title: The sedative effects of hops (Humulus lupulus), a component of beer, on the activity/rest rhythm.
abstract: The hop (Humulus lupulus), a component of beer, is a sedative plant whose pharmacological activity is due principally to its bitter resins, especially to the α-acid component 2-methyl-3-buten-2-ol. The mechanism of action of the resin of hop consists of increasing the activity of the neurotransmitter γ-aminobutyric (GABA), inhibiting the central nervous system (CNS).
  
  
  OBJECTIVE
  To analyze in an experimental model of diurnal animal the sedative effect of hop, a component of beer, on the activity/rest rhythm.
  
  
  METHODS
  Experiments were performed with common quail (Coturnix coturnix) similar to humans in the sleep-wake rhythm, isolated in 25 × 25 × 25 cm methacrylate cages, with food and water ad libitum, in a room with artificial ventilation (22 ± 1 °C) and a lighting cycle of 12L/12D (n = 5). The doses administered, close to the content of non-alcoholic beer, were 1, 2 and 11 mg extract of hop as one capsule per day, at 18:00 h for one week. A control group received capsules only with a methylcellulose excipient and a basal group received no treatment. The chronobiological analysis of the animals' activity captured and logged by the software DAS24 was performed using the Ritme computer program (cosinor methods).
  
  
  RESULTS
  With the dose of 2 mg, there was a statistically significant (p < 0.05) reduction of the arithmetic mean nocturnal activity (23 ± 3.0) with respect to the basal (38.56 ± 2.79), control (38.1 ± 2.8) and other doses groups 1 mg (52.04 ± 3.65) and 11 mg (47.47 ± 5.88). This dose of 2 mg, similar to the concentration in beer, was more effective in reducing nocturnal activity than the other doses of 1 and 11 mg, as well as preserving the circadian activity/rest rhythm.
  
  
  CONCLUSIONS
  The concentration of 2 mg of hop extract effectively decreased nocturnal activity in the circadian activity rhythm. On the basis of this investigation, administration of non-alcoholic beer would be recommended due to its hop content and consequent sedative action, which would be an aid to nocturnal sleep.
authors: Department of Physiology, University of Extremadura, Badajoz, Spain.
authors: L
authors: L
authors: Franco
authors: C
authors: C
authors: Sánchez
authors: R
authors: R
authors: Bravo
authors: A
authors: A
authors: Rodriguez
authors: C
authors: C
authors: Barriga
authors: Javier Cubero
authors: JC
authors: Juánez
mesh_terms: D000818:Animals; D001515:Beer; D001522:Behavior, Animal / Q000187:drug effects*; D002940:Circadian Rhythm / Q000187:drug effects*; D004305:Dose-Response Relationship, Drug; D005260:Female; D027582:Humulus / Q000737:chemistry; D006993:Hypnotics and Sedatives / Q000494:pharmacology*; D009043:Motor Activity / Q000187:drug effects*; D010936:Plant Extracts / Q000494:pharmacology*; D011784:Quail
chemical_list: D006993:Hypnotics and Sedatives; D010936:Plant Extracts