Ginseng and ginkgo biloba effects on cognition as modulated by cardiovascular reactivity: a randomised trial

Background There is some evidence to suggest that ginseng and Ginkgo biloba can improve cognitive performance, however, very little is known about the mechanisms associated with such improvement. Here, we tested whether cardiovascular reactivity to a task is associated with cognitive improvement. Methodology/Principal findings Using a double-blind, placebo controlled, crossover design, participants (N = 24) received two doses of Panax Ginseng (500, 1000 mg) or Ginkgo Biloba (120, 240 mg) (N = 24), and underwent a series of cognitive tests while systolic, diastolic, and heart rate readings were taken. Ginkgo Biloba improved aspects of executive functioning (Stroop and Berg tasks) in females but not in males. Ginseng had no effect on cognition. Ginkgo biloba in females reversed the initial (i.e. placebo) increase in cardiovascular reactivity (systolic and diastolic readings increased compared to baseline) to cognitive tasks. This effect (reversal) was most notable after those tasks (Stroop and Iowa) that elicited the greatest cardiovascular reactivity during placebo. In males, although ginkgo also decreased cardiovascular readings, it did so from an initial (placebo) blunted response (i.e. decrease or no change from baseline) to cognitive tasks. Ginseng, on the contrary, increased cardiovascular readings compared to placebo. Conclusions/Significance These results suggest that cardiovascular reactivity may be a mechanism by which ginkgo but not ginseng, in females is associated with certain forms of cognitive improvement

Cardiovascular data with respect to systolic, diastolic and heart rate readings for ginkgo and ginseng sixty minutes after treatment intake (also referred to as “time 2”) and before cognitive testing.

<p>Comparisons are made for placebo, medium and high dose.</p

Flow diagram graphically describes the design of the study: enrolment, intervention, follow-up and data analysis.

<p>In treatment sequence, the capital letters A, B, C represent the three possible combinations of treatment sequence (group A = Placebo-High-Medium; group B = Medium-Placebo-High; group C = High-Medium-Placebo).</p

Effects of Ginseng and Ginkgo Biloba on cardiovascular reactivity.

<p>Effects of Ginseng and Ginkgo Biloba on cardiovascular reactivity.</p

Cardiovascular data results with respect to systolic, diastolic and heart rate readings for participants in the Ginkgo Biloba group after completion of the cognitive tasks Berg, Stiowa and Vsppvt.

<p>Comparisons are between placebo, medium and high dose. Cardiovascular readings are expressed with respect to response differences between cognitive task and baseline, that is, 60 minutes after drug treatment and prior to cognitive testing (where an equal cardiovascular response to baseline = 100). * indicates statistical significance at the <i>p</i> <0.05 level.</p

As for Fig 4, but data results are for participants in the ginseng group.

<p>As for <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0150447#pone.0150447.g004" target="_blank">Fig 4</a>, but data results are for participants in the ginseng group.</p