Affect, Cognitive Change
Conditions
Keywords
Mentha, Mint, Essential oil, Cognition, Mood, Humans
Brief summary
This study investigates the cognitive and mood effects of mint essential oils in a group of healthy, human adults. The investigational product will also be tested in vitro to ensure a number of biological mechanisms.
Detailed description
The volatile components of essential oils (e.g. sage, lemon balm and rosemary)are found to exert a number of psychotropic effects and the monoterpenes in particular seem to be responsible for the cognitive and mood effects attributed to them. The current study aims to investigate the cognitive and mood effects of mint essential oil in humans and to ensure the efficacy of the investigational product by conducting in vitro analysis on central nervous system receptor binding properties. This will be achieved by analysing gamma-Aminobutyric acid A (GABAA), neuronal nicotinic and N-methyl-D-aspartate receptor (NMDA) glutamate receptor binding efficacy, acetylcholinesterase (AChE) inhibition, and gas chromatography-mass spectrometry (GC-MS) analysis will quantify % Limonene, % Carvone, % Menthone and % Menthol levels in the investigational treatment. Cognitive and mood assessment will be via a randomised, placebo controlled, crossover design in 24, healthy adults aged between 18-35 yrs which will involve x1 training and x3 testing visits to the lab (placebo, 50 (micro Litre) μL and 100 μL Mentha piperita essential oil).
Interventions
DIETARY_SUPPLEMENTMentha piperita
Commercially available essential oil suspended in an off-the-shelf vegetable oil.
DIETARY_SUPPLEMENTPlacebo
Inert placebo control in the form of vegetable oil. This matches the vegetable oil in the active intervention condition.
Sponsors
Procter and Gamble
Northumbria University
Study design
Allocation
RANDOMIZED
Intervention model
CROSSOVER
Primary purpose
OTHER
Masking
TRIPLE (Subject, Investigator, Outcomes Assessor)
Masking description
Double blind. Treatments were prepared and coded by a third party researcher who had no further involvement with the study.
Intervention model description
Randomised, placebo controlled, crossover
Eligibility
Sex/Gender
ALL
Age
18 Years to 35 Years
Healthy volunteers
Yes
Inclusion criteria
* 18-35 yrs * Free from illicit drugs, alcohol, prescription medication (apart from contraception in the case of women) and herbal extracts/food supplements at each assessment.
Exclusion criteria
* Head injury, neurological disorder or neuro-developmental disorder * English not 1st language (or not equivalent to a native English speaker) * Relevant food allergies/intolerances or digestive problems * Smokes tobacco * Drinks excessive amounts of caffeine (more than 600mg day as assessed by a caffeine consumption questionnaire) * Takes illicit social drugs * Pregnant, seeking to become so, or breast feeding
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Changes in cognition | 1, 3 and 6 hrs post-dose | Changes in cognitive function as assessed by the following tasks: immediate and delayed word and picture recognition; name to face recall; 'Sternberg' Numeric Working Memory task; Corsi blocks; serial 3 subtractions; serial 7 subtractions; rapid visual information processing; peg and ball and choice reaction time. All tasks provide an outcome measure of accuracy, speed and error. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Changes in mood | 1, 3 and 6 hrs post-dose | Changes in mood assessed via the Speilberger State-Trait Anxiety Inventory (STAI) and Bond-Lader visual analogue mood scales. Scores on both measures are calculated at baseline and scores from subsequent completions are subtracted from this to produce change (change from baseline) scores. For both STAI and Bond-Lader these are numerical scores. |
| Neurotransmitter receptor binding efficacy | 0 hrs | In Vitro analysis of investigational product for GABAA, neuronal nicotinic and NMDA glutamate receptor binding efficacy utilizing radioligand competition binding assays |
| Acetylcholinesterase inhibition | 0 hrs | In Vitro analysis of investigational product for acetylcholinesterase inhibition as described in Okello, Coleman and Seal (2015) |
| Quantification of monoterpene levels | 0 hrs | In Vitro analysis of investigational product for levels of % Limonene, % Carvone, % Menthone and % Menthol utilizing Gas chromatography-mass spectrometry. The method is described in Abuhamdah et al. (2015). |
Outcome results
None listed