Cognitive Effects of Mint Essential Oil

Volatile Terpenes and Brain Function: Investigation of the Cognitive and Mood Effects of Mentha Spicata/Piperita Essential Oil With in Vitro Properties Relevant to Central Nervous System Function

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.

Study Overview

• Status: Completed
• Conditions: Cognitive Change; Affect
• Intervention / Treatment: Dietary supplement: Placebo; Dietary supplement: Mentha piperita

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).

• Study Type: Interventional
• Enrollment (Actual): 24
• Phase: Not Applicable

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 16 years to 33 years (Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

Description

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

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Other
• Allocation: Randomized
• Interventional Model: Crossover Assignment
• Masking: Triple

Number of Arms

3

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Placebo Comparator: Placebo; Vegetable oil	Dietary supplement: Placebo; Inert placebo control in the form of vegetable oil. This matches the vegetable oil in the active intervention condition.
Active Comparator: High-dose mint essential oil; 100 μL Mentha piperita essential oil (in vegetable oil)	Dietary supplement: Mentha piperita; Commercially available essential oil suspended in an off-the-shelf vegetable oil.; Other Names: Peppermint
Active Comparator: Low-dose mint essential oil; 50 μL Mentha piperita essential oil (in vegetable oil)	Dietary supplement: Mentha piperita; Commercially available essential oil suspended in an off-the-shelf vegetable oil.; Other Names: Peppermint

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Changes in cognition	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.	1, 3 and 6 hrs post-dose

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Changes in mood	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.	1, 3 and 6 hrs post-dose
Neurotransmitter receptor binding efficacy	In Vitro analysis of investigational product for GABAA, neuronal nicotinic and NMDA glutamate receptor binding efficacy utilizing radioligand competition binding assays	0 hrs
Acetylcholinesterase inhibition	In Vitro analysis of investigational product for acetylcholinesterase inhibition as described in Okello, Coleman and Seal (2015)	0 hrs
Quantification of monoterpene levels	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).	0 hrs

Collaborators and Investigators

• Sponsor: Northumbria University
• Collaborators: Procter and Gamble
• Investigators: Principal Investigator: David O Kennedy, PhD, Northumbria University

Study record dates

Study Major Dates

• Study Start (Actual): March 14, 2016
• Primary Completion (Actual): June 9, 2016
• Study Completion (Actual): June 9, 2016

Study Registration Dates

• First Submitted: February 13, 2018
• First Submitted That Met QC Criteria: March 22, 2018
• First Posted (Actual): March 23, 2018

Study Record Updates

• Last Update Posted (Actual): March 23, 2018
• Last Update Submitted That Met QC Criteria: March 22, 2018
• Last Verified: March 1, 2018

More Information

Terms related to this study

• Keywords: Humans; Cognition; Mood; Mentha; Mint; Essential oil
• Other Study ID Numbers: SUB052_Forster_040216

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: Undecided
• IPD Plan Description: No plan is currently available

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No