Effect of Herbals on the Brain

Effect of Herbals on the brain

Objective classification of natural compounds and extracts in rats and humans

Natural compounds and plant derived products play an ever increasing role not only in medical therapy but also in medical prophylaxis using food supplements and functional food. The topic of this presentation will try to bridge the gap between animal studies and clinical trials using an electrophysiological approach validated for years in testing pharmaceutical preparations of chemically synthesized compounds. Common parameter in rat and humans is the local field potential as it is recorded from the depth of the rat brain and from the scalp of the human brain. These potentials - when recorded in the presence of drugs - are called electropharmacograms.

 



Fig. 1 Depiction of results of discriminant analysis based on electropharmacograms of mean data from healthy rats. Similar colour signalizes similar action.

In the rat field potentials are recorded from implanted steel electrodes and transmitted via a telemetric system wireless to the secondary amplifiers and further transmitted to evaluation units by means of a glass fiber. The experimental design consists in recording a pre-drug base line for 45 minutes before administration of the natural ingredients or plant extracts. Recording continues for the next 5 hours. Effects are described in % change from pre-drug values with respect to 6 frequency ranges for each of the four brain areas: frontal cortex, hippocampus, striatum and reticular formation = 24 variables. Extracts from decaffeinated green tea, Schisandra, Ginkgo, Ginseng, St. John`s Wort, Radix Rhodiola, Valeriana, Camellia, Guarana, Passiflora, Kava Kava and Avena sativa were compared to the actions of caffeine, quercetin, rutin, theanine, yohimbine, yangonine, kavain, methysticin and theogallin. All extracts and single ingredients produced electrical changes which could be differentiated from each other by feeding the data into a discriminant analysis, where the first three discriminant axes were coded into an additive colour mixture of the colours green, red and blue. The next three discriminant axes were coded into spatial x, y and z axes. Using this method products with a similar effect on the brain provide similar colours and are situated at a similar spatial location like seen for theanine, St. John`s Wort and Avena sativa or Kavain.


Fig. 2 Discriminant analysis of human data in the presence of T (decaffeinated theanine and theogallin enriched green tea extract), F (lozenge containing lavendula, oat, hops and lemon balm), G (drink containing extract of ginkgo and ginseng, N (homeopathic tablet containing passiflora) E (Ethanol), K (Klosterfrau Melissengeist), H (Hypericum= St. John´s Wort) and P (placebo). Numbers represent hours after administration. Recording during eyes open (a). Similar colour signalizes similar action or clinical indication.

In humans a similar approach is performed with data derived from EEG recordings under similar experimental conditions. After a predrug period and administration of the preparation recordings are performed at hourly intervals and expressed in % of the predrug baseline values. The data from the electropharmacograms (17 electrode positions and 6 frequency ranges = 102 variables) were fed into discriminant analysis. Data from a lozenge containing four plant derived extracts (lemon balm, oat, lavendula and hops), a drink containing ginkgo and ginseng as well as a decaffeinated green tea extract and a tablet containing passiflora were tested in comparison to placebo. It could be shown that the actions of the four preparations were entirely different from placebo. However, the hourly recordings within one trial showed the same colour. This proved the extremely high sensitivity of the method and the consistency of the observed effects.

The data document that field potentials from rats and humans are valid parameters for the description of effects of natural compounds and plant derived extracts on the brain.