PHARMACODYNAMIC EFFECTS OF 2 DIFFERENT HYPERICUM EXTRACTS IN HEALTHY-VOLUNTEERS MEASURED BY QUANTITATIVE EEG

A double-blind, randomized, placebo-controlled parallel-group trial (p hase I) was performed to evaluate the central pharmacodynamic effects of two hypericum extracts with different contents of hyperforin (0.5% and 5.0%) but identical hypericin content. Three groups of 18 voluntee rs between 18 and 35 years of age participated in the trial. The volun teers receiving verum took 900 mg of the extract once a day for 8 cons ecutive days. The primary aim of this study was to observe the frequen cy bands, i.e., delta (1.25-4.5 Hz), theta (4.75-6.75 Hz), alpha-1 (7. 0-9.5 Hz), alpha-2 (9.75-12.5 Hz), beta-1 (12.75-18.5 Hz),and beta-2 ( 18.75-35 Hz). This was the first study of its kind testing hypericum c ontrolled on the basis of its hyperforin contents. A quantitative topo graphic EEG (qEEG) was performed on days 1 and 8 as an indicator of dr ug-induced pharmacological action. The volunteers' electrophysiologica l data were obtained prior to application and 2, 4, 6, 8, and 10 hours post administration. Plasma samples for evaluation of the pharmacokin etics of hyperforin were also obtained. The qEEG results of the placeb o group on days 1 and 8 showed no significant changes with regard to t heir physiological daily rhythm. In both verum groups (0.5% and 5.0% h yperforin content), reproducible central pharmacodynamic effects were apparent in comparison to placebo, in particular with the extract cont aining 5.0% of hyperforin. A peak pharmacodynamic efficacy was observe d between 4 and 8 hours post administration. These results were confir med on day 8 of the trial. The extract containing 5.0% hyperforin show ed a marked tendency to produce higher increases in qEEG baseline powe r performances than the one containing 0.5% hyperforin. These higher b aseline outputs on day 8 were seen at the delta, theta, and alpha-1 fr equency values. Compared to placebo there was a significant increase i n qEEG power performance in the delta and beta-1 frequency values excl usively for the extract containing 5.0% hyperforin. The theta and alph a-1 frequency values showed a noticeable tendency more emphasized on d ay 8 than on day 1.Preclinical trials in rats have been observed with similar changes in the frequency bands mentioned above, especially in the cholinergic (delta), noradrenergic (theta) and serotonergic (alpha ) neurotransmitter systems. These experimental findings suggest that h ypericum extracts with a high hyperforin content have a shielding effe ct on the central nervous system.