake assay and with the whole-cell patch clamp technique in mouse peritoneal macrophages treated with methanol extract of R. longifolia leaves and fractions. The dye uptake was evaluated by flow cytometry and fluorescence microscopy. The R. longifolia extract and some fractions showed an inhibitory effect on the P2X(7) purinergic receptor in a dose-dependent manner. The ethyl acetate fraction exhibited the most potent inhibitory effects. The methanol extract and the butanol fraction showed the same inhibitory effects, despite their lower potency compared with the other fractions. The R. longifolia extract and some of its fractions may be anti-inflammatory because of their inhibitory effect on the P2X(7) receptor. Further investigation is needed to determine the pattern of inhibition and selectivity. Chromatographic analysis indicated the presence of bisflavonoids in the methanol extract fractions. A member of this chemical family is the most probable active compound responsible for the P2X(7) inhibitory effects present in the R. Longifolia extract and fractions.
authors.affiliation: Laboratory Evaluation and Promotion of Environmental Health, Oswaldo Cruz Institute (FIOCRUZ), Rio de Janeiro, Brazil.
authors.forename: José A A
authors.initials: JA
authors.lastname: Santos
authors.forename: Antonio Augusto
authors.initials: AA
authors.lastname: Fidalgo-Neto
authors.forename: Robson X
authors.initials: RX
authors.lastname: Faria
authors.forename: Ana
authors.initials: A
authors.lastname: Simões
authors.forename: Andrea S
authors.initials: AS
authors.lastname: Calheiros
authors.forename: Ana Luiza
authors.initials: AL
authors.lastname: Bérenger
authors.forename: Hugo C C
authors.initials: HC
authors.lastname: Faria-Neto
authors.forename: Maria Raquel
authors.initials: MR
authors.lastname: Figueiredo
authors.forename: Valber S Luiz
authors.initials: VS
authors.lastname: Frutuoso
authors.forename: Luiz Anastacio
authors.initials: LA
authors.lastname: Alves
mesh_terms: D000818:Animals; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000032:analysis / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology; D002463:Cell Membrane Permeability / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D005591:Chemical Fractionation; D028084:Clusiaceae / Q000737:chemistry*; D055808:Drug Discovery; D005419:Flavonoids / Q000009:adverse effects / Q000032:analysis / Q000302:isolation & purification / Q000494:pharmacology; D005456:Fluorescent Dyes / Q000378:metabolism; D017737:Macrophages, Peritoneal / Q000166:cytology / Q000187:drug effects* / Q000201:enzymology / Q000276:immunology; D008297:Male; D051379:Mice; D018408:Patch-Clamp Techniques; D010936:Plant Extracts / Q000009:adverse effects / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D018515:Plant Leaves / Q000737:chemistry*; D058920:Purinergic P2X Receptor Antagonists / Q000032:analysis / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D058486:Receptors, Purinergic P2X7 / Q000737:chemistry*; D012997:Solvents / Q000737:chemistry
chemical_list: D000894:Anti-Inflammatory Agents, Non-Steroidal; D005419:Flavonoids; D005456:Fluorescent Dyes; C546469:P2rx7 protein, mouse; D010936:Plant Extracts; D058920:Purinergic P2X Receptor Antagonists; D058486:Receptors, Purinergic P2X7; D012997:Solvents