A human pilot dose-finding study of Aloysia citriodora extract for CNS activity

Lemon verbena (Aloysia citrodora, Fam. Verbenacea) is used to ease digestion, to reduce nervousness in adults and children and for sleep disorders. This clinical study aimed to find out what dose of an Aloysia citriodora dry extract can change brain electrical activity, using “EnkephaloVision" method.

Aloysia citriodora was extracted with ethanol 30% – final dry extract composition: 70% native extract, 30% Maltodextrin. This trial was a DBPC, 4-arm, cross-over study. Placebo and Aloysia extract: 400, 600 and 800 mg were tested in 10 women. Ninety minutes after intake the following measurements were performed: questionnaire, performance of psychometric tasks and quantitative recording of electrical activity. The Ethics Committee from the University of Giessen gave approval for the study ([Fig. 1]).

Fig. 1 Representative scene from the video clip "d2-Test".

The active ingredients of Aloysia extract cross the blood-brain barrier and show CNS activity within 90 minutes. EEG data clearly show a dose-dependent effect of the Aloysia extract: 400 mg has a threshold effect on delta and theta activity in the brain. A 600 mg dose increases delta and theta activity as well as alpha activity, all statistically significant. An 800 mg dose results in statistically significant changes in all local brain areas.

Therefore, 600mg is the preferred dosage; it leads to mental activation when performing cognitive tasks. Alpha1 activity seems to be under the control of serotonin, while alpha2 waves indicate changes in dopaminergic activity. Both neurotransmitters play a key role in motivation and mood. In conclusion, Aloysia citriodora seems to have a specific influence on emotional brain processes.

Publication History

Article published online:
16 November 2023