Monoamine reuptake inhibition and mood-enhancing potential of a specified oregano extract

Br J Nutr. 2011 Apr;105(8):1150-63. doi: 10.1017/S0007114510004940. Epub 2010 Dec 21.


A healthy, balanced diet is essential for both physical and mental well-being. Such a diet must include an adequate intake of micronutrients, essential fatty acids, amino acids and antioxidants. The monoamine neurotransmitters, serotonin, dopamine and noradrenaline, are derived from dietary amino acids and are involved in the modulation of mood, anxiety, cognition, sleep regulation and appetite. The capacity of nutritional interventions to elevate brain monoamine concentrations and, as a consequence, with the potential for mood enhancement, has not been extensively evaluated. The present study investigated an extract from oregano leaves, with a specified range of active constituents, identified via an unbiased, high-throughput screening programme. The oregano extract was demonstrated to inhibit the reuptake and degradation of the monoamine neurotransmitters in a dose-dependent manner, and microdialysis experiments in rats revealed an elevation of extracellular serotonin levels in the brain. Furthermore, following administration of oregano extract, behavioural responses were observed in mice that parallel the beneficial effects exhibited by monoamine-enhancing compounds when used in human subjects. In conclusion, these data show that an extract prepared from leaves of oregano, a major constituent of the Mediterranean diet, is brain-active, with moderate triple reuptake inhibitory activity, and exhibits positive behavioural effects in animal models. We postulate that such an extract may be effective in enhancing mental well-being in humans.

MeSH terms

  • Animals
  • Anti-Anxiety Agents / chemistry
  • Anti-Anxiety Agents / metabolism
  • Anti-Anxiety Agents / therapeutic use*
  • Antidepressive Agents / chemistry
  • Antidepressive Agents / metabolism
  • Antidepressive Agents / therapeutic use*
  • Anxiety / prevention & control
  • Behavior, Animal
  • Benzoquinones / analysis
  • Benzoquinones / pharmacology
  • Biogenic Monoamines / physiology*
  • Brain / metabolism
  • Cymenes
  • Depression / prevention & control
  • Dietary Supplements* / analysis
  • Drug Discovery / methods
  • HEK293 Cells
  • Humans
  • Male
  • Mice
  • Monoamine Oxidase Inhibitors / chemistry
  • Monoamine Oxidase Inhibitors / metabolism
  • Monoamine Oxidase Inhibitors / therapeutic use
  • Monoterpenes / analysis
  • Monoterpenes / blood
  • Monoterpenes / pharmacology
  • Neurotransmitter Uptake Inhibitors / chemistry
  • Neurotransmitter Uptake Inhibitors / metabolism
  • Neurotransmitter Uptake Inhibitors / pharmacology
  • Neurotransmitter Uptake Inhibitors / therapeutic use*
  • Origanum / chemistry*
  • Plant Extracts / chemistry
  • Plant Extracts / metabolism
  • Plant Extracts / therapeutic use*
  • Plant Leaves / chemistry
  • Random Allocation
  • Rats
  • Serotonin Plasma Membrane Transport Proteins / genetics
  • Serotonin Plasma Membrane Transport Proteins / metabolism


  • Anti-Anxiety Agents
  • Antidepressive Agents
  • Benzoquinones
  • Biogenic Monoamines
  • Cymenes
  • Monoamine Oxidase Inhibitors
  • Monoterpenes
  • Neurotransmitter Uptake Inhibitors
  • Plant Extracts
  • SLC6A4 protein, human
  • Serotonin Plasma Membrane Transport Proteins
  • carvacrol
  • thymoquinone