Psychophysiological Effects of Zembrin^®Using Quantitative EEG Source Density in Combination with Eye-Tracking in 60 Healthy Subjects. A Double-Blind, Randomized, Placebo-Controlled, 3-Armed Study with Parallel Design

Abstract

The endemic South African succulent plant Sceletium tortuosum (L.) N.E. Br., family Mesembryathemaceae, is known as kanna in Nama, kougoed in Afrikaans, and sceletium in English. The plant has been used as a tea and as a masticatory for millennia by indigenous San hunter-gatherers and Nama pastoralists for endurance and well-being. It has been reported that the plant “gives strength to their limbs, and takes away pain, and makes their memory strong”. The current investigation aimed at the psychophysiological characterization of 25.0 and 50.0 mg of a special extract marketed as Zembrin ® in comparison to placebo using a new methodology called “EnkephaloVision”. This combination of EEG Neurocode-Tracking and Eye-Tracking allows for concomitant analysis of time epochs of only 364 ms duration. Spectral EEG analysis during cognitive and emotional challenges revealed statistically significant increases of delta (p ® within the frontal brain. It is these same increases of slow waves in the frontal brain that are described in the literature during performance of mental tests. This indicates a positive effect of Zembrin ® on the electrical activity of the brain during cognitive processing. In addition, alpha1 and alpha2 spectral power in the frontal brain was increased during several challenges including brain teasing, arithmetic calculations and performance of a memory test. From the literature, increases of spectral alpha1 power indicate a greater degree of calmness and may represent decreased depressive symptoms, while increases in alpha2 waves have been related to memory. Beta2 waves increased during mental performance in the presence of the higher dosage of Zembrin ® in parietal, occipital and temporal brain regions. In comparison to placebo, Zembrin ® induced frequency changes in the brain, which have been related to enhanced attention and memory. These results may represent a positive action of Zembrin ® on cognitive and emotional processes in the brain.