title: Amino acid content and acetylcholinesterase inhibition of Huperzia saururus infusion and decoction.
abstract: CONTEXT. Huperzia saururus (Lam.) Trevis. (Lycopodiaceae), an autochthonous plant species in Argentina, is used as a memory improver in traditional medicine. It was studied for this reason and the purified alkaloid extract did show significant activity on learning and memory. The species is mostly consumed in the form of infusions and decoctions.
  
  
  OBJECTIVE
  To evaluate the activity of the H. saururus infusion and decoction as inhibitors of acetylcholinesterase (AChE) and to determine the amino acid content in both extracts.
  
  
  METHODS
  Infusion and decoction were purified by ionic exchange chromatography and analyzed by high-performance liquid chromatography HPLC-UV, and the AChE inhibition of these extracts was evaluated by using the Ellman method.
  
  
  RESULTS
  Both infusion and decoction exerted strong AChE inhibitory activities (IC50=7.2 ± 0.4 and 22.7 ± 5.6 μg/mL, respectively). Among nine amino acids, arginine (Arg) was identified in a concentration greater than 9 mg/100 g of dried aerial parts in both extracts.
  
  
  CONCLUSIONS
  This high content of Arg could be considered a contributing factor to the activity on memory previously demonstrated for the H. saururus alkaloid extract, since Arg is implicated indirectly in mnemonic processes as a precursor in nitric oxide synthesis. Thus, the central effect of H. saururus could involve two different mechanisms, the cholinergic mechanism and the nitric oxide pathway.
authors.affiliation: Department of Pharmacy, School of Chemical Sciences, National University of Córdoba, IMBIV-CONICET, Córdoba, Argentina.
authors.forename: Mariana Guadalupe
authors.initials: MG
authors.lastname: Vallejo
authors.forename: Jesica Ayelen
authors.initials: JA
authors.lastname: Dimmer
authors.forename: María Gabriela
authors.initials: MG
authors.lastname: Ortega
authors.forename: José Luis
authors.initials: JL
authors.lastname: Cabrera
authors.forename: Alicia Mariel
authors.initials: AM
authors.lastname: Agnese
mesh_terms: D000110:Acetylcholinesterase / Q000378:metabolism*; D001120:Arginine / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D002800:Cholinesterase Inhibitors / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D002851:Chromatography, High Pressure Liquid; D002852:Chromatography, Ion Exchange; D004305:Dose-Response Relationship, Drug; D032501:Huperzia / Q000737:chemistry; D018697:Nootropic Agents / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D008517:Phytotherapy; D035261:Plant Components, Aerial; D010936:Plant Extracts / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D010946:Plants, Medicinal; D013056:Spectrophotometry, Ultraviolet
chemical_list: D002800:Cholinesterase Inhibitors; D018697:Nootropic Agents; D010936:Plant Extracts; D001120:Arginine; D000110:Acetylcholinesterase