Effects of chronic administration of Melissa officinalis L. extract on anxiety-like reactivity and on circadian and exploratory activities in mice

Phytomedicine. 2010 May;17(6):397-403. doi: 10.1016/j.phymed.2010.01.012. Epub 2010 Feb 18.


This study aimed to determine the effects of chronic (15 consecutive days of treatment) per os administration of Melissa officinalis L. extract (Cyracos, Naturex) on anxiety-like reactivity in mice. As measured by HPLC, Cyracos contains significant amounts of rosmarinic acid and the triterpenoids oleanolic acid and ursolic acid, which inhibit gamma-aminobutyric acid transaminase (GABA-T) activity and increase GABA levels in the brain (Awad et al., 2007; Awad et al., 2009). Thus, we evaluated Cyracos use in independent groups of C57BL/6 mice with regard to anxiety-like reactivity in an elevated plus maze and an open field task. We found that Cyracos significantly reduced anxiety-like reactivity in the elevated plus maze dose-dependently, but no significant effect was observed in the open field task. Parallel experiments in independent groups of mice showed that the Cyracosdose at which it exerted anxiolytic-like effects in the elevated plus maze did not alter exploratory or circadian activities. Therefore, our results demonstrate that Cyracos has anxiolytic-like effects under moderate stress conditions and does not alter activity levels.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • 4-Aminobutyrate Transaminase / antagonists & inhibitors
  • Animals
  • Anti-Anxiety Agents / administration & dosage*
  • Anti-Anxiety Agents / pharmacology
  • Anxiety / drug therapy*
  • Behavior, Animal / drug effects*
  • Cinnamates
  • Circadian Rhythm
  • Depsides
  • Dose-Response Relationship, Drug
  • Drug Administration Schedule
  • Exploratory Behavior / drug effects
  • GABA Agonists / administration & dosage*
  • GABA Agonists / pharmacology
  • Maze Learning / drug effects
  • Melissa / chemistry*
  • Mice
  • Mice, Inbred C57BL
  • Oleanolic Acid
  • Phytotherapy*
  • Plant Components, Aerial
  • Plant Extracts / administration & dosage*
  • Plant Extracts / pharmacology
  • Rosmarinic Acid
  • Triterpenes
  • Ursolic Acid


  • Anti-Anxiety Agents
  • Cinnamates
  • Depsides
  • GABA Agonists
  • Plant Extracts
  • Triterpenes
  • Oleanolic Acid
  • 4-Aminobutyrate Transaminase