Abstract
Zembrin® is a botanical functional food and dietary supplement ingredient sold in the USA, and Canada for enhancing mood, decreasing anxiety and stress and improving cognitive function under stress. It is a proprietary extract of a cultivated selection of Sceletium tortuosum. The present investigation aimed at the measurement of the effect of 25 or 50 mg of Zembrin® in comparison to placebo after daily repetitive intake for 6 weeks. Sixty healthy male (n = 32) and female (n = 28) right-handed subjects between 50 and 80 years old (59.7 ± 5.43 and 56.7 ± 5.88 years, respectively) were recruited. The EEG was recorded bipolarly from 17 surface electrodes (CATEEM®) before and 1 h after intake. Six cognitive tests were performed: d2-test, memory test, calculation performance test, reaction time test, number identifying test and number connection test. Three questionnaires were included: Profile of Mood States, Hamilton Anxiety Rating Scale and a sleep questionnaire. Quantitative EEG revealed increases of delta activity during performance of the d2-test, the number identification and number connection test in the fronto-temporal brain region. Higher theta activity was seen during relaxation and performance of the d2-test after intake of 50 mg of Zembrin®. Statistically conspicuous increases of alpha1 spectral power were seen in the relaxed state. With respect to alpha2 spectral power larger increases were observed in the centro- occipital region. Discriminant analysis revealed a projection of Zembrin® data into the vicinity of the calming preparation Calmvalera tablets and a Ginkgo-Ginseng mixture. Statistically significant improvement during performance of the arithmetic calculation test and number connection test was documented. The HAM-A anxiety score revealed a statistically significant decrease (p = 0.03) after six weeks. Zembrin® showed significant activity on three levels of evidence: questionnaires, psychometry and quantitative EEG. The results indicate that in healthy people Zembrin® improves some aspects of cognitive function, decreases anxiety, and may enhance mood.
Highlights
Since the first discovery of human electric activity by Hans Berger [1] electroencephalographic measurements were performed for diagnostic purposes but increasingly during exposure to numerous mental challenges aiming at a better understanding of cognitive and emotional processes
The results indicate that in healthy people Zembrin® improves some aspects of cognitive function, decreases anxiety, and may enhance mood
Sixty subjects were recruited and asked to visit the lab at two experimental days 6 weeks apart during which they had to take in daily placebo, 25 mg or 50 mg of Zembrin®
Summary
Since the first discovery of human electric activity by Hans Berger [1] electroencephalographic measurements were performed for diagnostic purposes but increasingly during exposure to numerous mental challenges aiming at a better understanding of cognitive and emotional processes. Spectral and multivariate analysis of EEG oscillations during mental activity in man had already been reported more than 40 years ago. Reflection of cognitive challenges in the quantitative EEG was reported to differ according to special tasks [3]. Due to the intimate relationship between psychometric testing and EEG spectral signatures it was even suggested that cognitive testing could be replaced by quantitative EEG measurements [6]. Quantitative EEG measurements in the relaxed state and during performance of cognitive tests are well suited to describe functional changes of brain activity induced by intake of food [7] [8], food supplements [9] or drugs [10]
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