Focus on Alternative and Complementary Therapies
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Focus Alternat Complement Ther©2005 Pharmaceutical Press
Focus Altern Complement Ther 2002; 7: 107–8
Ginkgo biloba and Panax ginseng represent two of the most widely used herbal medicines worldwide. Despite this, little is known about their acute effects on mood and cognitive performance, an area that has formed the focus of a series of studies from our group.
Each study used a placebo-controlled, double-blind, balanced, crossover design in which 20 participants received a placebo, or one of three active treatments of ginkgo or of ginseng on separate days. Each dosing day was separated by a 7-day washout period. Cognitive performance was assessed using the Cognitive Drug Research (CDR) computerised test battery immediately prior to treatment and at 1 h, 2.5 h, 4 h and 6 h thereafter. In addition, subjective mood changes were gauged using Bond–Lader mood scales. The results of the treatments on arithmetic tasks of differing mental effort are also reported.
The most striking results included a sustained improvement in ‘Speed of Attention’ following a single dose of ginkgo and improved ‘Quality of Memory’ following ginseng – an effect that was coupled with a time-specific reduction in self-rated alertness. In most respects, the cognitive profile of the ginkgo–ginseng combination was like that of ginseng alone, though without the mood changes. The ginkgo–ginseng combination also dramatically improved performance on arithmetic tasks requiring a relatively high level of ‘mental effort’.
These data are discussed in terms of the known and speculative mechanisms associated with each of the treatments.
