title: Anticholinesterase activity in an alkaloid extract of Huperzia saururus.
abstract: Huperzia saururus (Lam.) Trevis. (Lycopodiaceae) is used widely in Argentinian traditional medicine as an aphrodisiac and for memory improvement. An aqueous extract from the aerial parts was obtained by decoction, revealing the presence of alkaloids, among other constituents. By partition with organic solvent in alkaline media, alkaloids were extracted and then purified by gel permeation. We studied the anticholinesterase activity in vitro of the alkaloid extract using erythrocyte membranes and human serum as sources of acetylcholinesterase and pseudocholinesterase, respectively. The results show a marked inhibition of true acetylcholinesterase with an IC50 value of 0.58 microg/ml. Low inhibition of pseudocholinesterase was observed (IC50 value = 191 microg/ml). This shows a selectivity of the extract for the true acetylcholinesterase. Furthermore, chemical study of the bioactive extract was performed by GC-MS, revealing the presence of seven Lycopodium alkaloids, including some not identified previously: sauroxine, 6-hydroxylycopodine, N-acetyllycodine, lycopodine, lycodine, N-methyllycodine, and clavolonine. Further investigations will be undertaken in order to discover which compound/s are responsible for the aqueous extract's acetylcholinesterase activity.
authors.affiliation: Farmacognosia, Departamento de Farmacia, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, IMBIV (Instituto Multidisciplinario de Biología Vegetal, UNC-CONICET) Ciudad Universitaria, 5000 Córdoba, Argentina.
authors.forename: M G
authors.initials: MG
authors.lastname: Ortega
authors.forename: A M
authors.initials: AM
authors.lastname: Agnese
authors.forename: J L
authors.initials: JL
authors.lastname: Cabrera
mesh_terms: D000110:Acetylcholinesterase / Q000187:drug effects / Q000378:metabolism; D002800:Cholinesterase Inhibitors / Q000008:administration & dosage / Q000494:pharmacology* / Q000627:therapeutic use; D004305:Dose-Response Relationship, Drug; D004910:Erythrocyte Membrane / Q000201:enzymology; D006801:Humans; D032501:Huperzia; D020128:Inhibitory Concentration 50; D008517:Phytotherapy; D035261:Plant Components, Aerial; D010936:Plant Extracts / Q000008:administration & dosage / Q000494:pharmacology* / Q000627:therapeutic use
chemical_list: D002800:Cholinesterase Inhibitors; D010936:Plant Extracts; D000110:Acetylcholinesterase