Effect of Zembrin® on Brain Electrical Activity in 60 Older Subjects after 6 Weeks of Daily Intake. A Prospective, Randomized, Double-Blind, Placebo-Controlled, 3-Armed Study in a Parallel Design

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.